Report No: ACS9385 Public Disclosure Authorized Republic...

Document of the World Bank

Report No: ACS9385

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Republic of India

IN Technical Assistance Facility for Preparation of Rural Water Supply and Sanitation Project for Low Income States (RWSSP-LIS)

Technical Manual

. April 2015}

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SOUTH ASIA

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Rural Water Supply and

Sanitation Project for Low

Income States

Assam, Bihar, Jharkhand, Uttar Pradesh

Technical Manual

April 2015

Neer Nirmal Pariyojana

Volume-1

DRAFT

Acknowledgement

On behalf of the Ministry of Drinking Water and Sanitation, we gratefully acknowledge

the inputs, advice and support received towards preparation of the Technical Manual

from the Public Health Engineering Departments of the States of Assam and Bihar, the

Drinking Water and Sanitation Department of the State of Jharkhand, and the Rural

Development and Panchayati Raj Departments of the State of Uttar Pradesh. I appreciate

the work of Egis India Consulting Engineers Pvt. Ltd. in collecting information, and

involving the respective State Departments in discussions and obtaining feedback on

draft reports. We also appreciate the continuous guidance and support received from the

World Bank. We hope this document will help clarify technical issues and enhance the

understanding of technical aspects of the project implementing agencies.

Satyabrata Sahu

Joint Secretary (Water) to the Government of India

Ministry of Drinking Water and Sanitation

DRAFT

FOREWORD

The Ministry of Drinking Water and Sanitation (MoDWS) administers the National Rural

Drinking Water Programme (NRDWP) and Swachh Bharat Abhiyan - Gramin (SBM-G)

through which support is extended to the States for implementing water supply and

sanitation schemes in rural areas. In an attempt to meet the Government of India’s

Twelfth Five Year Plan, which is based on the theme of ‘Faster, Sustainable and More

Inclusive Growth’, and its own Strategic Plan for ‘ensuring drinking water security and

sanitized environment in rural India’, MoDWS is implementing Neer Nirmal Pariyojna

through the NRDWP and assistance from the World Bank through the Rural Water

Supply and Sanitation Project (the Project) in the four low income States of Assam,

Bihar, Jharkhand and Uttar Pradesh.

The Project adopted an integrated planning, designing, implementing and managing

water supply and sanitation schemes aiming at achieving sustainable water sources;

equitable distribution of water; water security at household, village and Gram Panchayat

levels; open defecation free villages; and clean and hygienic surroundings. The Project

also aimed at improving institutional capacity till Gram Panchayat (GP) level to facilitate

and scale-up community-driven, decentralized RWSS service delivery.

The purpose of this Manual is to facilitate achieving all of the above by introducing the

key concepts and providing practical guidelines for planning, designing, construction,

operation and maintenance (O&M) of rural water and sanitation services. This Manual

can at best serve as a general reference and guide. It will provide to the technical persons

a ready reference for their use and be an aid to the non-technical persons to participate in

the processes. However, the readers may consider them always in relation to their own

specific requirements, adapting and applying them within the context of their actual

situation. This is a dynamic document to be periodically updated to include new

technologies and practices.

I am sure this Manual will be of immense help to all the stakeholders for implementing

reliable, sustainable and affordable rural piped water supply and sanitation services under

the Neer Nirmal Pariyojna. I am pleased to acknowledge the valuable contributions of all

the four States and the World Bank in preparing this Manual and hope that the experience

from use of this Manual will be helpful in bringing out an updated version in course of

time, which could be useful for other states as well.

(Vijaylaxmi Joshi)

Secretary to the Government of India

Ministry of Drinking Water and Sanitation

Table of Content

Technical Manual i

Table of Content Volume-1

1. INTRODUCTION ............................................................................................................................. 1-1 1.1. Objective of the Project................................................................................................... 1-1 1.2. Objective of Technical Manual ....................................................................................... 1-1 1.3. The Scope of Technical Manual ...................................................................................... 1-2 1.4. Sector Vision and Strategy .............................................................................................. 1-2 1.5. Overview of Existing Institutional Arrangements ............................................................ 1-3 1.6. Who can Use the Manual ................................................................................................ 1-3 1.7. Limitations of the Manual ............................................................................................... 1-3

2. EXISTING WATER SUPPLY STATUS .......................................................................................... 2-1 2.1. Assessment of Water Supply Situation ............................................................................ 2-1

3. WATER SUPPLY PRINCIPLES ...................................................................................................... 3-1 3.1. Design Period ................................................................................................................. 3-1 3.2. Population Forecast ........................................................................................................ 3-1 3.3. Per Capita Water Demand and Demand Projection .......................................................... 3-1 3.4. Field Survey ................................................................................................................... 3-2 3.5. Preparation of Maps and Drawings ................................................................................. 3-2

3.5.1. Details to be shown on GP Base Map ....................................................................... 3-3 3.6. Preparation of GIS Base Map .......................................................................................... 3-3

3.6.1. Usefulness of GIS Maps in Comparison to Conventional Maps ................................. 3-3 3.7. Attributes of Drinking Water .......................................................................................... 3-4 3.8. Quality of Water – Physical, Chemical and Biological .................................................... 3-4

3.8.1. Virological Quality ................................................................................................... 3-7 3.8.2. Water Quality Standards and Significance-Norms for Acceptance ............................ 3-7

3.9. Water Quality Reports .................................................................................................... 3-8 3.9.1. Water Sample Quality Testing and Sample Collection Proforma ............................... 3-8 3.9.2. Water Quality Surveillance ....................................................................................... 3-9 3.9.3. Review of Source Water Quality............................................................................. 3-10

3.10. Types of Sources for Water Supply ............................................................................... 3-12 3.10.1. Surface Waters ....................................................................................................... 3-12 3.10.2. Artificial Impounding Reservoirs (Storage and Sedimentation Tanks) ..................... 3-12

3.11. Types of Water Supply Schemes ................................................................................... 3-13 3.11.1. Single Habitation/GP Water Supply Schemes (SHS/SGS) ....................................... 3-13 3.11.2. Small and Large Multi Village Water Supply Schemes (MVS) ............................... 3-13 3.11.3. Pumping Hours....................................................................................................... 3-14

3.12. Source Selection ........................................................................................................... 3-14 3.12.1. Ground Water ......................................................................................................... 3-14 3.12.2. Surface Source ....................................................................................................... 3-14

3.13. Assessment of Yield ..................................................................................................... 3-14 3.14. Treatment ..................................................................................................................... 3-15 3.15. Transmission Lines and Rising Mains ........................................................................... 3-16

3.15.1. Pumps .................................................................................................................... 3-16 3.15.2. Pipe Appurtenances ................................................................................................ 3-17 3.15.3. Service Reservoirs .................................................................................................. 3-17 3.15.4. Distribution System ................................................................................................ 3-18 3.15.5. House Connections ................................................................................................. 3-18 3.15.6. Pipe Material .......................................................................................................... 3-19 3.15.7. Flow Meters ........................................................................................................... 3-19

3.16. Provision of SCADA .................................................................................................... 3-20 3.17. Provision of Solar System ............................................................................................. 3-20 3.18. Land Requirement for Water supply Components ......................................................... 3-20

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Technical Manual ii

4. PRELIMINARY PROJECT REPORT ............................................................................................. 4-1 4.1. Water Security Plan ........................................................................................................ 4-1

4.1.1. Objective .................................................................................................................. 4-1 4.1.2. Integrated Approach ................................................................................................. 4-1 4.1.3. Community Participation .......................................................................................... 4-2 4.1.4. Preparation of Water Sources Inventory .................................................................... 4-2 4.1.6 Sustainability Measures ............................................................................................ 4-4 4.1.7 Criteria for Examining Locations of Groundwater Recharging Sites ......................... 4-5 4.1.8 Checklist/ Guidelines on Sustainability of Village Drinking Water Supply Schemes . 4-6 4.1.9 Water Balance Study ................................................................................................ 4-7 4.1.10 Format of Preparation of Water Security Plan ........................................................... 4-8

4.2 Water Safety Plan ........................................................................................................... 4-8 4.3 Reconnaissance Survey ................................................................................................... 4-9 4.4 Format for Preparation of Preliminary Project Report ...................................................... 4-9 4.5 Format for Data Collection ........................................................................................... 4-10

4.5.1 Data for Ground Water ........................................................................................... 4-11 4.5.2 Data for Surface Water ........................................................................................... 4-12

4.6 Capital Cost and O & M Cost ....................................................................................... 4-16 5. DETAILED PROJECT REPORT..................................................................................................... 5-1

5.1 Executive Summary ........................................................................................................ 5-1 5.1.1 Brief Description of Project ...................................................................................... 5-1 5.1.2 Salient Features of Project ........................................................................................ 5-1 5.1.3 Financial Aspect ....................................................................................................... 5-2

5.2 Format for the Project Report .......................................................................................... 5-2 6. TECHNICAL GUIDELINES-WATER SUPPLY COMPONENTS ................................................. 6-1

6.1. General ........................................................................................................................... 6-1 6.2. Field Surveys .................................................................................................................. 6-1

6.2.1. Sanitary Survey for Source ....................................................................................... 6-1 6.2.2. Topographical Survey ............................................................................................... 6-1

6.2.2.1. Survey ............................................................................................................ 6-1 6.2.2.2. Maps/Drawings: .............................................................................................. 6-1

6.2.3. Soil Investigation...................................................................................................... 6-2 6.2.3.1. Laboratory Tests ............................................................................................. 6-2 6.2.3.2. Field Tests ...................................................................................................... 6-3

6.3. Basic Design factors ....................................................................................................... 6-3 6.4. Rehabilitation of Existing Water Supply Schemes ........................................................... 6-3 6.5. Ground Water Source ..................................................................................................... 6-3

6.5.1. Tube well ................................................................................................................. 6-4 6.5.2. Methods of Drilling of Tube Well ............................................................................. 6-4

6.5.2.1. Percussion Drilling .......................................................................................... 6-4 6.5.2.2. Direct Rotary Circulation Drilling: .................................................................. 6-5 6.5.2.3. Reverse Rotary Circulation Drilling ................................................................ 6-5 6.5.2.4. Down-the-Hole (DTH) Hammer Drilling ......................................................... 6-6 6.5.2.5. Selection of Drilling Rigs ................................................................................ 6-6

6.6. Surface Water Sources .................................................................................................. 6-10 6.6.1. Design of Intake/Raw Water Collection Well .......................................................... 6-11 6.6.2. Impounding Reservoir/Summer Storage Tank ......................................................... 6-15 6.6.3. Sumps .................................................................................................................... 6-15 6.6.4. Water Transmission lines ........................................................................................ 6-15 6.6.5. Economical Size of Pumping Main ......................................................................... 6-19 6.6.6. Type of Transmission Pipe Lines ............................................................................ 6-20 6.6.7. Laying & Testing of Pipes ...................................................................................... 6-21

6.7. Valves .......................................................................................................................... 6-25 6.8. Anchor / Thrust Blocks ................................................................................................. 6-27

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Technical Manual iii

7. PUMPING STATIONS –ELECTRO-MECHANICAL APPLIANCES/ EQUIPMENT .................. 7-1 7.1. Pumping Station ............................................................................................................. 7-1 7.2. General Requirements of Pumping Stations .................................................................... 7-1

7.2.1. Space Requirement and Layout Planning of Pumping System ................................... 7-2 7.2.2. Foundation ............................................................................................................... 7-2 7.2.3. Height of Pump House for the Pumps ....................................................................... 7-2

7.2.3.1. For Vertical Turbine pumps............................................................................. 7-2 7.2.3.2. For Centrifugal and Submersible pumps: ......................................................... 7-3

7.3. General Guidelines ......................................................................................................... 7-3 7.4. The Basic Concepts of Pump Engineering ....................................................................... 7-3 7.5. Classification of Water Pumps ........................................................................................ 7-5

7.5.1. Vertical Turbine Pump ............................................................................................. 7-5 7.5.2. Submersible Pumps .................................................................................................. 7-6 7.5.3. Jet Pump................................................................................................................... 7-7 7.5.4. Horizontal Centrifugal Pump .................................................................................... 7-7 7.5.5. Vertical Centrifugal Pump: ....................................................................................... 7-7

7.6. Pump Efficiencies ........................................................................................................... 7-8 7.6.1. Energy Efficient Pumps ............................................................................................ 7-8

7.7. Choice for the Type of Pump and Selection of Pump ....................................................... 7-8 7.8. Installation of Pumps ...................................................................................................... 7-9

7.8.1. Foundation ............................................................................................................... 7-9 7.9. Limitations on Use of Pumps ........................................................................................ 7-11 7.10. Automation Aspects of Pumping Plants ........................................................................ 7-11 7.11. Pump Priming ............................................................................................................... 7-13 7.12. Pump Accessories ......................................................................................................... 7-13 7.13. Motors .......................................................................................................................... 7-15

7.13.1. Capacity ................................................................................................................. 7-15 7.13.2. Performance of Motors ........................................................................................... 7-15 7.13.3. Energy Efficient Motors ......................................................................................... 7-15 7.13.4. Voltage................................................................................................................... 7-16 7.13.5. Single Phasing on Three Phase Motor ..................................................................... 7-16 7.13.6. Earthing ................................................................................................................. 7-16

7.14. Design of Machine Foundation ..................................................................................... 7-17 7.15. Electric Connections ..................................................................................................... 7-18

8. WATER TREATMENT .................................................................................................................... 8-1 8.1. General ........................................................................................................................... 8-1 8.2. Methods of Treatment and Flow sheets ........................................................................... 8-1

8.2.1. Aeration ................................................................................................................... 8-3 8.2.1.1. By Air Diffusion ............................................................................................. 8-3 8.2.1.2. By Using Spray Nozzles .................................................................................. 8-3 8.2.1.3. By Trickling Beds ........................................................................................... 8-4 8.2.1.4. By Using Cascades .......................................................................................... 8-4

8.2.2. Screening ................................................................................................................. 8-4 8.2.3. Plain Sedimentation and Coagulation ........................................................................ 8-5 8.2.4. Coagulant Dosage..................................................................................................... 8-6 8.2.5. Choice of Coagulant ................................................................................................. 8-6 8.2.6. Rapid Mixing ........................................................................................................... 8-6

8.3. Types of Sedimentation Tanks ........................................................................................ 8-7 8.4. Tube Settler .................................................................................................................... 8-8 8.5. Treatment and Disposal of Settled Sludge ..................................................................... 8-10 8.6. Filtration ....................................................................................................................... 8-11

8.6.1. Slow Sand Filters ................................................................................................... 8-11 8.6.1.1. Design Criteria/ Considerations ..................................................................... 8-12 8.6.1.2. Working Time for Filters............................................................................... 8-12

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Technical Manual iv

8.6.1.3. Shape of Filter Bed ....................................................................................... 8-12 8.6.2. Rapid Gravity Filters .............................................................................................. 8-13

8.6.2.1. Rate of Filtration ........................................................................................... 8-13 8.6.2.2. Design of Filter Unit ..................................................................................... 8-13 Design Parameters of Rapid Sand Filters ........................................................................... 8-19

8.6.3. Comparison of Filters ............................................................................................. 8-21 8.6.4. Other Technologies used for Filtration .................................................................... 8-22

8.6.4.1. Pressure Filters .............................................................................................. 8-22 8.6.4.2. Infiltration Well ............................................................................................ 8-23 8.6.4.3. Low Cost Filtration Plants for Water Supply ................................................. 8-28 8.6.4.4. Reverse Osmosis ........................................................................................... 8-31

8.6.5. Criteria for selection of Non-Conventional Treatment Technologies ....................... 8-33 8.6.6. Disinfection of water: ............................................................................................. 8-33

8.6.6.1. Methods of disinfection: ................................................................................ 8-33 8.6.7. Sample Design of Conventional Water Treatment Plant .......................................... 8-39

9. SERVICE RESERVOIR ................................................................................................................... 9-1 9.1. Type of Reservoirs Used in Rural Water Supply ............................................................. 9-1 9.2. Location of Reservoirs .................................................................................................... 9-2 9.3. Capacity of Reservoirs .................................................................................................... 9-2 9.4. Reservoir Components .................................................................................................... 9-3 9.5. Structural Design of Water Tanks ................................................................................... 9-4

9.5.1. Flood Hazard ............................................................................................................ 9-8 9.5.2. Land Slides .............................................................................................................. 9-8 9.5.3. Test for Water Tightness of Structures: ..................................................................... 9-8

10. Distribution System .......................................................................................................................... 10-1 10.1. General ......................................................................................................................... 10-1 10.2. General Design Parameters for Distribution System ...................................................... 10-1 10.3. Types of Distribution Systems ...................................................................................... 10-2 10.4. Methods of Network Analysis ....................................................................................... 10-2 10.5. Hydraulic Network Analysis ......................................................................................... 10-3 10.6. Location of the valves: .................................................................................................. 10-4 10.7. House Service Connections ........................................................................................... 10-6 10.8. Flow Meters ................................................................................................................. 10-7

11. SCADA & Automation System ......................................................................................................... 11-1 11.1. SCADA ........................................................................................................................ 11-1 11.2. Control Philosophy of SCADA ..................................................................................... 11-1 11.3. Automation ................................................................................................................... 11-1

12. GROUND WATER RECHARGE .................................................................................................... 12-1 12.1. Need for Ground Water Recharge ................................................................................. 12-1 12.2. Ground Water Resources Sustainability ........................................................................ 12-2 12.3. Ground Water Availability ............................................................................................ 12-3 12.4. Ground Water Exploitation Status ................................................................................. 12-6 12.5. Ground Water Prospect Maps ....................................................................................... 12-7 12.6. Technological Options for Recharge ............................................................................. 12-7

13. SOLID AND LIQUID WASTE MANAGEMENT ........................................................................... 13-1 13.1. Assessment of Existing situation ................................................................................... 13-1 13.2. Solid and Liquid Waste Management Plan (SLWM) ..................................................... 13-1

13.2.1. Introduction ............................................................................................................ 13-1 13.2.2. Village Transact ..................................................................................................... 13-2 13.2.3. Data Verification .................................................................................................... 13-2 13.2.4. Strategy .................................................................................................................. 13-3 13.2.5. Checklist ................................................................................................................ 13-3

13.3. Solid Waste Storage, Collection, Transportation, Disposal and Recyclable System- ...... 13-4 13.3.1. General................................................................................................................... 13-4

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Technical Manual v

13.3.2. Non Biodegradable (Inorganic) Waste .................................................................... 13-4 13.3.2.1. Sanitary Landfill ........................................................................................... 13-4 13.3.2.2. Planning & Design of a Landfill .................................................................... 13-5 13.3.2.3. Location Criteria: .......................................................................................... 13-5 13.3.2.4. Assessment of Area Required (an Example) .................................................. 13-5 13.3.2.5. Development of a List of Potential Sites ........................................................ 13-5 13.3.2.6. Data Collection ............................................................................................. 13-6 13.3.2.7. Final Site Selection ....................................................................................... 13-6 13.3.2.8. Design Life ................................................................................................... 13-7 13.3.2.9. Additional area requirement for other services ............................................... 13-7 13.3.2.10. Technical Design Requirements .................................................................... 13-7 13.3.2.11. Sanitary Landfill in Marshy Regions ............................................................. 13-8 13.3.2.12. Base Sealing System ..................................................................................... 13-8 13.3.2.13. Leachate Management ................................................................................... 13-8 13.3.2.14. Leachate Generation ...................................................................................... 13-8 13.3.2.15. Leachate Collection ....................................................................................... 13-9 13.3.2.16. Leachate Pond and Treatment ........................................................................ 13-9 13.3.2.17. Access Road ............................................................................................... 13-10 13.3.2.18. Equipment / resources ................................................................................. 13-10 13.3.2.19. General Safety Measures ............................................................................. 13-10

13.3.3. Bio Degradable (Organic) Waste .......................................................................... 13-11 13.3.3.1. Composting Through N.A.D.E.P. System .................................................... 13-12 13.3.3.2. Vermi Composting ...................................................................................... 13-13 13.3.3.3. Bio Gas Plant .............................................................................................. 13-14

13.4. Liquid Waste Management ......................................................................................... 13-17 13.4.1. Sanitary Latrines and Safe Disposal of Human Excreta/Waste Water Disposal ...... 13-17 13.4.2. E – Toilet ............................................................................................................. 13-25 13.4.3. Bio – Toilets ......................................................................................................... 13-25 13.4.4. Septic Tanks ......................................................................................................... 13-26

13.4.4.1. Soak Pits ..................................................................................................... 13-29 13.4.4.2. Septage and Its Disposal .............................................................................. 13-29

13.4.5. Small Bore Sewer Systems ................................................................................... 13-30 13.4.5.1. Small Bore Sewers System .......................................................................... 13-30 13.4.5.2. Components ................................................................................................ 13-31 13.4.5.3. Need for Small Bore Sewer System ............................................................. 13-32 13.4.5.4. Design Considerations ................................................................................. 13-33 13.4.5.5. Appurtenances ............................................................................................ 13-34

13.4.6. Waste Water Treatment - DEWATS ..................................................................... 13-35 13.4.6.1. Components ................................................................................................ 13-35 13.4.6.2. Treatment Systems – Advantages & Disadvantages: .................................... 13-35 13.4.6.3. Space Requirements .................................................................................... 13-37 13.4.6.4. Performance ................................................................................................ 13-37 13.4.6.5. Pathogen Control ........................................................................................ 13-38 13.4.6.6. Septic Tank ................................................................................................. 13-38 13.4.6.7. Fully Mixed Digester .................................................................................. 13-38 13.4.6.8. Anaerobic Baffled Reactor .......................................................................... 13-39 13.4.6.9. Starting Phase and Maintenance .................................................................. 13-40 13.4.6.10. Calculating Dimensions .............................................................................. 13-40 13.4.6.11. Planted Soil Filters ...................................................................................... 13-40 13.4.6.12. Horizontal Gravel Filter .............................................................................. 13-41 13.4.6.13. Starting Phase and Maintenance .................................................................. 13-44 13.4.6.14. Calculating Dimensions .............................................................................. 13-44

13.4.7. Sullage Stabilization Ponds ................................................................................... 13-44 13.4.7.1. Anaerobic ponds ......................................................................................... 13-45 13.4.7.2. Facultative pond .......................................................................................... 13-45

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13.4.7.3. Maturation pond .......................................................................................... 13-45 13.4.8. Waste Water Treatment through Duckweed Pond: ................................................ 13-46 13.4.9. Waste Water Treatment through Forestry .............................................................. 13-46 13.4.10. Drainage and Grey Water Treatment ..................................................................... 13-48

13.4.10.1. Design Guidelines and Improvement of Drainage System ............................ 13-48 13.4.10.2. Catch Pits .................................................................................................... 13-48 13.4.10.3. Layout of Drains ......................................................................................... 13-49 13.4.10.4. Drain Sections ............................................................................................. 13-49 13.4.10.5. Kerb and Channel Drains ............................................................................ 13-50 13.4.10.6. Covered/Open Drains .................................................................................. 13-51 13.4.10.7. Hydraulic Design of Drain .......................................................................... 13-51 13.4.10.8. Treatment of Waste Grey Water .................................................................. 13-52 13.4.10.9. Root Zone Treatment System ...................................................................... 13-52

14. Construction Management ............................................................................................................... 14-1 14.1. Background .................................................................................................................. 14-1 14.2. General Strategy of Supervision .................................................................................... 14-1 14.3. Requirements of Site Engineer ...................................................................................... 14-1 14.4. The Site Engineer’s Report: .......................................................................................... 14-2 14.5. Construction Management of Work .............................................................................. 14-2

14.5.1. Civil Works ............................................................................................................ 14-2 14.5.2. Construction of Over Head Service Reservoirs (OHSR) .......................................... 14-3

14.5.2.1. General Guidelines for all type of Civil works ............................................... 14-6 14.5.2.2. Pipelines ....................................................................................................... 14-8 14.5.2.3. Tube Well ................................................................................................... 14-11 14.5.2.4. Construction of Slow Sand Filters: .............................................................. 14-11 14.5.2.5. Surface Water Treatment Plant: ................................................................... 14-11 14.5.2.6. Pump Sets Installation: ................................................................................ 14-11 14.5.2.7. Suction and Delivery Lines ......................................................................... 14-12

14.5.3. Electric Motor ...................................................................................................... 14-13 14.6. Inspection and Testing ................................................................................................ 14-13 14.7. Testing and Inspection at Manufacturer’s Work site: ................................................... 14-13

14.7.1. Electrical Connections .......................................................................................... 14-15 14.8. Solid and Liquid Waste Management .......................................................................... 14-15 14.9. Public Safety .............................................................................................................. 14-16 14.10. Trial Run & Commissioning ....................................................................................... 14-18 14.11. Exit Strategy ............................................................................................................... 14-18 14.12. Implementation Schedule ............................................................................................ 14-18 14.13. Institutional Responsibilities ....................................................................................... 14-18 14.14. Completion Plan & Reports ........................................................................................ 14-18 14.15. Environmental & Social Impact .................................................................................. 14-20 14.16. Environment & Social Management Framework ......................................................... 14-20

15. Operation& Maintenance ................................................................................................................. 15-1 15.1. General ......................................................................................................................... 15-1 15.2. Operation & Maintenance of Various Components for Water Supply Schemes.............. 15-2

15.2.1. Intake Works .......................................................................................................... 15-2 15.2.2. Tube Well .............................................................................................................. 15-3 15.2.3. Clear Water Sump &Reservoir ............................................................................... 15-3 15.2.4. Balancing Reservoirs and Elevated Reservoirs ........................................................ 15-4 15.2.5. Treated Water Quality ............................................................................................ 15-4 15.2.6. Water Treatment Plants .......................................................................................... 15-4

15.2.6.1. Water Treatment Components ....................................................................... 15-5 15.2.6.2. Records ......................................................................................................... 15-7

15.2.7. Distribution System ................................................................................................ 15-7 15.2.7.1. Sound Operation Practice .............................................................................. 15-7

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15.2.7.2. Preparation for Repairs .................................................................................. 15-8 15.2.7.3. Locating Water Mains ................................................................................... 15-8 15.2.7.4. Cleaning Pipelines......................................................................................... 15-9 15.2.7.5. Repairing Pipe Leaks .................................................................................... 15-9

15.2.8. Valves .................................................................................................................. 15-11 15.2.9. Meters .................................................................................................................. 15-12 15.2.10. Reservoir .............................................................................................................. 15-12 15.2.11. Machinery and Equipment .................................................................................... 15-14

15.2.11.1. Pumps ......................................................................................................... 15-14 15.2.11.2. Maintenance of Electric Motor .................................................................... 15-18 15.2.11.3. Burn-out of New Motors ............................................................................. 15-19 15.2.11.4. Schedule ..................................................................................................... 15-21 15.2.11.5. Tools required for repair of Pumps and motor .............................................. 15-22 15.2.11.6. Records ....................................................................................................... 15-22

15.2.12. Measures of Water Quality Control in field ........................................................... 15-22 15.2.13. Safety & Precautionary Aspects ............................................................................ 15-26 15.2.14. Chlorine Safety..................................................................................................... 15-27

15.2.14.1. Hazard of Chlorine ...................................................................................... 15-27 15.2.14.2. Working Safety around chlorine gas ............................................................ 15-28 15.2.14.3. Leak Detection (Chlorine) and Control ........................................................ 15-30 15.2.14.4. Repair and Maintenance of Chlorine System ............................................... 15-31 15.2.14.5. Hazard Recognition ..................................................................................... 15-32 15.2.14.6. Personnel Protective Equipment .................................................................. 15-32 15.2.14.7. Safe Work Practice ...................................................................................... 15-34

15.2.15. Records of key activities of O&M......................................................................... 15-36 15.2.16. Staff Position ........................................................................................................ 15-36 15.2.17. Inventory of Stores ............................................................................................... 15-36 15.2.18. Guidelines to be Followed by the Village Panchayat/ GPWSC for Operation and

Maintenance ......................................................................................................... 15-37 15.2.19. Suggestions for GPWSC ....................................................................................... 15-38 15.2.20. Water Revenue (Billing & Collection) .................................................................. 15-39

15.3. Operation and Maintenance of Solid Liquid Waste Management ................................. 15-40 15.3.1. Operation and Maintenance of Sanitary Landfill ................................................... 15-40 15.3.2. Operation and Maintenance of Twin Pit Pour Flush Latrine .................................. 15-40 15.3.3. Septic Tanks ......................................................................................................... 15-42 15.3.4. Small Bore Sewers ............................................................................................... 15-42 15.3.5. Horizontal Flow Gravel Filter of DEWATS .......................................................... 15-43 15.3.6. Anaerobic Baffled Reactor ................................................................................... 15-43 15.3.7. Drainage System .................................................................................................. 15-44 15.3.8. Exit Strategy......................................................................................................... 15-44

Volume-2: Annexures

Table of Content

Technical Manual viii

List of Table

Table 2-1: Checklist for Condition Assessment for Rehabilitation/Revitalization/Augmentation of existing water supply scheme ..... 2-2

Table 3-1: Recommended Physical & Chemical Quality of Water ...................................... 3-5 Table 3-2: Recommended Bacteriological Quality of Drinking Water ................................ 3-6 Table 3-3: Recommended Virological Quality of Drinking Water ...................................... 3-7 Table 3-4: Frequency of Sampling ................................................................................... 3-10 Table 4-1: Ground Water Recharging Techniques .............................................................. 4-5 Table 4-2: O&M aspects of Recharge techniques ............................................................... 4-6 Table 4-3: Capital Cost .................................................................................................... 4-16 Table 4-4: O & M Cost .................................................................................................... 4-17 Table 5-1: Details of cost of production of water ................................................................ 5-5 Table 5-2: Details of Income .............................................................................................. 5-5 Table 6-1: Gravel Sizes ...................................................................................................... 6-9 Table 6-2: Hazen William Coefficient Value adopted for design purpose ......................... 6-16 Table 7-1: Height of Pump House ...................................................................................... 7-3 Table 7-2: Height of Pump Room for Centrifugal and Submersible Pumps ......................... 7-3 Table 7-3: Application of Pumps ........................................................................................ 7-9 Table 8-1: List of Unit WTP Operation V/s Impurities Removed ....................................... 8-3 Table 8-2: Sedimentation Rates of Various Materials ......................................................... 8-5 Table 8-3: Specification of Gravel .................................................................................... 8-15 Table 8-4: Design Parameters ........................................................................................... 8-19 Table 8-5: observations of recuperation test...................................................................... 8-27 Table: 8-6: Result of Water Samples from the Wells ........................................................ 8-27 Table 8-7: Result of Water Quality at Inlet & Outlet of Filter Unit ................................... 8-29 Table 9-1: Lighting Conductor ........................................................................................... 9-4 Table 12-1: Ground Water Resources Availability, Utilization and Stage of Development12-4 Table -12-2: Categorization of Blocks on Ground Water Exploitation .............................. 12-6 Table 13-1: Selection Criteria of Landfill ......................................................................... 13-5 Table 13-2: Data Requirement for Sanitary Landfill ......................................................... 13-6 Table 13-3: Minimum inside the sanitary landfill ............................................................. 13-8 Table 13-4: Salient Details of Septic Tanks for User up to 50 ......................................... 13-28 Table 13-5: Advantages & Disadvantages of various type of Treatment System ............. 13-36 Table 13-6: Porosity Details ........................................................................................... 13-43 Table 13-7: Typical Details of Hydraulic Section for Various Types of Drains ............... 13-49 Table 14-1: Capacitor Ratings ........................................................................................ 14-14 Table 15-1: Trouble shooting procedure for tube wells ..................................................... 15-3 Table 15-2: Daily Activity Chart for Slow Sand Filter ...................................................... 15-6 Table 15-3: General Problems in Valve Maintenance ..................................................... 15-11 Table 15-4: Daily Log Sheet of Pump ............................................................................ 15-15 Table 15-5: Trouble Shooting, Problem and Remedies in Operation of Pumps ............... 15-15 Table 15-6: Faults in Motors and their diagnosis ............................................................ 15-20 Table 15-7: Toxic Effect of Chlorine .............................................................................. 15-28 Table 15-8: Skill requirement for O&M of Water Supply Scheme .................................. 15-36

Table of Content

Technical Manual ix

List of Figures

Figure 6-1: Intake Well .................................................................................................... 6-13 Figure 6-2: Floating Barge Intake ..................................................................................... 6-14 Figure 8-1: Tube Settler ..................................................................................................... 8-9 Figure 8-2: Figure of Alum Sludge Treatment and Disposal Methods ............................... 8-11 Figure 8-3: Rapid Sand Filter ........................................................................................... 8-18 Figure 8-4: Infiltration Wells ............................................................................................ 8-28 Figure 8-5: Low Cost Filter .............................................................................................. 8-30 Figure 8-6: Diagram of RO Plant...................................................................................... 8-32 Figure 8-7: Gaseous Chlorinator with Injector .................................................................. 8-36 Figure 8-8: Differential Pressure Feed Type Chlorinator .................................................. 8-38 Figure 8-9: Pot Type Chlorinators .................................................................................... 8-39 Figure 10-1: General Arrangement of Placement of Valves along the Alignment............. 10-5 Figure 10-2: House Connection ........................................................................................ 10-6 Figure 10-3: Flow Diagram of Pumping From Headworks to Service Reservoirs ............. 10-8 Figure 12-1: IWRM Process for Drinking Water Supply .................................................. 12-2 Figure 13-1: Leachate Collection...................................................................................... 13-9 Figure 13-2: Floating Gas Holder Plant .......................................................................... 13-15 Figure 13-3: Fixed Dome Biogas Plant ........................................................................... 13-16 Figure 13-4: VIP Latrine ................................................................................................ 13-18 Figure 13-5: Lay out Plan of Twin Pit Pore Flush Latrine ............................................... 13-19 Figure 13-6: Details of Shallow Junction chamber.......................................................... 13-20 Figure 13-7: Sectional Elevation of Twin Pit Pour Flush Latrine .................................... 13-21 Figure 13-8: Bio-Toilet .................................................................................................. 13-26 Figure 13-9: Schematic diagram of a small bore sewer system ....................................... 13-30 Figure 13-10: Typical solids interceptor tank .................................................................. 13-31 Figure 13-11: A typical small bore sewer cleanout ......................................................... 13-32 Figure 13-12: Fully Mixed Digester (Bio-Digester) ........................................................ 13-38 Figure 13-13: Anaerobic Baffled Reactor ....................................................................... 13-39 Figure 13-14: Anaerobic Baffled Reactor ....................................................................... 13-40 Figure 13-15: Horizontal Gravel Filter ........................................................................... 13-41 Figure 13-16: Horizontal Filter Details ........................................................................... 13-42 Figure 13-17: Root Zone Treatment System ................................................................... 13-47 Figure 13-18: Typical Sections of Drains ....................................................................... 13-50 Figure 13-19: Kerb and Channel Drains ......................................................................... 13-51 Figure 13-20: Root Zone Treatment System ................................................................... 13-54 Figure 14-1: Arrangement of Stacking of Pipe................................................................ 14-10 Figure 15-1: Self-Contained Breathing Apparatus (SCABA) .......................................... 15-33

List of Abbreviation

Technical Manual i


AC AE

Asbestos Cement Assistant Engineer

APL Above Poverty Line APWSC Anchalik Panchayat Water and Sanitation Committee ARWSP Accelerated Rural Water Supply Program ASTM BCC BEE

American Society for Testing and Material Behavioural Change Communication Bureau of Energy Efficiency

BCM Billion Cubic Meter BF Butter Fly BGL BNY BPT BWSC BRC

Below Ground Level Bharat Nirman Yojna Break Pressure Tank Bar Wrapped Steel Cylinder Block Resource Center

BPL Below Poverty Line BHP Break Horse Power BM Bench Mark BOD Biological Oxygen Demand CC Cement Concrete CE CI CPHEEO

Chief Engineer Cast Iron Central Public Health and Environmental Engineering Organisation

CPM Critical Path Method CM Cement Mortar CRSP Central Rural Sanitation Program CPU Central Processing Unit CRF CSC

Common Reserve Fund Community Sanitary Complexes

COD Chemical Oxygen Demand CGWB CWC DBMS

Central Ground Water Board Central Water Commission Data Base Management System

DBO Design, Build and Operate DDC Deputy Development Commissioner DDO DEWATS DI DO

Drawing and Disbursement Officer Decentralized Wastewater Treatment Systems Ductile Iron Dissolved Oxygen

DOL DSA

Direct On Line District Support Agency

DPMU District Project Management Unit DPR Detailed Project Report DSM District Sanitation Mission DTH Down-the-Hole DWSC District Water and Sanitation Committee DWSD Drinking Water and Sanitation Department DWSM District Water and Sanitation Mission E-in-C Engineer in-Chief EA Environmental Assessment


Technical Manual ii

EE EEC ELBR EMF ESR

Executive Engineer European Economic Committee Elevated Level Balancing Reservoir Environment Management Framework Elevated Service Reservoir

EDS Environment Data Sheet FC Faecal Coliform FSL Full Supply Level FTK Field Testing Kit FPARP GIS

Farmers Participatory Action Research Programme Geographic Information System

GI Galvanized Iron GoI GLBS GLSR

Government of India Ground Level Balancing Sump Ground Level Service Reservoir

GPM Gallon Per Minute GP GRP GPS

Gram Panchayat Glass Reinforced Pipe Global Positioning System

GP-WSC Gram Panchayat Water Supply and Sanitation Committee GSM HD HDPE HRC HRD

Group Special Mobile Heavy Duty High Density Poly Ethylene High Rupture Capacity Human Resource Development

HP Horse Power HFL Highest Flood Level HGM Hydro-geomorphologic Map Hrs Hours HT IC IEC IELBR IGLBS

High Tension Inverter Contactor Information Education and Communication Intermediate Elevated Balancing Reservoir Intermediate Ground Level Storage Balancing Sump

IEC International Electrotechnical Committee IDLH Immediately Dangerous to Life or Health IE Indian Electricity ICQSC Independent Construction Quality Surveillance Consultants IHHL IMD

Individual Household Latrine India Meteorological Department

IMIS Integrated Management Information System IMR IS IWMP IWRM

Infant Mortality Rate Indian Standard Integrated Watershed Management Programme Integrated Water Resource Management

IWAI Inland Waterways Authority of India ITI Industrial Training Institute IWSM Integrated Water Shed Management IWS JE/ AES

Integrated Water Services Japanese Encephalitis/ Acute Encephalitis Syndrome

JE Junior Engineer KL Kilo Litre


Technical Manual iii

KRC Key Resource Centre KM Kilometer KV KW LD LED LPCD LPM LT LWL MAR MBR

Kilo Volt Kilo Watt Light Duty Light Emitter Diode Litres per capita per day Litres Per Minute Low Tension Lowest Water Level Managed Aquifer Recharge Master balancing reservoir

LMVS Large Multi Village Scheme LIS Low Income State MCB MCCB MD MDPE M&E

Miniature Circuit Breaker Moulded Case Circuit Breaker Medium Duty Medium-density polyethylene Monitoring and evaluation

MCM Million Cubic Meter MIS Management Information System ML Million Litre MLD Million Litres per Day MGNREGS Mahatma Gandhi National Rural Employment Guarantee Scheme MOA Ministry of Agriculture MoDWS Ministry of Drinking Water and Sanitation MPN Most Probable Number MoU Memorandum of Understanding MOV MS MVS

Motorized Operated Valve Mild Steel Multi Village Scheme

MSL Mean Sea Level MSERW Mild steel Electro Resistance Welded MWL NADEP

Maximum Water Level Narayan Deotao Pandharipande

NAP NBA

National Afforestation Programme Nirmal Bharat Abhiyan

NBC National Building Code NB Nominal Bore NC Not Covered NCB National Competitive Bidding NDMA National Disaster Management Authority NFSM NGO

National Food Security Mission Non-Government Organization

NGP NHM

Nirmal Gram Puraskar National Horticulture Mission

NPMU NPSH NRC

National Project Management Unit Net positive suction head National Resource Centre

NR Non Return NRDWP National Rural Drinking Water Program NRW Non Revenue Water


Technical Manual iv

NRSA National Remote Sensing Authority NREGS NRSC NTU NWDP

Natural Rural Employment Guarantee Scheme National Remote Sensing Center Nephelometric Turbidity Unit National Watershed Development Programme

NWDPRA National Watershed Development Project for Rainfed Areas OD Outer Diameter ODF OHBR OHT OHSR

Open Defecation Free Over Head Balancing Reservoir Over Head Tank Over Head Service Reservoir

O&M Operation and Maintenance PAH Polinuclear Aromatic Hydrocarbon PC Partially Covered PCD Pitch Circle Diameter PE Polyethelyne PF Pour Flush PHED PLC PFR PIP

Public Health Engineering Department Programmable Logic Controller Preliminary Feasibility Report Project Implementation Plan

PLT Plate Load Test PMU PPM PPR

Project Monitoring Unit Parts per Million Preliminary Project Report

PRA Participatory Rapid Appraisal PRIs Panchayati Raj Institutions PSC PSI PVC PWS

Pre Stressed Concrete Pounds per square inch Poly Vinyl Chloride Piped Water Supply

PTC Power Test Code RCC RD RKVY RS RTU RWS RWSSD

Reinforced Cement Concrete Rural Development Department Rashtriya Krishi Vigyan Yojna Rapid Sand Remote Terminal Unit Rural Water Supply Rural Water Supply and Sanitation Department

RRR Regional Regression Recharge RL Reduced Level R&D Research and Development RO Reverse Osmosis RWSD Rural Water and Sanitation Department RWSS Rural Water Supply and Sanitation RWSS-LIS Rural Water Supply and Sanitation Project for Low Income States SBC Soil Bearing Capacity SCABA Self Contained Breathing Apparatus SCADA Supervisory Control and Data Acquisition System SCPT SDA SE

Standard Cone Penetration Test Service Delivery Approach Superintending Engineer


Technical Manual v

SGS Single GP Scheme SGSW SHG

Salt Glazed Stone Ware Self Help Group

SHS SLWM

Single Habitation Scheme Solid and Liquid Waste Management

SO Support Organization SMVS Small Multi Village Scheme SPT Standard Penetration Test SR SS SS SWSM

Service Reservoir Summer Storage Slow Sand State Water & Sanitation Mission

STP Sewage Treatment Plant SWD Side Water Depth SPMU State Project Management Unit SVS SWG TBM TDS

Single Village Water Supply Scheme Standard Wire Gauge Temporary Bench Marks Total Dissolved Solids

TAG Technical Advisory Group TCL Total Chlorine TSC UNDP UNICEF

Total Sanitation Campaign United Nations Development Programme United Nations Children's Fund

UDS Undisturbed Sample UP Uttar Pradesh UPJN UP Jal Nigam UTM VWSC VWSP

Universal Transverse Mercator Village Water and Sanitation Committee Village Water Security Plan

VLF Very Low Frequency VIP Ventilated Improved Pit WB WHO WQS

World Bank World Health Organization Water quality surveillance

WC Water Closet WL Weir Loading WRO WSSO WTP

Water Resource Organization Water and Sanitation Support Organization Water Treatment Plant

KLPE Cross Linked Poly ethylene ZOI ZP

Zone of Influence Zila Parishad/Zila Panchayat

Introduction

Chapter-1 Page 1-1

1. INTRODUCTION

1.1. Objective of the Project

The overall project development objective of the Rural Water Supply and Sanitation Project for Low Income States is to improve piped water supply and sanitation services for selected rural communities in the target states, Assam, Bihar, Jharkhand and Uttar Pradesh (UP), through decentralized delivery systems and to increase the capacity of the participating states to respond promptly and effectively.

The Project Aims to Achieve

Strengthening of the state level policy and planning activities in Rural Water Supply and Sanitation (RWSS) sector

Clearly defined institutional arrangements, roles and responsibilities at various levels (state, district, village) based on decentralized delivery models

Strengthening of capacities of all the key stakeholders in planning, designing, development, Operation and Maintenance (O & M) of rural water and sanitation services

Achieve good quality and adequate water for all communities, open defecation free villages, clean and hygienic surroundings

Sustainable water sources, equitable distribution of water and water security at household, village and Gram Panchayat levels

Improved institutional capacity till Gram Panchayat (GP) level to facilitate and scale-up community-driven, decentralized RWSS service delivery.

The Expected Physical Achievements During the Project Period Are

About 14600 habitations in around 2000 GPs covering about 7.8 million people shall be provided with safe and adequate piped water

About 2000 GPs shall prepare comprehensive water security and environmental sanitation plans to make their habitations secure and hygienic

Quality affected (arsenic/fluoride/iron)habitations covered under the Project in over 24 quality affected districts shall be provided with safe and potable water from surface sources / In fluoride affected area possibility to examine availability of fluoride free water in deeper strata may also be examined.

1.2. Objective of Technical Manual

The objective is to formulate the practical guidelines for planning, designing, implementation and operation & maintenance of Rural Water Supply & Sanitation works in the project area. This manual shall provide guidance for improving piped water coverage along with sanitation coverage and improving operation & maintenance performance.

Introduction

Chapter-1 Page 1-2

1.3. The Scope of Technical Manual

Assessment of existing situation Identification of desires/needs and capabilities of those communities that plan and

manage the services Identification of various feasible rural water supply and sanitation technologies that

respond to the expectations of the communities Design criteria for technology options for Rural Water Supply and Sanitation

schemes Significance of water quality and quantity Procedures and guidelines for selection of sources for water supply Population forecast methods Methods of field survey and investigations Guidelines for planning ground water recharge facilities Contents and formats for preparation of Preliminary Feasibility Report (PFR) Format and guidelines for preparation of Detailed Project Report (DPR) that includes

Standard designs, drawings, cost estimates and specifications for typical schemes proposed under the project such as water supply and sanitation works, checklists to be used by the engineers and beneficiary committees to ensure the goods and works are in conformity with the specification

Checklist and guidelines for quality control related to implementation of works pertaining to water supply and sanitation works

Checklist and guidelines for quality control related to operation and maintenance of Rural Water Supply and Sanitation works

The manual is to be used/ read with Technical Arrangements in Section-V of the Project Implementation Plan (PIP) prepared for the project

This Manual shall be read in conjunction with the Project cycle and Engineering Responsibility Matrix given in the PIP.

1.4. Sector Vision and Strategy

All the concerning states in consultation with the Government of India and the World Bank have expressed their vision on the RWSS sector. They want to improve the quality of life of rural communities by establishing sustainable and an affordable access, to adequate and safe water supply along with the use of effective sanitation, under the management of PRIs. The strategy to achieve its sector vision includes:

Reversing the decline in FC habitations by enhancing the technical, financial and environmental sustainability of water supply and sanitation services

Safeguarding water quality and securing reliable and safe sources for habitations with water quality problems

Government of India has published the following manuals which can be used conjunctively for reference:

1. Manual on Water Supply and Treatment, Published by Central Public Health And Environmental Engineering Organization, Ministry of Urban Development, Year 1999 or amended

Introduction

Chapter-1 Page 1-3

2. Manual on Rural Water Supply for O&M, Published by Department of Drinking Water Supply, Ministry of Rural Development, Government of India, year 2011

3. National Rural Drinking Water Programme published by Department of Drinking Water Supply, Ministry of Rural Development, Government of India, year 2010

4. Water Harvesting and Artificial Recharge manual, published by Department of Drinking water Supply, December 2004

5. Manual on Sewerage and Sewage Treatment, Published by Central Public Health And Environmental Engineering Organization Ministry of Urban Development, Year-2013

6. Manual on Solid Waste Management, Published by Central Public Health and Environmental Engineering Organization Ministry of Urban Development, Draft 2014 Edition.

1.5. Overview of Existing Institutional Arrangements

The current RWSS institutional setup is highly centralized, with the State level Department of Water Supply and Drainage (DWSD) / Public Health Engineering Department (PHED) /UP Jal Nigam (UPJN) being responsible for planning, construction and maintenance of water supply schemes. The state government has established the State Water & Sanitation Mission (SWSM) for planning and policy making and District Water & Sanitation Missions (DWSMs) in all districts for implementing the Sector Reform Project (SRP), the Swajaldhara program and the Total Sanitation Campaign (TSC). In all the four Project states, the existing institutional structure also assigns overlapping roles and responsibilities for policy-making, planning, implementation and management, to the same organization-i.e. the technical agency (PHED in Assam, Bihar, DWSD in Jharkhand and UPJN in UP). As the head of the technical agency, the Principal Secretary to the Government also plays the role of policy making (except in UP where the technical agency Jal Nigam is housed in a different department)

In addition, in UP state, the existing structure needs to be revisited, removing the separation between rural water and sanitation and integrating them under a single line of command as is practiced in most other states.

1.6. Who can Use the Manual

This Manual is meant for the following categories of users: Gram Panchayat/GPWSC functionaries involved in planning, designing, implementing, operating and managing the project, Govt. agencies and consultants, Agencies / persons involved in technical administration of the project, Non-government Organization and Support Agencies. , Besides this, the Manual can also be used as a guide for conducting training programs for the personnel from the above agencies.

1.7. Limitations of the Manual

The use of the Manual is limited to the World Bank Assisted Rural Water Supply and Sanitation Project with the project philosophy, design criteria and site-specific conditions of the single and multi-village schemes of four low income states namely, Assam, Bihar, Jharkhand and UP, , and of India. This manual is a step to start the project activities. Learning from the project implementation, the guidelines contained in this manual will be modified as necessary.

Existing Water Supply Status

Chapter-2 Page 2-1

2. EXISTING WATER SUPPLY STATUS

2.1. Assessment of Water Supply Situation

In the project states, many of the habitations are provided with water supply with hand pumps, mini water supply scheme, piped water supply schemes with ground water source and a few piped water supply schemes with surface water source. These schemes have been executed by the State Technical Department and some of these schemes have been handed over to the respective GPs for O&M. Some of the rural water supply systems are not functional or working below their designed capacity due to the following reasons:

Depletion/failure of sources Water quality problems Leakage in pipelines & OHSR Pump set failures and power problems Depletion of ground water tables Poor maintenance by GPs due to funds constraint, lack of technical knowhow and

lack of interest Non Payment of user charges towards the water consumed by the Village

Communities also no independent source of income.

In view of above, there is a need to assess the status of the existing water supply system and to estimate the rehabilitation needs so that the systems will become fully functional. Rehabilitation works have to be identified to facilitate integration of the proposed works with the existing works or system. The strategy shall be to identify the rehabilitation need of schemes into immediate and long term. In the immediate needs, there is no major investment but small additions and proper management may revive the schemes. Some of the works that could be included shall be:

Immediate repairs to pump sets Rectification of leakages in pipelines and valves Effective supervision of water supply works

In the long-term, substantial additional investments are to be made to upgrade the existing system to the desired level. Some of the works that could be included are:

Selection and provision of additional sources in the existing water supply schemes where quality and quantity of water availability is inadequate

Modifications to existing pipelines/pumps or provisions of new pipelines/pumps in case of existing pipelines and pumps are inadequate to cater the designed water demand

Strengthening/restoration of existing storage tanks or provision of new higher capacity tanks/additional tanks to cater for additional storage capacity to meet the designed demand

Additions and extensions of the existing distribution system or provisions of new distribution system where there is no pipeline network or existing pipeline network is inadequate or pipes are rusted/broken


Chapter-2 Page 2-2

Scope and extent of ground water recharging measures required for ensuring the source sustainability

Provision of House Connections with or without meters as the case may be (For large MVS, 24x7 supply domestic meters are essential).

Checklist for Rehabilitation of existing water supply scheme which includes conditions of accessories of OHSR such as pipe connections, valves and valve chambers, water level indicators, manhole covers and staircase etc. is given in following table:

Table 2-1: Checklist for Condition Assessment for Rehabilitation/Revitalization/Augmentation of existing water supply scheme1

S. No Attribute Yes/No (A) Source Improvement

1 Are present condition, adequacy, potability, yield, drawdown etc., known?

2 Are the slot portions of sedimentary bore well flushed using chemicals/ detergents? Or redevelopment of bore well?

3 Is geophysical survey done at the location of bore well for deepening the bore well? (Feasibility be considered)

4 Is detailed geophysical survey conducted for hard rock bore well for hydro fracturing?

5 Is it necessary to provide alternate bore well, if not possible to improve by the above methods?

Recommendation: (B) Replacement of Pump Sets

1 Is it necessary to replace the pump sets for improving the pumping quality?

2 Is it necessary to replace submersible pump sets in lieu of Jet pump sets to meet the demand?

3 Whether higher duty submersible pump set is suitable, if source is sufficient?

4 Whether the safe yield in the bore well was assessed with suitable pump to match the safe yield to avoid throttling of existing pump set?

Recommendation: (C) Pump Room

1 Is it necessary to construct separate pump room for the additional bore wells source drilled?

Recommendation: (D) Pumping Main / Distribution Main

1 Whether the condition of pipes of existing pumping main was checked?

2 Whether scouring was done for each 500 meters reach of entire pipe line, if silt deposited?

3 Whether the bursts and leaks if any were attended in pipe line and valve pits?

4 Whether air and scour valves were introduced? 5 Whether the damaged valves were replaced? Recommendation:

1Source : Based on APRWSSP-Technical Manual


Chapter-2 Page 2-3

S. No Attribute Yes/No (E) Overhead Tank 1 Whether the condition of existing OHSR was studied?

2 Whether rehabilitation of structure is necessary for utilizing the OHSR?

3 Whether additional OHSR is necessary for balance population of un served area?

4 Whether the additional OHSR is necessary for high level zone to affect supply for balance population?

5 Whether it is possible to utilize the existing OHSR even after rejuvenation?

6 Whether the condition of existing pipe connections for OHSR studied?

7 Whether the condition of valves and valve chamber checked? 8 Whether the condition of water level indicator studied? 9 Whether the condition of manhole covers checked? 10 Whether the condition of stairs of existing OHSR checked?

Recommendations (F) Public Stand Post/House Service Connections

1 Is the distribution main served areas inspected along with the GPWSC?

2 Whether the unauthorized house service connections were removed to save the water?

3 Whether the hose pipe connected to the taps by the residents were removed?

4 Whether the pit taps provided by the public were removed and stand post provided near the pit taps?

5 Whether the illegal Public stand post removed?

6 Whether the ferrules were provided for the public taps and house service connections to restrict the drawal of water?

7 Whether the existing public stand posts were repaired? Recommendations

Water Supply Principles

Chapter-3 Page 3-1

3. WATER SUPPLY PRINCIPLES

The chapter contains the basic design criteria of Single Village Water Supply Scheme (SVS) and Multi-Village Water Supply Scheme (MVS) to provide safe and adequate quantity of drinking water at individual household level.

3.1. Design Period

The rural water supply schemes are to be designed for ultimate period of 30 years.

Design period requirement for various project components are given below:

1: Water Source: a. Underground water: 15 years b. Surface Source: 30 Years 2: Intake Works of surface Source: 30 years 3: Raw Water Storage Tanks: 30 years 4: Pump house and civil works: 30 years 5: Pumps and Machinery: 15 years 6: Water Treatment units including 15 years (With space for capacity to meet ground level clear water reservoir: ultimate design period of 30 years) 7: Elevated Clear Water Reservoir: 15 years 8: Transmission Mains: 30 years 9: Distribution system: 30 years 10: Land: 30 years.

3.2. Population Forecast

Census Population of Year 2011 will be considered for forecasting the design population. The Base year shall be reckoned at commissioning of the schemes, prospective year will be 15th Year, and ultimate year will be 30th Year with respect of Base year. Ultimate year population will be used for design of intake, rising main, gravity main and distribution system. Prospective year population will be used for design of Water Treatment Plant (WTP), ground level/elevated clear water reservoir and pumps. In view of decreasing trend of rural population growth as noted in the Census 2011, the states will review this aspect and adopt a realistic district wise decadal growth rate for arriving at design population. References may be made to the various methods adopted in CPHEEO Manual and a sample presented at page 39-41 of 48 of Annexure-3 (Volume-2) of this Manual for projecting the population forecast.

3.3. Per Capita Water Demand and Demand Projection

For the projects, the rate of per capita demand of water shall be taken as 70 lpcd at consumer end. Bulk supplies to Institutions/Commercial/Industrial; if any, shall be considered extra. The water demand projection shall be done by multiplying the population projections with the per capita water demand for the respective year.


Chapter-3 Page 3-2

3.4. Field Survey2

Implementing departments will either themselves take up field survey or enlist the services of agencies for conducting topographical survey with total station to enable the departments to undertake preparation of the Detailed Project/Scheme Reports of Water Supply and SLWM works. Field survey shall be done with Total Station Survey.

The scope of the assignment shall include: Conducting detailed survey by using Total Station and co-relating the same with GPS data for raw water source area, pipe line route along/ across different road network for raw water pumping main, clear water pumping main, distribution network etc. The following details will be collected:

Field Survey Details: Desirable survey details/ features to be provided are as below:

i. Survey in the vicinity of proposed intake point of the river source giving details for accessibility to it, river bank conditions required for planning for type of intake structure etc

ii. Net levels at 3.0 meter grid for sites of Source, WTP location, sites for service reservoirs and pump houses which are to be identified in consultation with the implementing department and GP

iii. Generation of contour overlay at 1 meter interval for the WTP site iv. Longitudinal survey along proposed pipeline routes with spot levels taken at 30 m

intervals and at every changes of road alignment, road junction etc v. Cross sections along the pipeline routes at every 90 meters intervals and to include

road, rail, canal, river crossings and other cross drainage structures vi. Node to node length of the proposed pipe line route vii. RL of the each node (pipe junction; road junction; peak/ valley crest along the pipe

route etc.) above MSL viii. Road width (hard crust / side berm); any culvert / bridge; stream / nullah crossing;

trees/ poles etc. that may obstruct the pipe alignment ix. Prominent structures along the proposed route viz. Educational Institute, Govt. /

Semi Govt. Offices, Hospitals, Religious Institute etc. with their respective GPS data

x. Individual dwelling houses, available water body etc. with their respective GPS data xi. Establishing temporary bench marks (TBM) at different locations of the project area

on permanent structures viz., parapet of culvert / bridge; at plinth of old monument / Govt. offices / structures of existing water supply scheme (if any), with respect to Geodetic Triangulation Station bench mark (GTS BM, including co relating the TBM with GPS data).

3.5. Preparation of Maps and Drawings

Total station survey drawings shall be prepared on AutoCAD and converted to GIS. The data acquisition and processing for GIS base maps includes the following:

i. Collection of all data linked to GPS ground control survey for providing sufficient control points evenly distributed over the area

ii. Post processing of ground control data iii. Digitization for planimetric data captures

2Source: PIP


Chapter-3 Page 3-3

iv. Field verification, digitization and compilation of final maps v. Generation of maps for ground validation surveys. The report / survey drawings

shall have to be prepared in AutoCAD form. The Key map /Index Map for the complete project shall be made to a scale matching to A0 size paper. The detailed drawings shall be in 1:200 scale plotted to A3 size papers

vi. Data entry of the ground validation surveys for updating maps for any correction/mistakes

vii. Updating of the field verified data onto the digital data.

3.5.1. Details to be shown on GP Base Map

Within each GP, the base map shall contain different layers such as roads, water resources and important landmarks and public and private utilities, land use etc. The road maps shall additionally show:(a) existing water Supply schemes: Source bore well/ open well/ river/ canal, details of intake works including pump station (if any), transmission mains, water treatment plant, distribution layout with dia. and length, pipe material, reservoirs – type and capacity and staging, house service connections, public stand posts; (b) road network: Length and width of roads, road carpet details, road levels, culverts details, (c) storm water drains - cross section of all drains type of drains i.e. CC, Brick, etc.

3.6. Preparation of GIS Base Map

The base mapping in water and sanitation sector require the spatial present information which would be collected from different source at different scale for various field e.g. (i) administrative data (ii) project data including water sources using GPS (iii) water distribution network (iv) drainage network data (v) land base features like road network (vi) meteorological data (vii) social data etc. These data if required is correlated through field verification.

The basic task would be to compile-update-organize the data, after relevant quarries and analysis in suitable GIS format, for generation of various thematic maps. The major task would be to integrate the spatial and non-spatial i.e. descriptive information of geographic feature in the data base management system (DBMS). The generated information will be subjected to analysis considering various problems viz. social, economic, ecological, environmental, administrative, weather, agricultural etc. with the help of Spatial Analysis functionality of GIS software.

3.6.1. Usefulness of GIS Maps in Comparison to Conventional Maps

The advantage that GIS gives in comparison with conventional maps is that one can change the appearance of the information to any style as required. In conventional mapping a large amount of time and effort are spent to depict the physical features. The flexibility of GIS adds an extra dimension to this process, one can change the appearance depending on exactly what message is required to convey. Below are few advantage of having GIS maps over previous paper maps:

1) GIS maps are scalable, flexible and multiuser 2) It has advantage of integrating other secondary data 3) It is dynamic and reflects the changes over time and scale without much effort


Chapter-3 Page 3-4

4) It is much easier to update changes in geographical features over the period 5) It can efficiently store the data of any scale. In real sense it can accommodate, stored

and manipulate data. 6) It can provide the result of different analysis, linking with other features 7) GIS maps are cost effective resulting into greater efficiency 8) It provides better decision making by use of spatial analysis, network analysis, least

cost method and analysis of hot spot etc.

The concerned state department shall have to hire an agency carrying out the GIS base map preparation.

Total station survey drawings shall be prepared on AutoCAD and converted to GIS. The Data Acquisition and processing for GIS base maps includes the data as described at para 3.5 of this chapter.

Various GIS software’s like: Map Info, Arc view and Micro station shall be used for preparation of GIS based Map.

3.7. Attributes of Drinking Water

The drinking water shall be:

Free from disease producing organisms Colourless and clear Palatable, i.e. free from odours, Preferably cool Soft (not hard) Not causing scales or corrosion. Free from objectionable substances such as hydrogen sulphide, iron, and Manganese

etc. Unpolluted by substances in quantities that are toxic or have adverse physiological

effects and available in adequate quantities.

3.8. Quality of Water – Physical, Chemical and Biological

The objective of safe drinking water supply is to provide water free from pathogenic organisms, clear, palatable and free from undesirable taste and odour, of reasonable temperature, neither corrosive nor scale forming and free from minerals which could produce undesirable physiological effects.

For indian conditions the physical and chemical quality of drinking water should be in accordance the recommended guidelines presented in Table 3-1.


Chapter-3 Page 3-5

Table 3-13: Recommended Physical and Chemical Quality of Water

S. No.

Characteristics Acceptable Tolerance Limits

Rejection Remarks

1 Turbidity NTU 1 2 – 9 10 Consumer acceptance decreases 2 Colour (Units on

Platinum cobalt scale) 5 6 – 24 25

3 Taste and Odour Unobjectionable

Objectionable

4 pH 7 – 8.5 < 6.5 and >9.2

Water will affect the mucous membrane and water supply system

5 Total Dissolved Solids mg/litre (l)

500 501– 1999 2000 Consumer acceptance decreases. May cause gastro intestinal irritation.

6 Total hardness as CaCO3 in mg/lt

200 201 – 599 600 Encrustation in water supply structure and adverse effects on domestic use/ scale formation.

7 Chlorides (as cl) (mg/l) 200 201 – 999 1000 Taste, palatability and corrosion are affected.

8 Sulphates (as SO4) (mg/l)

200 201 - 399 400 Causes gastro intestinal irritation.

9 Fluorides (as F) (mg/l) 1.0 1.0 – 1.5 1.5 Results in dental / skeletal fluorosis

10 Nitrates (as NO3) (mg/l)

< 45 - > 45 May cause Methaemoglobineamia / Blue baby disease

11 Calcium (as Ca) (mg/l) 75 76 – 199 200 Encrustation in water supply structure and adverse effects on domestic use

12 Magnesium(as Mg) (mg/l)

< 30 31 – 149 150

13 Iron (as Fe) (mg/l) 0.3 0.2 – 0.9 1.0 Taste and appearance are affected and promotes iron bacteria and adverse effects on domestic user and water structure.

14 Manganese (as Mn) (mg/l)

0.05 0.05 – 0.5 0.5

15 Copper (as Cu) (mg/l) 0.05 0.05 – 1.5 1.5 16 Aluminum (as Al)

(mg/l) 0.03 0.04– 0.19 0.2

17 Alkalinity (mg/l) 200 201 - 599 600 Water will affect the mucous membrane and water supply system, taste

3 IS: 10500


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S. No.

Characteristics Acceptable Tolerance Limits

Rejection Remarks

becomes unpleasant. 18 Residual Chlorine

(mg/l) 0.2 0.3 - 1 >1.0

19 Zinc (as Zn) (mg/l) 5.0 6 - 14 15.0 20 Phenolic Compounds

(mg/l) 0.001 0.002

21 Anionic Detergents (mg/l)

0.2 0.3 – 0.99 1.0

22 Mineral Oil (mg/l) 0.001 0.02 0.03 TOXIC MATERIALS 23 Arsenic (mg/l) 0.02 –0.04 0.05 Water becomes toxic 24 Cadmium (mg/l) < 0.01 - > 0.01 25 Chromium (mg/l) < 0.05 - > 0.05 26 Cyanides (as CN)

(mg/l) 0.05 - 0.05

27 Lead (as PB) (mg/l) 0.05 - 0.05 28 Selenium (as Se)

(mg/l) 0.01 0.01

29 Mercury (total as Hg) (mg/l)

0.001 0.001

30 Polinuclear aromatic hydrocarbons (PAH) (µg/l)

0.2 0.02

31 Pesticides (total, mg/l) Absent RADIO ACTIVITY + 32 Gross Alpha activity

(Bq/l) 0.1 0.1

33 Gross Beta activity (Bq/l)

1.0 1.0

The Bacteriological quality of drinking water should be in accordance with the WHO guidelines and are shown below:

Table 3-24: Recommended Bacteriological Quality of Drinking Water

Organisms Guidelines Value All water intended for drinking E-coli or thermo-tolerant coli form bacteria Must not be detectable in any 100 ml sample Treated water entering the distribution system

E-coli or thermo-tolerant coli form bacteria Must not be detectable in any 100 ml sample Total Coli form bacteria Must not be detectable in any 100 ml sample Treated water in the distribution system E-coli or thermo-tolerant coli form bacteria Must not be detectable in any 100 ml sample

4Source: WHO guidelines for Drinking Water Quality Vol.1-1993


Chapter-3 Page 3-7

Organisms Guidelines Value Total Coli form bacteria Must not be detectable in any 100 ml sample. In

case of large supplies, where sufficient samples are examined, must not be present in 95% of samples taken throughout any 12 months period.

3.8.1. Virological Quality

Drinking water must essentially be free of human enteroviruses to ensure negligible risk of transmitting viral infection. Any drinking water supply subject to faecal contamination presents the risk of a viral disease to consumers. The following Table 3-3 shows the guideline criteria based upon likely viral content of source water and the degree of treatment. It is also necessary to disinfect the distribution system to guard against any contamination in distribution system.

Table 3-35: Recommended Virological Quality of Drinking Water

Type of Source Recommended Treatment Ground Water Protected deep wells; essentially free from faecal contamination

Disinfection

Unprotected shallow wells; faecal contamination Filtration and disinfection Surface water Protected, impounded upland water; essentially free from faecal contamination

Disinfection

Unprotected, impounded water or upland river, faecal contamination

Filtration and disinfection

Unprotected lowland rivers; faecal contamination Pre disinfection or storage, filtration, disinfection

Unprotected watershed; heavy faecal contamination Pre disinfection or storage, filtration, additional treatment and disinfection

Unprotected watershed; gross faecal contamination Not recommended for drinking water supply

3.8.2. Water Quality Standards and Significance-Norms for Acceptance

The quality of drinking water affects health of the consumers because certain diseases and toxic chemical compounds may be transmitted by water. Experience has shown that community health and supplied water qualities are directly related to each other and that an improvement of water qualities of drinking water supply is followed by an improvement in the community’s health. Hence, the water supply systems shall provide water that is safe and available in adequate quantity. A water supply engineer is expected to know what diseases are waterborne, what toxic chemicals are and how they get in to water supplies.

5Source: WHO guidelines for Drinking Water Quality Vol.1-1993


Chapter-3 Page 3-8

3.9. Water Quality Reports

The following are the observations to be incorporated in the tabular form while preparing water quality reports:

a) Review of existing water quality status in project villages b) Details of all existing water supply sources with clear markings (painted with blue

colour for potable sources and red colour for non-potable sources) in the villages marked with geographical/global positioning systems

c) Latest water supply analysis (physical, chemical and biological tests)/ water quantity results of all working sources should be incorporated in the report

d) Compare the latest water quality results with old available data (secondary data from Water Supply and Sanitation Department) and find out the difference

Justify the proposed source details from the quality angle. Also mention the distance of this source from the existing potable / non -potable sources.

3.9.1. Water Sample Quality Testing and Sample Collection Proforma6

1. Name and address of person requesting the examination 2. Name with designation of the personnel responsible for collection of samples 3. Date and time of collection and dispatch 4. Purpose of examination 5. Source of water and its location (well, tube well, stream, river, etc.) 6. Exact place and depth below surface, from which sample was taken 7. Weather at the time of collection and particulars of recent rainfall, if any 8. Does the water become affected in taste or odour after rainfall or under any particular

circumstances? 9. Are there any complaints from the consumers? If so, the nature of the complaint 10. Character of surroundings and proximity to drains, cess pools, cattle sheds, manure

heaps, grave yard, bathing ghats and other sources of pollution 11. Methods of purification and disinfection if any, details, dose of chemicals and points

of application 12. If from a dug well or a bore well:

Whether an old source or newly constructed Whether open or covered nature and material of cover Nature of staining or casing and depth to which constructed and whether it is in

good condition. Height and condition of parapet and apron Method of pumping or other means of raising water. Depth of well and of water surface from ground level. Whether the water is clear if flows out of tube well and remains clear if exposed

to air (4-6 hours) or becomes discoloured and turbid.

13. If from a river or stream or canal

Nature of flow and whether floods are common or rare

6Source: Based on APRWSSP-Technical Manual


Chapter-3 Page 3-9

Whether level of water is above or below normal of the flow level at the period of sampling during the year

Is there any bathing ghat, boat jetty, burial ground and sewer outfall? If upstream, give distance from sampling point.

14. If from lakes, impounded reservoirs and tanks.

How supplied (channel, stream, rain) Nature of catchment, whether conserved or not Nature and extent of weed growth Size and number of service reservoirs Whether open or covered How often cleaned and method of cleaning Date of last cleaning

15. Number of hydrants and sewers on the distribution system 16. Hours of pumping and supply 17. Population served 18. Any other particulars 19. Station

For water testing the samples should be collected in following manner:

i) Properly labelled ultimate requirement of sampling bottles to avoid any error ii) No significant change in samples between time of collection and conducting water

analysis and samples should be dispatched to lab under iced conditions as soon as practicable

iii) Samples should be examined within 24 hours after collection iv) De-Chlorination of sample is a prerequisite for bacteriological examination v) No contamination should take place while collecting the sample prior to examination

especially for bacteriological tests. For taking sample of water from a tap on distribution system, allow the water to run for 4 to 5 minutes thereby cleaning of service pipe

vi) The water sample shall be collected and its data sheet should be filled up along with sample for onward submission to water quality testing lab.

Quantity of Sample

i) For physical and chemical examination – Two samples of two litters in colourless or pale green bottles

ii) For bacteriological examination- 250ml sterilized glass bottles provided with ground glass stopper.

3.9.2. Water Quality Surveillance

Laboratories with adequate facilities and manned by qualified personnel are essential for inspection and evaluation of the suitability of water supplies for public use as well as for controlling the water treatment process. The ultimate aim of laboratory examination of water is to ensure that potable water conforming to the drinking water standards is supplied to the consumers.


Chapter-3 Page 3-10

a) Objective

i) To ascertain the quality of water in various rural water supply schemes (tube wells or surface source based) as well as in the distribution network.

ii) To examine physical, chemical and bacteriological quality to establish whether the drinking water is fit for human consumption and meets the standards as laid down in IS:10500 [List of all concerned IS codes of water supply & sanitation with latest amendments have been annexed at Annexure-13 (Volume-2)].

b) Location for sampling

Selection of location for sampling should indicate true representative samples

Selected consumer location at random In addition to above, raw water source and treated water should also be

analyzed in case of surface source based water supply schemes.

c) Type of sampling

Generally, for drinking water quality monitoring, grab samples should be preferred.

d) Frequency of sampling

Mainly depends on population served, size, source and type of the scheme is as shown in Table 3-4.

Table 3-4: Frequency of Sampling7

Source Minimum Frequency of Sampling & Analysis Remarks

Bacteriological Physical/Chemical Tube Well

Once initially, thereafter as

situation demands

Once initially, then 2 times yearly

Situation requiring testing: change in environmental conditions,

outbreak of water borne diseases or increase in incidence of waterborne

diseases Surface Source (Canal Source)

Once monthly Once initially, then 2 times yearly -

Residual Chlorine daily

Increase frequency of bacteriological test if situation

demands

Precautions shall be taken during collection, preservation and storage of samples.

3.9.3. Review of Source Water Quality

After the water quality report is received the parameters may be compared with the standards and if the water satisfies the standards up to the tolerance limit the same source can be accepted. If water parameters does not satisfy the prescribed standard, suitable

7APRWSSP-Technical Manual


Chapter-3 Page 3-11

treatment shall be recommended. If fluorides/ Arsenic / Iron and any other Heavy Metals are present in excess of permissible limits then other source should be explored. For further details on water quality CPHEEO Manual may be visited.

Adequately equipped analytical laboratory with competent analysts is an important and an integral part of any water quality monitoring and surveillance programme. The analytical determinations of different physical, chemical and bacteriological parameters must be carried out most efficiently and accurately. However, the laboratory infrastructure need shall necessarily depend upon the level of analysis desired, location and other support facilities available.

Realizing the need to institutionalize water quality monitoring and surveillance system, Government of India in Rajiv Gandhi National Drinking Water Mission has formulated an implementation plan based on three-tier structure or catchment area approach where existing resources available with grass root level education and technical institutions would be utilized. In case of need , these institutions should further be strengthened by providing additional resources.

a) Village Level

Water Quality Surveillance (WQS) must exist at the village level. Water quality monitoring is a felt need of the people, as in rural areas they perceive water which is clean, palatable and free from odour as safe quality water, though it may contains chemicals up to rejection limits. To make the WQS programme more effective, field kits for both chemical and bacteriological analysis are to be provided to all 10+2 schools having science stream or in the primary rural Health Centres. These field kits would mainly indicate the presence of turbidity, pH, hardness, chloride, fluoride, iron, residual chlorine and bacteriological quality. The field kit will be basically meant for qualitative assessment of water and would help to identify unsafe drinking water supply system immediately. In case, water is unfit for drinking, samples would be sent for detailed investigations to the district labs.

b) District Level

One Lab at each District which can provide actual values of various water quality parameters is required,

c) State Level

One State Level water quality testing laboratory is required which has to be considered as apex institute to decide actual values of the quality parameters in case of discrepancies between values intimated by more than one laboratory.

Further, for facilitating effective water surveillance programme, a mobile water testing laboratory should also be proposed under the control of RWS&S as this would help in identification of source of contamination as well as for identifying new potential water sources, besides it would also impart training to village and district level laboratory staff. The mobile laboratory would be fully equipped to carry out on the spot analysis of water and would be equipped with small fridge, hot air oven,


Chapter-3 Page 3-12

water bath and incubator. This will also help in assessing water quality during fares and at the time of epidemics in the area.

To summarize, Water testing laboratory should be stationed at Divisional Level/District Level; However Water testing Kits should be available at Gram Panchayat Level.

3.10. Types of Sources for Water Supply

After estimating the required quantity of raw water for the proposed water supply scheme it is necessary to identify a nearby water source / sources, which may be able to supply the required quantity and quality of water. If the available sources don’t supply required quality and quantity of water, then it is necessary to choose another water source at some other distant location. Another important consideration should be the long term sustainability of the source.

Nature provides water through various sources which can be grouped into:

a) Surface sources such as Ponds, Lakes, Rivers, Streams, Canals, Storage reservoir and Oceans

b) Sub Surface Sources such as Bore wells, Open wells, Springs, Infiltration wells and Infiltration galleries.

3.10.1. Surface Waters

Schemes based on surface water sources shall be designed only where:

Ground water is insufficient or having quality problem such as fluorides and / arsenic contamination (Higher than the permissible limit). When ground water source is not sustainable based on quantity adequacy to meet the design period demand or on the likelihood of gradual water quality deterioration as per available data of the area

Since the cluster of villages requiring surface water has to be large to make the scheme viable, some en-route villages (Which do not have quality problem) can also be clubbed with the surface scheme. However, with increasing number of villages, communication problems may affect operation and maintenance.

3.10.2. Artificial Impounding Reservoirs (Storage and Sedimentation Tanks)

In case of rivers, canals, dams and lakes necessary permission to withdraw required quantity of water must be obtained from the respective authority. Water if drawn from canals which need annual closure on account of maintenance or otherwise construction of impounding reservoir to meet the requirement of water for that period will have to be provided. Impounding reservoir will also be needed, in case of non-perennial rivers and or where river discharge reduces considerably during dry weather to meet the full requirement of the water supply scheme.

For more details, Chapter-6 (Volume-1) on “Technical Guidelines-Water Supply Components” may be referred.


Chapter-3 Page 3-13

3.11. Types of Water Supply Schemes

As per the Project proposals all water supply schemes are classified into following four categories:

Single Habitation Schemes (SHS) Single GP Scheme (SGS)-these would have more than one habitations but all within

the same GP Small MVS-covering a few GPs (typically 2-4) Large MVS- covering many GPS (typically 5 or more).

3.11.1. Single Habitation/GP Water Supply Schemes (SHS/SGS)

The piped water schemes (PWS) will be provided with local ground water source such as deep bore wells. The schemes will involve pumping from the bore well, construction of service reservoirs and piped distribution networks for providing house connections to all households. The small schemes will adopt disinfection with addition of bleaching powder solution. For all SHS/SGS, house connection cost will be included in project with saddle, ferrule and 10 m long MDPE pipe; however GI pipe will be used only in rocky strata. Surface source from the nearby canal / river if available can also be used with provision for treatment arrangement as prescribed by CPHEEO manual in case where ground water is not there of desired quality and quantity. Solar power will be provided wherever power is not available or is unreliable.

3.11.2. Small and Large Multi Village Water Supply Schemes (MVS)

Where the locally available ground water has quality and quantity problems, multi village water supply schemes with surface water as sources like river, ponds, lake etc. will be proposed where the water will be conveyed from long distances. These schemes may cover more than one GP and will involve construction of water treatment plant, service reservoirs for each GP/Habitation and piped distribution networks to provide house connections to all households. All MVS schemes will use disinfection mechanism based on chlorination systems. Bulk flow meters (For details refer Chapter-10 (Volume-1) on “Distribution System”) will be provided at the inlets of each village/GP’s OHTs. For all MVS also, house connection cost will be included in project with saddle, ferrule and 10 m long MDPE pipe; however GI pipe may be used only in rocky strata with appropriate size of pipe (15 mm) and ferrule.

Wherever high cost large MVS is proposed to serve peri-urban, large villages and large number of GPs, all households will be provided with metered connections and cost included in the project which will ultimately lead to 24x7 water services. Wherever consumer meters are provided these will conform to latest IS standards and will be provided with 5 years guarantee. Gaseous chlorinating plant can be considered for Large MVS ensuring the gaseous chlorine cylinders chain for smooth and adequate supply.

There would be stand-by arrangements of pumps as per the Guidelines of CPHEEO Manual on Water Supply & Treatment. Dedicated power supply will be provided for all the large MVS. Provision of diesel generating sets will be considered carefully in view of the high cost of diesel.


Chapter-3 Page 3-14

3.11.3. Pumping Hours

Ground Water: 8-16 Hours of pumping shall be proposed and Surface Source Based Schemes: 16-22 Hours of pumping shall be proposed.

3.12. Source Selection

3.12.1. Ground Water

Scientific selection of water sources is more important for the project area since the ground water table has been depleting very fast. Hence, the locations selected for water sources shall be amenable for recharging ground water into the aquifers. The presence of underground fractures in the geological formations will encourage seepage of water into the aquifers. The deeper the fractures better will be the yield. Hence, while doing the geophysical survey for selection of location of source (Bore well), particular attention is required to this aspect. The technology has progressed and now there are more reliable methods for conducting geological and geophysical investigations with instruments working on Very Low Frequency (VLF).

The exploration methods that can be adopted to locate the ground water are:

Geological Methods: Demarcating the boundary between lithological units, faults, fractures, fissures, formation characteristics, lineaments & dykes, intrusive and shear zones

Remote Sensing Techniques: interpretation of satellite images to locate lineaments and other structural discontinuities, mapping of various hydromorphic unit, vegetation, soil and land use and land cover categories

Geophysical Methods: Surface geophysical surveys using electrical resistivity, electromagnetic, seismic and magnetic methods to delineate the weak and water-saturated zone. These methods include Geo-physical exploration and geomagnetic method.

For more details, Para 5.2.4.3/Page 57 to 61 CPHEEO Manual on Water Supply & Treatment may be referred.

3.12.2. Surface Source

For detailed information on source selections, Para 5.2.7 Pages 96 -98 of CPHEEO Manual on Water Supply & Treatment may be referred:

The selection of Water sources shall depend upon the quality and sustainability of water on long term basis.

3.13. Assessment of Yield

Ground Water/Sub-surface Source: An accurate assessment of the yield of the source is essential to decide which source can be dependable. The yield of bore wells is to be assessed preferably in the lowest seasonal water level conditions. Care should be taken that the water pumped out is led away from the source and does not re-enter the source. The drawdown and discharge are measured and the results tabulated from which the yield


Chapter-3 Page 3-15

is assessed. Bore well yield is assessed on the basis of sand free discharge obtained at around 4.5m drawdown (Refer IS: 2800). The safe yield for pumping plant design is taken as 60% of assessed yield. For detailed procedure of assessment of yield, Chapter-6 (Volume-1) on “Technical Guidelines-Water Supply Components” and IS: 2800 Part-2 may be referred.

Surface Source

In the case of canals, the levels at which water can be made available and the quantum of water and the period for which the canal is flowing are used to assess the sizes of various components of the water supply scheme. Adequate storage of raw water for the period of canal closure is provided.

In case of other surface sources namely springs/small streams (Gadhera) shall normally be measured for three consecutive years of the driest season and lowest discharge shall be adopted. If summer discharge (April to May) for a particular scheme is available for one year only, but it has to be prepared because of urgency, then only 50% of driest discharge should be taken for utilisation. If the data is available for two years then 75% of minimum discharge may be taken. (Source: As per prevalent practice in Uttarakhand).

3.14. Treatment

Ground Water

Water source with presence of Fluoride and Arsenic shall be rejected and safe water source meeting quality and quantity requirement shall be selected. Treatment for disinfection is provided.

Surface Water

It may require conventional treatment consisting of sedimentation, filtration and disinfection. The treatment proposed for water shall be such that it is easy to manage the O&M by the village community. The following need to be considered wherever WTP is required:

Slow Sand Filters (For details, refer Chapter-8 (Volume-I) Rapid Sand Filters and dual media: declining rate will be provided for MVS Use of Tube Settlers instead of clari-floculators for capacity up to 30 MLD for

MVS8 Roof over filter beds will not be provided to all filters Chemical dosing: dosing pumps will be provided in WTP Preferred instrumentation in WTP: Alternative flow, measurement with calibrated

weirs Manometers for loss of head Operation of valves - manual, pneumatic and electrical – however manual operation

is preferred up to 30 MLD Recycle of back wash water shall be provided.

8Source: PIP


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a) Specific Treatment Plants

Suitable Eco-friendly RO plants for treatment of water with iron contamination problems can be provided wherever required. However to ensure sustainability, the maintenance contracts for these plants will include supply, installation and repairs or replacement for the guarantee period of five years.

Disinfection of drinking water: It shall be carried out by Gaseous chlorinators for large MVS (Surface source based). Bleaching Powder dozers will be used for SHS/SGS and or on-site generation of Hypo solution with electronic dosing pumps as described under Chapter-8 (Volume-1) on “Water Treatment”. Since the chlorinators, electro chlorinators and other such disinfection equipment are quite often found out of order even in urban areas, all equipment like, bleaching powder dozers, electro-chlorinators and gaseous chlorinators shall be procured as per design provided in DPR. Contract shall include operation and maintenance by the contractor for at least 05 years.

b) Alternatively

Promotion of Non-Conventional Water treatment technologies: (Cascade Aeration + Baffle/Pipe Mixing +Gravel Bed Flocculation + Tube settler +Filtration); The Baffle Mixing and Gravel Bed Flocculation have been the alternatives of Flash Mixing and Flocculation. There is no electro/mechanical components involved in Baffle mixing and Gravel bed flocculation, hence leads to energy saving as compared to Flash Mixing & Flocculation.

3.15. Transmission Lines and Rising Mains

Conveyance of water may be by gravity flow and/or pressure. Pipelines used for transmission of water, normally follow the profile of the ground surface closely.

Gravity pipelines have to be laid below the hydraulic gradient. All pumping mains will be designed using the concept of economical size and class of pipe checked for surge pressures as provided in the CPHEEO manual.

Common terms of pressure

Working Pressure: Working pressure may be defined as the actual pressure (including abnormal pressure such as water hammer) to which the pipe will be subjected during its operation

Test Pressure: Test Pressure may be defined as the maximum pressure, which the pipe can withstand without any leakage when tested for hydrostatic pressure in accordance with the standard methods of testing

Interrelation ship between the above mentioned 02 Pressures varies with the material of pipe which can be referred in the respective IS Code.

3.15.1. Pumps

Pumps shall be provided for all ground water based schemes/surface water based schemes. While calculating the capacity of pump, resulting suction head, delivery head


Chapter-3 Page 3-17

and frictional losses shall be worked out as per hydraulics which should be reworked out based on the capacity of selected pump available in market

Stand by pumps are provided for all schemes Dedicated power supply will be provided for MVS Pumping hours for SHS/SGS will be 8-16 hours (As per PIP Document) which will

be controlled with the help of dedicated programmable controller i.e. RTU Pumping hours for MVS and WTP will be 16-20 hours. (As per PIP Document);If

electric power is available for 24 Hours then pumping hours for Large MVS (Surface source) may be adopted to 22 Hours

Solar power will be provided wherever power is not available or is unreliable Provision of diesel generating sets in MVS, will be considered carefully in view of

the high cost of diesel SCADA will be provided in all large MVS to ensure equitable distribution of water,

control and measurement of flow at ESRs of habitations and communication of data to the control centre through RTU.

Pump Room

Pump Room is provided to accommodate the pump sets, accessories of pump sets, electrical meters, pressure gauges, chlorination plants and any other materials. The Pump Room should be planned considering space allocation, convenient placement and other requirement for the above. For more details, Chapter-7 (Volume-1) on “Pumping Station-Electro-Mechanical Appliances/Equipment” may be referred.

3.15.2. Pipe Appurtenances

In order to isolate the pipeline sections for tests, inspections, cleaning, repairs and efficient functioning of the distribution network system, a number of appurtenances such as sluice valves, scour valves, air valves, reflux valves, expansion joints, anchorages etc. are provided at suitable places in the pipe network.

Type of valves: (a) Gate valves will be used for online. (b) BF Valves for control of inlet to service reservoirs and control on branches of MVS; (c) Air Valves: IS: 14845; and (d) Dynamic valves wherever required. Dismantling joints will be provided for all Gate valves and BF valves.

3.15.3. Service Reservoirs

Capacity of Service Reservoir shall be calculated keeping in view the pumping hours and hence the realistic availability of electricity and water supply hours. Normally in rural areas electricity is available in shifts on rotation basis. Pumping hours will vary as per availability of electricity. However rate of pumping shall never exceed the safe yield (60% of Tested Yield) in case of ground water sources. Hence, before fixing the capacity of Service Reservoir, the required capacity should be worked out to balance the pumping rate and supply rate for worst-case scenario on the basis of mass curve subject to minimum of 8 hours of average daily demand. The staging of tank shall be kept such that the minimum residual pressure at the farthest point in the village is at least 7m. If elevated lands are available at a reasonable distance, ground level reservoirs can also be proposed for storage of water.


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Water Level Indicator in Service Reservoirs: Float type water level indicator will be used for SHS/SGS and Float type /ultrasonic water level indicator will be provided for MVS.

Stairs: Stairs to go up will be in RCC dog legged/spiral and stairs to enter OHSR will be in SS/RCC/Aluminium. All hand rails will be in RCC.

3.15.4. Distribution System

As 100% individual house connections are proposed then pipe network in the form of loop system be preferred as far as possible.

System design shall ensure that water is supplied to all households simultaneously without the need for operation of sluice valves. Depending on topography of the village the distribution system is divided into high level or low level zones or separate feeders from service reservoir are laid for high level and low level areas. Wherever difference between residual heads at households located high level and low level areas is more than 5 meters separate feeders shall be provided directly from the service reservoir to the high level and low level areas. Orifice plate may be provided to reduce excessive residual heads for supply to low lying areas where separate feeders cannot be provided.

For SHS/SGS, the distribution system may be designed for supply of 6 hours/day with peak factor of 4 or for supply of 8hrs/ day with peak factor of three. In MVS the supply will be for ≥ 8 Hours/day taking peak factor of 3 and with terminal pressure of 7 meters at household. The distribution system is designed using Loop network and whatever commercially manufactured sizes are arrived for the required flows and residual heads the same pipes are used. Minimum size of distribution system should be of 63 mm (OD) which may be cross checked so as to ensure minimum velocity of 0.6 m/s to prevent silting in distribution system. This criteria of minimum velocity as 0.6 m/s be cross checked for all other pipe sizes also.

Depth and Width of Trench required for laying the pipe

The pipes shall be laid with a minimum cover of 1.0 m. However, in narrow streets where deeper excavation may cause danger to the stability of foundations of adjoining structures, depth may be reduced to 60 cm with protective measure to safeguard pipe line. The width of trench required to lay pipes shall be outer diameter+30 cm and wider trench shall only be excavated near the coupler joint. Practice of measuring the uniform width of trench based on wider trench width at points of collar joints shall be discouraged. So that cost of the excavation could be reduced.

3.15.5. House Connections

All house connections must be provided only on the distribution system pipes and no connections will be given from the rising mains or bulk conveyance/feeder mains. There will be no public taps since all households are to be provided with house connections and their cost, with saddle, ferrule and 10 m long MDPE pipe will be included in project. In case of reorganization, rehabilitation, revitalization schemes, existing connections will be replaced with new house connections. This is to prevent illegal connections and loss of water.


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3.15.6. Pipe Material

Pipe represents a large proportion of the capital investment in a water supply scheme. The pipe material to be used in rising, transmission and distribution network shall be selected not only from the point of view of durability but also on life and overall cost which includes beside the pipe cost the installation and maintenance cost necessary to ensure the required function and performance of the pipe line throughout its design life time. Also selection of material and class of pipe should be based on specific design requirements including the local condition and its use. However, it will be governed by State Pipe Policy9.For further detailed analysis for selection of pipe material (refer to CPHEEO Manual on Water Supply & Treatment Clause 6.3.1 & Table 6.7).

In case of Ductile Iron pipe, appropriate pressure class of pipe will be chosen depending on the total head including static head (pressure) and likely water hammer head as per design. Normally DI pipe is used in rising (pumping) mains.

In case of DI Pipe with welded flange K-9 pipe shall be used. K-7 or K-9 pipes may be used depending on total head including water hammer, size of pipe and service conditions (Refer IS: 8329). For gravity/feeder mains, HDPE Pipe (PE 100) Class 6 Kg/cm2 and for distribution network PVC Class (6 Kg/cm2)/HDPE pipe (6 Kg/cm2) are preferred. GI pipes can be used in rocky strata only but it is vulnerable to corrosion and encrustation.

Preferred pipe material for pipe connections in Service Reservoir: DI – K 7 is preferred for all pipe connections. However State Pipe Policy shall prevail.

3.15.7. Flow Meters

Consumer Water Meters and Bulk flow Meters: In most of the water supply schemes in India complaints regarding excess readings as well as none functioning of meters are reported. Details regarding quality of meter as well as on installation of meter have been given at Chapter-10 (Volume-1) on “Distribution System”. Problems associated with metering arise particularly in the case of intermittent supply which is common in India. Many types of meters register air flows, which can lead to over-registration of consumption, especially in systems with intermittent supply, when water supply is re-established and the incoming water pushes air through the meters. Some types of meters become less accurate as they age and under-register consumption thus leading to lower revenues, unless they are being replaced regularly. Deliberate or incidental occurrence of human errors is also quite common in meter reading and billing. In several schemes consumer bills are based on monthly flat fees. Rational basis will be to issue bills based on actual consumption. Due to non-functional meters, billing is not based on real-time consumption but based on estimates of past or predicted consumption which results in lack of control over the water consumption. The new water meters for the project will have confirmed to IS: 779 to be tested through a third party and the supplier has to give a guarantee of five years and maintain the water meters during the guarantee period. Since most of the GPs have no meter readers on their rolls, the task of meter reading and billing can be included in the contract for supply, installation and maintenance of meters for 5 years.

9Refer Clause 9.11 Manual for preparation of DPR by MODWS for Rural Pipe Water Supply Scheme Dated 22nd February-2013


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The Bulk flow meters will conform to IS: 2373, with 5 years guarantee. The scope of work for Supplier will be supply and installation including repairs or replacement up to the guarantee period of five years. Since most of the GPs have no meter reader on their rolls, the task of meter reading and billing can be included in the contract for supply, installation and maintenance of meters for 05 years.

3.16. Provision of SCADA

Supervisory Control and Data Acquisition (SCADA) is a computer aided system which collects, stores and analyses the data on all aspects of O&M. SCADA will be provided in all large MVS, while for small MVS simple automation shall be provided. The details are provided at Chapter -11(Volume-1) on “SCADA and Automation”.

3.17. Provision of Solar System

Alternative power supply for meeting the requirement during power failure has been suggested in the PIP. It may not be possible to provide total energy demand for MVS through solar system. In case of SHS/SGS where the power requirement is small alternative energy source could be a solar power system. The details of the solar system for small installation have been furnished in Annexure-09 (Volume-2). The solar system shall provided based on the technical guidelines of Ministry of New and Renewal Energy under Rajiv Gandhi Solar Mission.

3.18. Land Requirement for Water supply Components

S. No. Description Land Requirement (Tentative)

1. Bore well with Reservoir (Ground water schemes)

50 mx50 m

2. Intake works (Surface Source) 30 mx30 m 3. Water Treatment Plant Per mld with

rapid gravity filters 0.15 Ha

4. Service Reservoirs 20 mx20 m

Preliminary Project Report

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4. PRELIMINARY PROJECT REPORT

This chapter describes the preparation of Preliminary Project Report (PPR) for a rural water supply scheme, which is essential to arrive at a techno-economical option in consultation with the rural community.

Before preparation of PPR, Water Safety and Security Plans are also to be prepared.

4.1. Water Security Plan

4.1.1. Objective

The objective to prepare and implement of water security plan is to ensure drinking water security through measures of improving/augmenting the existing water sources and conjunctive use of ground water, surface water and rain water harvesting based on village water budgeting. The plan must be prepared in accordance with NRDWP guidelines.

4.1.2. Integrated Approach

1. In order to achieve water security integrated approach shall be adopted by revival of traditional systems (Existing dug well if any, hand pump, tanks, ponds etc.), conjunctive use of surface and ground water. Rain water harvesting both at the community level and at the household level will ensure in reduction of risk and vulnerability. Conjunctive use means the use of existing sources for other than drinking, cooking requirements

2. For all ground water based water supply schemes (existing/new), ground water recharging mechanism should constitute an integral part of the system design (as suggested in NRDWP Guidelines-2013, Para 5)

3. Excess rain water at the household and community level should be recharged into the aquifer wherever feasible as per Chapter-12 (Volume-1) on “Ground water recharge”, which will not only improve ground water quality but will also ensure its adequacy

4. Factors which have contributed to the rapid deterioration of the water supply facilities resulting in non-availability of the designed service are: (i) over dependence on ground water causing depletion of ground water levels which also increases the incidence of quality problems (ii) sources going dry leading to systems become defunct due to competing demands of ground water from other sectors (iii) poor recharge (iv) large scale deforestation (iv) lack of protection of catchment areas (v) heavy emphasis on creation of new infrastructure instead of adequate attention to the maintenance of existing systems (vi) lack of ownership of water supply systems and sources by the rural community and poor operation and maintenance (viii) neglect of traditional water sources, systems and management practices

5. Various studies indicate that current farming practices waste at least 60 % of the water. Thus, there is enormous scope for water budgeting and social regulation of water uses for ensuring fresh water availability for drinking on a sustainable basis.


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4.1.3. Community Participation

It is necessary that the water security plan be prepared with the full participation of the community. The demographic and physical features of the village shall be captured during the preparation of the preliminary project report. Other information such as: (i) ownership of traditional water sources (ii) information regarding existing condition including need for additional works, shall be gathered during the visit to the village and consultation with the community. The community capability shall be assessed along with their desire/need about the project.

4.1.4. Preparation of Water Sources Inventory

(i) Hand Pumps

This will include details of hand pumps [India Mark-II& III, shallow hand pumps] their location, the water quality based on test results, usages of water drawn from them, and their present condition. Depending upon the water quality as per available test results, the identification of the hand pumps shall be done, which can be used as an alternative source of water supply during temporary failures of the proposed piped water supply system. Such failures do occur on account of disruption of electricity; when for a few days the community can draw water from these sources. It is, therefore, necessary to identify such hand pumps and the works required to make them useful for acting as alternative sources of water supply during such disruptions.

(ii) Dug Wells/Sanitary Wells

All dug wells (Pucca and Kuccha) should be inspected, especially those which do not go dry during summers and their location, depth of water in the well, condition of well structure, present usage of water drawn from them and any appurtenance provided for facilitating the drawal of water etc. be noted and water quality be got tested of such wells. Any well which could be categorized as sanitary well and whose water is used for drinking also need additional attention for deciding repair and modification to make them alternative source of water supply at the time of temporary failures for ensuring village water security. The sanitary well should have followings:

1. Proper masonry lining although the depth of well 2. Well should have raised platform for drawing water and bathing on that

platform should not be allowed 3. There should be proper drainage all around the well and waste water should

not be allowed to stagnate near the well 4. Wall should have proper covering so that dust and leave etc. do not enter into

well 5. There should be arrangement for drawing of water with wheel pulley 6. The well water is disinfected with pot chlorinator 7. Some villages may have step wells, baories and other traditional water

structures which according to the community information might have helped in providing water during severe droughts. Works necessary to protect these be identified and provided for in the water security plan.


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(iii) Village Ponds and Tanks

Details of all such ponds and tanks [Ponds with pucca structures] to be gathered showing their locations, their usages for bathing and washings, sources for drinking and bathing of animals be recorded as in most of the villages these meets domestic water demand other than that for drinking .The need for their repairs specially of those which do not go dry during summers and are owned by the community be identified. Some of these may need de-silting, repairs and interception of village waste water to avoid their pollution.

(iv) Springs

Some villages may have springs also which provide drinking water for a large part of the year. The quality of water be got checked and in case it is free from any harmful constituents; these need to be protected and their water should be disinfected for any bacterial pollution. Their summer discharge is measured.

(v) Rivers and Streams

Some of these may be perennial and some seasonal, their location distance from the village habitation, discharge during summers and the water quality be recorded. In some systems these may the sources for raw water supply on account of which necessary intake works will be constructed. The community may be using these for various purposes specially if for irrigation, there should be an understanding with the concerned authority about the minimum flow which will be kept at the intake point all the year round and the understanding with the concerned authorities such as owner and State Pollution Board so that no upstream pollution will be caused.

(vi) Dams and Reservoirs

At times some of the proposed water supply works may draw their raw water requirement from such sources. It is necessary that there should be an agreement in between the concerned authority to ensure required quantity of water supply even during the driest period; since these works also supplies water for irrigation and there is conflict regarding meeting water demand of various sectors especially during the drought period. The minimum water demand for the project area to be met for present demand and future water demand as well.

4.1.5 Monitoring

The detailed inventory of various existing water structure will make it possible to work out plans so as to rehabilitate them to ensure water security in case of any break down in the system. As such it is necessary to monitor the status of various water structures. Observations pertaining to discharge, quality, depth of water table etc. should be taken once in a year at a fixed period so that the results could be compared and any deterioration in the utility could be timely detected for remedial measures.

Ground water used for freshwater drinking supplies can be easily overexploited by other competing users like irrigation, industry, etc. When this happens it can become contaminated with salt water, fluoride or other gynogenic contaminants which make it


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unsuitable for use. Water available in rivers and lakes is sometimes polluted, making it harmful to plants, animals and people. Sustainability and safe sanitation practices are the forerunner for safe drinking water supply. Thus for any comprehensive water security plans, the preparation and implementation of the sustainability of source is very much required.

4.1.6 Sustainability Measures

Introduction

Water sustainability mean is the water availability to meet both current and future requirement. Sustainability measures include the following two main factors:

a. Withdrawals of large amounts of ground water that overstress the aquifers be prohibited

b. Fixed pumping schedule that minimizes negative impacts of over pumping of aquifers should be clearly adhered to.

Along with the above measure there is need for increasing the recharge to ground water system with the following: (For more details, refer Chapter-12 (Volume-1) on “Ground Water Recharge”)

1. Through injection well 2. Recharge shafts/wells by tapping storm water. 3. Rapid infiltration ponds

Water sustainability planning Tools

Sustainability planning tools Item Components-Ground Water Basis Watershed Assessment

Geomorphological features of watershed Watershed-wise

Remote sensing and GIS for land use and land cover analysis

Geological and Geophysical data analysis Hydrogeology of aquifers Water quality

Integration of thematic layers in GIS framework

Water Sustainability Water balance Village-wise Recharge activities Water Use Comparing supply and demand at

village/Panchayat level/Block level Village/Panchayat/ Block-wise

Recharge and Discharge data and Demand projection


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4.1.7 Criteria for Examining Locations of Groundwater Recharging Sites

Land facets

• Analysis of weathered zones • Delineation of pediment slopes and buried pediment areas.

Drainage Network

• Micro-watershed and drainage divide/ narrow valleys • Demarcation of change in course of drainage patterns • Perennial and seasonal streams • Study of surface water bodies • Study of changes in water spread areas of water bodies.

Fractures and Lineaments

• Identification of linear features, fractures and lineaments • Digital enhancement of fracture system for better location and interpretability • Location of fracture controlled stream segment positions • Demarcation of dykes as barriers to surface water outflows.

GIS Overlays

• Draping of different geomorphological layers • Superimposition of ground water level contour maps • Superimposition of ground water flow lines • Identification of recharge zones/ percolation areas • Demarcation of sites for percolation tanks and check dams for recharge of ground

water.

Strategy for ground water recharging for developing sustainable drinking water supply techniques are outlined below:

Artificial recharge techniques: The techniques group themselves into surface spreading, sub-surface, induced recharge techniques, aquifer modification and ground water conservation structures. The details are listed below in tabular form:

Table 4-1: Ground Water Recharging Techniques

Surface Spreading Method

Sub-surface techniques

Induced Recharge

Aquifer Modification

Ground Water Conservation Structures

Percolation ponds Injection shafts Infiltration galleries

Borehole Blasting Check dams

Recharge wells Collector wells

Hydro fracturing Sub-surface dykes

For further details and suitability of techniques refer Chapter-12 (Volume-1) “On Ground Water Recharge”.


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Various O&M and related procedures involved in building sustainability structures with resistance of communities are given below in table:

Table 4-2: O&M aspects of Recharge techniques

Sl. No. Item O&M Remarks 1 Percolation Ponds/Check

dams Community based with training

Zone of influence (ZOI) 1km downstream of dam and about 50-60m in transverse direction from Dam

2 Recharge Shaft driven with perforated borehole

Community based -

(i) Dia 2-3m Community based Desilting needed annually: no desilting if modular rain tank technique is used

(ii) Depth 10-35m depending upon position of Depth to water table

Community based -

3 Recharge Pit with borehole shaft (2x2x3m)

Community based Desilting needed

4 Recharge Trench driven with borehole

Community based Desilting needed

5 Recharging through hand pump

Community based -

6 Sub-surface Dykes or Dam Community based with training

ZOI about 100-500m upstream of Dyke

7 Recharge through dug wells Community based Desilting chamber required

4.1.8 Checklist/ Guidelines on Sustainability of Village Drinking Water Supply Schemes

The climate, topography, geology, hydrology, hydrogeology, geomorphology, source water availability including its quality as well as legal control and social and economic factors govern the efficiency of various types of ground water recharging interventions that provide strength and sustainability to rural drinking water supply schemes.

Various factors that influence Managed Aquifer Recharge (MAR) are listed below:

1. Influence of climatic Hydrology &Geo-morphology 2. Understanding of the components of Water Balance of area under recharge 3. Hydro-geomorphological factors 4. Geological conditions 5. Hydro-geological conditions 6. Source water availability 7. Ground water level data 8. Remote sensing imagery derived thematic layers (drainage net, weathered zones,

land facets and land use - land cover, soil types, lithology of rock formation etc.) 9. Socio-economic factors.


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4.1.9 Water Balance Study

Recharge is rather difficult to be measured directly. Setting up of a quantitative water balance study is the only approach to understand annual availability and distribution of source water over time and space.

The water balance is thus to be determined over watershed and for a village. Regarding methodology, it may be mentioned that the amount of water that seeps into watershed is the difference between rainfall that a watershed would receive and the sum total of water as evapotranspiration, surface runoff; base flow and component of change in storage that goes out of a watershed. Whereas rainfall and run-off is measured with use of rain-gauges &river-gauges, the base-flow is determined using stream hydrographic data. Evaporimeters are used for measuring evaporation. The change in ground water storage can be determined with use of ground water level and aquifer specific yield data determined from aquifer pumping tests of unconfined ground water. Similarly for


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confined ground water the data on change in piezometric surface & aquifer storage coefficient is needed for calculating change in storage of confined aquifers.

The recharge would depend upon amount of evaporation and silted-up sediment volumes of reservoirs. The studies would demand following methods to be used:

1. Measuring periodic water level changes in storage reservoir & ponds and calculating volumes of water.

2. Monitoring of ground water levels through observation wells & calculating recharge with use of data on specific yield of aquifers in the vicinity of water conservation and harvesting structures.

To make more clarity, the flow diagram of preparation of Water Security Plan has been depicted as below:

4.1.10 Format of Preparation of Water Security Plan

Name of the Scheme Name of Village Covered under Scheme Accessibility Type of Terrain Climatic Condition Socio-Economic Status Present/Future Population Existing Water Sources/Water availability Existing/Available drinking water infrastructure Existing/Proposed Ground water Recharging Techniques Gap Assessment Proposed Works to augment the existing Infrastructure and Water Sources.

GP based water security maps as per guidelines/criteria shall be linked with the District wise water security map.

4.2. Water Safety Plan

A Water Safety Plan will also be a part of this village water security plan using scientific planning tools i.e. remote sensing / GIS in conjunction with watershed. This water safety plan can be prepared specific to a scheme as per standard methods, prescribed for it. The water safety plans are primarily made to prevent contamination of water source, to treat the water to reduce or remove the contaminants. Developing a water safety plan would involve conducting hazard analysis of the water supply scheme, identification of the control measures, defining operational limits, establishing monitoring system, establishing corrective actions and incident response, establishing record keeping and validation and verification.

A copy of safety plan is to be attached with the PPR. The Project is designed for equitable water distribution through emphasis on 100% house connections with adequate quantity and pressure in the habitations covered. Infrastructure investments under the Project cover not only new but also rehabilitation of schemes, and strengthening and recharging of the water sources.


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In a demand based approach, the village expresses its demand for a water supply scheme. Preliminary discussions have to be held with the community about the likely water source for the project. Based on the likely water source, alternate options have to be given to the community based on capital cost and O&M cost. This is done by rough cost estimates of various components.

4.3. Reconnaissance Survey

A support agency consisting of social scientist, consulting engineer, geologist and the community shall go round the village for collecting the data required for preparation of the PPR. During the reconnaissance, the functioning of the existing water supply scheme is studied and the rehabilitation needs are noted. For the proposed scheme, the location of the water source is to be identified with the consent of the community. The ground water availability and quality of water may be ascertained by studying the water table in the existing sources and discussion with the community. Then the population estimation is to be done in consultation with the community. The future population may be assessed considering all the possible expansions.

A preliminary survey is to be done to assess geographical plans, contour plans and other related geographical and hydrological details. The site inspection should be made to identify the units of water works such as treatment units, service reservoirs, pumping main, distribution system. The highest ground level, the lowest ground level and lengths of various components of pipeline have to be approximately assessed. During the reconnaissance the nature of terrain and soil condition are noted and alignment for the drain leading to the disposal point is also identified and noted on the map. The source of power supply, financial aspects of the community is to be assessed. At the end of the reconnaissance, the extent of rehabilitation and scope of the proposed scheme along with the concept shall be formulated.

After collecting the field data, approximate sizes are arrived at an approximate cost for investment and O&M costs are worked out for various technology options for providing water supply, sanitation, roads and drains. Approximate rates for pipelines, water storage tanks, filtration units, ground water recharging structures are considered while preparing the line estimates based on the previous experience. Hence, a near reasonable line estimates for capital cost and O&M cost can be arrived at so that the community can take an informal decision. After that a PPR is prepared consisting of the executive summary, salient features, line estimates, capital cost and O&M cost for various technology options. The PPR will be presented to the community in a Gram Sabha, where various technology options will be discussed and the community will choose the most suitable options which are affordable to them (with respect to water supply and village sanitation). The land required for the implementation of the scheme should also be identified and acquisition if necessary shall be completed before detailed scheme report is too finalized.

4.4. Format for Preparation of Preliminary Project Report

The various details that are to be collected in the preparation of a PPR are broadly identified as follows:

1. Application from Village Community supported by resolution of the Gram Sabha for the demand of Water supply project


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2. For MVS, identification of villages, gram panchayats, group of villages to be covered under the project

3. Description of the area with reference to its location, terrain and accessibility 4. Socio-economic status, cultural activities, historic importance of the area 5. Present population of the area proposed to be covered in the project 6. Present status of water supply, past intervention and reason for failure if any. List of

the problems – deficiencies by inspection / local enquiry or studying the existing systems / records, if available

7. Land use in the area, master plan of the project area 8. Water requirement of projected population. Commercial and other non-domestic

requirements, if any, adopting appropriate per capita demand 9. Type of existing roads need for improvement, type of traffic, width of roads, etc. 10. Establish the need of project in the light of existing public and private facility and

future projected demands 11. Listing of the difficulties (if any) for implementation of the project and suggest

remedies to overcome them considering the local conditions 12. Identification of project components like water source, improvements to existing

infrastructure by augmentation or proposing new infrastructure , Adequacy of quantity and quality of water source. Also identify the components required for satisfactory service when project shall be completed

13. Preliminary cost of project (based on different options considered), share of beneficiaries

14. Cost of operation and maintenance 15. Suggest the most economical scheme for beneficial implementation suitable for the

project area with alternatives 16. Action plan for implementation of the project 17. Index plan to indicate the project area, existing facilities, proposed works and

schematic diagram showing salient details of the project to be enclosed in the report 18. Copy of water security plan & water safety plan.

4.5. Format for Data Collection

1. General Data Name of gram panchayat/Name of GPs/Villages (in case of MVS) 2. Name of the Mandal 3. Name of the District 4. Accessibility by road / rail 5. Terrain 6. Present population (year)/Census Population 7. Occupation of villagers 8. Climatic conditions of the area 9. Socio-economic status 10. Cultural activities 11. Religion 12. Historic activities 13. Whether covered under individual rural water supply scheme or mini water supply

scheme or not. Past history of existing water supply scheme 14. Source of present water supply, quantity and quality if existing 15. Adequacy of water supply 16. Water supply service – through stand post / cisterns, house service connections, if

existing


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17. Hours of water supply – morning, afternoon, evening (or) continuous, if existing 18. House connections – metered or non-metered, if existing 19. Water charges – fixed flat rate / variable rates 20. Disinfection arrangement.

4.5.1 Data for Ground Water

Details of existing water supply source like, open well/hand pump/tube well:

1) Size 2) Total depth 3) Water column depth/ground water level

a. During winter b. During summer

Details of Pump Set

1) Capacity of pump, BHP of pump & KW of motor 2) Type 3) Discharge 4) Head 5) No of pumps installed

Pumping Main

1) Size 2) Length 3) Material of pipe 4) Class of pipe

Storage

1) Ground level 2) Capacity 3) Size 4) Material of construction

Overhead Tank

1) Capacity 2) Staging/Height 3) Pipe size inlet 4) Pipe size of Outlet 5) Pipe size of Overflow 6) Pipe size of Washout 7) Material of pipe


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Distribution Network

1) Pipe size 2) Length in each size 3) Material of pipe and pressure rating

Status of Existing Drainage and Sanitation

1) Nature of drains -Kutcha/pucca/no drains 2) Size, shape and gradient 3) Service condition 4) Storm water disposal 5) Type of drain -stone slab / precast slab / Bricks / RCC / CC 6) Sanitation facility (if available) – Community / Individual Toilets 7) Mode of disposal of excreta 8) Describe the present practice in brief 9) Status of existing roads 10) Nature of roads - Mud / kutcha / Metalled / Asphalt/CC 11) Width of roads 12) Provision of storm water in drain design- considered/not considered 13) Type of solid waste generated and disposal system

4.5.2 Data for Surface Water

1) Name of scheme 2) Names of villages covered under scheme 3) Accessibility 4) Present population 5) Future population 6) Design period 7) Per capita water supply 8) Water supply for non-domestic requirements (Equivalent per capita) 9) Net water requirement [5x(7+8)] 10) Account of losses of water

a. Transmission b. Treatment units c. Distribution d. Unaccounted water

11) Water requirement (9+10) 12) Source of supply Stream/river : (storage to be provided if non perennial)Storage

Reservoir (Demand for low yield period of source) Irrigation canal : (provide storage equal to demand during canal closure period) Intake structure (to provide for drawal of water from surface waters)

a. Infiltration Wells b. Infiltration Galleries (optional for streams with sufficient sand depth) c. Intake Well / Floating Barge d. Intake Pipes


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e. Intake Chamber f. Intake well with 2 floors, one for pipes galleries and another floor for Motors

and panel boards. g. Double Deck Bridge from intake well to Abutments of the river for conveyance

pipe lines & for accessing foot path for maintenance. h. Approach Earthen Embankment Road up to Abutments.

13) Power lines & Transformer Yards/Substation for 24 hours continuous power supply for Intake structures: a. Distance in KM from nearest SUB STATION: b. Type of power lines required : HT or LT c. Transformers Yard size : d. Capacity of Transformers including stand-by arrangements: e. Type of Transformers: HT to HT , HT to LT or LT to LT

14) Raw water pumping machinery: To summer storage (SS) Tank, if provided

a. Hours of pumping (for ultimate demand, Q) = 22 hrs. b. Hours of pumping (For Prospective Demand) = suitably reduced. c. Discharge at Duty point (for Ultimate demand) Q = LPM d. Static Head e. (MWL at end - LWL of water source) = M f. Head losses due to Friction = M g. Other (minor) losses in Pipe lines = M h. (Suction + Delivery Losses, etc.) = As per design, M i. Total Head lift of pump set H (d+e+f+g+h) = M j. Combined Efficiency of pump sets : = %age k. Horse power = (Q x H)/(4500x)

15) Pumping Main from Intake structures to SS Tank (If provided)

a. Diameter of pipes: To be decided economically and Velocity of flow, Between 0.6 m/s to 2.0 m/s

b. Type of Pipes and details: To be decided economically and to suit the ground terrain of pipe line layout.

c. Length of pipe line: in M.

16) Summer Storage Tank (Impounding reservoir, large storage of water for summer periods/ in the absence of running water from streams)

a. Location of SS Tank: may be an abounded tank /Minor Irrigation Tank canal feeding

b. Quantity of water stored in SS Tank: in ML, quantity required for non-running period of canal/stream, and 50% evaporation and percolation losses

c. Dimensions of SS Tank, detailed grid levels, all required designs and drawings etc., details

d. Cut-off trench, Revetment, weir length, bypass arrangements, fencing etc. e. Area required for SS Tank: in Hectares f. Intake Chamber for collection of water from dead storage in SS Tank with gate

valve arrangements


Chapter-4 Page 4-14

g. Intake with 2 floors, one for pipes galleries and another floor for Motors and panel boards

h. Double Deck Bridge from Intake to Abutments of the river for conveyance of pipe lines & for accessing foot path for maintenance

i. Approach Earthen Embankment Road up to Abutments with revetment j. Measures to reduce infiltration losses in SS Tank if proposed.

17) Power lines & Transformer Yards for 24 hours continuous power supply for WTP

a. Distance in KM from nearest SUB STATION: b. Type of power lines required : HT or LT c. Transformers Yard size: d. Capacity of Transformers including stand-by arrangements: e. Type of Transformers: HT to HT, HT to LT or LT to LT

18) Raw water pumping machinery: To WTP

a. Hours of pumping (for ultimate demand, Q) = 22 hrs. b. Hours of pumping (For Prospective Demand) = suitable hours as per power

availability c. Discharge at Duty point (for Ultimate demand) Q = LPM d. Static Head (MWL at end - LWL of water source/jack well)= M e. Head losses Due to Friction = M f. Other (minor) losses in Pipe lines = M g. (Suction + Delivery Losses, etc.) = As per design, M h. Total Head lift of pump set H = M i. Combined Efficiency of pump sets : %age j. Horsepower= (Q ∗ H)/(4500 ∗ )

19) Pumping Main to WTP

a. Diameter of pipes : To be decided economically and Velocity of flow, between 0.6 m/s to 2.0 m/s

b. Type / Class of Pipes and details: To be decided economically and to suit the ground terrain of pipe line layout


20) Water Treatment Plant

a. Name of the Location of WTP b. Capacity of (WTP) Filters: c. Type of Filtration Plant: Slow Sand Filters or Rapid sand Filters for

Conventional WTP d. Brief details of units proposed e. Area required for arrangements of the Units in WTP.

21) Ground Level Storage Balancing Sump (GLBS)

a. Capacity–2.5hours of incoming discharge or balancing capacity between total outflow quantity and total inflow quantity in a day


Chapter-4 Page 4-15

b. Size of Tank whether Circular or Rectangular c. Free Board : 0.3 m d. Sizes of inlet & overflow arrangements in outside chamber e. Sizes of Scour Valve with, outside chamber arrangements.

22) Clear Water Pumping Main from GLBS to ELBR

a. Diameter of pipes: To be decided economically and Velocity of flow, b. Between 0.6 m/s to 2.0 m/s c. Type of Pipes and details: To be decided economically and to suit the d. Ground terrain of pipe line layout. e. Length of pipe line: in M

23) Elevated Level Balancing Reservoir

a. ELBR Capacity – 30 minutes of incoming flow, capacity adopted for higher staging for stability of ELBR.

b. Staging height – Required to flow by gravity to all drawals points in the network for Ultimate design discharge + 10% more.

c. Size of inlet: <= incoming pipe line diameter but velocity < 2.0 m/s d. Size of outlet: <= Outgoing pipe line diameter but velocity < 1.5m/s e. Size of scour: normally with <= 80mm f. Size of overflow: normally with <= outlet size., g. Bell mouth pieces to be provided for all verticals.

24) Clear Water Pumping Machinery for GLBS to ELBR

a. Hours of pumping -22 hours b. Hours of pumping (For Prospective Demand) = suitable as per hours of power

availability c. Discharge: For Ultimate Demand, suitable to outflow rate from ELBR, i.e.

equals to System Capacity of Transmission lines from ELBR at LWL d. Static Head (MWL at end - LWL of water storage/sump)= M e. Head losses due to Friction = M f. Other (minor) losses in Pipe lines = As per Design, M g. (Suction + Delivery Losses, etc.) = 3As per design, M h. Total Head on pump set H = M i. Combined Efficiency of pump sets:= %age j. Horse power = (푄 ∗ 퐻)/(4500 ∗ ).

25) Gravity Mains from ELBR to OHSR/Sumps of Habitations

a. Diameter of pipes - To be decided economically and velocity of flow, between 0.6 m/s to 2.0 m/s ,

b. Type of pipes and details - To be decided economically and to suit the ground terrain of pipe line layout.



Chapter-4 Page 4-16

26) Service Reservoirs

a. OHSR/GLSR Capacity – It is provided for on the basis of mass curve with required staging

b. Staging height – Required to flow by gravity while 7 m residual head maintained at all end points in the distribution network for Peak Ultimate design discharge

c. Size of inlet : <= incoming pipe line diameter but velocity < 2.0 m/s d. Size of outlet : <= Outgoing pipe line diameter but velocity < 1.5m/s e. Size of scour : normally with <= 100 mm f. Size of overflow: normally with <= outlet size., g. Bell mouth pieces to be provided for all verticals.

27) Distribution System: To be dealt independently, depends upon village population, power availability and social system of habitations and for satisfying the minimum velocity criteria v >=0.6 m/s

a. Design for peak factor: As mentioned at Chapter-2, Volume-1 with Minimum Terminal pressures of 7 meters at Household.

b. Size of pipes : Depends on Q, Minimum 63 mm (OD) and above as per design c. Length of pipe line & layout maps on topo sheets. d. Material of pipe: As per State Pipe Policy (Refer Chapter-2) e. Appurtenances: includes, water meters (bulk and consumer) f. Control valves – Gate Valves, Sluice valves, scour valves and air valves g. House service connection

28) Cost of components: (list the components and with their cost and Supervision charges etc.)

29) Financial aspects

a. Contribution by beneficiaries if any b. Grant in aid by state / central government

30) Annual maintenance and repairs: 31) Depreciation fund for replacement: 32) Total annual cost (30+31): 33) O & M cost per capita (32 ÷ population): 34) Capital cost per capita (28 ÷ population):

4.6. Capital Cost and O & M Cost

Table 4-3: Capital Cost

S. No. Description Rs. 1 Water supply source works 2 Intake structures 3 Pumping main 4 Treatment units (optional) 5 Storage at ground level 6 Service reservoirs 7 Pumping machinery from GL tank to elevated tank 8 Distribution System


Chapter-4 Page 4-17

S. No. Description Rs. 9 Electrical works 10 Land acquisition 11 Other unforeseen item of works

Total

Table 4-4: O & M Cost

S. No. Description Rs. 1 Annual maintenance and repairs

Civil works at 1% Electrical and Mechanical at 3%

2 Annual salary of operating staff 3 Annual energy charges 4 Annual chemical charges 5 Annual depreciation fund (@ 0.2% for civil works and @

2% for Mechanical and Electrical works)

Total

Usually in PPR an executive summary describing the concept of the proposed rural water supply scheme, including rehabilitation of existing water supply scheme and other components such as sanitation, drains and lane improvements etc. are to be provided.

Various options along with the water security plan as prepared in consultation with GPWSC, Support Organisation/ State Engineering Organisation will be presented before the Village Water Supply & Sanitation committee for selection of the option. The final selected option shall be detailed out at Chapter-5 (Volume-1) on “Detailed Project Report”.

Note: SLWM (Solid Liquid Waste Management) Project Report shall be prepared separately.

Detailed Project Report

Chapter-5 Page 5-1

5. DETAILED PROJECT REPORT

The DPR should be prepared on the basis of data/information obtained in response to Para 4.5.1 & 4.5.2 of Chapter-4 (Volume-1).

In this chapter following components are broadly covered:

(i) Field survey (ii) Design calculations (iii) Detailed plans and (iv) Detailed Cost Estimates and economics

The above components are to be described in following sections:

5.1. Executive Summary

5.1.1 Brief Description of Project

5.1.2 Salient Features of Project a) Name of project b) Name of district c) Population Year 2011; 2015; 2030 &2045 d) Source of water e) Rate of water supply f) Head work g) Nature of treatment h) Location of land of water works i) Conveyance main

Rising Main

Sl. No. Type of Pipe Class Diameter mm Length m

Distribution System:

Sl. No. Type of Pipe Class Diameter mm Length m

j) Details about Habitats:

Sl. No. Name of Revenue Village No. of Habitation

k) Service Reservoirs

Sl. No. Type Capacity of Service Reservoir, in KL

Staging Height, m


Chapter-5 Page 5-2

l) Disinfection Method

Type electrical mechanical diaphragm type chlorinating of xx gallon capacity Chemical : bleaching powder solution Maximum capacity – xx PPM Average chlorine – 0.50 PPM Residual chlorine – 0.20 PPM

5.1.3 Financial Aspect

Sl. No. Description Base Year Mid Stage (15 Years)

Design Year (30 Years)

1. Total estimated Capital cost 2. Per capita cost in Rs. 3. Total Annual O&M cost 4. Cost of water production in Rs.

Per KL

5. Average water production per day in KL

6. Annual income (i) No. of household (Able to pay

water tax)

(ii) Annual income from household 7. Net profit / Loss (+) (-)

5.2. Format for the Project Report

1. Authority 1.1 Introduction 1.2 Objective

2. Scope of Project 2.1 Area Covered in Project 2.2 Climate 2.3 Source 2.4 Quality of Water

3. Project Area 3.1 Location 3.2 Topography 3.3 Socio-economic condition

4. Existing Services (Water supply, sanitation, drainage & waste disposal) 5. Necessity of piped water supply scheme including present status of water supply 6. Design criteria (refer Chapter-3, Volume-1) 7. Design parameters (refer Chapter-3, Volume-1) 8. Population and water demand (refer para 3.2 and 3.3 of Chapter-3, Volume-1) 9. Rate of water supply and water requirement (refer para 3.3 of Chapter-3, Volume-1) 10. Proposals

10.1 Source of water supply 10.2 Safe yield of the source 10.3 Land acquisition 10.4 Power transmission line 10.5 Pumping plant


Chapter-5 Page 5-3

10.6 Disinfection 10.7 Pump house cum chlorinating room 10.8 Rising main 10.9 Storage reservoir& service reservoir 10.10 Distribution System – Bulk distribution lines & distribution lines 10.11 Maintenance staff – for common works & for internal village 10.12 Ground water recharging 10.13 Auxiliary work

(i) Boundary wall and gate (ii) SCADA (supervisory control and data acquisition)

10.14 Reinstatement of roads

Schedule of Rates: Present approved rates in the states shall be followed for preparation of cost estimates. For the rates of components which is not covered under the state schedule of rates should be worked out as per present market rates.

11. Financial Statement

11.1 Proforma for Summary of Cost

Sl. No.

Description of Work Amount (In Lacs)

Rate Amount (In Lacs)

1 2 3 4 5 1 Cost of work 2 Work contingency (%) of cost of

work (As per state specific)

3 Labour Welfare Cess (%) of cost of work(As per state specific)

4 For Detailed Survey and Preparation of Project (%) of cost of work (As per state specific)

5 Supervision Cost (%) of cost of work (As per state specific)

6 Environmental Management Frame Work Activities (1%) of cost of work

Grand Total (In Lacs)

11.1.1: General Abstract of Cost (Comprehensive)

Sl. No.



A BULK WATER SUPPLY WORKS A1 E & M WORKS (i) Tube wells / source works (ii) Pumping Plants & Chlorinating plants (iii) Transmission line, Power connection,

internal electrification and lighting of water works compound

(iv) Trail and run A2 CIVIL WORKS


Chapter-5 Page 5-4

Sl. No.



(i) Intake works (ii) Rising mains and bye pass arrangements (iii) Treatment Plants (iv) Storage / Service Reservoir (v) Pump House and Chloronome (vi) Bulk water distribution system &

appurtenant works up to entry level of Gram Panchayats

(vii) Site Development gate & approach road etc.

(viii) SCADA Sub Total Grand Total B INTRA-VILLAGE WORKS Intra Village distribution system and other

works

(i) GP1 (ii) GP2 Sub Total Grand Total

11.1.2: General Abstract of Cost (O&M Works)

S. No. Description of Works Cost of Works A BULK WATER SUPPLY WORKS (O&M of Bulk

Water Supply works for 5 years)

(i) Expenditure on Regular maintenance of works (ii) Electricity (iii) Chemicals (iv) Staff (v) Cess Sub Total (A) B INTRA VILLAGE WORKS (Intra-Village Water Supply Works ) 1 Expenditure on Regular maintenance of works 2 Staff Sub Total (B) Grand Total (A+B)

12. Tariff and Revenue

Based on the above financial statement, the economics of the scheme has been worked out. The tariff shall be fixed based on the annual maintenance cost and revenue generation from the community. The details of economics have been summarized in the Table 5-1 & 5-2 respectively.


Chapter-5 Page 5-5

Table 5-1: Details of Cost of Production of Water

Sl. No. Particulars Initial Stage (2015)

Mid Stage (2030)

Ultimate Stage (2045)

1 2 3 4 5 1 Population 2 Rate of water supply per capita per

day (In litres)

3 Maximum requirement of water per day (In KL)

4 Average requirement of water per day (In KL)

5 Average annual production of water (KL)

6 Total estimated cost of the scheme (In Rs)

7 Total annual income (In Rs.) 8 Total annual recurring expenditure

in Rs.

9 Net profit/loss 10 Per capita cost (In Rs.) 11 Cost of production of water per KL. 12 Per capita O& M cost (In Rs)

Table 5-2: Details of Income

Sl. No. Particulars Initial Stage (2015)

Mid Stage (2030)

Ultimate Stage (2045)

1 2 3 4 5 1 Design Population 2 Rate of water supply (In lpcd) 3 Daily water requirement (In Kl) 4 Annual water requirement (In Kl) 5 No. of houses 6 Annual charges from the

connection holders (In Rs.)

Total

13. Water Connections

No. of house connections per Gram Panchayat in this scheme:

Sl. No. Name of Gram Panchayat Name of Village No. House Connection

14. Conclusion

The following remark shall form the part of DPR:

“After implementation and commissioning of the project, the entire population of the project area shall be benefited with safe, clean and wholesome potable pipe water supply system thereby ensuring a clean and healthy environment”


Chapter-5 Page 5-6

With the above remarks, the DPR of the _________________ Gram Panchayat water supply scheme of amounting to Rs. ________________ lacs under World Bank Assisted Rural Water Supply and Sanitation Project for Low Income State (RWSSP-LIS) has been technically approved by the competent authority subject to the further community consultation.

15. Technical Statement

For detailed designing of the various components of water supply scheme, the Chapter-06 (Volume-1) on “Technical Guidelines-Water supply components” of this Manual may be referred.

The checklist for preparation of DPRs for SVS and MVS for all the States have been appended as Annexure 01 (Volume-2). The Engineering Responsibility Matrix for listing the Engineering activities at various stages of Project preparation has been appended as Annexure 02 (Volume-2). The Sample DPR is annexed as Annexure 03 (Volume-2). The CPM Chart shall be prepared in details for water supply system; for guidance sample CPM chart has been annexed [Refer Annexure-12 (Volume-2)].

To check on cost and time overrun at construction stage, the CPM chart shall be closely monitored.

The Guidelines for Complaint redressal system shall be as per NRDWP Guidelines.

To avoid delayed commissioning of the scheme; the concerned nodal agency should seek the permission from the relevant authorities like: Railways, Forestry, National Highway Authority of India etc. and the identification of the land for constructing any utilities be applied prior to finalizing the DPR. The bids for implementation of the works be called only after receiving all the sanctions.

16. Environmental Data Sheet (EDS) for Water Supply Schemes As per Annexure 23 of PIP (Volume II).

17. Disaster Management Data Sheet

As per Annexure 31 of Project Implementation Plan (Volume II).

18. Tribal Plan and Catchment Area Development Plan

As per PIP, Volume-II (Annexure 24.2)

Technical Guidelines-Water Supply Components

Chapter-6 Page 6-1

6. TECHNICAL GUIDELINES-WATER SUPPLY COMPONENTS

6.1. General

SHS/SGS

For each selected GP, preparation of water resources mapping is required. This has to be prepared with community participation. Total station survey and GIS based map along with community survey for selected GP will form part of the DPR. DPR of SHS/SGS will be prepared by respective GP with technical support of State Technical agency/ SOs with oversight of SPMU/DPMUs. All states/SPMUs will provide the design criteria to the SOs / consultants for preparation of DPRs.

MVS

In all GPs selected for a MVS, GIS based water security plan and total station survey along with the community survey should be conducted to prepare the GIS Based maps. The State technical agency will be responsible for preparation for DPR for MVS as per design criteria in consultation with the beneficiaries.

6.2. Field Surveys

The following surveys are required for formulation of DPR.

6.2.1. Sanitary Survey for Source

The sanitary survey of the area around the selected source of water should include test report of water quality, tapping of source for other uses and essentially possibility of pollution. In case of river it is suggested to do the transact walk (PRA Exercise) up to 2 Kms. of upstream and 1 Km of downstream to gather the information/data on possible sources of pollution (Type/location) especially industrial effluent to ensure the quality of water (Refer Format at Annexure-3, Volume-2)

6.2.2. Topographical Survey

6.2.2.1.Survey

As described in para 3.4, Chapter 3 (Volume-1).

6.2.2.2.Maps/Drawings:

A topographical map prepared in Auto CAD based on the total station survey should indicate the location (i) houses (ii) institutions (iii) markets (iv) hospitals/ health centres (v) important public buildings and (vi) industries.


Chapter-6 Page 6-2

Generation of maps for ground validation surveys. The drawings shall have to be prepared in AutoCAD form. The key map /index map for the complete project shall be made to a scale matching to A0 size paper. The detailed drawings shall be in 1: 200 scale plotted to A3 size papers.

Data entry of the ground validation surveys for updating maps for any correction/mistakes updating of the field verified data onto the digital data.

Drawings for DPR: Separate drawings shall be prepared for:

(i) Source, WTP and Reservoir sites for a scale of 1: 500 (ii) Key map / index map for longitudinal section along pipeline route made to a scale

matching to A0 size paper.

The detailed drawings shall be in 1: 200 scale plotted to A3 size papers:

(i) Cross sections along pipeline routes for a scale of 1: 200 plotted to A3 size papers (ii) Key Map / Index map for Road network within each GP to a scale matching to A0

size paper.

The detailed drawings shall be in 1: 200 scale plotted to A3 size papers.

6.2.3. Soil Investigation

For selection of type and design of foundation of the various structures such as reservoirs, buildings and pipe lines, sub-soil investigation is required. For foundation design of such structures trial pits shall be taken to a depth of 2 to 3 meters to assess the nature of soil. Bearing capacity of soil is determined by field tests and laboratory tests. Soil samples are collected and tested in laboratory to correlate the results obtained in the field. The safe bearing capacity (SBC) is the maximum pressure (load) which the soil can carry safely without the risk of shear failure.

The trial pits for pipelines shall be of size 1m x 1m and for a depth of about 1m to note the nature of soil preferably at 500 m intervals.

The SBC of soil may be determined by Two Methods:

Laboratory Test Field Test

6.2.3.1.Laboratory Tests

The SBC from laboratory test parameters may be determined through Undisturbed Soil (UDS) samples (IS 6043- determination of bearing capacity of shallow foundation). The other laboratory tests are: Unconsolidated un-drained tri-axial shear test (As per IS: 2720 (Part-11)); consolidated drained direct shear test (As per IS: 2720 (Part-13)) and unconfined compression test (As per IS: 2720 (Part-10)).


Chapter-6 Page 6-3

6.2.3.2.Field Tests

Field test can be performed by the following three methods:

Standard Penetration Tests (SPT): conducted in the boreholes at every change in stratum or at intervals of not more than 1.5 m whichever is less. The tests are conducted by connecting a split spoon sampler to a rod and driving it by 45 cm using a 63.5 kg hammer falling freely from a height of 75 cm. The tests are conducted in accordance with IS: 2131

Plate Load test (PLT): Shall be conducted in a pit at an elevation of the proposed foundation level under the worst estimated conditions by using square or circular plate of 300 mm, 450 mm or 750 mm size. The test plate shall be placed over a fine sand layer of maximum thickness 5 mm, so that the centre of plate coincides with the centre of reaction girder/beam, with the help of a plumb and bob and horizontally levelled by a spirit level to avoid eccentric loading. A minimum seating pressure of 70 g/cm2 shall be applied and removed before starting the load test. Apply the load to soil in cumulative equal increments up to 1 kg/cm2 or one-fifth of the estimated ultimate bearing capacity, whichever is less

For more details IS: 1888 may be referred.

Static Cone Penetration Test (SCPT): The static cone penetration is a specialized penetration test to obtain a profile of soil resistance with depth. The test was conducted in general accordance with IS: 4968 (Part III).

6.3. Basic Design factors

Population forecast: Refer Chapter- 3 Para 3.2 Per capita demand: Refer Chapter-3 Para 3.3 Design period: Refer Chapter 3 Para 3.1. Quality of water: Refer Chapter 3 Para 3.8

6.4. Rehabilitation of Existing Water Supply Schemes

To economise in project cost it is necessary that wherever feasible existing scheme in full or some of its existing assets be utilised. The performance of the existing scheme is to be assessed during supply hours and decide if any assets of existing scheme can be used or rehabilitated in the proposed scheme.

6.5. Ground Water Source

Tube well is the main source for Ground water based supply schemes

Tube Wells shall be drilled in accordance with Indian Standard IS: 2800 (Part – I), developed in accordance with IS: 11189 with latest amendments and tested in accordance with IS: 2800 (Part-II) with latest amendments.


Chapter-6 Page 6-4

6.5.1. Tube well

Tube wells collect the ground water infiltrated to deeper layers in the soil strata compared to dug wells and hence the quality of water will be good and can be supplied after disinfections (using bleaching powder).

6.5.2. Methods of Drilling of Tube Well

There are numerous methods of drilling wells and each method has advantages related to ease of construction, cost factors, character of formations to be penetrated; well diameter and depth, sanitary protection and intended use of the well itself. The basic principles of some of the methods are described here.

6.5.2.1.Percussion Drilling

The percussion method, often referred to as cable tool method, is one of the oldest, most versatile and simplest drilling methods. Construction involves repeatedly lifting and dropping of heavy string of tool either manually or power with a suspended with a cable.. The string of tools, in ascending order, consists of a bit, a drill stem, drilling jars and a swivel socket which is attached to the cable. The bit strikes the bottom of the hole, crushing, breaking and mixing the cuttings. Above the water table or in otherwise dry formations, water is added to dissolve the cuttings which are lifted out by means of a bailer. This method is most suitable for drilling in stratum where large boulders are encountered in abundance at different depths. Drilling in such unconsolidated formations require a pipe or casing that follows the drill bit closely in the well as the well is deepened to prevent caving in an to keep bore hole open.

Advantages and disadvantages of it is given below:

Advantages Disadvantages Rigs are relatively inexpensive, simple in design and requires little sophisticated maintenance

Penetration rate are relatively slow

Machines have low energy requirement Casing cost are usually higher and difficult to pullback in some geological conditions

Borehole is stabilized during the hole drilling operation

Not recommended for solid hard rock formations

Recovery of reliable samples is possible from every depth unless a heaving condition occurs

Wells can be drilled in areas where little make-up water exist and can be constructed with little chance of contamination

Wells can be bailed at any time to determine the approximate yield at certain depths


Chapter-6 Page 6-5

6.5.2.2.Direct Rotary Circulation Drilling:

The rotary rig drills by mechanical rotation of a drill bit at the bottom of a string of drill pipe. The typical string consists of a bit which scrapes, grinds, fractures or otherwise breaks the formation drilled; a drill collar of heavy walled pipe to maintain a straight hole; and a drill pipe which extends to the surface and imparts rotation to the bit. As the bit is turned drilling fluid (usually bentonite mixed with other suitable material) is circulated under - pressure which" lubricates and cools the bit, carries the cuttings in suspension to the surface, and plasters the wall of the hole to prevent caving in. The cuttings in suspension thus received at the surface could be geologically examined thereby identifying the depth of water bearing aquifer.

Advantages Disadvantages

Penetration rates are relatively high in all type of strata

Drilling rigs are costly and requires a high level of maintenance

Minimum casing is required during the drilling operation

Mobility of the rig may be limited depending on the slope and condition of the land surface

Rig mobilization and demobilization are rapid

Collection of accurate samples require special procedure

Well screens can be set easily as part of the casing installation

Drilling fluid management requires additional knowledge nd experience

6.5.2.3.Reverse Rotary Circulation Drilling

The reverse circulation rotary rig operates essentially in the same way as a direct rotary rig except that water is pumped up through the drill pipe rather than down through it. A string of drill pipes with a drill bit at the bottom is rotated by mechanical means. Plain water or a drilling fluid, depending on the strata conditions, is allowed to flow into the borehole; the drill cuttings along with water are sucked through the drill pipes by a centrifugal pump and thrown into a settling pit.

Advantages Disadvantages Porosity and permeability of the formation near the bore hole are relatively undisturbed

Large water supply is generally needed

Large diameter holes can be drilled quickly and economically

Reverse rotary rigs and components are more expensive

No casing is required during the drilling operation Rig mobilization and demobilization are rapid

Large mud pits are required

Well screens can be set easily as part of casing installation

Small drill sites are not accessible because of rig size


Chapter-6 Page 6-6

6.5.2.4.Down-the-Hole (DTH) Hammer Drilling

It is accomplished by a tool called the down-the hole hammer which is essentially a pneumatic hammer operated at the lower end of the drill pipe and combining the percussion and the rotary actions. The method utilizes compressed air for the rapid impacting action given by the hammer to the bit, thus crushing the formation into small chips which are flushed out through the annular space between the bore and the drill pipes by the upcoming compressed air.

Advantages Disadvantages Cutting removals is extremely rapid High cost Aquifer is not plugged with drilling fluids

Application restricted to semi consolidated and well consolidated formation

No maintenance cost for mud pumps Bit life is extended Penetration rate is high, especially with DTH hammer in highly resistant rocks such as Dolomite and Basalt

An estimate of the yield can be made during drilling from a particular formation

Wells can be drilled where lost circulation is problem

6.5.2.5.Selection of Drilling Rigs

On the basis of advantages and disadvantages shown above the site Engineer may adopt the suitable type of drilling rig for that particular site.

Well Casing

Well casing is a pipe and is used to prevent caving in of surrounding soil into the well or bore-hole. In case where casing is the permanent part of the tube well the lower portion has screen while the upper portion is used for housing the pumping equipment. The length and diameter of the casing pipe is selected on the basis of static water level, drawdown, discharge expected from the pump and the size of pump to be installed. The housing portion of the casing should be located such that the pump will always remain submersed in water and should be a few meters below the lowest drawdown level.

Steel tubes most suitable for varied type of water well drilling operations - either casing or drive are those made to IS: 4270. Unless otherwise agreed to between the supplier and the purchaser, the pipes shall be supplied in random lengths of 4 to 7 meters.

Screen Types

The following are the various types of well screens and slotted pipes as per IS: 8110:

Plain Slotted Pipes - These are pipes with slots cut by milling. Bridge Slotted Pipes - The slots here are not cut but pressed out.


Chapter-6 Page 6-7

Mesh Wrapped Screens - These are made by wrapping copper mesh over perforated steel pipe using spacers about 3 mm thick in between the copper mesh and the perforated pipe

Cage Type Wire-wound Screens - These are special type of screens wherein a con-tinuous trapezoidal or circular wire is spirally wound around a fabricated cage. The screen consists of wedge profile wire of various dimensions, resistance welded to a cylindrical body made of various members and cross sections of longitudinally arranged metal rods, which are in turn welded into cylindrical ring couplings at either end.

Material

The well screens and slotted pipes shall be made of either corrosion resistant material or steel pipes having sufficient thickness to guard against the effect of corrosion and to ensure reasonable life of tube well. The following are the recommended materials for various types of well screens and slotted pipes:

Low carbon steel or mild steel Stainless steel

Normally Stainless steel strainer is to be used and Low carbon strainer is to be adopted in case steel strainer is not commercially available. However for rural areas the required diameter of strainer is in the range of 150 mm to 250 mm and for these sizes stainless steel strainer is easily available in the market.

Design Consideration

Length of Screen

The length of screen shall be governed by the thickness of aquifer and shall be sufficient to obtain the specified yield from tube well. However, the minimum total length shall be such that the entrance velocity is less than the permissible entrance velocity of 0.03 m/s to ensure longer life of the well. The lengths of individual pipes shall be such as to afford easy handling for transport. Screen shall not be placed in at least 0.3 meter on both sides of the stratum.

Size of the Screen

The screen diameter shall be so selected that the percentage of slot area to screen surface area is generally between 20 to 25 percent, for gravel packed tube wells and 8-10% for natural packed tube wells.

Slot Size

The shape and size of the slots shall be such that the gravel or aquifer material is not allowed to block the open spaces. Based on the sieve analysis of the aquifer material, the size of the slot openings shall be determined in such a way that finer fractions remain outside the slots. The slots shall not be too wide to cause entry of the gravel and resulting in plugging. Sharp edges on the periphery of the pipe may offer resistance to flow and hence it is preferable to have smooth rounded edges.


Chapter-6 Page 6-8

The slot size for gravel pack shall be so selected as to retain at least 90 percent of the pack material. However, in case the well is not provided with gravel pack, slot size shall be such that it allows 40 to 60 percent of the aquifer material to pass through. The normal slot sizes shall be 1.0, 1.6 and 3.2 mm.

Cage Type Wire-wound Screens

The wrapping wire having a wedge profile with flat surface on the outside and producing expanding slots on the inside should be-used. This shape facilitates setting and back washing operation and also avoids the screens being clogged by fine particles.

For obtaining a minimum of 15 percent open area, the screen aperture shall not be less than 0.375 mm. The number and cross-section of the vertical support rods and the profile of the wrapping wire shall be such as to give sufficient axial and collapse -strength.

Choice of Strainer

It is recommended that for natural packed/ Gravel Tube wells Stainless steel Strainer shall be adopted

Guidelines for Gravel Packing

Gravel Packing as per IS: 4097

Need for Gravel Packing

The four common reasons for gravel packing are:

a. To increase the specific capacity of the well b. To minimize sand flow through the screen in fine formations c. To aid in the construction of well d. To minimize the rate of incrustation by using a larger screen slot opening where the

formation is relatively thin but very permeable and the chemical characteristics of the groundwater indicate potential for significant incrustation.

Criterion for Gravel Packing

The desirability of gravel packing decreases as the water bearing formation becomes coarser. Generally, formation with an effective grain size, D1O that is that size, than which only 10 percent of the formation is finer, or more than 0.30 mm and uniformity co-efficient of 5 or more can be safely developed without gravel packing.

Gravel Sizes

The gravel sizes shall be as given in Table 6-1.


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Table 6-1: Gravel Sizes

Sl. No. Grade Material Particle Size Range

mm IS Sieves (See IS: 460 (part 2)

1 A Fine gravel Over 2.0 to 3.35 2.0, 3.35 2 B Fine gravel Over 3.35 to 4.75 3.35, 4.75 3 C Medium gravel Over 4.75 to 6.3 4.75, 6.3 4 D Medium gravel Over 6.3 to 8.0 6.3, 8.0 5 E Coarse gravel Over 8.0 to 12.5 8.0. 12.5

To avoid trouble in placing and inspective of gradation, packs should not contain particles greater than 13 mm.

Thickness of Gravel

The thickness of gravel pack shall be limited to 13 to 18 cm. The size of the screen slot opening is governed, among other factors, by the size of the gravel or aquifer material which it has to retain. The slot size for gravel packed wells should be such that it retains about 90 percent of the gravel. For further details of gravel packing, IS: 4097 may be referred. For construction of Tube well IS: 2800 (Parts -1 & 2) may be referred.

Tube well Development

The development of a well is its treatment for the purpose of establishing the maximum rate of usable water by cleaning the produced water of turbidity, sand, sediment or other impurities introduced during drilling.

Method of Development

There are numerous methods of development and an important factor in all these is that the development work be started slowly and gently and increased in vigor as the well is developed. The development should be started as far as possible from the bottom of the screen because with this compaction takes place as the work progresses upward and the overlying material can move downwards. The known methods of development are described below (For more details refer IS: 11189):

Over Pumping

Over pumping means pumping the well at a higher rate than it will be pumped normally when it is put in service. It may be simpler to over pump in small wells or poor aquifers by employing the pumping equipment intended for regular use in the well.

Compressed Air

Another popular way of development is by using compressed air but it requires considerable equipment and skill on the part of the operator. The capacity of compressor should be at least 9.35 cum per minute at 250 PSI pressure for depth up to 200 meter. In case depth of bore well is more than 200 meter, a proportionately higher capacity compressor shall be used


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Calculation of Discharge

(A) Discharge of tube well shall be determined by using V-notch. The various observations which are required for deciding the yield of tube well at different drawdown has to be tabulated as given below:

SL. No.

Rated Discharge

Depression at rated

discharge

Specific yield

Total hours Run

Sand in ppm at end of test

Static water level

Pumping water level

cum/s m h M 1 2 3 4 5 6 7 8

(B) Discharge at 1.2 times normal yield or 1.5 times normal depression

Specific Yield

Total Hours Run

Sand in ppm at end of test

Static water level

Pumping of water

h M 1 2 3 4 5

Based on observations recorded in the tables given above, the discharge of tube well may be finalized as per relevant IS codes.

To make the design of tube well much more understandable, a typical example has been attached as Annexure 05 (Volume-2).

Factors Affecting the Performance of Tube Wells

Due to clogging the effective area of opening gets decrease this lead to increase of velocity through the opening and resulting into increase of head at the entrance.

The clogging in the well could be removed by following methods:-

1. Surging: to dislodge clogging and incrusting material 2. Chemical treatment: By acids, chlorine in loosening bacterial growths and slime

deposits, by using polyphosphates @ of 12.5 to25 kg for every kilo litre of water in the well.

6.6. Surface Water Sources

The following are the base surface water sources:

Canals Rivers Ponds / lakes Springs

Flow and Location: Preferably perennial flow and location to be safe and secure.


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Inlet works: Inlet chamber with screens, inlet to be below lowest summer water level.

Intake well: 4-6m dia. depending upon the capacity, sufficient space for pump house, pump sets, valves, panels etc.

Floating Barge: Shall be recommended mainly in case of Rivers with high variation in water level throughout the year.

6.6.1. Design of Intake/Raw Water Collection Well

When surface water is selected to be the technology option, it defines for specific structures for the drawal and transmission called intake well or raw water collection well. These are the structures placed in a surface water source to permit the withdrawal of water from the source. These are essentially used in lakes, reservoirs or rivers etc., where wide fluctuations in water level are expected.

Type of intakes:

Wet intakes Dry intakes Submerged intakes Movable and floating barge intakes.

Location and Design Considerations:

It shall be located such that the raw water can be withdrawn continuously over the year of best quality

It shall be nearer to the raw water sump The location shall be free from the water currents and swirls The entrance of large objects shall be prevented by screens The capacity of the conduit and depth of suction well should be such that the intake

ports to the suction pipes do not draw air. A velocity of 60-90 cm/sec will give satisfactory performance

The intake conduit shall be laid in a continuous rising or falling grade to avoid accumulation of gas or air

Normally, the size of the well shall be equal to 30 minutes of pumping capacity Intake well with pump house is generally constructed with R.C.C. as per site

condition. The floor level is kept above the high flood level to avoid submergence of pumps during floods. The floor area shall be enough to provide space for placement of pump motors, control panel, delivery piping and valves

Proper access shall be provided to the intake well for transport of pumps, etc.

For finalization of location of intake works; The Naval guidelines of Inland Waterways Authority of India shall be considered. For proposed location of water intake in the river, necessary permission from IWAI has to be taken to the effect that the intake point does not fall within the navigable channel maintained by IWAI there.

For finalization of location of intake works; The Naval guidelines of Inland Water Way Authority shall be considered.


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In tanks and canals where the fluctuation in water level is not appreciable the raw water can directly flow into the sump of jack well.

The diagrams of intake and raw water collection wells are shown in the Figures 6-1.


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Figure 6-1: Intake Well


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Figure 6-2: Floating Barge Intake


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6.6.2. Impounding Reservoir/Summer Storage Tank

Storage has to be provided for non-monsoon period plus allowance for silt, seepage, dead storage, and evaporation

It is recommended to explore possibility of using an existing tank to minimize the high cost of construction of impounding reservoir

If supply has to be drawn from existing tank or canal it may be drawn from live storage and also have facility for intake works to draw water from dead storage for drinking water supply system

Intake well in SS tank is to be located where dead storage is maximum Layer wise compaction of soils is to be ensured for the bund.

The storage tanks shall be provided for storing the requirement during the canal closer / source dry period. The water requirement of this period with a minimum of 50% extra is provided in the storage towards percolation and evaporation losses.

6.6.3. Sumps

Raw water sump: It acts as an equalizing reservoir which enables the units to work at a constant rate. It is provided for collection of raw water from intake well, and settled water sump is required at places to maintain uniform loading on various units such as filter beds etc.

Clear water sump: It is required for pumping in mains for supply and storage of water. Generally a circular sump is to be designed. Sump capacity is calculated on the basis of inflow and outflow of water at the sump.

6.6.4. Water Transmission lines

Conveyance of water may be by gravity flow and / pressure flow. Gravity pipelines have to be laid below the hydraulic gradient line of the transmission main. Pressure main is to be laid as per profile of the ground surface.

Hydraulics

The design of water transmission line is dependent on resistance to flow, available pressure or head, allowable velocities of flow, scour sediment transport, quality of water and relative cost. There are number of formulae available for use in calculating


Chapter-6 Page 6-16

the velocity of flow. Hazen Williams formula for pressure conduit and Manning’s formula for free flow conduits have been popularly used. In the transmission main, the full flow condition is prevailed so Hazen William Formula is used.

The Original Hazen William Formula:

푄 = 0.85 ∗ 퐶 ∗ 퐴 ∗ (푅) . ∗ (S) .

Where Q= Discharge in Cum/Sec C= Hazen William Coefficient A= Wetted Area of Pipe Conduit R =Hydraulic Radius of Pipe Conduit S= Hydraulic Slope (m/m)

Now the Modified Hazen Williams formula which was derived from Darcy-Weisbach and Colebrook-White equations is used.

Modified Hazen Williams Formula

The Modified Hazen Williams formula is used, for estimation of velocity, discharge and for loss of head due to friction.

The Modified Hazen Williams formula derived as

V = 143.534 CR r0.6575 S0.5525 h = [L (Q/CR)1.81] / 994.62 D4.81 in which, V = Velocity of flow in m/s; CR = Pipe roughness coefficient, (1 for smooth pipes; <1 for rough pipes); r = hydraulic radius in m; s = friction slope; D = internal diameter of pipe in m; h = friction head loss in m; L = length of pipe in m; and Q = flow in pipe in cum/s.

The value of Modified Hazen Williams co-efficient ‘CR’ for different pipe materials and the value adopted for design purposes are given in Table 6-2.

Table 6-2: Hazen William Coefficient Value adopted for design purpose

Pipe Material Recommended coefficient value New pipes Design Purposes

AC, RCC, PSC, HDPE, PVC, GRP, BWSC, SGSW, in lined DI/CI/MS & All New Pipes

1.0 1.0

DI/CI/MS 1.0 0.85 GI 0.87 0.74


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Resistance Due to Specials and Appurtenances

In pipelines there will be several transitions and appurtenances, which will add to the loss of head in addition to friction loss. These are normally expressed as velocity heads i.e.

= KV2 / 2g

Where

V = Average velocity in a pipe of corresponding diameter in m/s g = Acceleration due to gravity in m/s2 K = A specific resistance co-efficient for the specials of appurtenance

The values of K to be adopted for different fittings are given in the Manual on water supply and treatment published by CPHEEO (Latest Edition). However, in a rural water supply system it is recommended to calculate the head loss due to specials and appurtenances at 10% of frictional losses in pipeline.

However for short length segments the following % of losses over friction for account of other losses due to the specials and appurtenances are observed in the RWS field works.

Pipe line segment % on Frictional losses*10

Length < 50m 40% Length < 100m 30% Length < 150m 20% Length < 200m 15%

Water Hammer

Any sudden change in the flow velocity or pressure in a liquid line will produce hydraulic shock (water hammer). It is like a long, rigid spring; being stretched at a uniform speed is suddenly released. A pressure wave would travel back along the spring as it is compressed at the point of stoppage.

The pressure due to water hammer depends on the elastic properties of the pipe material.

퐻 = 퐶푉/푔

C =1425.000√1 + Kd/Et

Where Hmax = Maximum Water hammer head over the working pressure in m. C = Velocity of pressure wave travel m/sec. g = acceleration due to gravity in m/sec2 (9.81m/s2)

10 Technical manual Vol-1 APRWSSP


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V = normal velocity in the pipeline before sudden closure in m/sec. K = Bulk modulus of water (2.07x108 Kg/sq m) d = Inner diameter of pipe in m t = wall thickness of pipe in m E = modulus of elasticity of pipe material

For D.I Pipes = 1.70 x 1010 Kg/Sq.m For PVC = 3.00 x 108 Kg/Sq.m For C.I. Pipes = 7.50 x 109Kg/Sq.m For HDPE Pipes = 9.00 x 107Kg/Sq.m For AC pipes = 3.00 x 109 Kg/Sq.m For PSC pipes = 3.50 x 109Kg/Sq.m For WI pipes = 1.80 x 1010 Kg/Sq.m For RCC pipes = 3.10 x 109 Kg/Sq.m For Steel pipes = 2.10 x 1010 Kg/Sq.m For BWSC pipes = 1.0 -1.5 x 1010 Kg/Sq.m For GRP pipes = 1.0 – 2.0 x 109 Kg/Sq.m

The actual water hammer head can be calculated and added to the working pressure to arrive at the class of the pipe which shall be able to withstand the total head on account of water hammer plus the working head (allowable internal pressure of pipe lines can be increased for shock loads considerations as per the provisions in codes for various type of pipes). Since water hammer head is a function of velocity, choosing a higher diameter pipeline reduces the velocity and hence reduces the water hammer head. However, cost effect has to be studied for choosing higher diameter pipe to minimize water hammer head or changing the pipe material or increasing the pressure class of pipe to withstand the water hammer head.

Special Devices for Control of Water Hammer

Zero Velocity Valve

The principle behind the design of this valve is to arrest the forward moving water column at zero momentum i.e. when its velocity is zero and before any return velocity is established.

With sudden stoppage of pumps the forward velocity of water column goes on decreasing due to friction and gravity. When the forward velocity becomes less than 25% of the maximum, the flap starts closing at the same rate as the velocity of water. The flap comes to the fully closed position when forward velocity approaches zero magnitude; water column on the upstream side of the valve is thus prevented from acquiring a reverse velocity and taking part in creating surge pressures. The bypass valve maintains balanced pressure on the disc and also avoids vacuum on the downstream side of valve if that column experiences certain reversal.

The main advantages of zero velocity valves are:

(i) Controlled closing characteristics (ii) Low loss of head due to streamlined design.


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Air Cushion Valve

The principle of this valve is to allow large quantities of air in the pumping main during separation, entrap the air, compress it with the returning air column and expel the air under controlled pressure so as to dissipate the energy of the returning water column. An effective air cushion is thus provided.

The valve is mounted on Tee joint on the rising main at locations where water column separation is likely. The valve has a spring loaded air inlet port, an outlet normally closed by a float, spring loaded outlet poppet valve and an adjustable needle valve control orifice.

When there is sudden stoppage of pump due to power failure, partial vacuum is created in the main. With differential pressure, the spring loaded port opens and admits outside air into the main. When the pressure in the main becomes near atmospheric, the inlet valve closes under spring pressure. The entrapped air is then compressed by the returning water column till the proper valve opens. With float in dropped position, the air is expelled through poppet valve and controlled orifice under predetermined pressure thus dissipating the energy of the returning water column.

Opposed Poppet Valve

As the name implies, the valve has two poppets of slightly different areas mounted on the same stem. The actual load on the stem is thus the difference in loads on the two poppets and is thus light. A weak spring is therefore, able to keep the valve closed under normal working pressure. If pressure in the water main increases beyond a certain limit, the increase in differential pressure overcomes the holding pressure of the spring, opens the valve and allows water to discharge through both the poppets.

On account of the light spring the valve is able to open quickly and thus reduce the peak surge pressure to the desired limit.

Air Vessel

If the profile of a pipeline is not high enough to use a surge tank or discharge tank to protect the line, it may be possible to force water into the pipe behind the low pressure wave by means of compressed air in a vessel. The pressure in the vessel will gradually decrease as water is released until the pressure in the vessel equals that in the adjacent line.

6.6.5. Economical Size of Pumping Main

The economical sizing of pumping main has to be adopted as it not only economise the capital cost but also recurring cost. For a given discharge, if smaller diameter of the pipes is selected the velocity of flow increases. However the increased velocity results in higher frictional loss and hence increases total pumping head, which requires increased HP of the pump. This leads to higher pumping cost and may offset the reduction in initial cost due to the smaller diameter pipe. Normally, the combined effect is a net increase in cost.


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On the other hand if too large a diameter of the pipe is used the cost of pumping will be less, but the initial investment in cost of pipeline and pumps has an annuity, which depends on the rate of interest and period of repayment of loan taken for capital investment. The annual operating cost of the pumps will vary depending on HP/KW of pumps (depend on size of pipeline). For the most economical condition we must choose such a pipe size, whose annuity due to initial cost together with the annual pumping cost will make the total annual expenditure minimum. The size of such a pipe is called economic size of the pipe.

The most economical size for conveyance shall be based on proper analysis of the following factors:

The period of design considered or period of loan repayment Different pipe sizes against different hydraulic slopes Different pipe materials, which can be used for the purpose and their relative costs

as laid in position The duty, capacity and installed cost of pumps sets required against the

corresponding sizes of pipelines under consideration The recurring costs on energy charges for running pump sets, staff for operation of

the pump sets, cost of repairs and renewals of pump sets, and cost of miscellaneous consumable stores

While selecting the class of the pipe higher of the following shall be considered, twice the working pressure at the top of the bore well and Working pressure at the top of the bore well water hammer pressure

Pressure rating of the Pipe should be decided accounting for the water hammer also. While putting of the capital cost of the pipe line, suitable pipe rating shall be considered considering water hammer pressure as well. The rate of interest on the loan shall be considered as per prevailing rate.

Normally the pipe size required to give a velocity of 0.9 m/sec for a given discharge is worked out and the nearest commercially available size of pipe is selected. In addition two sizes of pipes above and below the selected size are chosen for design purpose. This is done to obtain the size of the pipe, which together with the pumping cost will make the total annual expenditure minimum. In addition, the class of the pipe thus selected shall also be able to withstand the pressure due to water hammer effects plus the static head.

All pumping mains will be designed using the concept of economical size and class of pipe checked for surge pressures as provided in the Appendix 6.5 of CPHEEO Manual on Water Supply & Treatment.

6.6.6. Type of Transmission Pipe Lines

Cost of Pipes incurred a large proportion of the capital investment in water supply sector. Therefore it is utmost important to select the pipe materials in a judicial manner. Two types of pipes are:

1. Gravity Pipelines 2. Pressure Pipelines


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The following provisions should be considered while conducting the structural design of the pressure pipes:

Internal pressure of water including water hammer pressure to be resisted by using materials strong in tension

Pressure due to external loads in the form of backfill and traffic load to be resisted by materials strong in compression

Longitudinal temperature stresses created when pipes are laid above ground to be resisted by providing expansion joints

Longitudinal stresses created due to unbalanced pressure at bends, or at the points of change of cross section – to be resisted by holding the pipe firmly by anchoring it in massive blocks of concrete or stone masonry.

Selection of pipe materials must be based on the following considerations:

The initial carrying capacity of the pipe and its reduction with use, defined, for example, by the Hazen-Williams coefficient C. Values of C vary for different conduit materials and their relative deterioration in service. They vary with size and shape to some extent

The strength of the pipe as measured by its ability to resist internal pressures and external loads

The life and durability of pipe as determined by the resistance to corrosion; to erosion, disintegration and to cracking

The extent of difficulty in transportation, handling and laying and jointing under different conditions of topography, geology and other prevailing local conditions

The safety, economy and availability of manufactured sizes of pipes and specials near the project area

The availability of skilled personnel in construction and commissioning of pipelines The ease is of operations and maintenance.

Pipe of material including of rising main, transmission main, and distribution network shall be selected by the nodal agencies of the respective state based on the specific design requirement including local conditions. This should be governed by the State Pipe Policy.

6.6.7. Laying & Testing of Pipes

Field Hydraulic Test for MS pipelines: After erection at site and after the concrete anchor/ thrust blocks have been constructed. The entire pipeline shall be subjected to a hydraulic test as follows, to the required test pressure as per Clause 11 of IS: 5822. When the field test pressure is less than 2/3 the works test pressures the period of test should be at least 24 hours. The test pressure shall be gradually raised at a rate of 0.1 N/mm2 per minute. If a drop in pressure occurs, the quantity of water added in order to re-establish the test pressure should be carefully measured. This should not exceed 0.1 litre/ mm of pipe diameter per km of pipeline per day for each 30 m head of pressure applied. The contractor shall provide and maintain all requisite facilities, instruments, for the field testing of the material. All pipes, specials, valves and civil works shall be replaced by the contractor free of cost if damaged during testing.

Field Hydraulic Testing of DI pipelines: After the pipes and fittings are laid, jointed and the trench partially backfilled except at the joints the stretch of pipe line as directed


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by Engineer shall be subjected to pressure test and leakage test as per relevant IS codes. Where any section of the pipeline is provided with concrete thrust blocks or anchorages, the pressure test shall not be made until at least five days have elapsed after the concrete was cast. If rapid hardening cement has been used in these blocks or anchorages, the tests shall not be made until at least two days, have elapsed. Each section of' the pipe line shall be slowly filled with water and all air shall be expelled from the pipe by tapping at points of highest elevation before the test is made. The duration of test shall be 8 hours. No pipe installation shall be accepted until the leakage is less than the number cm3/hr as determined by the formula:

푄퐿 = 푁퐷√푃3.3

Where, QL = the allowable leakage in cm3/hr N = number of joints in the length of the pipeline. D = diameter in mm, and P = the average test pressure during the leakage test in kg/cm2

Should any test of pipe laid indicate leakage greater than that specified above, the defective joints shall be repaired by contractor at no extra cost to owner/engineer until the leakage is within the specified allowance. Necessary equipment and water used for testing shall be arranged by contractor at his own cost. Damage during testing shall be contractor's responsibility and shall be rectified by him at no extra cost to owner/engineer. Water used for testing shall be removed from the pipe and not released in the excavated trenches. After the tests mentioned above are completed to the satisfaction of owner/engineer, the backfilling of trenches shall be done as per specifications in layers.

Procedure for Hydraulic testing of Ductile iron (D.I.) / P.V.C.: In case of D.I. pipes the permissible quantity of water added into the pipe during testing in twenty hours of test is 0.1 litre per mm dia./ km. of pipe for a pressure of 30 meters, while that for P.V.C. pipe is 0.15 litre per km. length of pipe i.e. for 10 mm dia. of D.I. pipe it is 1.0 litre and that for 10 mm nominal dia. of P.V.C. pipe is 1.5 litres.

For further details about the P.V.C./H.D.P.E. pipes relevant I.S. specifications are as below:

IS: 7634 (part 1-5), IS: 8008 (parts 1-7), IS: 7634 (parts1-3), IS: 3076 and IS: 4984

For D.I. pipes IS: 8329.

Flushing and Disinfection of Mains: The pipeline shall be disinfected before commissioning for use. After testing the main, it shall be flushed with water of sufficient velocity to remove all dirt and other foreign materials. When this process has been completed, disinfection (using liquid chlorine, sodium or calcium hypochlorite) shall be done as per of IS: 5822.

Laying and jointing of u-PVC and HDPE pipes:

Due precaution in preparation of the trench for lying of pipes should be taken especially in rocky formations to ensure that the trench bottom should be free from any rocky projections. The trench bottom shall be carefully examined for the presence of hard objects such as flints, rock projections, tree roots etc. in fine grained soft soil free from all such objects the trench bottom be brought to even finish so as to provide uniform support to the


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pipes all through its length. In cases of rocky, uneven trench it is necessary to provide a layer of sand or alluvial earth equal one third the diameter of pipe or 100 mm thick whichever is less under the pipes. The trench should be narrow and of width 0.30 mm over the outside diameter of pipe and its depth should be 0.60-1.0 m below the ground depending on the traffic condition at the place. Where heavy traffic will pass across the pipe line proper cover above the pipe shall be provided to ensure that traffic load does not come on to the pipe. In cases where the pipe has to cross some rivulet the pipe should be laid at least 2 m below the bed level (or below scour depth) to protect the pipe from scouring.

Jointing of PVC pipes can be made in following ways:

a) Solvent cement b) Rubber ring joint c) Flanged joints d) Threaded joint.

For solvent cement joints the surface to be glued should be thoroughly be scoured with dry cloth and preferably be chamfered to 30 degree. The solvent cement is applied with a brush evenly to the outside surface of the spigot on one pipe and to the inside surface of the socket on the other. The spigot is then inserted immediately in the socket up to the shoulder and thereafter a quarter turn is given to evenly distribute the cement over the treated surface. The excess cement if any must be removed at once with clean cloth. The time taken in jointing should be minimum not being more than one minute and the joint should not be disturbed at least for the five minutes thereafter as about half strength is only achieved in 30 minutes and full by 24 hours. Gluing should be avoided in rainy or foggy weather as the joint will not gather adequate strength and the colour of cement will turn cloudy and milky due to water contamination.

In case of HDPE pipes, jointing is done by welding of pipe ends .This is done by heat welding where the two ends of the pipes to be welded are heated by holding the ends pressed to the hot plate and afterwards pressing the two ends to each other such that the two pipes become one. HDPE pipes may by jointed using Electro-Fusion Welding with couplers and / or Butt fusion welding. These welding can be done by machines so designed. The Machines are manufactured and marketed by reputed companies. For bending the cleaned pipe is filled with sand and compacted by tapping with wooden stick and the pipe ends are plugged. The pipe section is heated with flame and the portion is bent as required .In case of PVC pipes standard bends are available which are jointed with pipe ends with solvent cement as explained above for pipe jointing. Socket and spigot joints for all PVC pipes are preferred up to 150 mm diameter. The socket length should at least be one and a half times the outer diameter of the pipe for sizes up to 100 mm and equal to the outer diameter of the pipes for sizes more than 100 mm. The pipe lines those are laid earlier, shall be charged full of water and plug at both ends. This would avoid the damage to the gasket and thereby avoiding subsequently leakages when commissioned.

For further details on laying and jointing of PVC pipes, reference can be made to IS: 4985, IS: 7634 (Part-1to3).

Testing of Pipes: After laying and jointing, the pipe line must be pressure tested to ensure that the pipes and joints can withstand the maximum pressure to which it is subjected under


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working conditions in the field. The maximum pressure field test pressure is the maximum out of the following:

a) One and a half times the maximum sustained operating pressure b) One and a half times the maximum static pressure in the pipe line c) Sum of the maximum sustained operating pressure and the maximum surge pressure d) Pressure as mentioned in c) above subject to a maximum equal to the work test

pressure for any pipe fittings incorporated in the pipe line.

The field test pressure should not be not less than two third the work test pressure for the class of pipe used and should be applied and maintained for at least four hours during which in the visual inspection no leakage be noticed. The test period be increased to at least 24 hours. For this the test pressure shall be gradually increased at the rate of 1kg/square cm/minute. If a drop in pressure occurs, the measured quantity of water is added in order to establish the test pressure. The quantity of water thus added should not exceed 0.1 litre per mm of pipe diameter per km of pipe line length subjected to testing for each 30 meter head of pressure applied.

The procedure for the test mentioned above is as follows:

a) At a time one section of the pipe line between two slice valves is taken up for testing which normally is around 500 meters

b) One of the valves is closed and the water is admitted into the pipe from the other. The air must be allowed to escape by manipulating air valves suitably .In case there are no slice valves in the section, one end of the pipe section can be sealed temporarily by fixing an end cap with air relief vent for escape of air during the filling of the line. The pipe line thus filled is allowed to stand for 24 hours before it is tested

c) After filling the sluice valve on the other end is closed and the section is thus isolated. d) Pressure gauges are fitted at suitable intervals on the crown into the holes provided e) The pipe section is then connected to the delivery side of a pump through a small

valve f) The pump is then operated till the pressure inside reaches the desired value

(maximum test pressure as explained above to which the line is to be tested).This can be measured from the pressure gauges fixed

g) On attaining the required pressure the valve is closed on the pump side h) In case the pressure drops a measured quantity of water is added and the pump is

restarted so as to attain the test pressure. This observation is thus carried out for the specified duration and during all this period the test pressure is maintained and the total quantity of water added in the pipe line for maintenance of the pressure is recorded which the idea about the leakage and this should not be more than the quantity as worked out @ 0.1 litre per mm diameter of per kilo meter length of pipe subjected for testing.

It should be noted carefully that during testing the end cap should remain firmly fixed as any disturbance will result into leakage at this end thereby dropping the pressure recorded in the gauge. For this the end cap needs to be properly anchored with wooden planks and hydraulic jack. It has been observed that when the pressure in the pipe line rises the thrust on the planks and hydraulic jack increases such that the same is equivalent to the force equivalent to the area of cross section of the pipe multiplied by the pressure inside the pipe which is at times quite high .The anchorage thus


Chapter-6 Page 6-25

should be at least twice the force so exerted. At times this is also observed that the whole pipe line shift laterally.

6.7. Valves

i) Sluice Valves

Sluice valves as per IS: 14846 on main line is provided to stop and regulate the flow of water in the course of ordinary operations and in an emergency. The principle considerations in location of the valves are accessibility and proximity to special points such as branches, stream crossings, major summit points etc.

Sluice valves of the same size (For smaller dia. pipes used in RWS), as per diameter of the main line pipe are normally used for isolating sections of pipe. Sluice valves are sometimes used for continuous throttling which may cause erosion of seats and lead to body cavitation. Wherever small flows are required, the bypass valve is more suitable for this purpose as compared to throttling the mainline valve.

ii) Scour Valve

Scour Valves as per IS:14846 are the Sluice Valves located in valley portions in the alignment of pipe lines, so as to facilitate emptying of the pipe line whenever required for maintenance of the pipeline. The outlet of the scour valve has to be connected to a natural drain. However, precautions must be taken to ensure that the wastewater from the drains does not enter the water supply pipelines. During installation of the valve, it should be ensured that it is always accessible for operation. A proper valve chamber with locking arrangement is required to protect the valve and prevent misuse. The size of scour valve shall normally be equal to half the diameter of the main line. Protection by way of stone pitching or concrete block beneath the scour valve is required, since the scour water erodes the setting place of valve.

iii) Air Valves

Air release valves as per IS: 14845 is designed to expel air automatically from the pipelines, which tends to accumulate at the high points in the pipeline. Normally in gravity flow pipelines, when the pressure in the pipe falls below the atmospheric pressure, air has to be drawn in, to prevent collapsing of the pipes to prevent the pipe from such collapse (vacuum). Additionally Air valves also release any entrained air which might accumulate at high points in the pipe line during normal operations. For most cases in water works and pumping practice, two types of air valves are required. These are known as a) large orifice air valve and b) small orifice air valve.

Large Orifice Air Valve

The Purpose of this type of valve is to discharge air during filling or charging of mains and to admit air to mains while they are being emptied. They pass air at high rates of flow with small pressure difference either in to or out of the pipes on which the valve is fixed. The ball, which forms the valve element although buoyant, is rigid being covered with vulcanite. During normal service condition this ball is maintained in contact with its seating usually of leather backed rubber by the pressure in the main and cannot leave this seating except when the pressure falls practically to that of


Chapter-6 Page 6-26

atmosphere. This occurs at various sections of a main when it is either being charged or emptied. When the pipes carrying a large orifice air valve, are empty, the valve is open and remains in that position until the ball is carried on to its seating by the arrival of water. Once on this seating and under pressure the valve cannot open and remains in that position even if the pipe is full of air until the pressure drops. It will be seen therefore that this valve will not release air accumulations under conditions of normal working pressure. When such a valve is discharging at a high rate, there is a risk that the ball although lying in a fully open position in the absence of water may nevertheless suddenly be caught in the escaping air stream and closed when it may refuse to open again until the pressure has been reduced. The ball of the valve in such a case would have to be held down during filling operation. This defect has been overcome in a large orifice air valve of the advanced design known as kinetic air valve. In this air valve water or air enters from the bottom side of the ball and the air rushing around the ball exerts the pressure and loosens the contact with the top opening and allows the ball to drop down. When the solid water reaches the ball, however it is at once displaced and instantly closed.

Small Orifice Air Valve

The Purpose of this valve is to discharge air which may accumulate in sections of a main under working conditions that is under the running pressure in the main. The orifice is relatively quite small and is sealed by a floating rubber covered ball at all pressures above atmospheric pressure except when air accumulates in this valve chamber. When air has accumulated to depress the water level sufficiently the ball falls away from out let orifice and the air escapes through this orifice until the water level rises again causing the ball to reseal the orifice. The diameter of the ball in a small orifice air valve is related to maximum working pressure and for a given size of orifice increase with this pressure. The orifice is not less than 2.5 mm in diameter. The size of air valve shall be ¼ to 1/6 of pipe diameter.

Double Air Valves

In many instances both large and small orifice air valves are required at the same point on a main and it is usual in such cases to fit a combined air valve in a single fitting. Double air valve is used for different dia. of pipe:

Valve Size (mm) Diameter of Pipe (mm) 40 Up to 100 50 125 – 200 80 250 – 350 100 400 - 500

Air inlet valves are used at peaks. A manually operated sluice valve is introduced between the air valve and the main pipe to isolate the air valve for the repairs. Normally, air valves are used with size equal to D/4 where D is the diameter of the main pipe on which the air valve is placed.

iv) Reflux Valves

Reflux valves as per IS: 5312 is also called check valves or non-return valves, which automatically prevent reversal of flow in a pipeline. They are useful in pumping


Chapter-6 Page 6-27

mains when positioned near pumping stations to prevent back flow when the pump is shutdown. The reflux valve is normally provided on delivery side of each pump to prevent back flow into pump impeller and to avoid rotation of impeller in reverse direction. The size of the valve is equal to the same size as the pipeline on which it is installed. Reflux valves shall have by pass valves, which can be used for priming in the suction line before starting of the pumps.

6.8. Anchor / Thrust Blocks

Internal pressure including water hammer creates transverse stress or hoop tension. Bends and closures at dead ends or gates produce unbalanced pressure and longitudinal stress. When pipes are not permitted to change length, variations in temperature likewise create longitudinal stress. External loads and foundation reactions including the weight of the full conduit, and atmospheric pressure produce flexural stress.

Bends end closures at dead produce unbalanced pressure and longitudinal stress in the pipeline. Further when pipes are not permitted to change length due to variations in temperature, pipes also expand and create longitudinal stress. Anchorages are necessary to resist the tendency of the pipes to pull apart at bends and restrain or direct the expansion and contraction of rigidly joined pipes under the influence of temperature changes. (Refer Appendix 6.6 of CPHEEO Manual on Water Supply & Treatment for Design of thrust block).

Technical guidelines on Water Pumping Stations & Water Treatment Plants have been elaborated in Chapters 7 & 8 (Volume-1) respectively.

Pumping Stations –Electro-Mechanical Appliances/ Equipment

Chapter-7 Page 7-1

7. PUMPING STATIONS –ELECTRO-MECHANICAL APPLIANCES/ EQUIPMENT

7.1. Pumping Station

The pumping units required for pumping water are housed in a building known as Pumping Station or Pump House. Serious thought must be given to this aspect as a properly designed layout will not only give a neat and pleasant appearance but also results in ease of operation and maintenance. The material for the construction of pumping station should be fire proof. The building of the pump house should offer an attractive look which arouses public faith and confidence in the water supply scheme. Care should be taken to avoid dampness in case of construction of pump house below ground. Necessary provision for semi rotary pump for dewatering floor water should be made. The building should be very well lightened and ventilated. The height of roof should be sufficient to accommodate the functioning of overhead crane. The door openings should be large enough so that the machinery can be taken in and out without any difficulty. In case of large pumping station with a provision of ramp in front of door opening to enable the truck to load and unload crane. Door openings are generally located at one end of the building. The floor of the pump house should be properly sloped to drain off water when floors are washed or when there is water through a leaking joint inside the pump house. Care shall be taken to avoid water entering the electrical equipment’s.

7.2. General Requirements of Pumping Stations

The following points deserve careful thought while deciding the general over all requirements of a pumping system:

Adjust the layout of pumping plant in such a way that there is no suction lift, if possible or there should be minimum suction lift. There should be least possible number of bends particularly on the suction side to keep the losses to minimum

Provide pumps of different capacities of maximum efficiency in case of variation in demand

Provide largest pumping unit in duplicate or make provision for two pumps in reserve

Make provision for overhead travelling crane in case of large installations and various equipment installed in the pumping station should be accessible to the overhead crane without disturbing the other units. In case of vertical pumps with hollow shaft motors, the clearance should be adequate to lift motor clear off the face of the coupling and also carry the motor to service bay

Pumping station should be well lighted and well ventilated Prefer location of the pumping station on the bank of the river instead of bed.

Likelihood of floods, hill slides near the pumping station area should be critically examined.


Chapter-7 Page 7-2

7.2.1. Space Requirement and Layout Planning of Pumping System

The layout of various equipment’s requires skill and experience. Adequate space should be provided around each unit like pump, motor, valves, piping, control panels etc. Additional space should be provided for future expansion. Space requirement of equipment should be based on the catalogue of the equipment. It is necessary to have at least 1.0 m clearance between various equipment’s. Minimum 1.5 m wide unobstructed space should be available throughout the pump house building.

A clear space of not less than 0.914 m (3 ft.) in width shall be provided in front of switch board. If there are any attachment or bare connections at the back of the switch board, the space (if any) behind the switch board shall be either less than 0.230 m (9”) or more than 0.762 m (30”) in width measured from the farthest outstanding part of any attachment or conductor. If the space behind the switch board exceeds 0.763 m in width, there shall be a passage way from either end of the switch board clear to the height of 1.830 m (6 ft).

7.2.2. Foundation

The foundation of pump house building requires careful consideration. The function of the foundation is to transmit all dead load of the structure including weight transmitted by overhead travelling crane and superimposed loads from a structure to the soil on which the structure rests. The width of the foundation is far more important than the depth.

7.2.3. Height of Pump House for the Pumps

7.2.3.1.For Vertical Turbine pumps

Height of Pump House for Single floor pumps house for the vertical turbine is shown in Table 7-1.


Chapter-7 Page 7-3

Table 7-1: Height of Pump House

S.No HP of Pump Pump

floor to corbel top

Corbel top to roof slab

bottom

Pump floor to bottom of roof top

Lifting equipment

1 Up to 50 HP - - 5.5 Monorail 2 51 – 150 HP 5.0 1.5 6.5 Hand operational crane 3 151 – 300 HP 5.5 1.5 7.0 - do - 4 301 – 500 HP 5.5 2.0 7.5 Electrically operated

crane 501 and above 5.5 2.5 8.0 - do -

Source: APRWSSP-Technical Manual

7.2.3.2.For Centrifugal and Submersible pumps:

Height of Pump for Centrifugal and Submersible Pumps in meters is shown in Table 7-2

Table 7-2: Height of Pump Room for Centrifugal and Submersible Pumps

S.No HP of Pump Pump floor

to corbel top

Corbel top to roof slab bottom

Pump floor to bottom of roof top

Lifting equipment

1 Up to 150 HP - - 4.0 Monorail 2 151 – 300 HP 3.5 1.5 5.0 Hand operational

crane 3 301 and above 4.0 2.5 6.5 Electrically

operated crane Source: APRWSSP-Technical Manual

7.3. General Guidelines

Pump room should be constructed near to the source, to minimize the cable size and Length

Construction of a new pump room may be avoided, if the community prefers to use the existing panchayat owned building, if situated nearby the source to minimize the estimate cost

Necessary lighting arrangements inside and outside the pump room should be provided for the convenience of the Pump Operator to operate the Pump set during night hours

Proper earthing should be ensured as per IE rules Pump room door should be fixed in such a way that it can be opened outwards only The pump room shall be constructed for centrifugal/jet pump sets following the

drawings and detailed estimates as per prevailing practice in the states.

7.4. The Basic Concepts of Pump Engineering

A pump is a machine which when driven by power from external source, raises water or any other fluid from lower level to higher level or increases the pressure i.e., it receives mechanical energy and raises the potential energy of fluid. Hence, the pump is just the inversion of hydraulic prime mover. Mainly there are two types of pumps, roto dynamic or dynamic pressure pumps and reciprocating or positive displacement type. The


Chapter-7 Page 7-4

behaviour of positive displacement pumps is much different from that of the dynamic pressure pumps.

When a tank is to be filled in a definite time period, the quantity of water to be delivered in a definite time period is the rate of discharge.

To raise the head of water and to deliver it at a certain rate, power is required to drive the pump. This may be manual, mechanical or electrical. The pump takes power from the ‘Drive’ and delivers it to water. In this it consumes some of the power for itself. Hence the ratio of the power delivered to the water to the power taken from the drive expresses the efficiency of the pump.

Head Considerations

The pump sucks water and discharges it at a specified point. So the total head of the pump consists of two parts: (1) suction side head (2) delivery side head.

Suction Side: On suction side, the pump draws water either (a) from the suction sump wherein water is below the centre line of the eye of the pump, or (b) from a suction well where in level of water is above the centre line of the eye of the pump.

When the suction level is below the centre line of the pump, the pump (1) lifts water through the distance between the centre line of the pump and the suction water level when the pump is working. This is called static suction lift (hss). (2) the pump also overcomes the frictional losses in the suction pipe line and pipe fittings.

Suction Lift (hs): This is the total of static suction lift (hss), the frictional losses in suction piping and the entrance losses at the beginning of the suction piping (hfs) and the pressure reduction due to velocity in suction pipe (numerically equal to the velocity head; (Vs

2/2g).

Therefore hs= hss+hfs+Vs2/2g

Suction lift as measured on the test bed is the reading indicated by vacuum gauge or water or mercury manometer at the suction side of the pump plus or minus the vertical distance between the point of the gauge or manometer and the centre line of the pump, according to the point of attachment of gauge above or below the centre line of the pump.

Delivery Head (Hd): This is the sum of (i) static elevation difference between pump centre line and delivery point + (ii) Head loss in the delivery line.

Total Head (H): The total head of the pump comprises of (1) the suction head and (2) delivery head. It may be noted that the total head would be either the addition of suction lift head and delivery head or the difference between the delivery head and suction head as the case may be.

The total head is called the Pump Head, Pump Total Head or Total Dynamic Head. The total head H developed by the pump is customarily meters of water column in metric measure. Head in meters can be converted into pressure in kg/cm2 by dividing the head in meters by 10 (1kg/cm2 = 10 m head of water), Average fluid velocity V, is in meters/second (m/sec) where V = Q/A, Q is discharge in m3/sec and A is cross sectional


Chapter-7 Page 7-5

area of flow passage in square meter (m2). Acceleration due to gravity g, in meters/Sec2 is assumed to be 9.81 m/Sec2.

Friction Loses or Friction Head in Piping System

This is the equivalent head required to overcome the resistance of pipe, valves (foot valve, gate valve, non-return valve etc.) and fittings (couplings, elbows, bends, tapers, tees, reducers etc.) Friction head exists both on suction and delivery sides of the pump and varies with the flow rate, size of piping, interior condition of pipe and type of pipe.

Various type of friction losses are given below:

a) Loss of head in pipes b) Loss of head due to enlargement of cross section of pipes c) Loss of head due to contraction of cross section of pipes d) Loss of head due to bends in pipes e) Loss of heads due to pipe fittings such as tees, valves, expansion joints and strainers

with foot valves etc.

7.5. Classification of Water Pumps

The pumps are categorised as given below:

7.5.1. Vertical Turbine Pump

For obtaining ground water, bores are drilled even up to 150 m depth. The pump used under this situation is a multistage pump with vertical spindle. The pump is kept well under water. All the impellers and at least 3 m of suction pipe, with a strainer at the end, are placed below the water level. The motor or the engine is fixed on the ground level. The vertical shaft is co-axial with the rising main or delivery pipe and it is supported by several bearings which are water lubricated. This pump has an overall efficiency of about 70% to 80%. Such pumps are capable of discharging 300 to 52000 litres/minute. These pumps are used for lifting water from deep tube-wells.

In turbine pumps water flows in general direction of the axis of the pump through number of stages depending upon the head required. This pump is very compact. A powerful pump can be built in small dia. bores holes when larger flows are required. This pump works at much higher speed, which makes the system compact and lighter but it renders it more liable to break down and more difficult to repair.

When pump is driven by an engine, a belt drive is employed for small and medium type pumps and toothed gearing for large sizes. The advantage of directly coupled pumping set is that it requires about 25% less power. It is necessary to have impellers and guide vanes made of corrosion resistant metals. The deep well turbine pump installation practically seals tube well from the exterior, thus protecting water from contamination.

Criteria for selection of Turbine Pumps requires following details

Dia. of open well or bore well If bore well, dia. and length of tube along with total depth


Chapter-7 Page 7-6

If bore well, whether it has been tested for verticality and if tested, results of verticality test

Depth of water level from the ground level in the driest season Expected depression in water level at the specified discharge Quantity of water required in lpm Vertical static height from the ground level to the delivery outlet point Running length and size of delivery pipe Number and sizes of fittings to be used on the delivery side Type of driver, electric motor or engine In case of electric motor, volts, cycle etc In case of oil engine drive, full particulars of engine, engine pulley dia and direction

of rotation of engine.

7.5.2. Submersible Pumps

The submersible pumping set should conform to IS: 8034 with latest amendment. The pump should be fitted with dynamically balance enclosed type impeller. Each impeller shall be balanced dynamically to grade of G 6.3 (6.3 mm/s). The pump shaft shall be guided by bearing provided in each stage bowl. The surface finish of shaft or of the protecting sleeves should be 0.75 micron Ra Max. The inlet passage of the suction casing shall be stream lined to avoid eddies. The suction case shall be fitted with a strainer of corrosion resistant material. Suitable sand guard shall be provided just above the suction case bearing to prevent the entry of foreign material into suction case. The pump should be provided with the non-return valve above the pump discharge case with standard flanged connection. The individual casting part or pump as a whole in assembled condition should be able to with stand a hydrostatic pressure of 1.5 time maximum discharge pressure. The gaskets & seals used shall conform to IS: 5120. The cable clamp of adequate size is supplied for fixing submersible cables to the rising main pipes.

The pump shall be directly coupled to a submersible motor. The submersible motor shall be squirrel cage induction motor conforming to IS: 9283 or latest capable of operating on 415+ 6% volts, 3 phase 50 cycles. A.C. supply both pump and motor shall run at 2900 R.P.M. The water lubricated thrust bearing should be of adequate size to withstand the weight of all rotating parts as well as the imposed hydraulic thrust. The motor shall be protected by means of cable glands, rubber seals etc. from ingress of bore well water, sand and other foreign material. The motor shall be provided with breathing attachment like bellows, diaphragm etc. to compensate the volumetric variation due to change in the temperature. The motor shall be made of corrosion resisting material or suitable materials to resists corrosion under normal conditions. The rotor shall be provided with shaft protecting sleeves having a surface finish of 0.75 micron. The starter shall be star delta. Submersible cable of standard make for submersible motor shall conform to IS: 694 (Part-III). The flanged column pipe shall conform table 2 IS: 1239 (Part-1) or latest (Medium Class) Table – 2.

Normally they are installed at 1.5-2.0 m below the lowest safe yield level (means water level after drawdown) during summer under continuous operation. Hence it is necessary to install electronic water level indicators to read the water level in the bore well ensuring the required minimum submergence (1.5m) also to avoid drawing of the silt/sand from the bottom. It is preferable that the lowest part of the pump is 3m above bottom of the well. The casing pipe is taken to a height of about 45cm above the ground level and is


Chapter-7 Page 7-7

covered with a bore cap. The H.P of motor shall be 15% in the excess of maximum H.P required under all heads of working. Performance guarantees shall be based on laboratory tests corrected for field performance.

Submersible pumps are often a ‘tight’ fit in tube well as their outside dia. is usually only 1-2 cm less than the internal hole of the well casing. Consequently great care is needed during installation and removal of these pumps. A water proof electric cable connects the motor.

7.5.3. Jet Pump

In this type of pump the kinetic energy of high velocity jet of water is converted into water pressure in the portion of suction pipe immediately following a restricted opening or throat similar to discharge of venturi-meter. These pumps are also called sometimes Ejector Pumps. These pumps are less efficient than any other type of pump discussed so far but these have certain advantages which make these pumps suitable for very small supplies where conditions favour their installation. Jet pump is essentially a small centrifugal pump which forces water down a well at high pressure. This high pressure water, issuing from a jet into the throat of a venture tube, causes a larger volume of water at lower pressure to be delivered from the rising main. In this type of pump priming is necessary. Unless the whole system is filled with water, the operation will not start.

The jet pump should not be installed where the suction lift is less than 6 m because a more efficient centrifugal pump can work under this situation in a better manner. Jet pumps work normally with a lift ranging from 6 m-55 m below ground and discharges range 570 lph to 22500 lph against a delivery head of about 15m. At all times jet must be covered by at least 1.5m of water so that well is not emptied completely.

7.5.4. Horizontal Centrifugal Pump

The specification covers the design, performance, manufacturing, shop testing, and erection, testing and commissioning at site of the horizontal centrifugal pumps.

The design, manufacture and performance of the horizontal centrifugal pumps shall confirm to the latest revisions of the following codes and Indian Standards, in addition to other stipulations and standards mentioned elsewhere in the specification.

IS: 1520- Horizontal centrifugal pumps for clear cold fresh water IS: 5120- Technical requirement roto dynamic special purposes pumps IS: 5639- Pumps handling chemicals and corrosive liquids IS: 5659- Pumps for process water

7.5.5. Vertical Centrifugal Pump:

The specification covers the design, performance, manufacturing, shop testing, erection, testing and commissioning at site of the vertical centrifugal pumps.

The design, manufacturer and performance of the vertical centrifugal pumps shall conform to the latest revisions of the following codes and Indian Standard in addition to other stipulations and standards mentioned elsewhere in the specification.


Chapter-7 Page 7-8

IS: 1710 Vertical Turbine Pumps for clear, cold, fresh, water.

IS: 5120 (with latest revision) Technical requirements for roto dynamic, special purpose pumps.

The material of construction for the various components of the pumps shall conform to the applicable standards like ‘American Society of Testing & Material (ASTM)’ and Indian Standards.

7.6. Pump Efficiencies

Pump efficiencies:-This varies with type of pumps and the manufacturer’s propriety designs. At the time of selecting and testing of pumps the specific characteristics of the pump should be obtained. Along with these the motor characteristic should also be made which gives motor output and motor efficiency relationship. Based on these the suitable motor and pump be selected.

7.6.1. Energy Efficient Pumps

BEE STAR RATED ISI marked Submersible pump sets to IS: 8034 with Amendment No. 1, suitable for bore size 100 mm, for use in bore wells for handling clear cold water having motor to IS 9283: 2013 with amendment. 1 & 2 of wet type for continuous rating operating at 3000 rpm synchronous, suitable for 415 V +/- 6%, 3 Phase AC supply and specifications.

7.7. Choice for the Type of Pump and Selection of Pump

Prior to the selection of a pump for pumping station, detailed consideration has to be given to the various aspects as follows:

a) Nature of water, whether raw or treated b) Type of duty required i.e. whether continuous, intermittent or cyclic c) Present and projected demand and pattern and pattern of change in demand d) The details of head and flow rate required e) Type and duration of the availability of the power supply f) Selecting the operating speed of the pump and suitable drive/driving gear g) The efficiency of pump and consequent influence on power consumption and the

running cost h) Various options possible by permuting the parameters of the pumping system,

including the capacity and number of pumps including stand byes, combining them in series or parallel

i) Options of different modes of installation, their influence on the costs of civil, structural constructions, on the case of operation and maintenance and on the overall economics.

The final selection of the pump should be done in considerations of the parameters of head, discharge and speed as per Para 11.1.4 of CPHEEO Manual on Water Supply & Treatment. For consideration of the suction lift capacity in the pump selection, Para 11.1.5 and for consideration of the system head curve in pump selection, Para 11.1.6 of the same CPHEEO Manual may be referred.


Chapter-7 Page 7-9

In general the application parameters and suitability of various types of pumps are presented in Table 7-3.

Table 7-3: Application of Pumps11

Pump type Suction-capacity to lift Head Range Discharge range Low 3.5m

Medium 6 m

High 8.5 m

Low upto 10 m

Medium 10–40 m

High Above 40 m

Low upto 30 L/s

Medium Upto 500 L/s

High Above 500 L/s

Centrifugal horizontal end-suction

OK OK OK OK OK No OK OK OK

Centrifugal horizontal axial split casing

OK No No OK OK No No OK OK

Centrifugal horizontal multistage

OK OK No No OK OK OK OK No

Jet – Centrifugal combinations

When limitations of suction lift are to be overcome

OK OK No OK No No

Centrifugal vertical turbine

When suction lift is to be avoided

OK OK OK OK OK OK

Centrifugal vertical submersible

When suction lift is to be avoided

OK OK OK OK OK OK

Positive displacement pumps

Normally self priming Limited only by the pressure which casing can withstand

OK OK No Easy adaptation for dosing of meter.

7.8. Installation of Pumps

Pump installation: Most pumps to be mounted horizontally are supplied as fully assembled unit while those to be mounted vertically are supplied as sub-assemblies. The installation has to be under taken in following five stages:

i. Preparing the foundation and locating the foundation bolts ii. Locating the pump on the foundation bolts, however resting on levelling wedges

to permit easy levelling and also filling the gap with grout iii. Levelling iv. Grouting v. Alignment

7.8.1. Foundation

The right type of foundation is most important for the success of any pumping installation. All pump installations require base plates and foundation blocks. The foundation block for the pumping unit is designed for (a) weight of the pumping unit, (b)

11 CPHEEO Manual on Water Supply & Treatment-Latest Edition –Table 11.3


Chapter-7 Page 7-10

weight of concrete foundation block, (c) area of foundation block (d) isolation of foundation block from the surrounding structure to absorb the vibration.

In order to meet the above requirements, the foundation block must be adequate in size and mass, rest on an adequate bearing surface, provide an accurately finished mounting surface and be provided with necessary anchor bolts. The size of the foundation concrete block and anchor bolts are generally supplied by the manufacturers of the pumping units.

The size of foundation block depends upon the dimensions and weight of the pumping unit. The following minimum standards are recommended:

a) Length and width of foundation block should exceed the length and width of the base plate of the equipment by minimum 15 cm on either side. The position of holding down bolts generally determines the width and length of the base

b) The depth should be adequate to provide weight equal to 1.3 to 1.5 times the weight of the equipment and that there is sufficient depth to accommodate the holding down bolts properly. The weight of the foundation block should be sufficient to counter-act the sliding against horizontal thrust and to resist the uplift effect. The depth of the base must be such that the bottom is on satisfactory bearing stratum

c) The area of the concrete block for machinery must be sufficient to spread the load on the ground without exceeding the safe bearing pressure. The centrifugal pump owing to common fabricated base plate and adequate holding down arrangements create vibration to nominal extent. When vibration is transmitted to ground, the bearing pressure considerably decreases in comparison to as generally assumed for the class of ground upon which the base bears

d) The foundation anchor bolts used to hold the equipment in place should be of the material recommended by the manufacturer of the equipment. Anchor bolts are usually supplied by the manufacturer along with the equipment. The diameter of bolts is according to the mounting holes of the equipment. The length should be equivalent to minimum embedded length of 30 times the dia. plus necessary length for J or L hook. An additional 14 to 15 cm length should be provided above the top surface of foundation for grouting sole plate, shims, equipment base washers and nuts, plus small variations in surface level of the foundation block. While laying the foundation block concrete, the location of holes is left in concrete, with the help of a sleeve of pipe or by some other suitable means to allow for adjustment required for the bolts to conform to mounting holes locations. The holes are filled in with concrete after fixing in position the pumping installation

e) It is very important to isolate the foundation block of the equipment from the building structure because of vibrations. Cork rubber or lead sheet is used in case of heavier pumping installations. Manufacturer’s instructions should be followed in respect of isolation materials. Cork or lead sheet is provided between the foundation block and the lower soil. Isolation can be obtained by filling in sand between the foundation block and the side soil. For continuous vibration due to machinery, an allowance of 25% or more by increasing the total load should be made. A single base should be provided under various supports of pumping machinery and sudden changes in depth and width should be avoided

f) Chain pulley blocks or overhead crane is required for the installation, maintenance and repair of the pumps and motors. Depending upon the requirement and the weight of different component of the machinery, simple spur gear pulley blocks with high tensile steel chains, single or double girder type, hand operated or power operated over-head cranes are provided for handling the equipment. Despite the increasing use


Chapter-7 Page 7-11

of power operated overhead cranes, there remain many situations where the use of hand operated crane is ideal either for economic or operational reasons. Following types of girders are required as follows :

Double Girder Type

(Capacity 2 to 25 tons. Span 3 to 15.25m)

Heavy structural steel sections are bolted to fabricate steel end carriages to form a rigid and stable bridge structure. Four double flanged tram wheels carried on fixed axles carry the crane. Two of these tram wheels are given to provide the long travel motion, the effort being applied to a larger dia. Chain wheel keyed on to steel shaft spanning the full length of the cane bridge.

Single Girder Type

(Capacity 1/2 to 10 tons, span 3 to 15.25m)

The single Girder is basically similar in construction to the double girder crane, the two bridge girders being replaced by a single girder, with the hoisting unit built into a trolley which travels along the lower flange of the girder. The basic hoist unit is the worm gear pulley block which can be arranged for either push or hand gear travel.

7.9. Limitations on Use of Pumps

Do not run the pump: Well beyond the recommended range of the particular pump Without lubricating the bearings with grease or oil, as the case may be With liquid other than specified With less NPSH than recommended With delivery valve completely closed for longer period When misaligned Without lubricant to the stuffing box either internal or external Unless periodically checked When undue weight on suction and delivery side flanges Without proper priming When strainer is removed from suction.

7.10. Automation Aspects of Pumping Plants

For efficient and cost effective aspects of the Pumping Plants, automation of pumping plant is required. Following aspects should be considered for automation of pumping plant:

1. As the electric supply is erratic in rural/remote areas, the potable water supply is also affected by the same. IC is very important to utilize the electrical motor of pumping plant at “off peak hours” to get rid of power scarcity at “peak load hours”. So for these requirements, some sort of automation, rather involvement of


Chapter-7 Page 7-12

“Artificial Intelligence” is required to minimize the manual errors in the operation only

2. In water tanks provision of over flow is very common phenomenon. Due to slight human carelessness, plenty of potable water is being wasted. As potable water is precious, it’s proper management is necessary for the survival of human race. Thus some device which can regulate and optimize the required amount of water and conservation of energy due to need based automatic run of the motor has become necessary

3. Human being has their own limitation. Manual operator can’t observe the control panel continuously and thus they can’t prevent the damage caused by nuisance in power system e.g. single phasing, over loading, tripping & restoring of fault/healthy condition momentarily. Further to detect & rectify the dry running condition is beyond the human control without observing the panel continuously during their (pump operator) duty period; continuous observing is simply impractical by all means. Hence the motor is exposed to extensive damage

4. For optimum and judicious use of power, we need time controlling devices. We should prevent the pump/motor to get operated at “peak load hours” & allow the operation of motor/pump at “off peak hour”. This will provide us continuous supply of water and at the same time maximum judicious utilization of power supply too. This system/concept is also necessary for booster pump water supply system (Direct injection system) by the help of pre-set timer

5. We need to record the total/cumulative hours for which motor has run. By the help of it we could calculate the total amount of water pumped by the plant, efficiency of motor, condition & level of ground water can be analyse. This will help us to minimize/optimize the electrical energy/ ground water use

6. Mechanization has made human beings dependent on automation. For uninterrupted water supply if a motor/pump burns out, damaged extensively or fails to operate in time the masses will suffer beyond the imagination.

7. Hence the device, we need should provide us all the above condition on a compact display system which will help in its effective monitoring.

8. Keeping in the view the socio-economical factor, scarcity of potable water in future and maintenance/operation problems the automatic pump operating system have been designed, developed and produced in India by some of the firms

9. The “Automatic Controller” a dedicated designed controller (on digital signalling principle) will regulate the ON/OFF of electric motor for maintaining optimum desired level of water in tank/reservoir in all weathers all the time. This will minimize the wastage of precious potable water & wastage of electric power & on other hand, uninterrupted water supply to the masses.

10. “Single Phasing preventer” prohibits the use of motor/pump under faulty conditions i.e. single phasing and unbalanced power supply & provides 3 second time delay system as well

11. “Dry Running Preventer” is there to stop the motor under dry condition to protect it to get burnt. “Overload Relay” is there as first line protection device; it protects the motor in overloading condition

12. “Back up protection” is provided as second line protection by HRC fuse links 13. Time controller device/feature restricts/allows the motor to run according to preset

time slot. Approx. 45 time settings can be fed with minimum time slot of 20 minutes and there is no limit for the maximum time set. The clock can run even for150 hour in one set and is regulated by rechargeable batteries


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14. Pumping time recorder records the total time for which motor has run & by it, one can calculate the total water lifted. The recorder can record 99,999,99 hours Cumulatively and will get reset automatically

15. “Artificial Intelligence” is provided in this system to synchronize all the components with each other. In simple, it the replacement of “human intelligence”

16. As no system is fool-proof, but failure must be on safer side. Keeping this view in mind Auto/Manual changeover switch is provided for manual operation at will, especially when we desire more water than present time

17. Display panel should be very compact, precise & clearly visible 18. It should be robust and pleasantly powder coated and vermi proof, corrosion free

and well ventilated 19. The manufacturer should provide warranty of one-year time, with prompt and

effective after sales service.

For detailed specification on Automation of pumping plant, Chapter-11 on SCADA & (Volume-1) may be referred.

7.11. Pump Priming

When the pump is at rest for some time, water leaks from the casing of the pump and suction pipe and to suction sump. The casing and the suction pipe thus remain filled with air. If pump is started under this condition, it will produce only negligible pressure difference across the impeller which is inadequate for the creation of proper vacuum to enable water to rise along the suction pipe to reach the impeller. It becomes, therefore, necessary to first fill up suction pipe and casing of the pump with water. This filling up operation is termed as ‘Priming’.

There are several priming methods which may be used for many types of pumps:

1. With a flooded suction 2. A bypass around the discharge check valve 3. The separate air drawing pump from the casing at the main pump to give priming

action 4. An ejector for priming 5. A priming tank holding the supply of water 6. Vacuum pumps manually and automatically controlled to prime the main pump.

In case of small pumps, priming is accomplished by pouring water directly in the casing through a funnel. The air vent cocks provided over the casing are kept open for expulsion of air during priming process. When the air has completely been displaced from the pump casing and suction pipe and the piping system on suction side is throughout filled with water, the air cocks are closed and the pump started.

7.12. Pump Accessories

Foot Valve

This is a sort of check valve which is fitted at the bottom or foot of the suction line. The foot valve remains open while the pump is running. When the pump is stopped, the foot valve closes and it prevents water in the suction line to drain back to suction sump as long as the seat of the foot valve closes tightly.


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At several occasions the foot valve falls to seat tightly and suction piping gets emptied. In most of the cases the rate of leakage is small and it is usually possible to start the pumping after doing required priming of the pump. In case, water being pumped contains small particles of foreign matter, the trouble is further increased. Another big disadvantage in the application of foot valve is that it has high frictional loss.

The foot valve should be of hinged flap type with a clear passage for water of at least the same area as that of the suction pipe. The foot valve should be provided with an efficient strainer to prevent foreign matter from being drawn into the pump. The clear area of the openings of the strainer should be at least 3 times the area of suction pipe for clear water. Much more area is required for water containing foreign matter.

Suction Sump and Suction Piping

For best results, the sump or sump bays are located parallel to the direction of flow. In case the flow approaches from an angle it creates high local velocities and dead spaces which result in non-uniform velocity and increase in entrance losses. The pipes should be arranged in such a manner that the flow to any pump should not be required to pass another pump before reaching it. The inflow in the suction sump should be at the farthest end from the suction pipe to avoid effect of turbulence.

Delivery Pipes and Fittings

A check valve (non-return or reflux valve) and a gate (sluice) valve is installed on the delivery line. The check valve is fixed between the pump and the sluice valve to protect the pump from abnormal pressure and to avoid water getting back though the pump upon shut down or power failure. The sluice valve is used for priming operation and starting. The sluice valve is closed before stopping the pump. When a reducer is required in between pump delivery end and delivery line because of the change in diameters of the two, the reducer is fixed between the reflux valve and the pump. Pressure relief valves, air valves, reflux valves and scour valves are also provided on the delivery line.

Mani folding the discharge header is a usual practice in the design because with this parallel operation can be achieved readily. Interconnecting of discharge headers affords additional system flexibility and added protection in the event of pipe failure.

Devices for reducing water hammer effect will provide a fairly good idea of the requirement of fittings required for a particular system. The design of discharge and suction line required to be connected with reciprocating type pump is done with about 50% in excess of the normal working pressure

The discharge piping should be supported close to the pump flange to prevent vibration and strain on the pump casing. The velocity in the delivery pipe is usually 1.5 to 3.5 m/sec, generally about 2.5 m/sec.

A pressure gauge is fitted on the delivery side to indicate pressure during the working of pump.


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The sluice valve on delivery side of the centrifugal pump must be closed when the pump is being started and till it builds up pressure.

7.13. Motors

7.13.1. Capacity

The power required to drive the centrifugal pump from shut off to maximum capacity varies. Power requirement is minimum at shut-off head and maximum at or near the maximum capacity. Operations of pumps at heads below the normal increase the load of the drive and sometimes causes overload.

Therefore in order to avoid continuous overloading of the electric motor, the rated KW of the motor should exceed the KW calculated by the following percentages:

For a pump requiring up to 1.5 KW, add about 50% For a pump requiring from 1.5 to 3.7 KW, add about 40% For a pump requiring from 3.7 to 7.5 KW, add about 30% For a pump requiring up to 7.5 to 15 KW, add about 20% For a pump requiring up to 15 to 75 KW, add about 15% Above 75 KW about 10%.

Electric motors below 1/3 hp are not used for driving pumps. For 50 c/s frequency, the speed of an induction type motor may be about 1450 to 2900 rpm. Indian Standard 6295 specifies an allowance for the falloff overall efficiency up to 2% for electric motors for every 300 m altitude above mean sea level. Care should be taken in selecting the motors. It should be large enough to avoid overload and not too large that power is wasted.

7.13.2. Performance of Motors

Motors are designed to produce their rated horsepower, torque and speed at specific line voltage, line frequency and ambient temperature. The motor will work at a specific efficiency and power factor when all these conditions are met.

The normal operating conditions of a motor are indicated on its name plate with values of horse power, speed, ambient temperature and frequency. Any change in conditions from the motor name plate will change the performance of the motor.

7.13.3. Energy Efficient Motors

In line of provision of the Energy Conservation Act 2001. It is the requirement of the day to reduce Specific Energy consumptions to keep loads to the minimum. Electric Motors consume substantial energy in water supply pumping by providing energy efficient motors. We not only limit the initial power load but also energy consumption is reduced considerably. Efforts have been made to reduce the power loss due to heat generation in motor to the extent of 40% by using best quality of materials. That makes motor efficient to draw lesser power from the system. Based on the International Standard IEC 60034-30 (2008), the Bureau of Indian Standard (IS) have released IS: 12615 which defines new Efficiency Classification of single speed, three phase induction motors. The new range of motors not only reduces energy consumption but also lead to higher energy savings. For


Chapter-7 Page 7-16

example if a 75 kW Pole premium motor is used instead of standard efficiency motor at 85% full load for 5840 Hrs. (1 Year of running the total saving from only one motor will be about 9000KWh).

The method of cooling shall be governed as per IS: 6362. The motors are to be operational at nominal voltage and frequency with tolerance as per IS: 325. Government of India has constituted a statuary body by the name of Bureau of Energy Efficiency (BEE) under the Ministry of Power. The bureau rates the different electrical equipment’s on the basis of their energy efficiency and awards different number of stars, 5 for highest energy efficiency.

For various star ratings, overall efficiency shall be as follows:

Star Rating Overall efficiency as per IS: 8034: 2002 4 Star >= 1.15 & 1.20 5 Star >= 1.20

The cost of motor also increases accordingly. Thus over all economics may be worked out based on capital cost of motor along with capitalised value of the recurring expenditure per year for the working life of the motor.

7.13.4. Voltage

Motor is designed to operate through 3 phases, 50 c/s, 415 + 6% & 415 – 15% voltage AC supply. It shall operate satisfactorily at the name plate rating with + 10% variation from name plate voltage. Within + 10% voltage, a motor is expected to operate pump safely and continuously. If the motor voltage never increases beyond 70%, the centrifugal pump would not reach normal operating speed.

Different motor voltage from name plate rated voltage will affect the motor speed, power factor and efficiency established for rated voltage and load.

7.13.5. Single Phasing on Three Phase Motor

Occurrence of single phasing on three phase motor will cause overheating and possible burnout. Theoretically a three phase machine will not start on single phase but in the running position if one lines is broken motor will continue to run but with unbalanced current loading as described below:

In case of both star delta connecting motors, a break in one phase of the supply means that the output taken from the machine must be reduced to less than half of the normal output. To minimize the risk of such a break in one phase of the supply, check the distribution fuses. They should have the capacity of at least three times the full load current rating of the motor.

7.13.6. Earthing

Various types of earth electrodes in use are Rod and Pipe electrodes, Strip electrodes and Plate electrodes. Round and flat sections of copper and GI wire are used for earthing purpose. No earth wire shall have cross sectional area less than 3 mm2.


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7.14. Design of Machine Foundation

Depending on the type of pumps the structural support of the pump shall be designed. For example the vertical turbine pumps which have motor at the top supported on girders and the pump submerged in water along with the assembly shall have proper structural support to take care of pump and assembly loads along with the load of pump, the water inside the piping as well as the extra load on account of vibrations. The centrifugal pumps inside the dry sump are supported on the floor through the base plate fixed on the pump block. For such installation the foundation should be adequate to absorb vibrations and to form a permanent rigid support for the base plate. The capacity of the soil should be adequate to withstand the entire load of the foundation and the dynamic load of the machinery. Thus the total load in such cases will be as below:

a) Construction loads b) Three times the weight of the pump c) Two times the weight of motor.

In case of vertical turbine pumps additional load of water in the column pipe as well as half of the weight of the unsupported pipe connected to the pump flange has also to be taken into account. Depending on the safe bearing capacity of the soil at times it becomes necessary to spread the load through providing a raft in the floor of the slab. Based on the total load and the bearing capacity of the soil at times pile foundation may become necessary. The structural designs have therefore to be done as per overall design of the pump house structure.

Foundations for the machines have to be specially designed taking into consideration the impact and vibration characteristics of the load and the properties of soil under dynamic conditions. While many of special features relating to the design and construction of such machine foundation will have to be as advised by the manufacturer of machine, still a large part of the details will have to be according to certain general principle of design covering machine foundation. There may be different type of machines requiring foundations of different types and such different foundations shall have to be designed based on the design guide line laid down in respective codes relating to type of machine. Such as reciprocating machine requires rigid type foundation and impact type machine requires hammer type foundation. As already mentioned properties of soil under dynamic conditions plays an important role in achieving successfulness of the particular machine foundation in topic. Pumping plant (machine) foundation is one of them and it is designed with respect to relevant code. As already explained the manufacturer has to provide relevant data for designing apart from those available in relevant IS code of practice. IS: code 2974 (part- 4) seems to be best suited for design of pumping plant machine foundation.

Following Table shows IS Codes references (With latest revision) for designing of machine foundations:

Ref to IS code Type of Machine Type of foundation/ Any other comment

IS: 2974 (Part -1) Reciprocating Machine Rigid block foundation IS: 2974( Part -2) Impact Type Machine Hammer foundation( drop & and

forge hammer foundation) IS: 2974 (Part -3) Rotary Type Machine of Med & High


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Ref to IS code Type of Machine Type of foundation/ Any other comment

Frequency IS: 2974 (Part -4) Rotary Type Machine of Low Frequency < 1500 rpm. Used for crusher,

pumps, motor, generator, compressor and rolling mills

IS 2974 (Part -5) Impact type Machine other than hammer ( forging, stamping press, pig breaker, elevator, hoist tower, drop hammer& jolter)

Foundation supporting impact causing machines and equipment other than hammers.

7.15. Electric Connections

Electric connections: A control panel has to be installed for which space requirements have to be provided as per I.E. Rules which are as below:

(i) A clear space of 915 mm in width in front of switch board, where circuit breakers are to be installed recommendation of the manufacturer be followed for the requirement of the draw out space

(ii) If there are any attachments or bare connections at the back of the switch board, the space, the space behind the switch-board shall be less than 230 mm or more than750 mm width

(iii) If the switch-board width is more than 760 mm, there shall be passage-way from either end of the switch-board clear to a height of 1830 mm.

The various provisions to be made in the panel are:

1) For receiving the supply- circuit breaker or switch and fuse units 2) For distribution-bus bar, switch fuse units, circuit breakers 3) For controls-starters; level-controls and time delay relays, if needed 4) As protections- under voltage relay, over-current relay, hot fault relay, single phase

preventer 5) For indications and readings-phase indicating lamps, voltmeters and ammeters.

For different ranges of voltage, various type of cables shall be used. These are described as below: S. No.

Range of voltage Type of cable to be used IS Ref

1. 10-230 V or 30 -415V

PVC insulated, PVC sheathed IS 1554 (Part-1)-2010

2. Up to 6.6KV PVC insulated, PVC sheathed XLPE , Cross linked, Polyethylene Insulated, PVC Sheathed

IS 1554(Part-1)-2010 IS 692-2010 IS 7098-2011

3. 11 KV Paper Insulated, lead sheathed IS 692-2010

The size of cable should be such that the total drop in the voltage calculated as resistance multiplied by current is less than 3 % of the voltage.

Following points should also be considered while selecting the size of the cable:


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(i) The current carrying capacity should be appropriate for the lowest voltage, the lowest power factor, and the worst condition of the installation i.e. ducts condition

(ii) The cable should also be suitable for carrying the short circuit current for the duration of the fault

(iii) The duration of the fault should preferably be restricted by 0.1 second by proper relay setting

(iv) Appropriate rating factors should be applied when cables are laid in group parallel and /or laid below ground

(v) For laying cables suitable trenches or racks are provided.

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8. WATER TREATMENT

8.1. General

The aim of Water Treatment is to produce and supply water that is hygienically safe, aesthetically attractive and palatable, in an economical manner. Though the treatment of water would achieve the desired quality, the evaluation of its quality should not be confined to the end of treatment facilities but should be extended to the point of consumer use. In this, different operations are carried out for making raw water obtained from various sources fit for use.

In Bihar, Jharkhand and U.P states, the ground water is the main source of water supply to the villages. Thus for most of the schemes such as Singe Village Scheme (SHS/SGS) source of water supply is normally adopted ground water as it is economical which do not require much treatment and can be supplied with disinfection alone. If ground water is effected with fluoride/arsenic contamination, treatment plants are not suggested due to possible environmental problem of refuse/sludge handling. Thus in such area water will be provided with surface source. For other chemical contamination in water, specific treatment plants are to be provided which needs skilled personnel for operation and constant attention apart from high capital and O&M cost.

Ground water may be extracted from tube wells or dug wells. Surface water can be extracted through intake wells, infiltration gallery and infiltration wells. Generally water from infiltration gallery/infiltration well does not require any treatment other than disinfection. Surface water directly taken from streams, canals, dams and ponds required proper treatment as per impurities of raw water.

8.2. Methods of Treatment and Flow sheets

The aim of water treatment is to produce and maintain water that is hygienically safe. The method of treatment to be employed depends on the nature of raw water constituents on the desired standards of water quality. The unit operations in water treatment include aeration, flocculation and clarification, filtration, disinfection, softening, deferrization, de-fluoridation and water conditioning and many different combinations of these to suit the requirements.

In the case of surface waters and ground waters, when the water has turbidity below 10 NTU plain disinfection by chlorination is adopted as shown in flow diagrams (a) & (b).

When the ground water contains excessive iron, dissolved carbon dioxide, aeration followed by flocculation (rapid and slow mixing) and sedimentation, rapid gravity or pressure filtration and disinfection may be necessary as in flow diagram (c).

In surface waters with turbidity not exceeding 50 NTU and where sufficient area is available, plain sedimentation followed by slow sand filtration and disinfection are practiced as shown in flow diagram (d).

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Conventional treatment including pre-chlorination, aeration, flocculation (rapid and slow mixing) and sedimentation, rapid gravity filtration and post chlorination are adopted for highly polluted surface waters laden with algae or other microorganisms as shown in Flow diagram (e).

Sometimes, unconventional flow sheets may be adopted for waters of low turbidity (below 1 to 15 NTU) and containing low concentration of suspended matter as in flow diagram (f).

Water with excessive hardness needs softening as in flow diagram (g), for removal of dissolved solids, demineralization by ion exchange may form a part of the domestic or industrial as in flow diagram (h).

1. STORAGE 6. SEDIMENTATION 2. CHLORINATION (PRE) 7. SLOW SAND FILTRATION 3. AERATION 8. RAPID SAND FILTRATION 4. RAPID MIXING 9. SOFTENING 5. FLOCCULATION – SLOW MIXING 10. CHLORINATION (POST) 11. DEMINERALISATION

However application of Water treatment method is described in Annexure-06 (Volume-2).

The description of common operation and impurities removed are described as below:

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Table 8-1: List of Unit WTP Operation V/s Impurities Removed

S. No. Operation Impurities Removed 1 Aeration (a) Dissolved Gases CO2, H2S etc.

(b) Dissolved minerals like Fe, Mg, Mn (c) Dissolved organic matter causing bad taste and odour, Floating matter

2 Screening Floating matter 3 Sedimentation

1. Plain 2. Aided with coagulation

Large and heavier solids Smaller and lighter suspended solids

4 Filtration Fine suspended and colloidal matter and some living organism including bacterial contamination

5 Disinfection Killing of living pathogenic organism i.e. protozoa, bacteria, virus etc.

6 Chemical Dissolved minerals, other organic materials, salts causing hardness, precipitation Fe, Mn, fluorides.

7 Special Process Taste and odour by using activated carbon, aeration etc. Source: APRWSSP-Technical Manual

The above operations are discussed below:

8.2.1. Aeration

It is the process of bringing water in intimate contact with air, while doing so the water absorbs oxygen from the air. The carbon dioxide gas is also removed up to 70% and up to certain extent bacteria is also killed. Iron, manganese and H2S gas are also removed up to certain extent from the water.

Aerators are broadly classified in four categories:

A. Diffused Type B. Spray Type C. Mechanical Type D. Gravity Type

8.2.1.1.By Air Diffusion

In this method perforated pipes are fixed in the bottom of the settling tanks. The compressed air is blown through the pipes which comes out in the form of bubbles and stirs the whole water at greater speed. During the upward moment of the air, it is thoroughly mixed with the water and does its aeration. The aeration tanks are usually made 2.5 to 3.0 m deep and work on the principle of continuous flow, having minimum detention period of 15 minutes (at the average flow). The quantity of air consumed varies from 0.3 to 0.6 cu.m. per 1000 litres of water.

8.2.1.2.By Using Spray Nozzles

In this method the water is blown up in the air into the fine sprays to a height of 2 to 2.5 m under water pressure of 0.7 to 11.5 kg/cm2. When small particles of water come in contact of greater surface area of the air, they absorb it and the water is aerated. The

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dissolved gases like H2S, CO2 etc. escape into the atmosphere and the oxidation of various substances and organic matter takes place.

8.2.1.3.By Trickling Beds

In this method the water is allowed to flow on the trickling beds of coke which are supported on the perforated bottoms of the trays. The water is allowed to trickle from the top to the bottom under gravitational force. During this downward movement, the water gets mixed up with the air and the aeration takes place. The size of the coke tray ranges between 50 and 75 cm. The efficiency of this method is more than ‘cascades’, but it is less effective than the method of spray ‘nozzles’.

8.2.1.4.By Using Cascades

In this method the water is allowed to fall over a series of concrete steps or over a weir etc. in thin film. During the fall, the water gets thoroughly mixed with the atmospheric air and gets aerated.

In the rural water supply schemes the gravity type cascade aerator may be used. The design parameters are given below:

1. No. of steps = 3 to 6 normally 2. Space requirement = 0.015 to 0.045 sqm/cum.h 3. Head required = 0.5 to 3 m 4. Tread of Step = 20 to 40 cm 5. Rise of step = 20 to 40 cm 6. Velocity of water = 0.6 m/s to 0.9 m/s

CO2 removal efficiency = 20 to 45% H2S removal efficiency = 35%

Figure is given below:

8.2.2. Screening

Screens are generally provided in front of the pumps or the intake works, so as to exclude the large size particles such as debris, trees, animals, bushes etc. Coarse and fine screens are to be provided for better result. While designing screens clear opening should be

Cascade Type Aerator

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provided. The materials which are deposited on upstream of screen should be removed regularly manually or mechanically

8.2.3. Plain Sedimentation and Coagulation

Plain sedimentation is required from one to several days without subsequent filtration. Plain sedimentation has little effect in removing small suspended particles in water. The larger and heavier particles, however, settle depending upon their size and the velocity of flow in water where chemicals are introduced to hasten the process of settling, the addition of chemical is called ‘Coagulation’. The process of addition of chemicals to separate the dissolved impurities out of solution is known as ‘Chemical Precipitation’ and the sedimentation process after the addition of chemicals is described as ‘Sedimentation’ or ‘Post Sedimentation’.

River or stream waters with heavy loads of silt even up to 5000 ppm during rainy season are subjected to sedimentation both before and after coagulation or precipitation. Much longer settling time is required for basins preceding slow sand filters than for rapid sand filters. Rectangular tanks have lengths commonly up to 30 m but larger lengths up to 100 m have also been adopted.

The factors influencing the sedimentation process are:

1. Size, shape and weight of floc 2. Viscosity and temperature of water 3. Effective average period available for sedimentation (Detention period) 4. Effective depth of tank 5. Surface area 6. Surface over flow rate. 7. Velocity of flow 8. Inlet and outlet design.

Table 8-2: Sedimentation Rates of Various Materials

S. No. Type of material Dia. (mm) Rate of settlement (m/h) 1 Coarse sand 1.0 365.75

0.5 193.84 2 Fine sand 0.25 97.53

0.10 29.26 3 Silt 0.05 10.61

0.005 0.14 4 Fine clay 0.001 0.005

0.0001 0.00005 Source: APRWSSP-Technical Manual-Table 7.1

1. It is necessary to study the characteristics and nature of the suspended matter present in the raw water.

2. Viscosity and temperature of water: Viscosity of water has definite influence on the efficiency of settling process. The rate of sedimentation of water at 30 C temperatures is 2.3 times more than that at zero degree celsius temperature. It is, therefore, necessary to keep this influence in view while designing the settling tanks intended to handle cold waters.

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8.2.4. Coagulant Dosage

Although there is some relation between turbidity of the raw water and the proper coagulant dosage, the exact quantity can be determined only by trial. Even thus determined, the amount will vary with other factors such as time of mixing and water temperature. The use of the minimum quantity of coagulant determined to be effective in producing good flocculation in any given water, will usually require a fairly long stirring periods varying from 15 to 30 minutes in summer and 30 to 60 minutes in the colder months, as water temperatures approach the freezing point.

Addition of coagulants in excess of the determined minimum quantity may increase bactericidal efficiency. It is, however, usually more economical to use the minimum quantity of coagulant and to depend on disinfectant for bacterial safety.

Very finely divided suspended matter is more difficult to coagulate than coarse particles, necessitating a large quantity of coagulant for a given turbidity. The cation-exchange capacity of the particles of turbidity bears a significant relationship to the success of flocculation.

8.2.5. Choice of Coagulant

In selecting the best coagulant for any specific treatment problem, a choice has to be made from among various chemicals, each of which may offer specified advantages under different conditions. The common coagulants used in water works practice are salts of aluminium viz. filter alum, sodium aluminate and liquid alum and iron salts like ferrous sulphate (Copperas), ferric sulphate, and ferric chloride.

Selection of aluminium or iron coagulants is largely decided by the suitability of either type or its easy availability. Both filter alum and ferric sulphate have certain specific advantages. Alum does not cause the unsightly reddish brown staining of floors, walls as against ferric form of iron salts. The dissolving of ferric sulphate also offers difficulties not encountered with alum. The trivalent aluminium iron is not reduced to a more soluble bivalent iron, as may be the case when ferric salts are used with waters high in organic matter. On the other hand, ferric floc is denser than alum floc and is more completely precipitated over a wider pH range. Also good flocculation with alum is not possible in some waters.

The choice of the coagulant to be used for any particular water should preferably be based upon a series of jar tests, so planned that it will permit accurate comparison of the materials, being studied under identical experimental conditions. The coagulant dose in the field should be judiciously controlled in the light of the jar test values.

8.2.6. Rapid Mixing

The purpose of rapid mixing is to disperse coagulant throughout the mass of water rapidly and uniformly to create a homogeneous system. These help in the formation of micro-flocs and results in proper utilization of coagulant and avoid premature formation of hydroxide which leads to less effective utilization of the coagulant.

The devises used for rapid mixing can be broadly classified as:

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a. Gravitational or Hydraulic Mixers b. Mechanical Mixer c. Diffusers and injection mixers d. Inline mixers.

(A) Gravitational or Hydraulic Mixing: In rural water supply scheme hydraulic jump mixer is recommended.

(1) Hydraulic Jump Mixer: The arrangement of hydraulic jump mixer consists of combination of a chute followed by a channel with or without sill. Coagulant is introduced to the water ahead of its entrance into an open, slopping portion. In passing down the flume, super critical velocity i.e. 3 to 4 m/s is created by the chute and the channel with a gentle slope induces the jump. These flumes constructed for the purpose of measurement of flow in the water works system can also be used in which the hydraulic jump occurs at the throat of the flume. The loss of head in hydraulic jump mixing is to the extent of 30 cm to 60 cm. In case of large plants this arrangement of measuring device can be used as a stand-by to mechanical mixers. For small plants this can directly serve the purpose. Overflow weirs have also been used for rapid mix. A head loss of 0.3 m to 0.6 m across the weir and detention time 2 seconds have been reported.

8.3. Types of Sedimentation Tanks

The three types of sedimentation tanks are:

1. Rectangular tanks 2. Circular tanks 3. Hopper bottom tanks

1) Rectangular Tanks

These are rectangular in plan and consist of large number of baffle walls. The function of baffle walls is to reduce the velocity of incoming water to increase the effective length of travel of the particle and prevent the short circuiting. These tanks are generally provided with channel type inlet and outlet extending on the full width. The floor between two baffles is made like a hopper sloping towards centre where sludge-pipe is provided. The sludge is taken out through sludge outlet under hydrostatic force by operating the gate-valve.

2) Circular Tanks

These are generally not used in plain sedimentation, but are mostly used in sedimentation with coagulation. There are two types of circular sedimentation tanks classified on the basis of flow of water inside it.

a. Radial flow circular tank

The water enters in this tank through the central inlet pipe placed inside the deflector box. The deflector box deflects the water downwards and then it goes out through the holes provided in the bottom sides of the deflector box. The water flows radically from the deflector box towards the circumference of the tank, where an outlet is provided on the full periphery. All the suspended

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particles settle downward on the sloppy floor and clear water goes through the outlet. The sludge is removed on the story floor and clear water goes through the outlet. The sludge is removed by scrapper (known as raking arm), which continuously moves around the floor at a very small velocity. The maximum velocity of raking arm does not exceed 4.5 metres/hour.

b. Circumferential flow circular tank.

Water enters in the tank through two or three vertical slits. There is one rotating arm in the tank, which allows the water to move along the circumference of the tank. Water while moving at very low velocity allows its suspended impurities to settle in the tank, which can be removed from sludge outlet. The clear water is drawn over a small weir type outlet.

3) Hopper Bottom Tanks:

These are vertical flow tanks, because water flows upward and downward in these tanks. The water enters in these tanks from the top into deflector box. After flowing downwards inside the deflector box the water reverses its direction and starts flowing upward around the deflector box. The suspended particles having specific gravity more than one, cannot follow the water at the time of reversing its direction, and settle in the bottom, from where they are removed through sludge outlet pipe under hydrostatic pressure. Rows of decanting channels are provided at the top to collect the clear water. The water after flowing in the channel is taken out from the outlet channel provided on one side of the tank. These tanks are mostly used in sedimentation with coagulation process.

8.4. Tube Settler

This manual is prepared for village water supply schemes and for it rapid settling unit i.e. Tube Settler may also be most suitable technology for sedimentation.

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Figure 8-1: Tube Settler

Settling efficiency of a basin is primarily dependent upon surface area and is dependent of depth. Attempts have been made to use this concept to achieve better efficiency and economy in space as well as cost. Wide shallow trays inserted within conventional basins with a view to increase the surface area have not met with success. However, very small diameter tubes having a large wetted perimeter relative to wetted area providing laminar flow conditions and low surface loading rate have shown good promise. Such tube setting devices provide excellent clarification with detention times of equal to or less than 10 minutes. Tube configurations can be horizontal or steeply inclined. In Inclined tubes (about 60 degree, sludge will not slide down the floors. Under such situations, hosing down the sediments may have to be resorted to. With horizontal tubes (normally inclined at 5 degree) auxiliary scouring of settled solids is necessary. While tube-settlers have been used for improving the performance of existing basins, they have also been successfully used in a number of installations as a sole settling unit. It has been found that if one-fifth of the outlet end of a basin is covered with tube or plate settlers, the effective surface loading on the tank is nearly halved or the flow through the basin cab be nearly doubled without impairment of effluent quality.

The tubes may be square, circular, hexagonal, diamond shaped, triangular, and rectangular or chevron shaped. A widely used material for their construction is thin plastic sheet (1.5 mm) black in colour, though plastic pipes have also been used. There are number of proprietary devices such as Lamella clarifier.

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The performance of the tube settlers is normally evaluated by a parameter, Sc, defined as

Sc = Vsc (Sin Q + LR Cos Q) / Vo

Where,

Vsc = Critical settling velocity of the particle, (m/d) = 120 m/d normally assumed Vo = Velocity of flow along the tube settler, (m/d) Q = angle of inclination of tube to horizontal LR = relative length of tube settler = L/D Ratio upto 20 L = Actual length of tube, (m) D = Diameter of tube, (m) Sc, should be (4/3) for circular tube, 11/8 for square tube, 1 for parallel plates

To account for transition zone at tube inlet, it is recommended to increase the relative length LR by an amount L’

Where L’ = 0.058 x Vo x D/µ µ = Kinematic viscosity of fluid

Therefore Sc = Vsc [Sin Q + {(L/D) – 0.058 (Vo x D/µ)} Cos Q]

Loading rate per tube may be used 1.2 m/h.

The tube settler module was modified by Mr. Bhole by turning the square tube through 45 degrees and hexagonal tube through 30 degrees to horizontal so that the original flat bottom becomes hopper bottom. The hopper bottom helps to concentrate the settled sludge in the hopper which slides down more efficiently. The performance of the tube settler was further improved by inserting partition plates of about 15 cm length with suitable gap between them. The partition plates reduced to a great extent the interference of the water travelling in the upward direction with the down sliding settled sludge. The plates also created additional surface for settlement of the sludge and reduced the vertical distance of floc travel. Studies showed that performance of this modified tube improved by 30 to 40%.

8.5. Treatment and Disposal of Settled Sludge

The settled sludge is withdrawn intermittently or by continuous bleeding. The sludge is withdrawn by opening of a sluice valve or through a telescopic pipe.

There are various methods of treatment and disposal of sludge, as shown in following diagram. But in rural water supply where ample of land is available, lagooning may be quite economical and finally may be sent to landfill sites.

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Figure 8-2: Figure of Alum Sludge Treatment and Disposal Methods

8.6. Filtration

Screening and sedimentation removes a large percentage of the suspended solids and organic matter present in raw supplies. The percentage of removal of the fine colloidal matter increases when coagulants are also used before sedimentation. But however, the resultant water will not be pure, and may contain some very fine suspended particles and bacteria present in it. To remove or to reduce the remaining impurities still further, and to produce potable and palatable water, the water is filtered through the beds of fine granular material, such as sands etc. The process of passing the water through the beds of such granular materials called as filters, is known as filtration.

Filtration may help in removing colour, odour, turbidity, and pathogenic bacteria from the water. Very fine and colloidal particles of un-settable nature cannot be removed in sedimentation process alone. Water coming out of settling tanks and clarifiers is fit for filtration. In the process the water from sedimentation tank is allowed to pass through a bed of sand and the filtrate is collected at the bottom through the under drains. The action of filtration through the filter media retains finer and colloidal particles of silt and clay. The filters are periodically washed and put to use again.

The two types of filters are

Slow sand gravity filters; and Rapid sand gravity filters

8.6.1. Slow Sand Filters

Slow sand filtration is a simple and low-cost method of purifying water. It uses local materials and skills. Basically it is a large tank containing sand bed. Slow sand filters can achieve the following:

Reduce turbidity of the row water by about 90% Reduce bacterial count of raw water by 85% or so

Alum Sludge Treatment and Disposal Methods

RAW WATER SOURCE

WATER TREATMENT PLANT

ALUM SLUDGE OTHER WTP WASTE

DIRECT DISCHARGEWASTE WATER TRT

PLANTTHICKNING & DEWATERING

ALUM RECOVERY

LAGOON

Receiving Stream LAND DISPOSAL

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However if the turbidity of raw water is greater than 50 mg/l, a pre- sedimentation facility is necessary prior to filtration to prevent short filter nuns.

8.6.1.1.Design Criteria/ Considerations

1 Rate of Filtration : 100 lph /m2 (Normal) 200 lph /m2 (maximum overload)

2 Design period : 10 years 3 No. of filter units : Area in Sqm No of units

Up to 20 2 20-249 3 250-649 4 650-1200 5

4 Depth of water over sand : 1m (exceptionally as high as 2 m) 5 Effective size of sand : 0.2 to 0.3 mm Uniformity coefficient : 3.0 to 5.0 6 Sand (Sand should not contain

more than 2 % of calcium and manganese calculated as carbonate)

7 Depth of sand bed : 1.0 m 8 Under drainage : General tendency of using standard bricks with

dimensions 5 x11 x 22 cm. Joints in under drainage shall normally less in width

9 Gravel bed gradation : Top most layer 1 to 2 mm (Normal depth of each layer Second layer 3 to 6 mm of 6 cm, the total depth 30 cm) Third layer 9 to 18 mm Bottom layer 27 to 54 mm

10 Internal depth of filter bed Internal depth of filter bed

: 0.20 m

11 (Usual dimensions) : : Filter media : 1.00 m

Gravel drains : 0.30 m Brick drains : 0.20 m Total depth : 2.70 m

12 Water depth : 1.00 m 13 Effluent weir level above Sand

bed : 20-30 mm

14 Length of filter run : Not exceeding 6-8 weeks

8.6.1.2.Working Time for Filters

As for as possible the units should work for 24 hours continuously. Intermittent working may be proposed when design is necessary from other considerations.

8.6.1.3.Shape of Filter Bed

The shape should generally be rectangular. For certain capacities optimal sizes has been worked out so that the wall perimeter for a given area is minimal. On the principle of minimal perimeter, the optimal dimensions are worked out for the specific requirements.

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The design parameters as recommended in CPHEEO Manual.

8.6.2. Rapid Gravity Filters

Filters design to operate at much higher rate than slow sand filters are called ‘Rapid’ Gravity Filters or Rapid Sand Filters.

In this type of filters, the raw water first undergoes a preparatory treatment. Water entering the rapid sand filters contains flocks formed during the pre-treatment process. The filter media used in this type of filter is of coarser variety and the operation head is also higher. A suitable pre-treatment of raw water is of paramount importance for efficient performance of rapid gravity filters. Understandably no rapid gravity filter, which receives water without pre-treatment of water with un-coagulated colloidal matter, can work satisfactorily. This filter remove large amount of impurities in a short time resulting in quick clogging necessitating, frequent washing with cleaning interval between 24 to 48 hours, depending upon the quality of water being fed to the filters. Since these filters require frequent cleaning no chance is left for formation of biological slime to form the filtering mat, as is in case of slow sand filters, which proves so much effective in improving the quality of the filtrate.

8.6.2.1.Rate of Filtration

The standard rate of filtration recommended in CPHEEO manual on water supply and treatment is 80 to 100 lpm/m2 (4.8 to 6 m3/m2/hr). In recent past, there has been a decided trend towards higher rates of filtration by using coarser sand and improving the pre-treatment system. In the country a higher filtration rate up to 240 lpm/m2 has been achieved. Usual practice is to adopt filtration rate of 80 lpm/m2. Piping arrangements consisting of inlet and outlet etc. are designed at 100% over load for emergent situations.

8.6.2.2.Design of Filter Unit

a) Area: Rapid sand filters should be so designed that the number of units should be sufficient for total quantity of water to be handled without any over loading. In the design of large size filter, very vital factor which deserves consideration is the rate of supply of wash water and the hydraulic problems in achieving equal distribution of wash water, area being large. CPHEEO Manual on water supply, Govt. of the India recommends the maximum area of 100 m2 for single unit for plants greater than 100 mld consisting of two halves each of 50 m2 area. In order to obtain flexibility of operation, minimum of four units are recommended which should be reduced to two in case of small plants.

b) No. of Units: Morrell and Wallace developed an equation which may be used as a guide for number of filter units. It is N = Q /4.69, where

N = Number of filter units Q = Plant capacity in M3/ hour

Allowing for repairs, renewals etc., and the bed could be designed for 23 hours of operation per day or alternatively extra bed may be provided to make up for this loss of time.

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c) Dimensions : As for the dimension of the filter box, the ratio of length to width averages 1.25 to 1.33 and minimum over all depth of 2.6 m including a free board of 0.5 m is adopted. The settled water is brought into filters in such a manner that it causes least turbulence; otherwise it will break up the residual flocs. The filter boxes are constructed in R.C.C or masonry (stone or break). The CPHEEEO manual recommends that where seasonal extreme temperature is not prevalent, it is not necessary to provide roofing over the filters, the operating gallery alone being roofed over.

d) Specification of Sand: Since sand bed is the heart of filtration plant, selection of sand needs great care. Although finer sand is more effective in filtration of water, it has higher frictional resistance and as such it cannot be economically used except in case of slow sand filers.

The sand should be of following specifications:

(i) Effective size of sand shall be 0.45 to 0.70 mm (ii) Uniformity coefficient shall be 1.3 to 1.7 (iii) Sand shall be hard, resistant quartz and free from clay, dust, roots and other

impurities (iv) It should contain less than 2 % lime and magnesium calculated as carbonates

and soluble in dilute hydrochloric acid in 24 hours at a temperature of 70 deg F.

(v) Silica contents should not be less than 90% (vi) Specific gravity shall be in the range of 2.55 to 2.65 (vii) Wearing loss shall not be more than 3 % (viii) Ignition loss should not exceed 0.7 % by weight (ix) Soluble fraction in hydrochloric acid shall not exceed 5 % by weight.

e) Depth of sand: The layer of sand is usually 60-75 cm. The depth of water over this sand top varies between 1 m to 2 m. The free board shall be at least 50 cm.

The depth of sand that can be checked against breakthrough of floc through sand bed depth required by Hudson formula:

Qd3h/l = B x 29323 where

Q is in M3/M2/h, d in mm sand size and h and l in m, terminal head loss and depth of bed respectively. B is break through index whose value ranges between 4 x 10-4 to 6 x 10-3 depending upon response of coagulation and degree of pre-treatment in filter influent. Assume B = 4 x 10-4 for poor response to filtration and average degree of pre-treatment, terminal head loss of 2.5 m, rate of filtration = 5.0 x 2 = 10 m3/m2/hr (assuming 100% over loading of filters under emergencies) and assuming d = 0.6 mm as mean diameter.

10 x (0.6)3 x 2.5 = 4 x 10-4 x 29323xl

Minimum depth of sand (l) required to avoid break through = 46 cm. Hence assumed depth of 60 cm is adequate to avoid breakthrough of flocs.

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f) The Gravel Layer: The function of gravel layer is to support sand layer and to distribute wash water. The gravel should preferably be natural rounded and not crush stone. The specification of gravel, as recommended by Cox in WHO monograph series 49, ‘operation and Control of water Treatment Processes’ as shown in following table:

Table 8-3: Specification of Gravel

Range in size, mm Range in depth, cm 63 – 38 13 – 20 38 – 20 8 – 13 20 – 12 8 – 13 12 – 5 5 – 8 5 – 2 5 - 8 Total depth 39 -62

CPHEEO Manual on water supply and Treatment recommends the size of gravel from 50 mm at the bottom to 2 to 5 mm at the top with 45 cm depth.

The gravel and its size gradation can be estimated as under:

Assume a size gradation of 2 mm at top to 50 mm at the bottom. The requisite depth l in cm of component gravel layer of size d in mm can be computed from empirical formula.

l = 2.54 k (log d) K varies from 10 to 14 for K-12, the depth of various layer of gravel are: Size, mm 2 5 10 20 40 Depth, cm 9.2 21.3 30.5 40 49 Increment, cm 9.2 12.1 9.2 9.5 9 Provide a gravel depth of 50 cm

For strainer or wheeler type under-drain system, minimum size of gravel shall be 2 mm and maximum 50 mm with 30 to 50 cm depth and for perforated pipe under drain system, size of gravel shall be 2 mm minimum and 25 mm maximum with 50 cm depth.

g) Filter Bottom and Under Drainage System: The function of the under drainage system is to collect the filter water reaching down through the sand and gravel layer and to distribute uniformly upward the back wash underneath the gravel.

Because the rate of wash water is several times higher than the rate of filtration, the rate of wash water is therefore the basis of design for under drainage system. Various types of under drainage system are adopted. Most commonly used under-drainage systems consist of grid of pipes into which strainers are fitted. A main, called ‘Manifold’ is placed longitudinally along the centre of the bottom floor from which several 75-100 mm dia. pipes called ‘Laterals’ are placed across spaced 150 to 200 mm centre to centre. Another system consists of vitrified clay blocks with perforations at intervals. Still another type of system is of porous silica plates mounted on the

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support. The system has the drawback of getting clogged by minute quantities of alumina.

The pipe grid system consists of cast iron, asbestos cement or concrete pipe etc. the design criteria for manifold and laterals, warrants that the loss of head occurs in the strainers or openings and not in the manifold or laterals in order to achieve uniform flow of wash water and rate of filtration throughout the area of filter. The velocity of jets issuing from openings or strainers is lost against the filter bottom or in the layer of supporting gravel surrounding the pipes.

The head lost should, therefore, be equal to the driving head during wash. Usually the controlling head is set between 1 to 4.5m. The ratio of total area of opening in the under drains to total cross sectional area of laterals should not exceed 0.5 for perforations of 12 mm size and should reduce to 0.25 for perforation of 5 mm. The ratio of total area (perforations) to the filter area should preferably be 0.003 to 1 except with special bottoms. A filter area of 100 sqm. would be provided with under-drain perforations having total area of 0.3 sqm. The total cross sectional area of laterals should be about twice the total area of strainers or laterals opening and cross sectional area of manifold should be equal to 1.5 to 2 times the total that of laterals. The ratio of length to dia. of laterals should not exceed 60.

The spacing of laterals is approximately equal to spacing of orifices and shall be equal to 30 cm. In general filtered water and wash water piping should be designed to provide a velocity of flow not greater than 0.9-1.8 m/sec and 2.4-3.6 m/sec respectively.

h) Wash Water Troughs: Wash water troughs are constructed in concrete, asbestos cement, plastic and steel etc. Wash water troughs are located in such a manner that the horizontal travel of dirty water over the surface of sand in the filter box is kept between 0.6 to 1.0 m before it reaches the trough, but there are successful units where dirty water travel has been as high as 3 m, as recommended by CPHEEO manual. For free falling rectangular trough with level invert, the discharge capacity Q in m3/sec may be computed from the equation Q = 1.376 bh3/2, where b is the width of trough in m and h is water depth in m.

Wash water troughs should be so located that their lower surface is slightly above the expanded sand i.e. 50 mm or more during filter washing with cross sectional area sufficient to provide required capacity. The top edge of the trough should be as far above the undisturbed sand surface as the wash water rises in one minute. Necessary adjustment can be made by selecting a size with more width and less depth. The trough should be large enough to carry all the water delivered to it with at least 50 mm space between the surface of flowing water in the trough and the upper edge of the trough. Any submergence of trough will reduce the efficiency of wash.

i) Washing of a Filter: Washing of a filter is done with clean water which can be managed from either pumping clear water from clear water gallery to wash water tank or from distribution mains, if the distribution line is available nearby treatments units or from the rising main if the treatment units are located near the pumping main, as the case may be.

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The necessity of washing a filter arises when the filter media gets so dirty that maximum gravity head is required to force the water through filter bed. The material deposited on sand through the course of filtration process, increases the resistance to the flow of water. When the loss of head becomes too great, filter is washed. For this purpose loss of head indicators are provided to show the condition of the filter sand. Filter should be washed when loss of head reaches 1.8 to 2 m. In clear filter initial loss of head is 0.10 to 0.15 m. Length of filter run should not be less than 24 hours with a loss of head not more than 2.0 m.

Process of Washing: Washing of filter is not merely an operation of a flow control valve; rather it deserves more attention to make the back washing process really effective.

For achieving the best result the following steps should be adopted.

1. Close the influent valve A and allow the water level on the top of sand to drop till it reaches a point just 15 cm above the sand this way the settled water is conserved.

2. Close the delivery sluice valve D. 3. Conduct inspection of filter beds to check cracks, mud balls and mounds etc. 4. Open the scour valve B. 5. Gradually open the wash water sluice valve C taking 50 to 60 seconds time

to apply a flow at the rate of above 0.5 m3/m2/min, failing which wash water will be introduced so rapidly that compacted surface of sand is uplifted as a mass until a portion cracks and clean bottom sand and small size gravel is carried towards crack in fast horizontal flow.

6. Continue washing at low rate for 2-3 minutes to afford sufficient time for the floc to get dislocated. Wash water rising through laterals, strainers, gravel and sand carrying with it arrested impurities will be collected by the troughs and passed out through the scour valve.

7. Open wash water sluice valve ‘C’ further so as to give maximum sand expansion decide such as 40 to 50 % and it should be continued for a period of one minute or till water becomes relatively clearer. Now closed the wash water sluice valve and also close the scour sluice valve. Valve E which allows filtered water to waste to sewer is then opened. Allow the sand to settle for 2 minutes and then close the valve.

8. Open gradually influent sluice valve A ensuring some water cushion is available on the top of sand to avoid unnecessary turbulence and open more sluice valve to make the water reach its normal level and then open the outlet sluice valve to put the filter bed back to use.

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Figure 8-3: Rapid Sand Filter

High Velocity Wash Water System: High velocity wash water is applied normally where no other agitation (air agitation) is provided. The rate at which the wash water is applied is 600 lpm/m2 of filter surface or 60-70 cm/min rise in the filter box for the period of 10 minutes. The sand should expand 130 to 150 % of its undisturbed volume. For high rate wash, the pressure in the under drainage system should be 6-8 m with wash water requirement being 700 l/m/sqm for a duration of 6 to 10 minutes. If the pre-treatment is effective, the quantum of wash water would amount to 1% to 2.5% of the total amount of water filtered each day. Amount in excess of 2.5 % indicates the need to investigate for corrective action.

Cox in ‘operation and control of water treatment processes (WHO monograph series 49) recommends the modern practice to design wash water system to produce rate up to 56 m3/m2/h or 90 cm raise/minimum (Allowance for high water temperature in tropics justified the use of maximum rate up to 72 m3/m2/h or 120 cm rise/min). Rate of rise of wash water depends upon the effective size and uniformity coefficient of sand used.

Capacity of back wash pumps and wash water tank: Pumps required filling up the wash water in less than 8 hours are provided. The tank should be of sufficient capacity (normally to hold 1.5 times the volume of water needed to wash a single bed) to back wash one filter for at least 10 minutes at the designed rate of wash water flow. Where numbers of filter units are four or more, the capacity of the storage tank must be sufficient to supply wash water to two filter units, at a time. The height of wash water tank should be sufficient to provide the desire rate of flow.

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Surface Wash System: There is a recent development to supplement conventional back washing by means of surface wash. In this system the stirring of expanded filter bed is done mechanically with rakes and hydraulically with jets of water. The grid of the pipe for using the surface wash consists of horizontal header pipes suspended on wash water trough. Secondary pipes vertically down wards are connected with horizontal headers, extending within 10 cm of the surface of sand bed. The bottom tips of the vertical pipes of not less than 25 mm dia. have holes of 2.5 mm dia. at an angle of 300 to the horizontal. The spacing of vertical pipes is maintained at 60-75 cm, centre to centre. The pressure used in the system ranges between 0.70 to 2.10 kg/cm2. The system can be installed in the existing filter beds also. The rotatory type shall consist of rotating unit suspended at a height of 50-75 mm at adequate intervals to provide complete coverage .Jet nozzles are on sides and bottom to rotate at a rate of 7 to 10 rpm.

Air Wash System: In this system, compressed air is used to achieve scrubbing action with less volume of water. Compressed air is forced through the under drain system before wash water. It is preferable to use air through separate piping located in between gravel and sand. It results in better washing. In separate air piping, air is introduced in about the same volume and at the same time water is introduced through the under drains. Air is forced at the rate of 0.6 to 0.9 m3 of free air per minute per square meter of filter area @ 0.35 kg/cm2 till such time the bed is thoroughly agitated i.e. for about 5 minutes, and water is forced through separate under drain system simultaneously at the rate of 0.4 to 0.6 m3/m2/minute.

In common system of under-drainage piping for air and back wash, the volume of air and back wash being the same, free air is forced through the under-drains until the sand is thoroughly agitated i.e. for about 5 minutes. Wash water is then introduced through the same under-drains at the rate Stated in the former case.

There is trend to discourage air wash system because poor results are achieved with limited volume of wash water. This difficulty can be overcome by increasing the capacity of wash water pump to feed sufficient quantity of water to remove dirt from the loosened material.

Design Parameters of Rapid Sand Filters

The design parameters given below are based on the recommendations given in CPHEEO Manual as shown in the Table 8-4.

Table 8-4: Design Parameters

1 Rate of Infiltration 80 lpm/sqm with inlet and outlet designed for 100% overload

2 No. of filter units Morrel and Wallace formula here N= (Q/4.69)^0.5 No. of filter units Q = Plant capacity cum/hr Minimum 2 units

3 Area Maximum 100 Sqm for single unit, for plants greater than 100 MLD, Consisting of 2 halves. Each 50 Sqm. Min 4 units reduced to 2 in case of small plants.

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1 Rate of Infiltration 80 lpm/sqm with inlet and outlet designed for 100% overload

4 Dimensions Length to breadth ratio = 1.25 : 1.33 5 Depth of filter box Overall 2.6 m, including 0.50 m freeboard 6 Design criteria for sand Effective size 0.45 to 0.7 mm. Uniformity coefficient not

more than 1.7 and not less than 1.3 7 Depth of sand Average depth 0.75 m 8 Design criteria for gravel As per gravel layer design given above 9 Under drainage system,

thumb rule As recommended by Cox. For filters washed at the rate of 15 cm to 90 cm/min wash water rate of rise

a) Ration of total area of orifice to the filter area served in the range of 0.15 to 0.5% and preferably about 0.3%

b) Ratio of cross sectional area of lateral to area of orifice served 2 to 4:1 preferably 2:1

c) Dia. of orifice: 6 mm to 18 mm d) Spacing of orifices: 30 cm for 18 mm dia. orifice, and

7.5 cm for 6 mm dia. e) Ratio of areas of manifold feeding the laterals to the

area of laterals served 1.5 to 2.1 f) Spacing of lateral: closely, approximately spacing of

orifice. g) Length of lateral on each side of manifold: not more

than 60 time their dia. h) Orifice located downward from 300 to 600 with

verticals. 10 Filter back washes (with

water alone) Hydraulics of system to be fixed on 50% sand expansion. Modern practice to design wash water rate to rise 90 cm/minute in the filter box. In tropical weather, with high temperature maximum rates up to 120 cm/minute are justified. Erosion or corrosion of metal around these holes may be minimized by lining the holes with a brass or bronze brushing.

11 Back wash with air water Compressed air used @ 0.6 to 0.9 m3/m2/min of filter surface @ 0.35 kg/cm2 pressure for 5 minute; Then wash water @ 0.4 to 0.6 m3/m2/minute

12 Wash Air tank Capacities to hold at least double the amount of air necessary to wash one filter. Capacity of compressor to refill the tank between washings.

13 Surface Wash system In addition to conventional wash system, through separate pipe grid under pressure 0.7 to 2.10 kg/Sq cm.

14 Filter Bed agitators Wash water under at least pressure of 2.7 atm. The jet action causes arm to revolve at 18 rpm

15 Mechanical Rakes Speed @ 10 – 12 rpm 16 Wash Water troughs Spacing, so that each trough serves same filter are. Max

horizontal travel of dirty water is kept between 0.6 to 1.0 m. Thus the distance of trough from the wall shall not be more than 1.0 m and clear distance between two troughs to be not more than 2.0 m. Lower surface of trough above sand surface to permit 50% expansion without having sand grains hit the

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1 Rate of Infiltration 80 lpm/sqm with inlet and outlet designed for 100% overload troughs. Bottom of trough may be horizontal or in slope not exceeding 1 in 37. Top of the trough to be always horizontal. Formula: Q = 1.376 bh 3 / 2 where b = width of trough in m h = water depth in m Q = flow in m 3 / sec

17 Gullet Slightly larger than double the X- section of trough 18 Wash water tank Capacity of wash water tank 1 to 6% of filtered water.

Sufficient for at least 10 minute wash of one filter at design rate or 5 to 6 minute wash of two filters without refilling of 1.5 times the volume of water required for single bed for at least 10 minute; Bottom of tank normally 9 to 11 m above wash water troughs.

19 Pressure as measured in under drains

4.50 m to 5.0 m

20 Means of wash i. Elevated tank into which water is pumped at a rate to fill the tank between washings.

ii. Wash water pump which operates only when filter is being washed.

iii. By taking water from distribution system. 21 Pumping Equipment In duplicate, as a factor of safety capable of filling up the

wash water tank in less than 8 hours. 22 Depth of water over sand 1.0 to 2.0 m 23 Free Board 0.50 m 24 Head loss 2.5 m (min) to 3.0 m (maximum) 25 Conduit dimension Velocity, mps

i. Influent conduits carrying raw water --- 0.9 to 1.8 ii. Influent conduits carrying flocculated water --- 0.8 to

1.8 iii. Influent conduits carrying filtered water --- 0.9 to 1.8 iv. Drainage conduits carrying spent wash water --- 1.2 to

1.4 v. Wash water conduits carrying clear wash water --- 2.4

to 3.6 vi. Filter to waste connection --- 3.6 to 4.5

8.6.3. Comparison of Filters

Rate of Filtration: The major difference in various types of filters lies in the filtration head i.e. the head which makes water to flow through the filter and consequently the rate of filtration. The rate of filtration in slow sand filters is about 2 to 2.5 lpm / m2 whereas the rate of filtration through rapid sand filters is usually 80 to 100 lpm/m2. Thus the rate of filtration through rapid type is 40 to 50 times faster than those of the slow type

Area Requirement: Keeping in view the rate of filtration, the area required for rapid sand filters is theoretically only 4 to 5% of the area needed for slow sand filters. In practice, the reduction in the area requirement is partly offset by the additional space

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needed for pre-treatment works required with rapid type filtration and the figure is thus likely to be around 20 %. Slow sand filters require large area, correspondingly large structure and volume of sand

Loss of Head: The head loss in slow sand filters ranges between 1.0m to 1.5 m, while it is 2.50 m to 3.0 m in case of rapid sand filters

Compactness of Design: As already discussed slow sand filters need large areas for their installation but are simple to operate whereas rapid filters can be constructed in more compact units fitted with automatic devices

Filter Media: Filter media required in slow sand filters consists of finer sand while sand used in rapid type filters is of coarser quality

Flexibility in Operation: In rapid types filters adjustments can be made according to variation in demand where as slow sand filters are less flexible to meet any emergent situation of demand

Method of Cleaning Filters: Slow sand filters require infrequent operation of cleaning by unskilled labourers using hand tools not requiring regular flushing to waste of wash water. Unless the water being treated is of high turbidity, slow sand filter may work for weeks together even months without involving cleaning operation. The necessity for cleaning rapid type filter arises at frequent intervals usually only after one or two days. Cleaning is generally done by high pressure back washing and compressed air or mechanical agitation is used. The system is more sophisticated requiring constant and skilled supervision. Wastage of water required for back washing is 2 to 3 % of total water treated

Pre-treatment: Rapid filters cannot run without pre-treatment such as coagulation and flocculation etc. which are expensive processes while slow filters do not need pre-treatment of water, but slow sand filters work well only when the turbidity does not exceed 50 ppm

Post Filter Treatment: The filtrate from rapid sand filters need disinfection whereas water from slow sand filters can be supplied without any further treatment

Bacterial purification: Slow sand filters give effective bacterial removal. The pathogenic bacteria are completely eliminated to 99 % in slow sand process where as only fixed bacterial load is removed in rapid sand filtration process thus necessitating post chlorination

Colour and Odour: Slow sand filters are less effective in removing colour and odour from water. These give poor results with water of high algae content unless pre-treatment is practiced while rapid sand filters can effectively handle colour and odour problem

Corrosiveness: Addition of coagulants increases the acidity and reduces pH value rendering the water corrosive. Slow and filters do not need addition of chemicals and thus produce an effluent, which is more uniform in quality and is less corrosive.

8.6.4. Other Technologies used for Filtration

8.6.4.1.Pressure Filters

Pressure filter consists of closed vessel (cylindrical tank) usually of steel containing a filter media through which water is forced under pressure. In this process water under pressure is subjected to filtration without the pressure being dissipated and thus it avoids double pumping. The pressure filter cylinders are designed to stand water pressure of 10 kg/sqcm. Although as per practice, rate of filtration usually is 4.8 cum/sqm/h, due precaution is needed even at this rate of filtration. The pressure filters are compact and

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can be prefabricated and move to site. Coagulation and flocculation is normally achieved in top portion of filter. These filters are most suitable for small water supply scheme. However, the effectiveness of the back wash cannot be directly observed; and it is also difficult to inspect, clean and replace the sand, gravel and the underlines.

They may be used for SHS / Single Village Schemes where population is less and surface source scheme with regular treatment may be very expensive for small communities.

Sketch of Pressure Filter

Note: Instead of using all valves separately present trend is to have a ‘Multi Port Valve’.

8.6.4.2.Infiltration Well12

At places, where boulder stratum is found in the upper surface and rocky stratum in the deeper surfaces, it is seen that the construction cost of tube well for drinking water is very high and discharge of it is low which also decreases with time. For such strata if surface water is available throughout the year, construction of infiltration well is cheaper and the available discharge is more. Design of such infiltration wells depends on the requirement of discharge, ground water level and the distance of the well from the stream.

Design of Infiltration Well

Notations A = cross sectional area of the bottom of well, m2 C = percolation intensity coefficient (=1 for coarse sand) D = diameter of well, m h1, h2 = depression from top and its value after recuperation, respectively, m

12 Journal of Institutions of Engineers of India (Vol-62, Pt EN2 February 1982

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Chapter-8 Page 8-24

H, Ho = depression head and its value for top (critical), respectively, m Q = discharge, m3/hr r = depth of well, m t = thickness of well steining, m T = time, hr V = velocity, m/hr z = mass density of submerged soil, kg/m3 = angle of internal friction, degree

The discharge of a well is determined by recuperation test. But it was not possible to perform this test at the time of design. Hence, a discharge of 4500 lpm (1000 gpm) was assumed, which was double of the actual discharge available from tube wells constructed in this area.

Diameter of Well

The formula for discharge is

Q = Av = Ac H

Assuming c = 1 and H = 4 m, area and diameter are,

A = 4500 × 604 × 1000 = 67.5 m

D = 9.273 m = 10 m (say)

Depth of Well

The general ground water table in the area is approximately 2 – 3.5 m below the ground level.

r = Depth of water table + depression head + depth of water to be left for critical depression head = 3.5 + 4 + 2.5 m = 10 m

Design of Staining

The depth of well curb is 1 m. Depth of well staining is 10 m below ground level. The mass density of submerged soil z is 1100 kg/m3and angle of internal friction i 15O. By Rankin’s theory,

Earth Pressure =1 − sin 1 + sin ∗ 푍 =

1 − 푠푖푛150°1 + 푠푖푛150° ∗ 1100 ∗ 10 = 6490푘푔/푚

Water pressure at the bottom of well staining is also to be considered. The maximum probable ground water level from the bottom of staining is taken as 6.5m.

Density of water = 1000 kg/m3

Water pressure at bottom = 1000 x 6.5 kg/m2

= 6500 kg/m2

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Chapter-8 Page 8-25

Total pressure at bottom = 6490+6500 kg/m2 = 12990 kg/m2

Taking permissible compression stress in brickWork to be 109300 kg/m2, and assuming 1 m height of the staining the force balancing becomes

12900(10 + 2푡) ∗ 1 = 109300 ∗ 2푡 ∗ 1

t =129990

2 ∗ 96310 = 0.67 = 65푐푚

Provide a minimum thickness of two and half brick, ie, 57.15 cm. In addition to this, 1 cm is taken for the joint between two bricks and 7 cm thick cement slurry or 3 brick wall. t = 65 cm; D = 10m; Outer diameter of well, D + 2t = 11.30 m Cubical content for one meter height of staining = (11.302 – 102) x1 = 21.74 m3

Vertical staining rods are to be provided @ 7.15 kg/m3 of masonry as per Public Works Department Standards.

So the reinforcement to be provided is

7.15 x 21.74 kg = 155.44 kg.

Provide forty 25 mm diameter bars on equal spacing. Provide 12 mm diameter bars as distribution steel @1.5 m throughout the height of staining.

Well Curb:

Well curb was designed adopting Public Works Department’s criteria, as follows:

1. Flat iron, 50 mm x 14 mm to be laid and sleeve nut screwed very tight; after 10 cm of 1:2:4 cement concrete bond is laid and cured, the remaining 7 cm should be concreted, and all the staining rods must be cut to correct length, top of bottom rods should be kept in one level.

2. The vertical angle of curb should be approximately 30O. 3. Main reinforcement of curb should be 0.5% of the cross-sectional area of curb. 4. Cutting edge to be 150 x 150 x 12 mm angle iron with 150 x 12 mm mild steel plate

welded diagonally with angle and 250 x 12 mm plate welded with vertical edge of angle.

5. RCC curb to be in 1:1½:3 cement with high quality stone aggregates.

Reinforcement in the well curb is to be provided by the criterion on 3 above.

Area of well curb (A) = 70 x 15 + (70+15) x 85/2 = 4662.5 sqcm

퐴푟푒푎 표푓 푆푡푒푒푙 푟푒푞푢푖푟푒푑 =4662.5 ∗ 0.5

100 = 23.32푐푚

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Provide twelve 18 mm diameter curb bars, 10 mm diameter link bars as distribution steel and also provide 12 mm diameter anchor bars. The super structure and slabs, etc. may be designed as per requirements.

General:

To get better yield, flow in a combination of radial and spherical patterns, weep holes should be provided in the staining. In all, 17 holes have been provided at equal distances approximately 1 m above the bottom of staining at another layer of 17 holes 2 m above, such that two holes do not come in one vertical line. The size of each weep hole is 15 x 15 cm, on the inner side of staining wall and 30 x 30 cm on the outer side. Water flows inward from outer side; therefore, each hole is fixed with a box of copper plate with perforated plates on both the opening sides. The filter media filled in these boxes are coarse sand and layers of graded gravels diameter 6, 13 and 20 mm from outside to inside direction of Filter Box (Refer Figure 8-4).

If necessary plugging can also be done at the bottom of the well with the following materials in layers laid upwards: (i) coarse sand, and (ii) gravels of sizes 5-10 mm, 10-20 mm, 20-25 mm, and 25-50 mm in diameters.

Discharge of Infiltration Well:

The first well was constructed at a distance of 35 m away from the canal source. The discharge was measured by constant level pumping set of 4500 lpm (1000 gpm) capacity.

Internal diameter of well = 10 m Depth of water in the wells = 6m. Drawdown = 2.22 m

A discharge of 4500 lpm can therefore be safety taken from this well. The depression is on the safer side from the critical one. Therefore, in case of emergency, 50% more discharge, ie, 6750 lpm approximately may also be drawn from it.

The second well was constructed at 135 m away from the canal. The discharge of this well was calculated by recuperation test and constant level pumping set. In this well sinking in subsoil was done only up to 5.6 m.

Recuperation Test

The discharge is given by

Q =2.303푇 log

ℎℎ 푥퐴퐻

and the observations of recuperation test are recorded in Table 8-5

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Chapter-8 Page 8-27

Table 8-5: observations of recuperation test

Time, min Water Height in Well from Bottom, m

Time, min Water Height in Well from Bottom, m

0-10 0.5 70-80 2.22 10-20 0.7 80-90 2.40 20-30 0.95 90-120 2.50 30-40 1.20 120-150 3.00 40-50 1.50 150-180 3.40 50-60 1.77 180-360 5.60 60-70 2.02

The depressions before and after this test are

h1 = 5.6 – 0.5 = 5.1 m h2 = 5.6 – 3.4 = 2.2 m T = 180 min = 3 hr

With average depression head (H) of 4 m, the discharge is

Q =2.303

3 log 5.12.2푥

3.144 푥10 푥 4

= 2557 litre/ minute (average yield)

Therefore, a 2250 litre/minute discharge can safely be drawn from this well.

Constant Level Pumping Set:

With inside diameter of well as 10 m and depth of water as 5.6 m, and using a 2250 litre/minute (500 gpm) capacity pump, the drawdown is 2.40 m. So, the depression is on the safe side of it Critical value. Therefore it is safe to draw at an average discharge of 2250 1/mt from this well.

Laboratory Test Result:

The water samples from the wells were tested and following results obtained and presented in Table as mentioned below:

Table: 8-6: Result of Water Samples from the Wells

Tests Ganges Canal Infiltration Well pH Value 7.9 7.5 Turbidity, mg/1 (silica scale) 98.0 7.0 Amoniacal nitrogen, mg/1 0.014 0.008 Organic nitrogen, mg/1 0.009 0.006 Total counts on Agar at 37OC 24 hr, counts/ml

27 5

MPN coliform, counts/100 ml

9 -

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The water drawn from these wells is thus potable and may be supplied after chlorination.

For more efficiency it may also be converted in radial wells.

They may be used for SVS and MVS where population is less as traditional surface water source based scheme may be very expensive for small communities.

Figure 8-4: Infiltration Wells

8.6.4.3.Low Cost Filtration Plants for Water Supply13

The filter unit uses the river bed itself as the filter medium. These types of units may be used for small villages/communities near the perennial river having flow throughout the year having permeable bed. The manufacturing cost, the installation cost and the running cost are very low. The quality of the filtered water is comparable to that from any other filtration process.

13 Journal of Institutions of Engineers of India (Vol-61, Pt EN3 June 1981)

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Chapter-8 Page 8-29

Filtration is a combination of physical and chemical processes for separating suspended and colloidal impurities from water by its passage through a porous bed, usually made of gravel and sand or other granular material.

The first two filter plants are normally used for water supplies and are very costly.

Technique of Filtration

This technique of filtration was first used in England and an Indian firm in Bombay has started manufacturing such filter units named as SWS on this technique in India. This unit may be installed in river permeable bed.

This type of filter unit converts area of River bed into sand filter. This filter plant converts an area of river bed into a low maintenance sand filter. It is made of 3 mm thick MS plate rectangular box with a false ceiling consisting of a slotted plate below false ceiling and filled with coarse sand and gravels in the box with a wire mesh at the bottom (Refer Figure 8-5.).

This unit was immersed with the open end facing down to the river bed such that the top of the unit is not less than 30 cm below the river bed and 60 to 90 cm below top surface of water. In this unit, the river bed itself works as the filter media and therefore chemicals for coagulation, filter media for filtration and back washing are not required. The false ceiling chamber has one 80 mm pipe outlet with non-reflux valve. The non-reflux valve is attached to flexible suction pipe which goes to pump installed at safe place (above HFL).The suction head should not be more than 7 m for efficient functioning. After installation it was connected with a pump of 720 lpm (158 gpm) discharge at 30 m head. The filtered river water should be pumped into the river for about 20 hours in the beginning to develop the filter bed to get clean and pure water. After this period the water is driven into the pipeline after its chlorination with solution of bleaching powder through a pressure feed type chlorinator.

Results

The analysis of the raw and the filtered water indicated the following improvements:

Table 8-7: Result of Water Quality at Inlet & Outlet of Filter Unit

Parameters Value (At Inlet of Filter Plant)

Value (At Out let of Filter Plant)

Turbidity 75 ppm 2 ppm Colony count on agar 48 hrs at 37OC

Infinite Nil

72 hrs at room temperature Infinite Nil Positive coliform count 10 ml 5/0 Nil 1 ml 5 Nil 0.1 ml 5 Nil Probable number of coliform organism in 100 ml

1800+ Nil

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Chapter-8 Page 8-30

In this filter unit the precise nature of the sand, etc. of the river bed is not very important, provided there is a range of particle size for the filtration process. The unit must be placed in a permeable bed, preferably not less than 60 cm deep. To obtain good quality water, effective surface area of river bed to be used as filter should be 1.25 m2 for a discharge of 1 m3/hr of filtered water, Thus to get 600 lpm discharge the required effective area is 7.50 sqm. With our 60 x 60 x 30 cm box with false ceiling of 40 x 40 x 10 cm and effective area of 9 sqm can safely draw water to the tune of 600 lpm. By it the suspended matter is removed down to 0.1 micron (0.00004 inches). If more quantity of treated water is required than another box can be installed after 6 m and one suction pipe can be attached to both of reflux valve in series and larger capacity pump can be installed.

The limitation of this technique is this, that it can be installed only in permeable bed and having surface water throughout the year. In the case of non-permeable bed, it is recommended that a area of 7 x 7 x 1.5 m should be dug out and filled with filter media before installing this box.

They may be used for SHS / SVS where population is less (For details, Figure 8-5 may be referred).

Figure 8-5: Low Cost Filter

30-6

0 cm

100

cm30

cm

SlottedWooden Plate15mm Thick & 5mm Slit

Stream

Water Movement

60 c

m

80 mmDia Flexible

Non Reflex

3 mm ThickMS Plate Box

To pump

100

cm

100 cm

70 cm

Section

Schematic Diagram Of The Filter Unit

Graded

Permeable Bed

Filter Media

HDPE Pipe

Valve

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8.6.4.4.Reverse Osmosis

Reverse Osmosis is a membrane permeation process for separating relatively pure water from less pure water. The solution is passed over the surface of an appropriate semi permeable membrane at a pressure in excess of the effective osmotic pressure of the feed water. The permeated water is collected as the product and the concentrated solution is generally discharged. The membrane must be highly permeable to water, highly impermeable to solutes and capable of withstanding the applied pressure without fail.

Advantages: Removal of all types of chemical contaminants including total dissolved solids and bacteria.

Technical Specifications and Process Details:

1. The Plant should be designed based on the following Raw Water properties.

a) Total Dissolved Solids (TDS) : up to 5000 ppm b) Total Hardness : up to 1000 ppm as CacO3 c) Fluorides : up to 1.5 ppm

2. The components of Reverse Osmosis Plant are as follows:

Raw water storage tank Raw water is fed into this tank Raw water pump To pump raw water into the inlet of dual media filter. Dual media filter with filter mesh

Suspended impurities present in raw water are removed.

Activated Carbon filter Water goes through the activated carbon filter in which odour and colour are removed. The hardness of the water is removed to prevent membrane scaling due to calcium carbonate and calcium sulphate salts.

Cartridge filter The water passes through cartridge filter to reduce the SDI below acceptable limits for the RO membrane that is 4. The cartridge also takes care of presence of any foreign particles and prevents it from going into the pressure pump to prevent any damage to the pump.

High pressure pump It pumps water at high pressure through RO block. R O Block The major quantity of dissolved salts is rejected with rejected

stream and almost pure water comes out as separate stream. U V sterilizer The permeate water shall be collected in a blending tank where

activated carbon filter water will be mixed to bring the water quality as per the required specifications.

Product storage tank Collects the treated water.

A typical flow diagram of RO Plant is given in Figure 8-6

The TDS of water shall be reduced to a major extent in the R.O section. The treated water quality expected out of R.O section shall meet IS Standard for drinking water.

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Figure 8-6: Diagram of RO Plant

1 . V illa ge - L o e j 2 . T a luk a / D is tr ic t - M a n g r o l/ J u n a g a rh 3 . P re s e n t P o p u la tio n liv in g in v illag e - 2 0 4 0 4 . N o . o f H o us e ho lds - 3 6 0

5 . D r in k ing w a te r R eq u ire m e n t - 1 0 2 0 0 lp d 6 . N on d r in k in g w a te r re q u irem en t - 7 1 4 0 0 lp d 7 . A n im a l w a te r req u ire m e n t -N il--

8 . N o . o f la rg e a n im a l - N il 9 . S u pp ly ra te 5 lp c da . D r in k in g - 3 5 lp c db . N o n D r in k in g - 2 0 lp c dc . A n im a l - 1 0 . Y ie ld o f W e ll - 2 5 0 lp m

11 . T D S V a lue - 5 5 9 0 p p m 12 . R O R e c o ve ry - 3 5 % 1 3 . R aw w a te r re qu irem en t - 3 4 0 0 0 lp d (e x c lu d in g a n im a l)

1

W e lls R a w w a te r m a in

2

R a w w a te r R e s e rv o ir

3

3 2 m m Ø H D P EL - 1 5 0 m

C a p . - 5 K L .S yn te x T a n k

F ilte r F e e d P u m p

4

M u ltim e d ia F ilte r

5

M 3 0 - 1 N o .C a p . - 4 .8 m /h r .

R O F e e d F lo w

8

R O P e rm e a te T a n kR O w a s te w a te r T a n k

1 1

C a p - 3 .0 m /h rS to n e M a s o n a ry C h a m b e r

3

T o m e e t fu l l d a ily re q u ire m e n tO p e ra tin g h o u rs / d a y - 8

D r in k in g W a te r

R .O .

9

1 0

1 .2 5 m / h r.M o d e l - E 4 - 1 1 0 0 0

(S k id )

R e c o v e ry - 3 0 %

Io n s in p p m - M a y 2 0 0 91 . C a lc iu m - 2 7 82 . M a g n e s iu m - 1 6 73 . S o d iu m - N .A .4 . C h lo r id e - 1 6 9 05 . F lu o r id e - 0 .1 66 . B ic a rb o n a te - 2 6 07 . N it ra te - 5 6 2 .6 18 . S u lp h a te - 2 6 49 . p H - 7 .1 21 0 . T D S - 5 5 9 0

B

U .F . F e e d F lo w

6

M o d u le s - 5 N o s .

4.8 m /h r3

C a p a c ity - 1 .0 m /h r3M o d e l -

P R O P O S A L

N o n D r in k in g a n d a n im a l w a te r re qu ire m e n t w ill b e m e t th ro ug h e x is tin g h an d p u m p s o f w h ic h s ev e n te en ha nd pu m p s a re to b e c on s tru c te d .

U .F . P e rm e a te T a n k

7

C a p a c ity - 1 1 0 0 l it re s3

3 .3 0 m /h r3

R e s e rv o ir

C a p . - 5 K L .S yn te x T a n k

W a s te W a te rR e s e rv o ir

1 N o .C a p a c ity - 5 m /h r. - 2 5 m3 3 - 1 N o .

C a p a c ity - 4 .3 m / h r .- 2 5 m

3

9 0 m m Ø P V CL - 5 0 0 m .

T o u n d e rg ro u n db o re u n d e r g ra v ity

S u p p ly th ro u g h2 0 li tre s C a p a c ity C a n s

A

W e ll - 1 N o . (E x is tin g )P u m p s - 1 N o . - 1 0 0 lp m

- 3 0 m h e a d - 1 .0 B H P

D o s in g S y s te m( i) A n ti S c a la n t D o s in g - A - 0 .5 lp h p u m p - T a n k 5 0 li te rs -0 .1 0 8 K g /d a y( ii) p H C o rre c tio n D o s in g - B - 0 .5 lp h p u m p - T a n k 5 0 l ite rs -0 .0 4 4 K g /d a y

N o n D rin k in g W a te r re q u ire m e n t is n il.

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Chapter-8 Page 8-33

8.6.5. Criteria for selection of Non-Conventional Treatment Technologies

Following Criterion shall be considered while selection of Non –Conventional technologies:

a) Degree of contamination in Raw water quality b) Land requirement c) Capital cost d) O&M cost e) Ease in O&M

Based on the above criterion, the brief description and adoptability of the various non-conventional treatment technologies (used for SHS/SGS) have been described as mentioned below:

1. Pressure Filter: It may be used, where turbidity and pollution in the raw water is not very high. There is also some storage of treated water for its back washing. There should not be rise of water level during the floods more than 3-4m. The requirement of land is less i.e. 5x5m. Due to use of coagulant, bleaching powder and backwashing fresh water, the maintenance cost is on higher side.

2. Infiltration Well: It is used where the surface water is available throughout the year and the adjoining strata are permeable. The cost of construction of Tube well is very high due to boulder stratum in the upper surface. On the availability of discharge, it may also be used for SMVS. The level requirement near the source for its construction is about 20x20 m. The maintenance cost is less as no coagulant is required in filtration and there is no requirement of back washing. The capital cost is high.

3. Low Cost Filtration Plant: It may be used where the surface water is available throughout the year and the stratum below the water is permeable. There could not be rise of water level during the floods more than 3 to 4 m. The land requirement is 5x5m for pump house cum Chloronome. No coagulant is required and only water may be supplied after chlorination. This is cheapest in capital and maintenance cost. It will be useful for small communities.

4. Reverse Osmosis: If there is not any option to get potable water, then this method may be adopted. Due to costly maintenance and disposal of waste water is not environmental friendly. The extra land is also required for placement of RO Plant.

8.6.6. Disinfection of water:

The process of killing the infective bacteria from the water and making it safe to the user is called disinfection. In the filtration unit all type of bacteria are not removed, thus disinfection is required for bacteria free water, to prevent various diseases and their epidemics causing disasters to the public life.

8.6.6.1.Methods of disinfection:

The disinfection of water can be done by the following common methods:

a) Disinfection by Boiling Water The water can be disinfected by boiling for 15 to 20 minutes. By boiling water all the disease-causing bacteria are killed and the water becomes safe for use. This process

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can only kill the existing germs but does not provide any protection against future possible contamination. It may be done at household level.

b) Disinfection by Passing Ultra-Violet Rays

Ultra-violet rays are invisible light rays having wave lengths of 1000 to 4000 m. Sun rays also have ultra-violet rays which can also be utilized in the disinfection of water. In the laboratory they can be obtained by the ultra-violet ray equipment, which essentially consists of mercury vapours enclosed in quartz bulb and passing current in it. Ultra-violet rays are good disinfectants and kill the disease bacteria. After removing the turbidity and the colour of water, then disinfection by ultra-violet rays can be done.

c) Disinfection with Iodine and Bromine

It has been seen that addition of Iodine and Bromine in the water kills all the pathogenic bacteria. The quantity of Iodine and Bromine should not exceed 8 ppm and they can kill bacteria in minimum contact period of 5 minutes.

d) Disinfection with Ozone

Ozone is an excellent disinfectant. It is used in gaseous form, which is faintly blue in colour of pungent odour. Ozone is an unstable allotropic form of oxygen, with its every molecule containing three oxygen atoms. But as the ozone is highly unstable, it breaks down into ordinary oxygen and liberates nascent oxygen.

e) Disinfection by Excess Lime

Lime is usually used at the water works for reducing the hardness of water. It has been noted practically that if some additional quantity of lime is added than what is actually required for removal of hardness, it will also disinfect the water while removing the hardness.

f) Disinfection by Potassium Permanganate

This is the most common disinfectant used in the village for disinfection of dug well water, pond water or private source of water. In addition to the killing of bacteria it also reduces the organic matters by oxidizing them. Due to its good oxidizing quality, it is sometimes added in small dose 0.05 to 0.10 mg/litre in the chlorinated water. In the rural areas it is common practice to dissolve a small amount of potassium permanganate in a bucket of water and mix it with the well water frequently, to kill the bacteria.

g) Disinfection by silver Ionization Plants

In silver ionization system the disinfections of water with silver ions start simultaneously with pumping of water whereas in conventional chlorination, chlorinated bleaching powder solution is to be prepared beforehand. Chlorination of water has many drawbacks like chlorine smell, generation of carcinogenic by-products, low residual effects, corrosion of metal parts of chlorinators, pipe line and specials whereas, silver ionization has advantages like high residual effects, odour

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less and non-corrosive. The regulation of silver ionization is automatic. Chlorination regulation depends on strength of bleaching powder and is totally manual. In view of above the disinfections of drinking water with silver ionization has been introduced in all of the new water supply schemes. Conventional chlorination kills bacteria whereas silver ionization effectively destroys viruses, bacteria, spores and fungi. The other advantages of silver ionization are as under:

I. Bacterial disinfection efficiency will be 100% even at high level of E-coli (4000 to 5000/ml)

II. Silver ions remain in water even after 51 hours after ionization without any significant loss

III. No change in physio-chemical characteristics in treated water IV. Silver ionization is safe, consumer friendly and reliable method over conventional

disinfections using chlorine/ bleaching powder V. Maintenance involves cleaning of electrodes daily and replacement of electrodes

after the design life VI. Silver ionization ensures complete disinfections of drinking water without the

problem of smell with chlorine/ bleaching powder.

Limitations/Disadvantages in this Process:

Huge cost is involved in capital / operation and maintenance More chances of theft No tracking of checking the disinfection effect at consumer end.

h) Electrolytic Chlorination-Sodium Hypo Chlorite Solution Using Common Salt

Principle of Operation

Chlorine is instantly produced by electrolyte brine solution. Common salt is mixed with water to prepare brine solution. This solution is passed through an Electrolyser of electrodes comprising of anodes and cathodes, which are energised by D.C. current to produce NaOCl. The equipment used is called electro chlorinator. The overall chemical reaction is as follows:

2NaOH+Cl2 NaOCl+ NaCl+ H2O

Considering the disinfection quality and economical aspects of disinfection, chlorination is the most suitable technology for the rural schemes.

i) Disinfection with Chlorine Gaseous Chlorination

Chlorination with Chlorine gas using a vacuum chlorinator is a very effective disinfection process for water treatment. It is cheap, easily available, reliable, and easy to handle, easy to measure and it is capable of providing residual disinfecting for a long time, thus protecting from future contamination. For MVS, this technique of disinfection is very effective. The schematic diagram of chlorinator with injector is shown in Fig 8-7

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Chapter-8 Page 8‐36

Forms of Chlorine

Free chlorine in the form of liquid chlorine or as chlorine gas As combined chlorine in the form of bleaching powder.

Chlorination with Bleaching Powder

Bleaching powder is usually practiced for disinfection of rural water supply. In order to achieve maximum destruction of bacteria a minimum contact period of 30 minutes between the bleaching powder solution and the water is required. If the bleaching powder is added in the OHSR the addition has to be done before stopping of pumps since the turbulence due to pumping will enable mixing of bleaching powder solution and the incoming water. Adding bleaching powder directly into OHSR is not advisable, as lime gets deposited and causes choking. It can also corrode the concrete.

However, the distribution system outlet must be opened only after a minimum period of 30 minutes after stoppage of pumping.

Figure 8-7: Gaseous Chlorinator with Injector

Water Treatment

Chapter-8 Page 8-37

Normally, the bleaching powder contains 30 to 35 % of chlorine when it is fresh. Since bleaching powder loses its chlorine content with time, it is desirable to assume that bleaching powder contains 25 % of chlorine while determining dosage of bleaching powder. Hence, in order to give chlorine dosage of 1 mg / lt. Bleaching powder of 4 mg/lt. is to be dosed. After addition of the bleaching powder the residual chlorine in the OHSR water has to be about 1 mg/lt, to ensure minimum residual chlorine of 0.2 to 0.3 mg/lt. at the consumption point. Any abnormal changes in the residual chlorine level or absence of residual chlorine will indicate the contamination of water.

A chloroscope shall be used to check the residual chlorine content. A sample of water is taken in a test tube and a few drops of the reagent is added to the water and shaken. If residual chlorine is present, the water in the test tube will turn to yellow. The concentration of residual chlorine is indicated by the intensity of the yellow colour i.e., the deeper the yellow, higher will be the concentration of residual chlorine. The comparator kit provides accurate comparison of colours and hence assesses quantity of residual chlorine.

Differential Pressure Type Chlorinator

It can be used for dozing of chlorine through online chlorination. In this case, the differential pressure chlorinator is fitted into the raising main. Here bleaching powder solution is introduced into pumping mains using the principle of differential pressure created in the pumping main by introducing a venture-flume or an orifice plate. Air release cock is provided at the top of the chlorinator to release the air during each loading of the rubber bag with bleaching powder solution. The chlorine solution is prepared using bleaching powder and allowed to settle for a period of about 20 to 30 minutes to settle down. The clear decanted solution is filtered and filled into the rubber bag. When the pump starts due to high pressure developed prior to the orifice plate, water enters into the gap between the rubber bag and the tank and starts compressing the rubber bag. Due to this the solution in the rubber bag rises and is injected into the pumping main beyond the orifice plate where reduced pressure is created, because of venture/orifice. When the pump set is put off the non-return valve in the outlet pipe prevents the entry of water into the rubber bag. The dosage can be adjusted as in the pipe carrying the bleaching powder solution the glass tube portion has a float which indicates the dosing of solution in ppm.

For tube well based scheme the Differential Pressure Feed Type dosing Equipment is most suitable.

Chapter-

-8

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Water Treatment

Chapter-8 Page 8-39

Pot Type Chlorinator

Chlorination with pot holes at the bottom or Double Pot Chlorinator may also be used by directly placing it into service reservoir or in the dug wells. Fig: 8-9

Typical Design of Capacity of Chlorinator

Assume the required dose of chlorination at source is 0.5 ppm which will be sufficient to maintain the residual chlorine at end point upto 0.2 ppm. The discharge of tube well is 2200 lpm and it runs for 22 hours.

Rate of Chlorination = 0.5 ppm = 0.5 mg/l Quantity of water to be disinfected = (2000 x 22 x 60) / 1000 = 2640 Kl/d Interval change of dose = 24 hours Strength of solution = 2% Available Chlorine in bleaching powder = 25% Total Chlorine requirement = 2640 x 0.5/1000 = 1.32 kg/d Quantity of bleaching power = 1.32 x 100/25 = 5.28 kg/d Capacity of Chlorinator for 2% strength = 5.28 x 100/2 = 264 litre Say = 270 Litre per day Say 12 litre capacity per hour

8.6.7. Sample Design of Conventional Water Treatment Plant

The location of WTP should be closed to raw water source for ease in O&M and reduction of associated capital expenditures. The sample design of water treatment plant of 6.5 mld capacity has been annexed at Annexure 08 (Volume-2).

Figure 8-9: Pot Type Chlorinators

Service Reservoir

Chapter-9 Page 9-1

9. SERVICE RESERVOIR

Service reservoirs are structures which are built at any convenient point in the water distribution arrangement between the original source and the consumer end. The function of the reservoir varies considerably depending upon their type and need. The general functions of a reservoir are detailed below:

To equalize the rate of flow, adjusting a variable demand rate to the rate of supply not equal to it. This allows the pumps to work at a steady constant rate which not only improves their efficiency but also reduces the cost of their operation and maintenance

To equalize pressure and to make it possible to pump water at an average constant head and thereby reducing the size of the pump and also pumping cost, since peak pressures are taken over from the pump

To provide and maintain the desired pressure in remote areas To provide necessary time for contact time for chlorine disinfection To store water for emergencies such as fires and break-down periods To provide economy and safety to the distribution system The pumping can be carried out in shifts and during hours convenient to the operating

personnel and availability of power To carry out any repairs to the conveying mains between the source of supply and the

reservoir without interruption of water service Balancing tank at the end of distribution system with a nominal capacity of 1 or 2

hours where direct pumping into the distribution system is adopted for acting as relief valve. For such arrangements ground storage tanks are used for direct pumping which involves a suction head.

9.1. Type of Reservoirs Used in Rural Water Supply

Ground Level Service Reservoir (GLSR): They are generally of masonry, Brick/Stone, R.C.C. Steel and HDPE

Over Head Service Reservoir (OHSR): These are also generally made of R.C.C. and Pressed Steel

Anyhow material of construction of tanks is left to the state.

When the reservoirs need not be over head, it is most economical to adopt ground level reservoirs. Where treated water is to be stored, these reservoirs are usually built with masonry walls and may be completely underground or partially underground depending upon the topography of the locality. Ground level reservoirs are usually covered, unless very large in area. The cover protects the water against contamination from wind borne material, birds and other sources, and it also prevents growth of algae and other plant life which might affect the taste and appearance of water.

Service Reservoir

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Overhead reservoirs are generally costly and are provided only if the ground level reservoirs cannot provide the required pressure in the distribution system. Storage of water in overhead tanks located at strategic points are usually necessary to provide sufficient pressure in the distribution system, unless the terrain is hilly enough to permit the use of ground level tank to maintain desired pressure in the distribution system. A low level reservoir is of service only in equalizing the operations of filters, deep well pumps, low lift pumps and conduits bringing water from a distant source. High level reservoirs act as equalizers to the entire supply system, including pumps and some of the distributing mains.

In Multi Village schemes Over Head Balancing Reservoir (OHBR) is provided at headworks site to collect treated water from sumps and transfer to different OHSRs in villages for distribution. OHBR is only for providing head and not for distribution purpose. In Multi Village schemes small reservoirs which acts as raw water and clear water sumps of adequate capacities are provided for pumping plants at places where pumping is required.

9.2. Location of Reservoirs

The three possible locations of Reservoirs are:

i) Locating the reservoir in central point with respect to distribution area. This will reduce the size of distribution mains and will cause better equalization of flow during peak demand periods. More uniform pressure will prevail in the system

ii) Locating near the beginning of the distribution system. This is adopted where the distribution area is at a lower level. Then the length of the pumping main becomes shorter, but the length of the distribution system mains becomes more

iii) Locating the reservoir site at a suitable altitude. It depends on the availability of land at suitable altitudes. It is necessary that bottom water level shall be at such a height that allows for frictional losses in the distribution mains and required residual head in any part of the system. This can be ensured either by locating the reservoir on high ground or by building on a tower.

9.3. Capacity of Reservoirs

While designing the storage of a reservoir, the first consideration is the capacity which will be provided. To great extent this depends upon the type of supply and is influenced by two main factors: (i) necessity of catering for peak demand periods and (ii) provision of reserve to cover normal break down or maintenance interruptions.

Service storage capacity will be provided for on the basis of mass curve as per CPHEEO manual, with minimum of 8 hours capacity.

Designs of Overhead water tanks (OHSR): The states have opted for inviting bids for overhead water tanks (OHSR) along with design and construction. In order to ensure that disaster risks are addressed effectively. States will ensure all designs done either by the

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contractor or department are in conformity with latest IS codes for concrete considering seismic and wind loads, and shall be checked by IITs or Government engineering colleges.

Shape of Reservoirs

The economical shape of the reservoirs should be selected. Few of the recommended shapes are given below:

Circular Ellipse Square Rectangular Intz type only for OHSR Shaft type for OHSR

Depth: The depth of the reservoir should always be determined taking site conditions into consideration. Where the depth is very shallow, temperature effects are felt which are likely to affect the potability of water and permit growth of organism. Shallow depths mean larger area and more land cost. At the same time, if the depth is large, this will increase the cost of walls, since these walls have to be thick. The most economical depth is determined by trial.

9.4. Reservoir Components

In addition to the main reservoir /tank body (Foundation), bottom, floor, walls and roofs); Followings are the various components of reservoirs:

(i) Ventilation: Roofs should have ventilators with wire mesh screen to prevent entry of mosquitoes etc. The height of the vents, in case of a ground level reservoir should prevent entry of frogs, worms etc.

(ii) Inlet Pipe: The size of inlet pipe is kept equal to the size of rising main/pumping main with the same size of sluice valve; In case of gravity feed reservoir, it is equal to size of feeder main with an inlet sluice/gate valve of the same size

(iii) Outlet Pipe: It should not be more than the diameter of initial distribution pipe line with the same size of sluice valve

(iv) Over flow pipe: It should not be less than the diameter of inlet pipe. The discharge of this pipe should be connected to the proper drainage system

(v) Washout/Scour Pipe: This is to be 100 mm dia. and provided at the bottom of the reservoir with a sluice valve before the T- junction with the over flow pipe. The down pipe should have a gravity chamber at the bottom

(vi) Ladders/Stairs: Ladder to stair case will have to be provided one from the ground level to the roof of the over-head reservoir and one from the inspection chamber of the roof to the floor level of the reservoir to facilitate access for proper maintenance. A helical stair may also be provided. Ladder can be made with flat iron 63 x 10 mm on sides 25 to 30 cm apart 45 cm wide, 20 mm dia. Iron ladder

Service Reservoir

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are constructed with an angle of 750 (preferred) to vertical at the floor. Ladder shall have minimum 200 mm clearance from any obstruction such as pipes and railing with minimum horizontal clearance of 75 mm from any obstruction such as columns and walls etc., String should be carried one metre above the landing point or roof etc for 750 increased to 1.75m for vertical. If the length of ladder is more than 6 m, welded steel mesh cage with minimum clearance of 0.75 m is provided from 2.15m above ground or floor level. Railing should be 0.90 m above ground or floor level. Railing should be 0.90 m to 1.0 m high at landing and hand rail to be from 25 cm for ladder at 600 to 10 cm for 750, above for the sides of the ladder

(vii) Water Level Indicator: Whether reservoir is supplied water by gravity or through pumping, it is essential that water level inside the reservoir, be known at any desired time and for this purpose, water level indicators are provided. Float type water level indicator will be used for SHS/SGS and Float type /ultrasonic Water level indicator/digital will be provided for MVS

(viii) Lightening Conductor: It is important to provide an efficient system of lightning conductor to arrest the damage against lighting for overhead reservoirs. The materials used above ground and below ground are shown in Table: 9-1.

Table 9-1: Lighting Conductor

Material Above Ground

Below Ground

Round galvanized wire No. 4 SWG No. 4 SWG Galvanized iron strip 20 x 3 mm 32 x 6 mm

(ix) Manhole cover with medium duty shall be provided at the roof of the reservoir of size (60cmx60cm).

9.5. Structural Design of Water Tanks

Clear water reservoirs, settling tanks, aeration tanks etc. are supported on the ground directly while overhead tanks for water supply may be constructed on masonry walls/columns, concrete staging or on towers. Material used may be steel, concrete, pre-stressed concrete, polythene or masonry. From design point of view, tanks may be classified according to their shapes such as rectangular, circular, pyramid, conical, intze type and other modern shapes such as spheroids and folded plates.. Reinforced Cement Concrete (RCC) structures are built now days.

The structural design may be got done by some Consultant or State Department Engineer. The software like: (i) STAD-PRO (ii) ANSYS may be used for designing of water tanks.

IS: 3370 with latest Edition code deals with the structures for the storage of liquids.

Part-I General Requirements Part-II Reinforced concrete structures

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Part-III Pre-stressed concrete structures (Revised in 2013) Part-IV Design tables (Revised in 2013)

The components such as top dome, cylinder, conical shell and bottom dome have been analyzed individually and designed. Ring beams have been provided at the junction of cylinder top dome, cylinder and bottom dome.

The stipulations outlined in the relevant Indian Standards mentioned in the references have been followed in the design. The top dome, top ring beam, cylinder, middle ring beam, conical shell and bottom dome have been designed for un-cracked conditions, whereas bottom ring beam, columns, braces and foundation are designed for cracked condition. The container portion is designed with permissible stress concept, whereas the supporting structure is designed on limit State concept.

Specifications & Design Features:

Water retaining structures must be built with impermeable walls which will not crack under storage or due to shrinkage and temperature stresses. It should be noted that no amount of over design in steel or concrete can help to overcome the durability problem. For durability, quality of concrete should be aimed at and not quantity. For general guidance, according to IS: 456 the material used shall be of the following specifications:

a) Cement: The cement shall be ordinary portland cement or rapid hardening Portland cement conforming to IS: 269 or blast furnace slag cement conforming to IS: 455. The use of low heat cement is not covered by the provisions of IS: 456

b) Aggregates: All aggregates shall conform to either IS: 383 or IS: 515. For heavily reinforced concrete members as in case of ribs of main beams, the nominal maximum size of aggregate should usually be restricted to 5 mm less than the minimum clear distance between the main bars or 5 mm less than the minimum cover to the reinforcement, whichever is smaller

c) Water: Water used for both mixing and curing shall be free from injurious amounts of deleterious materials. Potable waters are generally considered satisfactory for mixing and curing. Water for concreting and curing should confirm to IS: 456

d) Reinforcement

i) Mild steel and medium tensile steel bars and hard drawn steel wire shall conform to IS:432 (Part-I)

ii) Grade Fe 415 conforming to IS: 1786 iii) Deformed bars conforming to IS:1139 iv) Cold twisted steel bars conforming to IS:1786 v) Hard drawn steel wire fabric conforming to IS:1566 vi) Structural steel sections conforming to IS:226. vii) Lap length = 50 x diameter of bar

All reinforcement shall be clean and free from loose mill scale, dust, loose rust and coats of paints, oil or other coating which may destroy or reduce the bond. Adhering lime wash

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or cement grout shall be permitted at the Engineer’s discretion so long as it is not excessive or loose.

a) Concrete: In general, the concrete is of seven grades designed as M15, M20, M25, M30, M35 and M40. In designation of concrete mix, the letter ‘M’ refers to the Mix and the number to the specific 28-day works cube compressive strength of that mix in N/mm2

b) Flexible Joints: Special attention shall be given to flexible joints, construction joints, expansion joints and temporary construction joints

c) Shrinkage Stresses: Shrinkage stresses shall be investigated in case of rich concrete mixes and thick walls or in pre-stressed tanks. Coefficient of shrinkage may be taken as 300x10-6 (As per IS:3370 with latest revision)

d) Length of Bond: The minimum length for bond, or the minimum length of an overlap for liquid containers, keeping in view the permissible stresses of steel comes to 25 d, where d is the dia. of bar. For practical purposes, the minimum length of an overlap 30 d, or minimum length 300 mm should be adopted.

e) Quality of Water: The quality of water shall confirm as per IS: 456 f) Quantity of Water: The quantity of water required per 50 Kg of cement for various

mixes which provides a maximum slump about 150 mm. g) Cube Tests: Compression tests are made on 150 mm cubes, which should be made,

stored, and tested. For cubes made at site, these should be cast from one batch of concrete. Identification marks should be made on cubes. Two sets of three cubes each are preferable and one set should be tested at seven days and other at 28 days .If one set of three cubes is made, they should be tested at twenty eight days. The strengths of cubes in any set should not vary more than 15% of average, unless the lowest strength exceeds the minimum required. The seven days tests are a guide to the rate of hardening; the strength at this age for Portland cement concrete should be not less than two-third of the strength required at twenty eight days.

h) Permissible stress (Ref: IS: 3370) i) Roof of the Tanks: Under side of the roof of tanks storing chlorinated water get

usually corroded due to deteriorating action of free chlorine. Hence such roofs must be in concrete minimum M-30 grade and additional surface treatment for chlorine protection is required to be applied

j) Safe bearing Capacities of Soil: The design of foundation should be done as per results of the test conducted for safe bearing capacity of the soil at the project site.

k) Wind Pressure: Since the primary factor in the design of isolated structure is the force of wind, careful consideration is necessary to avoid either under-estimating this force or making an unduly high assessment. Due account should be taken of the susceptibility of narrow shafts to the impact of gust of winds. The total lateral force is the product of specified pressure and the maximum vertical projected area and a factor of safety of at least 1 ½ is required against overturning. Local meteorological records should be consulted to determine maximum wind velocity.

Strong high speed winds affects only the structures which are high such as OHSRs. The OHSRs are designed for Loads due Wind/ storm speed as per IS: 875, considering the specified wind speed for the respective damage risk zone and

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designed as per IS: 11682 with latest amendments. The foundations of these structures are designed as per the IS: 2950(Part-I) with latest amendments for the Raft foundation and IS: 2911 for Pile Foundations. IS: 875, Code of Practice for structural safety of buildings: Loading Standards. provides the figures of maximum basic wind pressure ever likely to occur in respective areas including winds of short duration, meaning thereby winds in which the maximum speed is attained suddenly and lasts for a few minutes only such as in squalls. The distribution and intensity of the resultant pressures due to wind depend upon the shape of the surface upon which the wind impinges.

Assam: Very high damage risk zone -B

Bihar: Part of the State falls in high damage risk zone and part of it in Moderate damage risk zone-B,

Jharkhand: Most Part of the State falls in Moderate damage risk zone – B and some part in high damage risk zone,

Uttar Pradesh: Most Part of the State falls in high damage risk zone) and District Sonebhadra in Moderate damage risk zone-B

Seismic effect in design: India has been divided in 5 seismic zones for design purpose. The design should be done by taking the values of proper zone of seismic effect of the project area.

Accordingly considering the stresses and forces of that magnitude for the respective areas as stated above, all the Service reservoirs are designed and constructed as per IS:1893(Part-1) and IS:2014 (Part-2) Fifth Revision, and the staging of the OHSR is designed as per IS:11682 with latest amendments. All RCC liquid retaining structures are designed as per IS: 3370 (Part-1) and (Part-2) with latest amendments and as per IS: 456. The construction of these structures shall also done considering the practices of National Building Code 2005 accordingly. The foundations of these structures are designed as per the IS: 2950(Part-I) with latest amendments for the Raft foundation and IS: 2911 for Pile Foundations. Thus the possible effect/impact of seismicity (Earthquake) is mitigated in designs. The cost of “Mitigation measures” is inbuilt and hence no separate provision is required.

Assam: Earthquake hazard Zone V (very high damage risk zone)

Bihar: Part of the state falls in Earthquake hazard Zone III (moderate damage risk zone) and part of it in zone II (low damage risk zone)

Jharkhand: Part of the state falls in Earthquake hazard Zone III (moderate damage risk zone) and part of it in zone II (low damage risk zone)

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Uttar Pradesh: Part of the state falls in Earthquake hazard Zone IV (high damage risk zone) and part of it in zone III (moderate damage risk zone)

9.5.1. Flood Hazard

Assam: The District which falls in Brahmaputra plains is liable to floods Bihar: The Districts which falls in Gangetic plains are liable to floods Jharkhand: Not Flood prone

Uttar Pradesh: Project Districts which falls in Gangetic- plains are liable to floods Thus, the Schemes/works of the villages falling in flood prone area in Gangetic- Brahmaputra plains are designed and constructed in such a way that they are above High Flood Level (HFL). Moreover, the intake works are proposed in such a way that they take care of such eventuality and provisions are made accordingly. The mitigation measures are taken and provided in the schemes.

9.5.2. Land Slides

As per the Map of Geological Survey of India, all four project states are in very low hazard zone; However, the Technical Committee of National Disaster Management Authority is updating the map and according to them Assam is moderately affected and Jharkhand is marginally affected.

After checking the site conditions if required some protection works to mitigate and reduce the risks may be considered to be proposed as per the following Codes

IS: 14496(Part-2), IS: 14458 (Part 1 to 3), IS: 14680 and national Building code 2005.

However, for specific scheme the exact risk hazard zone may be checked and exact stresses and loads have to identified and considered for the designs. All the designs and construction of the components of the scheme/project should be done accordingly as per the relevant IS codes and Specifications.

The checklist for disaster management is provided in the sample DPR Annexure 03 (Volume-2)

9.5.3. Test for Water Tightness of Structures:

All liquid retaining structures including underground reservoir, and different units of water treatment plant like inlet chambers, flocculator, clarifier, filter etc. shall be deemed to be satisfactory water tightness test as per relevant clause of IS:3370. The contractor shall fill the reservoir to MWL for conducting the water tightness test of the reservoir. The filling of the reservoir shall be gradual and not more than 15 cm of raise in water level per day shall be permitted. Full water level is to be maintained for 24 hours. During this period the structure under full working head of water shall not develop defects which will endanger its stability nor shall it show signs of any leakage. The fall in

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Chapter-9 Page 9-9

water level of the reservoir shall not be more than 10 mm. in 24 hours after which the satisfactory test certificate will be issued by the engineer. The Contractor shall rectify the defects noticed and carry out the tests again and repeat the testing operation till successful result is obtained and accepted by the Engineer.

The sample design of OHSR is annexed as Annexure 07 (Volume-2).

Distribution System

Chapter-10 Page 10-1

10. Distribution System

10.1. General

The distribution system is provided to convey water to the household consumer at adequate residual pressure in sufficient quantity. The requirements for the distribution systems are network of pipes connected to reservoirs with valves at suitable locations for efficient operation and maintenance. Adequate residual pressure at maximum demand depending upon the hydraulic capacity of the system should be provided.

10.2. General Design Parameters for Distribution System

Peak Factor: In SHS/SGS rural water supply schemes 6 hours distribution of water is being provided and hence a peak factor of 4 is to be considered for design of distribution lines. For MVS, water supply of 8-24 hours supplies to be provided with peak factor of 3.

Pressure Requirements: The minimum residual pressures in all rural water supply schemes should be available in the distribution system as per recommendations of the CPHEEO Manual i.e. 7 m at household level.

Minimum Size of Pipe in Distribution System: Minimum size of pipe in distribution system of 63 mm (Outer Diameter) is recommended, but it may be reviewed to get minimum velocity of 0.6 m/s, which is required to prevent silting.

Layout Distribution System-Zones: The ground elevations play a very important role in planning of laying out a distribution system. The zoning depends upon the density of population, type of locality and topography etc. When there is an average difference in elevation more than 5 m between zones then each zone should be served by a separate main. This philosophy shall facilitate in designing of distribution system for equitable distribution. The valves between zones should be kept closed and used only under emergent situations.

The groups of distribution pipes to varying levels should, however, be kept as separate as possible. But when the higher levels are adjacent to the reservoir from which the leading mains originate, the pipes should have larger dia. at starting and until they have passed through, and supplied the higher parts, they should then be reduced in dia. as they continue towards the lower levels.

Survey/ Map: The pre-requisite to sound design of distribution system is a complete survey covering all roads and indicating elevations of all important point proposed as well as present roads. The plan of the villages can be shaded to show density of population and anticipated number of persons per acre should be indicated.

Distribution System


Location of Service Reservoirs in Different Zones: As already discussed where the levels vary considerably, it would be desirable to lay a separate set of leading main to each range of levels. Location of reservoir in a zone should be finalised by considering the following aspects:

Nearer to treated water source At the higher elevation part of the ground Centrally located of the distribution area.

10.3. Types of Distribution Systems

The various types of distribution system are

a) Grid Area System: This system eliminates the dead ends and thus permits circulation of water. In case of heavy draft on leading mains or branch lines, the system permits drawing of water from other connected mains. By locating the valves properly, in case of repair of one pipe the area from which water is cut off can be reduced to one block only, keeping the supply in rest of the area uninterrupted. Valves are generally installed three at crosses, two at Tees, and one on single hydrant branch.

The only disadvantages in this method are that the distributing mains are rather more complicated and more turn-off valves are necessary and the labour in turning off various sections in the sub-districts is slightly greater.

b) Dead-End System: As the name implies this is a system in which the main line is laid on the main road, from these, smaller pipes serve individual streets but do not connect at their ends with other mains. In this system if a pipe line near the centre of the system develops fault, a large area will be without water.

c) Compromise System: In most of the cases, only compromise system is possible. In

this system the pipes provide circulation only where it is provided at reasonable costs, but where it is not feasible to connect the pipe ends they are left unconnected and adequate arrangement for flushing through hydrants is made. The examples of such cases are that it is costly to lay a pipe line across a rocky bed of the stream or under a rail road multiple tracks or a multilane highway etc. Under such situation, dead ends are unavoidable.

In rural water supply schemes, grid area system is being recommended.

10.4. Methods of Network Analysis

The network analysis method in the design of water distribution system consists of sizes of pipes, sizing of reservoirs and fixing the location of reservoirs and pumps etc. suitable for the proposed layout. The modified Hazen-William’s formula is popularly used for finding out the size of the pipe for a given flow.

Distribution System


1) Trial and Error Method: In this method, the heads or flows are assumed in the pipe system and the corresponding heads and flows obtained by the use of tables in CPHEEO Manual, based on modified Hazen-William’s formula, the nearness of assumed head or flows is tested. The process is repeated till the time the head losses and flows agree within 0.3 m and 2% respectively when a correct solution is found.

2) Computation in Dead End System: The design of dead end distribution system is

done taking into consideration of present & prospective population, topographical map of the town and the layout of the piping etc.

3) Hardy Cross Method (Balancing Heads): The methods discussed above can be

employed to any distribution system. The problem becomes more complex when there are series of interconnected endless line in the layout of the system. For such systems, a method developed by Professor Hardy Cross is most widely used. The Hardy Cross method is a controlled trial and error process in which the heads are balanced. In layout of a system like grid iron, water travels and reaches different points by more than one route. It is, therefore, necessary first of all, to find out the quantities of flow passing via each route.

10.5. Hydraulic Network Analysis

A pipe network map corresponding to the road network of the village is prepared for hydraulic analysis. The total length of present pipe network is calculated. The estimated population/households for the design period are arrived at. From this data the households per running meter of network is calculated and hence the demand per running meter of the pipe network is calculated. The demand for each pipe section is arrived calculating from the end point as per the number of the households per running meter. The cumulative demand is calculated for each branch and for the trunk main. This demand is average demand; however, the network is to be designed for the peak flow. The pipe network is then analyzed for the estimated demand using the suitable peak factor.

Input Data

In the hydraulic network design one of the important criteria is the head loss allowed in the distribution system. This is also an important constraint required in the optimization of pipe sizes required in the linear programming model. The use of smaller diameter pipes results in higher head loss which calls for higher staging heights of OHSR to ensure desired residual pressure at the farthest delivery point. On the other hand, use of higher diameter pipes results in lower head losses but increase the cost of the pipeline. Hence the pipe sizes selected shall be optimized using the maximum and minimum head loss that can be permitted. Usually a minimum head loss of 0.5 m/ km and maximum head loss of 5 m/ km are adopted in a rural water supply system.

The minimum head loss is calculated as the drop in elevation from the LWL of the OHSR to the lowest point in the village divided by the distance from the OHSR to the lowest elevation point along the network. The maximum head loss is calculated as the

Distribution System


drop in elevation from the MWL of the OHSR to the highest point in the village divided by the distance from the OHSR to the highest elevation point along the network.

Next important input to the analysis is the Hazen – William’s coefficient ‘C’ for design purpose is to be given as input based on the type of pipe material used in the network.

The network should be designed using software Watergem/Loop/Epanet/or any other latest software.

10.6. Location of the valves:

One sluice valve shall be located at the starting point of the distribution system near the OHSR to cut off or restore the flow from OHSR into the distribution system. Each branch is also provided with one sluice valve for controlling the flow into that branch. Valves on the main line are not recommended. However, main line valves may be installed where it is necessary to isolate the supply of water to the various zones. The need for Scouring a distribution system arises rarely. However, in an intermittent supply, water stagnates in valley portions, which has to be drained out so that stagnant water is not supplied to the consumers. Hence scour valves are provided in the valley portions. The size of scour valve in a distribution system of rural water supply shall not normally exceed 50 mm. Further this valve must be protected against misuse and provided with a masonry chamber and a cover with a locking arrangement. The outlet of scour valve shall be connected to a drain. It should be ensured that wastewater from the drain will not contaminate the drinking water through the scour pipe. All drain crossings of the distribution system pipes shall be provided with an outer casing pipe to prevent contamination by the drain water. Air valves are provided at the highest points of mains to release air so that bursting of pipes can be prevented. The whole arrangement is shown in Figure: 10-1 as mentioned below:

Distribution System


Figure 10-1: General Arrangement of Placement of Valves along the Alignment

Chapter-

10.7.

-10

House Serv

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Page 10‐6

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Distribution System


the project with a five year maintenance guarantee. The water meter fixed should conform to IS: 779.

10.8. Flow Meters

Water shall be conveyed to OHSR by installing bulk meters confirming to IS: 2373 at the inlet point in a Village. The bulk meter shall be taken with 5 years guarantee from the supplier.

Guidelines for Selection, Installation & Maintenance of Domestic Water Meters

The following points shall govern the selection of meters as per IS: 779:

ii) The maximum flow shall not exceed the nominal capacity of the meter. iii) The continuous flow shall not be greater than the continuous running capacity

rating.

Inferential water meter has the same accuracy as the semi-positive type at higher flows. It passes unfiltered water better than a semi-positive meter and is lower in cost.

Special care is necessary in selecting the most suitable meter where large rates of flow may exist for short periods. The normal working flow shall be well within the continuous running capacity specified in IS: 779. As high rates of flow over short period may cause excessive wear if the meter chosen is too small for the duty.

Owing to the fine clearances in the working parts of meters, they are not suitable for measuring water containing sand or similar foreign matter, and in such cases a filter or dirt box of adequate effective areas shall be fitted on the upstream side of the meter. It should be noted that the normal strainer fitted inside a meter is not a filter and does not prevent the entry of small particles, such as sand.

Installation of Meter: A meter shall not be run with free discharge to atmosphere, if the static pressure on the main exceeds 10 m head of water, otherwise the meter is liable to be overloaded and damaged. For house connections and similar applications, there shall always be some resistance on the downstream side of the meter.

A Meter shall be located where it is not liable to get severe shock of water hammer, which might break the piston or damage the rotor, and the position shall be such that it is always full of water. If the meter body or adjacent pipes become partially drained of water, the accumulated air, when passed through the meter, is registered as water and may cause inaccuracies and perhaps damage. The inaccuracies may be more pronounced in the case of inferential meters. Thus we should avoid the use of such type of meters. In the case of intermittent water supply system, where there are frequent changes of air locks, the piston of the semi-positive meter often breaks. In such a case, it is advisable to ensure that the top of the meter is below the level of the communication pipe.

Semi-positive meters may be fixed in any position, with the dials facing upwards or sideways, and they may be installed in horizontal or vertical pipe runs without affecting wearing properties of accuracy at normal service flows. Where backWard flows are anticipated, reflux valves are recommended to be provided. A stop valve should be provided on the upstream side to isolate the meter whenever necessary.

Distribution System


Inferential meters shall be installed in position for which they are designed in the case of meters confirming to IS: 779. They shall be placed horizontally with dial facing upwards. However, where meters are to be installed in vertical pipelines, details shall be as agreed to between the manufacturer and the purchaser.

Turbulent flow of water affects the accuracy of the meter. There shall, therefore, be straight lengths of pipes upstream and downstream of meter for an equivalent length of ten times the nominal diameter of the pipe.

Meters liable to damage by frost shall be suitably protected. It is possible to incorporate frost protection devices in certain types of meters, if ordered. Several devices are adopted, the, most common among them being a collapsible metal ring which, under frost pressure, allows the top plate carrying the mechanism to lift and thus safeguard the body, or a metal disc in the body which gives way under pressured. These devices have the following disadvantages:

a) The damaged ring or plate requires immediate replacement in order to stop wastage and restore water supply to consumer

b) Water runs to waste till the meter is attended to which means loss of revenue c) Damage is discovered only after thawing has started.

Figure 10-3: Flow Diagram of Pumping From Headworks to Service Reservoirs

SCADA & Automation System


11. SCADA & Automation System

11.1. SCADA

SCADA (Supervisory Control and Data Acquisition) will be provided in all large MVS, while for small MVS simple automation shall be provided.

Brief description of Supervisory Control and Data Acquisition (SCADA) to be provided is given below:

The system is designed for ultimate flows and has to serve the present demand which will progressively increase. The hydraulic design done for ultimate demand is to be checked for residual heads for present demand and intermediate demand also. The residual heads (pressures) are also to be regulated and need to be adjusted for progressive changes in demand. The inflow into ESRs has to be controlled to the required rate of flow and also to control the cumulative flow. When the ESRs overflow the level is to be sensed and the flow into ESR is to be stopped. To achieve this control of inflow into the ESR with manual operations is infeasible and not desirable. It is necessary to provide flow and level measurement & control device. Apart from the above, the flow measurement also helps in analyzing the water losses and water auditing in the system. The availability of dependable quality power is always an issue which affects the performance of the control devices.

11.2. Control Philosophy of SCADA

Main Components of Flow and pressure measurement and controls are: (i) ultrasonic level (ESR) sensor & transmitter (ii) pressure sensor & transmitter (iii) pressure reducing valve (if required) (iv) turbine flow meter with signal generation (v) valve actuator motor (vi) valve actuator drive (MOV) (vii) programmable logic controller/remote terminal unit (viii) battery power Backup system including for motor actuator and solar back up.

The flow and pressure are monitored through the flow measured device and it will be transmitted to RTU. When the flow varies from the set point of flow then the MOV will operate by automatic command from the RTU to regulate and achieve the required design flow at inlet of the ESR. The level in the ELSR will be monitored and transmitted to RTU. When the maximum water level reaches in the ELSR, MOV at inlet will close by automatic command from RTU. When the water level falls below maximum water level in the ELSR MOV at inlet will open by automatic command from RTU. The battery back-up system is required with charger facility with minimum 24 hour battery back-up and solar connectivity enabled.

11.3. Automation

The detailed specification of this automation is given below:

Particular of Supply: Three phase 415Volts _+6%, 50Hz.AC



Technical Particular

Type of pumps Vertical turbine / Submersible Capacity of pump LPM Horsepower of the motor HP Fluid to be pumped Water Character Reasonably clear Temperature Normal Specific Gravity Normal Viscosity Normal

Auto Control Panel

The pump auto control panel comprises of the following equipment / functions for automatic start & stop of the unmanned pumps, with references to two point water level i.e. predetermined higher & lower level of water in the overhead tank & preset timings, along with the necessary protective devices, covered under this specification and star – delta starter.

Automatic Water Level Controller

This controller is suitable for two point water level control for controlling upper & lower level in the same tank but of multiple tanks of variable heights , it is capable of starting with respect to lower level of higher tank .This controller is capable of to monitor the predetermined two point water level in the overhead tank to ensure the automatic starting of the pump as soon as the water level reaches the predetermined lowest point in order to eliminate the emptying of water tank and also overhead tank reaches highest point of predetermined water level in order to avoid the overflowing , thus wastage of water.

Starter

It should consist of STAR-DELTA starter to be operated by & with the help of “Artificial Intelligence” unit (described later in this chapter) to start & stop the motor / pump, with protection of thermal overload relay. Electronic timer is used to change the star into delta connection.

Auto /Manual Switch

The system has a provision of auto/manual switch, in order to operate the pump in both mode i.e. auto & manual, in case of abnormality.

Phasing Preventer

It has a provision of negative sequence current / voltage sensing single phasing preventer in order to offer protection against single phasing, reverse phasing and phase unbalance condition.



Dry Run Protection It has a prod less type dry run protection, working on negative sequence current sensing principle, to ensure the perfect protection of motor/pump against dry-run condition.

Mains Indication

It has a provision of neon indication lamps for the indication of the availability of three phase supply.

Trip Indications of Protective Devices

All the protective devices are equipped with the “trip” indication on the front of the panel to get informed about the tripped devices simply by visual indication.

Led Light Indicator

It has a provision of LED indication lamp for indication of ON/OFF operation of the motor/pump.

Main Switches With Short Circuit Protection

It has a provision of MCCB or MCB of appropriate rating to work as main switch to the panel & protective device under short circuit condition.

Over Voltage and Under Voltage Protection

It has a provision of protective device to trip the operation of motor/pump under faulty conditions as per I.E. Rule 1956 or as per the site requirement.

This equipment is designed on fail-safe principle in order to isolate the pump automatically from the mains in case of malfunctioning or non-functioning of any of the protective devices with visual indication for each individual protective device separately.

Over Load Protection

It has a provision of electronic protective device with time required to trip under over-load condition ranging 3-5 second maximum. It does not malfunction or trip under momentary faults /overload due to nuisance in power supply.

Duel Sequence Timer

It has a versatile and ever alert controlling device for motor/pump, set to be used for time based automatic start and stop operation of motor/pump approx. 45 times per day automatically, as per pre-set timings for ON/OFF operation of pump ( without the need of operator) in order to ensure the regular rest to the pump. This has a battery backup facility to preserve in its memory, the set timings till resumption of power, even if power fails to maximum 7 Days or 150 hours. This has a bypass arrangement for manual operation in case of mal-functioning or non-functioning.



Hour Meter

It has a provision of hour counter in order to facilitate the cumulative recording of working hours of pump of 5.2 digits.

Artificial Intelligence

It has a provision of an electronic chip along with the combination of control gears to replace the “human intelligence” & simulate all signals/parameters from all the protective & control devices discussed under this specification under digital mode of operation. If all the protective and control devices permits then it send the signal to the starter unit to get the motor/pump “ON / OFF”. Under normal operating conditions, it is the replacement of “human intelligence”.

Electrical Panels

A panel is an essential component of the electrical machinery. Various functions which the panel board has to serve are:

To receive the power supply Distribution Controls Protection Under voltage relays Over current relay.

The components of panel board are:

Starters Level controls Single phasing preventer 3 Phase indicators Dry run preventer Capacitors AVO meter.

Starters

The principal methods of starting three phase squirrel cage motors are Direct Online (DOL), Star Delta and Auto-Transformer.

When using direct starting, the only control gear is a switch or circuit breaker which serves to isolate the motor from the supply. Some starters have two positions for the operating handle, Off and On (or Run). The Start position of the latter type cuts out the overload coils and this is the only difference between the two types of starters.

If the motor fails to start when the starter handle is moved to start position, the handle should not be moved over to run position but should be immediately returned to Off position otherwise both motor and starter will get damaged.



Transformers

Transformers are located outdoor which should be as near to the pump house as possible to keep the leads shortest.

The outdoor sub-station should have:

(1) lightening arrestors (2) Gang operated disconnections. In indoor sub-station circuit breakers are provided (3) Dropout fuses for small outdoor sub-stations (4) Overhead bus bar and insulators (5) Transformers (6) Current transformer (7) Fencing (8) Earthing-very comprehensive, covering every item in the sub-station in

accordance with IS:3043.

Ground Water Recharge


12. GROUND WATER RECHARGE

12.1. Need for Ground Water Recharge

India has had a rich tradition of ground water recharge which is more than two millennia old. Evidence of this tradition has been found in ancient texts, inscriptions and archaeological remains. Sub-surface storage of harvested rain water through recharge to ground water reservoir is a relatively recent technique. In this technique, the harvested rainwater is transferred to the aquifer through civil structures like recharge pit, recharge trench, tube well / recharge well, recharge shaft, check dam, percolation tank, etc. This process of augmentation of ground water reservoir at a rate exceeding that under natural conditions of replenishment through suitable civil structures is known as artificial recharge. The source water for recharge can be runoff from the catchment area, canal water or treated waste water.

The dependence on ground water as a reliable source for meeting the requirements for drinking, irrigation and industrial uses in India has been rising rapidly during the last few decades. Ground water development has occupied an important place in Indian economy because of its role in stabilizing agriculture and as a means for drought management. In many parts of the country, ground water development has already reached a critical stage, resulting in acute scarcity of the resource. Over- development of the ground water resources results in declining ground water levels, shortage in water supply, intrusion of saline water in coastal areas and increased pumping lifts necessitating deepening of ground water abstraction structures. These have serious implications on the environment and the socio-economic conditions of the populace. Worsening ground water quality has also adversely affected the availability of fresh ground water in several areas. The prevailing scenario of ground water development and management in India calls for urgent steps for augmentation of ground water resources to ensure their long-term sustainability. The diverse nature of the terrain and complexities of hydro-geological settings prevailing in the country makes this a challenging task.

In this context Central Ground Water Board ( CGWB), an apex organization at Central level under the Ministry of Water Resources has prepared guidelines as well as master plan for artificial recharge to ground water for augmenting ground water resources through scientifically designed artificial recharge structures to harvest non-committed surplus runoff which otherwise runs off into sea. A number of pilot schemes and demonstrative artificial recharge schemes have been implemented by the Board in association with various State Government Organizations since the 8th plan period. These are aimed at popularizing cost-effective ground water augmentation techniques suitable for various hydro-geological settings, to be replicated by other agencies elsewhere in similar areas. Based on the valuable experience gained from such activities, the Board has also brought out a number of publications on various aspects of artificial recharge. The ‘Manual on Artificial Recharge of Ground Water’ 2013 is the latest in this series and has updated information on various aspects of investigation techniques for selection of sites, planning and design of artificial recharge structures, their economic evaluation, monitoring and technical auditing of schemes and issues related to operation and maintenance of these structures.

Chapter-

12.2.

-12

Ground W

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Page 12‐2

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12.3. Ground Water Availability

The ground water resources availability for the identified districts have been collected from CGWB. Also the ground water levels and ground water resource maps (Quality and Quantity) have been obtained and given in Table 12-1.



Table 12-1: Ground Water Resources Availability, Utilization and Stage of Development

ASSAM S.

No. District Annual Replenishable Ground Water Resource

Nat

ural

Disc

harg

e D

urin

g N

on

Mon

soon

Per

iod

Net

Gro

und

Wat

er

Ava

ilabi

lity

Annual Ground Water Draft Allocation For

Domestic &

Industrial Water

Uses up to 2025

Net Ground Water

Availability for Future Irrigation

use

Stage of Ground Water

Development (%)

Monsoon Season Non Monsoon Season Total

Irri

gatio

n

Dom

estic

&

Indu

stri

al W

ater

Su

pply

Total Recharge

from Rainfall

Recharge From Other

Sources

Recharge from

Rainfall

Recharge From Other

Sources

1 Bongaigaon 90094 17681 30817 4429 143021 7151 135870 55501 2265 57766 2884 77484 43 2 Hailakandi 23134 225 10860 59 34279 3428 30851 698 1421 2119 2067 28086 7 3 Jorhat 78769 4641 49493 1171 134075 6704 127371 14537 2572 17109 3465 109368 13 4 Kamrup 111641 24031 42757 6299 184729 18473 166256 64476 7121 71597 10516 91264 43 5 Morigaon 47312 8337 19046 2090 76785 7678 69106 26166 2023 28189 2975 39965 41 6 Sibsagar 98417 5114 41461 1289 146281 14628 131653 16027 2677 18704 3623 112002 14 7 Sonitpur 152313 17909 72300 5066 247588 12379 235209 33339 4308 37647 5998 195872 16

State Total

(ham) 1895002 219554.2 861468 59009.3 3035034 253733 2781300 533313 69312 602625 97724.83 2150262.2 22

Bihar GROUND WATER RESOURCES AVAILABILITY, UTILIZATION AND STAGE OF DEVELOPMENT

S. No.

District Annual Replenishable Ground Water Resource Natural Discharge

During Non

Monsoon Period

Net Ground Water

Availability


Domestic & Industrial

Water Uses up to 2025

Net Ground Water


use


Development (%)

Monsoon Season Non Monsoon Season Total Irrigation

Domestic &

Industrial Water Supply

Total Recharge

from Rainfall

Recharge From Other

Sources

Recharge from

Rainfall

Recharge From Other

Sources 1 Banka 28525 9454 6732 1696 46408 3670 42738 12774 3017 15791 4333 25630 37 2 Begusarai 49136 4279 7198 5966 66579 6496 60083 30735 4415 35150 7611 21737 59 3 Munger 24811 4170 4019 1074 34074 3168 30907 6922 2046 8968 2888 21097 29 4 Muzaffarpur 72596 17624 11172 14987 116380 9327 107052 50152 7126 57277 10839 46061 54 5 Nalanda 50219 11542 7002 3303 72067 5872 66195 38547 4425 42972 5509 22139 65 6 Nawada 41977 5061 6829 1874 55741 4377 51364 18531 3592 22123 5807 27025 43 7 Patna 72339 15644 10352 7449 105784 9329 96455 44052 8708 52760 12859 39544 55 8 Purnea 68281 7244 18860 4538 98923 8856 90066 34240 4966 39207 8528 47298 44 9 Saran 50251 12024 8105 10351 80731 4285 76446 36798 6661 43459 9582 30066 57

10 W. Champaran 94993 24177 12402 25594 157166 15717 141450 30220 5744 35964 9275 101955 25 State Total

(ham) 1892376 392116 339621 238498 2862611 242034 2620577 979351 156253 1135604 256351 1384877 43

State Total (bcm)

18.92 3.92 3.4 2.38 28.63 2.42 26.21 9.79 1.56 11.36 2.56 13.85 43



JHARKHAND S. No. District Annual Replenishable Ground Water Resource

Nat

ural

D

ischa

rge

Dur

ing

Non

M

onso

on

Peri

od

Net

Gro

und

Wat

er

Ava

ilabi

lity Annual Ground Water Draft Allocation

For Domestic & Industrial Water Uses up to 2025

Net

Gro

und

Wat

er

Ava

ilabi

lity

for

Futu

re

Irri

gatio

n us

e Stage of Ground Water Development (%)


Dom

estic

&

In

dust

rial

W

ater

Total Recharge from Rainfall

Recharge From Other Sources

Recharge from Rainfall

Recharge From Other Sources

1 Dumka 19935 2314 6301 1506 30056 3006 27051 5578 1804 7382 2455 19018 27 2 E-Singhbhum 22920 146 6114 683 29863 2708 27156 2346 3287 5633 4966 19844 21 3 Garhwa 25880 1555 4041 2436 33912 2839 31073 9257 1710 10968 2510 19306 35 4 Khunti 10029 744 4281 901 15955 1596 14360 3350 709 4059 963 10047 28 5 Palamu 32841 1542 4772 318 39472 3392 36080 9182 2510 11692 3761 23137 32 6 Saraikela 15537 617 4329 277 20759 1900 18859 912 1298 2210 1731 16217 12 State Total

(ham) 445603 13662 110922 26381 596569 55482 541087 116782 44059 160841 62062 362243 30

Uttar Pradesh GROUND WATER RESOURCES AVAILABILITY, UTILIZATION AND STAGE OF DEVELOPMENT

Sl. No. District Annual Replenishable Ground Water Resource Natural Discharge

During Non

Monsoon Period

Net Ground Water

Availability


Domestic &

Industrial Water

Uses up to 2025

Net Ground Water


use


Development (%)


Domestic &

Industrial Water Supply

Total Recharge

from Rainfall

Recharge From Other

Sources

Recharge from

Rainfall

Recharge From Other

Sources

1 Allahabad 75509 23963 0 25921 125393 10248 115144 77428 9421 86849 22562 15155 75 2 Ballia 49060 15736 15379 20098 100273 8075 92198 52035 6473 58508 10737 29426 63 3 Basti 63603 11158 15173 13606 103539 9415 94124 66166 4831 70996 7392 20566 75 4 Behraich 90799 6801 19718 13280 130598 10845 119753 63726 6556 70282 10732 45295 59 5 Deoria 59898 10742 11739 17144 99522 8844 90678 59180 7308 66489 8538 22960 73 6 G.B.Nagar 18333 8025 2796 19522 48675 4174 44501 38206 1778 39984 3001 3295 90 7 Ghazipur 61401 25712 11594 33306 132012 13201 118811 74173 7586 81759 13419 31219 69 8 Gonda 79192 9606 19530 16393 124722 9041 115681 75878 6654 82532 11105 28697 71 9 Gorakhpur 116399 13413 23040 21825 174677 16197 158480 94910 7621 102532 11655 51915 65 10 Kushi Nagar 56246 32363 11599 40069 140277 12787 127490 68869 6371 75240 7306 51314 59

State total

(ham) 4077837 1136994 541075 1769552 7525458 668004 6857454 4599580 348728 4948308 536083 1721792 72

State Total

(bcm) 40.78 11.37 5.41 17.70 75.25 6.68 68.57 46.00 3.49 49.48 5.36 17.22 72



12.4. Ground Water Exploitation Status

The ground water contributes nearly 85 % of the rural water supply, at places, however, there has been over exploitation of ground water and deterioration in ground water quality reported. Also, in some areas semi critical blocks have been found to slip into critical category. In general the ground water development in the blocks / districts covering project area states are low in as much as in state of Assam and Bihar all the blocks fall in safe category. The district wise status of ground water exploitation in terms of categorization of blocks for Jharkhand and Uttar Pradesh is given in table below.

Table -12-2: Categorization of Blocks on Ground Water Exploitation

SL.NO. DISTRICT BLOCK/MANDAL/TALUK Categorization JHARKHAND

1 E.Singhbhum Jamshedpur Over-exploited 2 Garhwa Ramna Semi-critical

UTTAR PRADESH

1 Allahabad

Bahadurpur Semi-critical Dhanupur Semi-critical

Karchhana Critical Kaurihar Semi-critical Pratappur Semi-critical Saidabad Semi-critical

Urwa Semi-critical 2 Ghazipur Ghazipur Semi-critical Jakhaniya Semi-critical Karanda Semi-critical Saidpur Semi-critical 3 Sonbhadra Ghorawal Semi-critical

In Assam and Bihar, there are no critical or semi critical zones hence not furnished in the above table Criteria for selection of sites for recharge structures

Depending upon geomorphologic and physiographic conditions as well as conditions suitable for recharge, availability of source water the approach for artificial recharge has been recommended suiting to the environment.

The suitability of an aquifer for recharging has been estimated from the following parameters; Surface material which has to be highly permeable so as to allow water to percolate easily.

The unsaturated zone should present a high vertical permeability, and vertical flow of water should not be restrained by less permeable clayey layers.

Depth to water level should not be less than 7 to 10 m.



Aquifer transmissivity should be high enough to allow water to move rapidly from the mound created under the recharge basin.

An adequate transmissivity for recharge is also a good indicator of the aquifer capacity to produce high well discharge and therefore easily to return the water stored.

12.5. Ground Water Prospect Maps

NRSA have prepared Ground Water Prospects and Recharge Zone Maps for Project States of Assam, Bihar, Jharkhand and Uttar Pradesh. These maps are deciphered & used in identifying sites suitable for developing ground water based supplies in no-source habitation areas. Such maps also help in identifying suitable sites for recharging ground water. These maps are given in detailed at Annexure-10 (Volume-2)

12.6. Technological Options for Recharge

Artificial Recharge Issues

Artificial recharge techniques will address following issues at various at various types of water supply scheme levels.

Increase sustainable water yield in areas where over-exploited, critical and semi-critical development have variously depleted aquifers. Conserve and dispose of run-off in storage for future needs improve the quality of deteriorated ground water through dilution.

Remove bacteriological and other impurities from sewer and waste-water so that water is reused. The problems of water table decline and water quality deterioration are present variously in parts of some blocks/villages in the identified study districts. The use of artificial recharge techniques shall benefit communities ground water based water supply and reverse/improve falling water table and dwindling water quality due to high arsenic in, fluoride, nitrate, and iron levels in ground water of water supply scheme areas.

Design Criterion

The basic requirements for recharging the ground water reservoir are:

Availability of non-committed surplus monsoon rainfall runoff in space and time. Identification of suitable hydro geological environment and sites for creating

subsurface reservoir through cost effective artificial recharge techniques.

Design Considerations

The important aspects to be looked into for designing a aquifer recharge system to augment ground water resources are:

Hydrogeology of the area including nature and extent of aquifer, soil cover, topography, depth to water level and chemical quality of ground water

The availability and quality of source water, one of the prime requisite for ground water recharge, basically assessed in terms of non-committed surplus monsoon runoff



Area contributing runoff like area available, land use pattern etc. Hydro meteorological characteristics like rainfall duration, general pattern and

intensity of rainfall.

Potential Areas

Where ground water levels are more than 8 m deep and declining on regular basis Where substantial amount of aquifer has been de-saturated Where availability of ground water is inadequate in lean months Urban areas where infiltration of rain water into subsoil has decreased drastically

resulting into diminished recharge to ground water reservoir.

Scientific Inputs for Effective Recharge

The efficacy of artificial recharge schemes depends largely on the scientific input of source water availability and capability of ground water reservoir to accommodate it, which requires detailed knowledge of geological and hydrological features of the area for site selection and design of artificial recharge structures. While assessing the availability of source water, which is one of the prime requisites for ground water recharge, careful consideration has to be given to committed monsoon storages, so that the recharging of non-committed surplus monsoon runoff in the given area does not have adverse environmental impact like drying up of existing lakes/ponds/reservoirs due to reduction in inflows from their catchments. In particular, the features, parameters and data to be considered are geological boundaries, hydraulic boundaries, storage capacity, porosity, hydraulic conductivity, transmissivity, natural discharge of springs, water balance, lithology, depth of the aquifer and tectonic boundaries. Detailed knowledge of dimensional data of the aquifer i.e. their thickness and lateral extent is necessary for evaluation of the storage potential. The availability of sub-surface storage space and its replenishment capacity govern the extent of recharge.

Constraints of Effective Recharging

Some of the constraints include:

Source water availability for recharge and aspect of recharging in up Stream of watershed depriving downstream habitants

Lack of understanding of the aspect of rainfall intensity and distribution that determines the design of water capturing and its infiltration into aquifers

Presence of low permeable strata on high permeable deposits Occurrence of bad quality water at shallow depth.

Provisioning and Augmenting Water Supplies for Small and Large Communities

Ground water is dependable, instant and preferred source for rural communities. CGWB 3D Aquifer maps, ground water quality maps, NRSA designed ground water prospects zone maps, particularly know as hydro-geomorphological maps, depth to water level and piezometer levels , geophysical resistivity data shall be analysed in designing and improving rural water supply scheme of various type.



Over area covered with hard rocks, a watershed approach shall be considered in identifying the type of recharge structure which would be a check dam, sub surface dyke system or small nala bunds and for flat alluvial terrain unlined percolation ponds along with bore wells shafts depending upon hydrogeology of the area shall be recommended to improve recharge and water supply by small / regional rural water schemes.

The watershed structures weather check dam, subsurface dam, ponds, open wells, nala bunds etc. would need to be protected and maintained and managed to get maximum benefits. It is here the convergence of MNREGA, IWMP, NWDPRA, RKVY, ARDWS etc. would facilitate water supply management and recharging.

State level watershed mission, Self Help Group (SHG) working under IWMP project, watershed committees, NGOs and various level stakeholders should converge towards decision taking leading to improvement in water supply scheme at local and regional level. Manual is thus intended to besides other things; help improve sustainable development of water sources / sewage in rural communities.

Choice for Recharge Methods

The depth to water table, soil permeability, Hydraulic conductivity & Transmissivity of unconfined aquifer shall play a large role in choosing appropriate methods of recharging ground water sources. The following ground water recharge techniques commensurate with depth of aquifer are identified study districts (CGWB Guidelines) shall be caused for adaptation. These are as described as below :

(i) Percolation Pond (ii) Dug Well Recharge (iii) Recharge Through Shaft (iv) Recharge Through Shaft with Recharge Well (v) Recharge Trench (vi) Recharge Pit with Bore Well (vii) Check Dam (viii) Subsurface Dyke

The selection of above mentioned methods shall be locations specific and depend upon the several local factors like: (i) hydro geological parameters (ii) geo-morphological parameters (iii) water (iv) soil permeability/conductivity/transmissivity of the acquifer. The brief sample design of recharge structures (for guidance purpose only) has been attached at Annexure-11 (Volume-2). However for selection of recharge methods including planning & design; The recommendation of Central Ground Water Board/State Ground Water Board may be referred.

Convergence Strategy

Water has been at the core of various development schemes initiated by different Ministries of the Government of India. There has been increasing recognition over the years of the need for water conservation and efficient water management. Ground water is a common pool resource and mostly being developed through private entrepreneurship. Due to ubiquitous nature of ground water, it is the most preferred source; Hence very often it is being developed in an unscientific way leading to over-exploitation, decline in water level and other environmental problems. Judicious development of ground water



with suitable conservation measures is the need of the time. Several efforts are being made in this direction by different Govt. departments as well as stakeholders who have as their critical components, water conservation and water management issues.

Various Central Ministries have number of centrally sponsored programme/ schemes. As many as nine centrally sponsored schemes have been launched by GoI which have affinity with Water Resources, Agriculture, Rural Development and Environment. Such schemes/ programme include Dug-well Recharge Scheme, Natural Rural Employment Guarantee Scheme (NREGS), Integrated Watershed Management Programme (IWMP), Farmers Participatory Action Research Programme, (FPARP), Rashtriya Krishi Vigyan Yojna (RKVY), National Watershed Development Programme (NWDP), National Afforestation Programme (NAP), National Horticulture Mission (NHM), National Food Security Mission (NFSM) and Bharat Nirman Yojna (BNY) and sustainability of Rural Drinking Water Supply etc.

Central and State Departments are spending large amounts on such schemes for development of living conditions of rural areas. All such schemes haves one thing in common and that is the element of recharge that accrues directly and indirectly through implementation of these schemes leading to improvements in the availability of water and its quality, locally and regionally. Ministry of Rural Development has already worked out the convergence modalities on water recharge measures such as construction of check dams, recharge shafts under NREGA and running maintenance under watershed programme / RRR of Water Bodies; creation of ponds under NREGS and linking under RKVY programme of Ministry of Agriculture ( MOA), etc. The artificial recharge activities in most cases cannot be taken up by individuals. It would require group action at community level or even by farmer’s level with financial assistance by the Government and financial institutions. There is also a need to work out the viable model under Public – private partnership mode. Further, the success of the programme would also depend upon inter-agency cooperation for joint programming, planning and implementation. Following are the excerpts of various sustainability schemes of the Government which have water recharge as one of the critical components:

1. National Afforestation Programme: The overall objective of the scheme is to develop the forest resources with people’s participation. Financial support under the scheme is also provided for soil and water conservation

2. National Project for Repair, Restoration and Renovation of Water Bodies (RRR): Under the scheme, the states are to take up restoration of water bodies having original irrigation cultivable command area of 40 ha to 2000 ha to revive, augment and utilize their storage and irrigation potential

3. National Rural Employment Guarantee Scheme (NREGS): One of the most successful programmers of Govt. of India, among the works undertaken under NREGS, water conservation, ground water recharge and water harvesting has high priority which culminates with creating durable assets in rural areas through legal guarantee of 100 days of employment

4. HARYALI : The objective of the project is to harvest every drop of water other than employment generation, poverty alleviation community empowerment etc. This scheme is already in vogue, various water conservation measures suggested needs to be integrated with this scheme.



Relevant components of the recommended measures for water conservation and artificial recharge to ground water may be dovetailed with the above schemes which would enable effective implementation.

A multi-faceted strategy is needed to be adopted towards achieving convergence among various programme/schemes having common goals. Convergence in essence is a mean to achieving integrated planning and implementation at grass-root level. First step is in this direction would be identifying potential areas/schemes for convergence which have similar and common goals. The exercise of convergence should commence at grass roots with process of grass-roots planning. MNREGA is model national programme for convergence in Agricultural level programmes. Common goals of improving & augmenting existing rural drinking and allied water supplies should be set up in terms of physical & financial targets.

Institutional arrangements to facilitate convergence exist at various levels like at (i) villages (ii) block and (iii) district level. Institutional at village level are gram panchyats and village level water and sanitation committees, at block level it is block panchayat and at district level it is zila parishad for planning at districts level. Convergence in programmes towards maximization of return from investments can be achieved through Technical Advisory Groups (TAGS) at gram panchayat level, where knowledgeable extension officers can facilitate convergence.

In view of common objective under various centrally sponsored schemes, a common ‘Recharge Fund”, should be built to promote augmentation of rural drinking water supplies.

Convergence, therefore, at gross-root institutional levels would enable participatory approach in the implementation of common programme & schemes with common goal of affecting recharge & sustainability to drinking water sources in rural areas. However, the knowledge & know-how at gross –roots being limited, the dissemination of knowledge would form part of convergence. The States & Department level coordination committees can generate know-how for dissemination at gross root level. Standing committees for planning can serve platform for convergence. The introduction and up- gradation of appropriate technologies should form integral part of convergence strategy & plans. In fact, convergence is an opportunity for institutions to resort the R&D in augmentation of recharge techniques and methods through special and Common Recharge Fund (CRF).

Solid and Liquid Waste Management


13. SOLID AND LIQUID WASTE MANAGEMENT

13.1. Assessment of Existing situation

During the site visit conducted at 04 states, the general observations are:

1. Non availability of sufficient space of placement of leach pit 2. Pit emptying is a cultural problem 3. On subsequent uses the pit porosity is reduced 4. Improper disposal of waste water create unhygienic conditions 5. Non availability of proper drainage system causes unhygienic conditions 6. Non availability of proper solid waste management system that includes: waste

collection, transportation, processing, recycling or disposal.

In absence of any other solution, the same leach pit system is being practiced in rural areas even now. Besides, with the increasing use of water supply, disposal of grey water from kitchen and bath and black water from existing conventional septic tanks have added to sanitation problem to formidable heights.

13.2. Solid and Liquid Waste Management Plan (SLWM)

13.2.1. Introduction

Solid and liquid waste management is the collection, transportation, processing, recycling, or disposal of waste materials, usually produced by human activity, in an effort to reduce their effect on human health, local aesthetics or amenity. The objectives of waste management is primarily to protect human health, reduce environment pollution and make rural areas clean, besides promoting recycling and reuse of both solid and liquid waste after providing necessary treatment. Considering village layout, its topography, the possible place of final disposal say natural drain, pond, or for afforestation etc., the most cost effective alternative acceptable to the community be adopted.

Depending on the arrangement of the houses along the village street, the type of pavement and the village topography the street drains could be on one side or both sides ,or could be as centrally laid pipe drains with proper covering at crossings.

The drain should cover all the village area so that at no place, water remains stagnated and it is not necessary that there is only one outfall point. However the drain should have sufficient carrying capacity to carry storm water and should have sufficient slopes to generate self-cleansing velocities, which may not be possible in all the cases. The street pavement could be allowed to carry storm water also where pavement slopes permit the same.

Deep and too narrow drains be avoided and the top width of the drain should be kept considering the street width and the type of traffic plying over it. All these considerations



need adequate data about the village layout as well as slopes, type of pavement, street width etc.

A master plan for village environmental sanitation shall be prepared for:

I. Human waste II. Liquid waste both grey and black water III. Solid waste both organic and inorganic waste.

In preparing the plan, following considerations be kept:

Technology suggested should as far as possible be simple, cost effective and easy to maintain

Plan should be socially acceptable considering community practices, social customs and traditions

Plan should be compatible considering, climate, topography and geo-hydrological conditions of the village

Community level skills, their experiences and suggestions in view of their living habits are kept in view.

13.2.2. Village Transact

The solid and liquid waste management plan [SLWM] should be prepared only after detailed field survey including household survey and a walkthrough in the village along with the community. This will generate the required information about the environmental problems being faced in the village and the community’s approach towards these. During the transact walk participatory rapid appraisal (PRA) in the village, it will be fruitful to identify problem and to suggest possible alternatives for mitigating them. Against the problems faced by the community, it will help in arriving at the acceptable solutions agreed by the community. As each village has their own problems, there cannot be one single SLWM for adoption by all the villages. It is suggested that during discussions at the time of village transact, community decision will be required to sort out issues such as locating proposed works such as treatment plant/ disposal facility. In such issues the decision of the village panchayat will be necessary especially if it is a panchayat land. During the site visit, the identification of desire/need and capabilities of the community shall be assessed. This would facilitate in proper planning, designing, constructing and O&M of the solid and liquid waste collection, transportation, treatment and disposal.

13.2.3. Data Verification

A checklist of the various information to be gathered during the household survey and field visit to be prepared to assist in the formulation of the village SLWM. This information be checked and physically verified to avoid any disputes during implementation of the plan. The common observation is that in some household there may not be sufficient space to construct the two pits required for twin pit pour flush sanitary latrine. The alternative such as combining the two pits into one or providing small bore sewers for carrying the wastewater to disposal points etc. be examined. Likewise there may be other issues such as alignment of drains, providing open or



covered/pipe drains etc. which have to be looked into as per specific condition and requirements of the village.

13.2.4. Strategy

The strategy for preparing the SLWM plan for the village is to manage the waste as far as possible at the household community level. For this, the various options available are detailed out in this chapter. The solid waste which consists of house sweepings, kitchen waste, garden waste, cattle dung and waste from cattle shed, agro waste [all bio-degradable] along with broken glass, metal, waste paper, plastics, and cloths etc. [all non-bio-degradable] should as far as possible be segregated at the household level itself. The non- biodegradable waste could be stored safely at a corner of the house and could be recycled or sold to the vendor [kabadi walla]. The bio-degradable waste should be collected and composted.

13.2.5. Checklist

Checklist for preparation of SLWM Plan for village:

1. Total population and no. of households in the village 2. No. of households having sanitary latrines or septic tanks for safe disposal of human

excreta 3. No. of households without latrines or dry pit type latrines requiring sanitary

latrines, and the no. of people who defecates in open 4. No. of households where twin pit pour flush latrines could be constructed as sufficient

space is available for the construction of the two pits. In case of non-availability of space, other alternatives such as combining the two pits into one or any other alternative is feasible

5. In case no other alternative is possible whether community latrines with septic tanks will have to be provided

6. Considering the depth of subsoil water level, the substrata characteristics, flood proneness and location of water sources do any special treatment is required, if so the details of the treatment be decided

7. No. of houses having cattle, the no. of cattle in each such house and their present method of disposal of cattle dung including the cattle yard waste. Is their sufficient space in cattle yard to carry out composting as per various alternatives, if not is there any possibility of providing for the village compost plant on cost as well as benefit sharing basis amongst the participants?

8. Does the village have street sweeping arrangement or the house sweepings are thrown on the street? Can the households be motivated to segregate the waste into two parts i.e. bio degradable and non-bio degradable?

9. Does the household have adequate space to carry out composting, vermi composting thereby taking care of their waste in the household itself?

10. For non-bio degradable solid waste left after use through recycling is there any opportunity for sale to the vendor [Kabbadi wala]? if not can it be organized at the panchayat end?

11. How many houses have enough space to practice kitchen gardening for disposal of bathroom waste? In any case street drains will have to be provided for taking care of rain water discharge.



13.3. Solid Waste Storage, Collection, Transportation, Disposal and Recyclable System-

13.3.1. General

The solid waste generated from various users like domestic, institutional and commercial (if any) have been broadly classified into two categories : (i) biodegradable (organic) and (ii) non-biodegradable (inorganic ) waste. Organic wastes apart from human excreta are: (i) household kitchen left over (ii) fruits and vegetables peelings agriculture waste and (iii) cow as well as other animal dung. These waste are highly degradable and if not disposed of within few days, may exerts foul smell and generates fly, mosquito and other nuisance inform of insects and rodents. Such wastes could be converted into compost which is used in farming as good manure. This manure provides adequate quantity of Nitrogen, Phosphorous and Potassium which are required in plant growth besides providing humus for increasing porosity of soil.

Inorganic wastes are metal, glass, plastic, stone, sweeping and debris etc. Part of these waste could be exchanged with money, while balance could be disposed of on sanitary landfill. Front end loaders, trucks, Tractor/Trolley etc. shall be used for collection and transportation of solid wastes.

The solid waste management system for inorganic & organic waste has been described as below:

13.3.2. Non-Biodegradable (Inorganic) Waste

Instead of throwing house sweeping and other waste outside the house, it is suggested that the waste be segregated into two categories separately i.e. bio degradable (organic) and non-biodegradable (inorganic) waste and be placed into two separate pits of dimensions 1.5’ x 1.5’ x 1’ deep dug in a corner of the courtyard of the house. After segregation, the non-bio degradable (inorganic) waste like glass, plastic, metal, paper etc. could be disposed of to the vendors in exchange of some commodities or even money. In some villages, those near the town such vendor facility is available while in other villages these could be developed once the system for segregation of waste at the house itself is practiced and the waste are available for recycling. Till then the collection of inorganic waste can be taken out of the pit when full and disposed of at the village dumping ground outside the habitation. There is need to improve the village dumping ground into a sanitary landfill. The details of sanitary landfill are given below. Segregating the two type of wastes will improve the aesthetic look of the village and its surrounding and will reduce the growth of rodents and flies etc. which presently inhabits at the village dumping ground, where at present mixed (organic and inorganic waste) are dumped.

13.3.2.1. Sanitary Landfill

In almost all villages of the four low income states (Assam, Bihar, Jharkhand and Uttar Pradesh) at present there is no system for sweeping streets, collection and transportation of waste to disposal site. As such it is suggested that no waste should be thrown out of the household and it should be segregated into organic and inorganic wastes at the household itself. The inorganic waste consists of glass metal, wood, paper stone and masonary debris, part of which could be recovered and recycled.



13.3.2.2. Planning & Design of a Landfill

Steps for planning design, implementation and operation of a Sanitary Landfill are:

1. Site selection 2. Design of sanitary landfill 3. Implementation of sanitary landfill 4. Operation of sanitary landfill 5. Closure and post closure measures.

13.3.2.3. Location Criteria:

Criteria for identifying suitable land for sanitary landfill has been furnished in the Table 13-1 as mentioned below:

Table 13-1: Selection Criteria of Landfill

S. No Place Minimum Siting Distance 1 Habitation 500 m 2 Rivers, lakes, water bodies 200 m 3 Non meandering water (canal,

Drainage etc.) 30 m

4 Highway or railway line 300 m from centre line 5 Coastal regulation zoning Sanitary landfill site not permitted 6 Earthquake Zone 500 m from fault line Fracture 7 Flood prone area (100 year) Sanitary landfill site not permitted 8 Water table Over 2 m below bottom landfill base

liner 9 Airport 20 km

Source:- Central Pollution Control Board – Guidelines for Selection of Site

13.3.2.4. Assessment of Area Required (an Example)

An assessment about the quantity of the waste have therefore to be made prior to selection of sanitary landfill site. Assuming a per capita generation of waste of 100 gms per day for an active fill period of 20 years in a village having a population of 1000, the quantity of waste which will be put into the sanitary landfill during this period works out to 730 tons ∗ ∗ ∗

∗ . Assuming that one ton waste occupies one meter

cube volume, the area required to accomodate this much of waste will have an average fill depth of 4 meter works out to 182.50 sq meter. Taking 30% (thirty percent) as area required for supporting infrastructure, the total area required is around 250 sq meter. Depending upon the design population of the village and the expected collection percentage of the waste generated the area of landfill site be worked out and a few probable sanitary landfill site be identified. Further the site has to be finally selected based on draft rules prepared for Municipal Sanitary landfill site.

13.3.2.5. Development of a List of Potential Sites

In areas where land is scarce, degraded sites such as abandoned quarry sites or old waste dump sites can be considered. The required area for a sanitary landfill including



the related infrastructure has been worked out in earlier paragraph. For population of 1000 and active fill period of 20 years, the area requirement shall be 250 square meter with average fill depth of 4 meter.

13.3.2.6. Data Collection Following data must be collected for the landfill sites:

Table 13-2 below presents the data to be collected:

Table 13-2: Data Requirement for Sanitary Landfill

S.No. Data Information 1 Ground Water

Maps The depth to ground water below the land surface as well as regional ground water flow.

2 Rainfall Data Precipitation data is used for designing the amount of possible leachate

3 Wind Map Wind rose indicates the predominant wind direction, based on which landfill infrastructure has to be located

4 Seismic Data The seismic activity of a region has to be considered in the design of Sanitary Landfill

5 Road Maps Accessibility of the site.

The possible sites should be evaluated concerning the topographical conditions and the availability for landfill site such as:

a) Sufficient size of land b) Flat area with low inclination c) Connection to highways and conditions of the access roads d) Flooding during monsoon e) Land use and soil type f) Depth to ground water table (as observed in open wells or bore wells) g) Information concerning the sub-ground h) Crossing of electrical lines i) Actual settlement patterns (eventual new or informal settlements).

13.3.2.7. Final Site Selection

The final selection of the site amongst the best alternatives should be done by comparing: a) The environmental impact b) Social acceptance c) Land availability d) Transportation costs e) Sanitary landfilling costs (site specific costs are to be considered).

Transportation costs may be compared on the basis of average hauling distance from the centre of the waste generation.



13.3.2.8. Design Life

The life of a sanitary landfill will comprise of an active period and a closure and post- closure period. The ‘active’ period may typically be 20 years depending on the availability of land area. The ‘closure and post-closure’ period for which a sanitary landfill will be monitored and maintained will be 25 years and more after the active period is completed.

13.3.2.9. Additional area requirement for other services

The space requirement for filling of waste to be placed in a sanitary landfill should be roughly calculated as per considerations mentioned in para 13.3.2.4 above. However the total sanitary landfill area would be larger than the area required for the filling area to accommodate all infrastructure and support facilities as well as to allow the formation of a green belt around the sanitary landfill.

From a technical point of view it is important to guarantee the runoff of rainwater. Therefore minimum inclinations have to be maintained at the slopes. Every footprint of the disposal area of landfill will have to maintain a certain minimum height to meet these inclination requirements. The height of the sanitary landfill is also constrained by the overburden pressure on the soil.

A sanitary landfill with considerable heights can interfere with the landscape and cause visual disturbance.

A sanitary landfill site will comprise of the area in which the waste will be filled as well as additional area for support facilities.

In sanitary landfill site, following facilities must be located in the layout: Access roads Small room as office space Demarcation of the sanitary landfill areas and areas for stockpiling cover material

and liner material Drainage facilities Location of leachate treatment facilities Location of monitoring wells.

For each sanitary landfill site, a layout has to be designed incorporating all the above mentioned facilities. The layout will be governed by the shape of the Sanitary Land fill area. However for a small sanitary land fill site; usually space for access road and for leachate treatment being very small could be accommodated in additional ten percent of area as worked out above for filling of waste and is sufficient to accommodate the support facilities also.

13.3.2.10. Technical Design Requirements

The design of the sanitary landfill focuses on optimized leachate management, as leachate generation is a main source of potential environmental pollution. It is



important to minimize leachate generation and to avoid leachate being retained for a long time in the landfill body.

A landfill can be both above ground or partially below ground, based on the local hydro- geological situation and the availability of land. Above ground landfills have advantage that leachate can flow by gravity according to the natural surface slope; leachate is collected in the main leachate pipe (header pipe) which is laid to extend beyond the footprint of the landfill.

At locations where water table is not close to the ground surface, landfill can be at a level below the ground level, by excavation, to accommodate more waste per unit area of land.

13.3.2.11. Sanitary Landfill in Marshy Regions

Sanitary Landfill should not be constructed in marshy areas. Under such circumstances the local authority should access a regional landfill facility outside the marshy area.

13.3.2.12. Base Sealing System

The shape of the site should be adapted to the existing conditions with a minimum of fills and cuts. However the mass which will be replaced by the sealing system has to be excavated. The base area has to have a sufficient slope to guarantee draining of leachate and storm water. Minimum inclinations are indicated in Table 13-3.

Table 13-3: Minimum Inclination Inside the Sanitary Landfill

Area Minimum Inclination Base sealing 3% for leachate pipes, roof profile Main leachate pipe 1.0 % Secondary leachate 3.0 % Final slopes Not less than 1:4 and not greater than 1:20

13.3.2.13. Leachate Management

One of the most important objectives of a successful landfill management system is to avoid leachate generation as far possible and to efficiently drain the leachate contained in the waste body and from other contaminated areas. As per the rules, organic and hazardous wastes should be diverted away from the landfill.

13.3.2.14. Leachate Generation

The principal sources of leachate generation include:

Moisture content of waste entering the landfill Infiltration from direct precipitation on the waste surface Sealed areas of landfill which are only partially covered with waste Surface water flow onto the active face of the landfill.



13.3.2.15. Leachate Collection

The leachate from the waste body will be collected in the drainage layer system and in the secondary drain pipes made of HDPE and will be directed to the main leachate pipes outside the waste body. The entire process of construction and arrangement of leachate collection system is illustrated thorough Figure 13-1 as below:

Figure 13-1: Leachate Collection

Leachate Collection pipes is to be connected to a sump, through the liner (in case of below ground landfills)

The primary criterion for design of the leachate collection system is that all leachate be collected and removed from the landfill at a rate sufficient to prevent a hydraulic head greater than 12 m from occurring at any point over the lining system. The system is designed to remove the accumulation of storm water resulting from a 25-year, 24-hour storm, within 72 hours. Other design criteria include the following: Bottom of the leak detection layer and the leachate collection layer is sloped at a

minimum 2% Granular drainage layer is 30 cm. thick with hydraulic conductivity >1 x 102 cm/s. The system must be designed to minimize clogging The system is located above seasonally high water table System must be designed to handle the runoff from a 25 year, 24 hour storm.

13.3.2.16. Leachate Pond and Treatment

The leachate pond is a basin to retain and pre-treat leachate within a period of several days. The pond allows sedimentation and biological stabilization. The leachate pond should have two basins to achieve an optimal leachate management. As per Rule, bio degradable should not be disposed of in landfills. Based on the characteristics of the leachate, treatment processes may include: physical, chemical and biological processes.

One of the simple techniques used to manage leachate is to spray it in lined leachate ponds and allow the leachate to evaporate. Since the quantity of leachate in village sanitary landfill will be very small, hence the leachate can also be disposed of by forestry all along the sanitary landfill site.



13.3.2.17. Access Road

The access road to a sanitary landfill should be constructed in accordance with the following design parameters: Widths of roadways 4 meter in small country side sanitary landfill 20 cm stabilized sub-foundation layer

13.3.2.18. Equipment / resources

The Sanitary landfill should be supplied with: Water Supply Power Communication (Telephone) External Lighting Fire Fighting (external)

Site security is among the most important considerations in landfills. The site has to be peripherally fenced and access to the landfill limited to one entrance gate, which will be locked when the site is unattended. The fence will also keep children, unwanted / unorganized scavengers, cattle and animals out of the site. It will also protect litter to be blown out of the landfill site.

13.3.2.19. General Safety Measures

General Safety Measures have to be applied during the operation of the landfill, regardless of the nature of ongoing activity or location in the landfill. Given below is a list of priority measures, which should be elaborated based on site specific conditions: Maximum traffic speed should be 20 km/h Every person working on the landfill should have a yearly medical examination No one should be allowed to operate at the landfill without a mobile

communication system (mobile telephone) Smoking should be prohibited except in designated smoking areas Ingestion of food is restricted outside designated areas General hygienic requirements while working on the landfill have to be applied.

Person Related Safety Measures

Workmen have to be equipped with the following personal protection equipment: Safety boots (always to be used while working outside the buildings) Reflective vests (always to be used by all staff working outside the buildings) Safety helmets (to be used in case of risk of injuries to the head e.g. during

construction, loading or unloading activities, while operating machinery etc.) Gloves (to be used in case of risk of injuries to the hands e.g. during

loading/unloading or maintenance activities) Ear protectors (to be used while working in noisy areas) Disposable dust mask (to be used e.g. in case of exposure to dust).



The landfill management has to strictly enforce the use of personal protection equipment.

First Aid

Considering the specific conditions at a sanitary landfill, it is strongly recommended that First Aid training needs to be given to staff working in the landfill on a regular basis.

Fire Protection and Prevention

To prevent fire incidents the following rules have to be applied: Banning smoking in all areas of the sanitary landfill Handling material on fire as well as setting to fire materials on the landfill are

strictly forbidden Waste that has been unloaded in the filling area has to be examined visually

for potential fire sources (glowing ash or glowing burning remains). If fire sources are located, these have to be neutralized with cover material immediately

All mobile equipment/vehicles should be furnished with a fire extinguisher.

Fire Control

In case of fire, the following basic rules of conduct have to be complied with: Every fire has to be reported immediately The preservation and the protection of lives and health have priority before the

fire fighting. Endangered persons have to be alerted and saved from the range of dangers

Rescue of people has priority over fire fighting Alarm signals have to be paid attention to.

13.3.3. Bio Degradable (Organic) Waste

Storage and improper disposal of organic waste breeds odour and fly nuisance. Organic waste could be conveniently converted into useful manure for village farms thereby saving in cost of chemical fertilizers besides improving the quality of soil in farm land. Use of artificial chemical fertilizers reduces the fertility of soil as they do not contain humus necessary for growth of organism in the soil and inhibits the water absorption capacity since humus which improves the soil porosity is not present. Presently in most of the villages the animal dung along with agriculture waste is dumped in pits outside the village or in animal yards near the house. This method of dumping reduces the quality of compost available from these pits since most of the nutrients are lost as these pits are exposed to the sun and other weather vagaries. Leaches from these pits cause pollution of water sources and are also responsible for odour nuisance. It is necessary to organize safe disposal of these organic wastes scientifically to reap full benefits along with improvement in environmental sanitation status of the village. Two of these methods discussed below are economical, technically feasible and are being practiced in quite a large numbers of villages and households.



13.3.3.1. Composting Through N.A.D.E.P. System

Unlike the present system of dumping animal dung, agriculture and other organic waste a simple method based on aerobic and anaerobic digestion requiring air, suitable temperature and water for the process has been developed. This consist of construction of a rectangular enclosure on plain levelled ground of length 10 feet, width 5 feet made with honeycombed brick/ stone work in mud mortar. Opening on the opposite walls should be of width 7 inches each and should each be in front of opening in opposite wall on the other side as far as possible. The height of this enclosure wall is about 3’ and the top two layers of the wall should be of 1:6 cement mortars to ensure structural strength. The width of the enclosure should not exceed 6’ while the length could be extended so as to store more waste. As far as possible such enclosure is constructed near the farm under the shadow of tree on wet ground. The enclosure wall from inside and outside should be hand plastered with a mixture of cow dung and mud in a ratio of 2:1 all around. The enclosed bottom ground is wetted with water preferably with cow urine. A 6 inches thick layer of leaves and other agriculture waste cut in small pieces be laid all over the ground inside the enclosure. This first layer of the organic waste is fully wetted with a mixture of about 4 kg of cow dung mixed with 5 buckets of water. Over this layer another layer of screened earth with about 40-50% of water is laid. This process is repeated for about 10-12 times so that the enclosure gets fully filled up. Filling of subsequent layers as mentioned before could be raised in a conical shape up to a height of 15 feet with slope all around. The whole stack is then painted with a thick plaster of screened earth and water. The stack be allowed to get digested which will take around 90-120 days. The stack needs to be kept wet such that in case cracks develop in the mound it should be covered with mixture of dung and water. A visual inspection through the opening of the enclosure wall will show that the waste is converted into compost and a sample could be taken through the opening which will show earthly manure with sweet smell. The properly digested manure thus prepared will look like a granular tea leaves and be taken out slowly through the 5 feet wide face and be screened. The screened manure is then stored into gunny bags which should be stored in a shady area with adequate humidity for 30- 45 days. This manure can be applied into the field during ploughing and can even be spread after the initial growth of plant during evening time of the day.

The construction of above mentioned enclosure is not a major engineering activity and does not cost much. It involves use of fifteen hundred bricks, one bag of cement, four bags of sand and six bags of aggregate. It can convert 1500 kg of agriculture waste, about 100 kg of cow dung and 4 buckets of screened earth. However, the process of filling in layers with cow dung and agriculture waste as well as hand plastering with mixture of water and dung is quite cumbersome. However like any other agricultural activity it can be undertaken by the farmers. It resolves the problem of solid waste disposal with considerable physical and economic benefits. The only constraint is the collection of 90-150 kg of dung which could be collected from number of animals. This constraint arises since most of the household converts the cow dung into sundried dung cakes which are used as fuel in preparation of meals. However as a joint venture amongst few household having animals and the quantity of compost thus generated could accordingly be shared as per contribution of dung and labour. Otherwise, this whole activity could be organized at the community level by the village panchayat or its subcommittee responsible for water and sanitation project. In any case it will result into large saving in foreign exchange by reducing the quantity of imported chemical



fertilizers and will also generate considerable benefit through increasing the fertility of the soil which has been reported to be reducing due to large scale use of chemical fertilizer. It will also reduce pollution of water sources as with use of lot of chemicals particularly excess of nitrogen, pollution in ground as well as surface water has been reported.

13.3.3.2. Vermi Composting

It is another method of safe disposal of the organic solid waste. It could be organized at the community level on a large scale as well as at household level on small scale. This will help a lot if all households with courtyard having space for construction of pit takes care of disposing their kitchen as well as other organic household waste by carrying out vermi composting at their own end. This will also augment the production of vegetable and fruits in their kitchen garden. This activity can be carried out by the ladies of the household themselves with some support by way of physical labour and small capital investment.

It consists of digging small pit of length 2 feet, depth 2 feet and width 4 feet. If more space is available the length could be increased. The pit should be dug in a corner of household where drainage water does not stagnate and is protected from flooding by rains by providing small thatched cover. After digging the pit a sand layer of about 2-3 cm. (one inch) thickness is laid at the bottom of the pit. A layer of partly digested cow dung in thickness of 5-6 cm. (2 inches) is then laid over it. The third layer to be laid is of vegetable matter such as leaves, small sized agricultural waste and kitchen waste. This layer has to be covered with the mixture of earth and partially digested cow dung. Another layer over it would be of organic matter 8-10 cms (4 inches) thick which should be covered with a earth layer of 1 cm (1/2 inch) thickness. After 7 days, 1000 number worms are placed over it. Within 5 days yellow coloured material appears which in fact worm are eggs. In 20 days black coloured matter which crumbles easily appears on the surface indicating thereby that the organic matter is converted into compost. Within 60-70 days about 15-20 kg compost thus gets produced which should be screened and any undigested waste be left into the pit. The compost thus prepared should be stacked in bags which should be well protected against sun and strong winds. At times some worms come along with the un- screened compost which should also be returned into the pit. Thus a cycle of worms is created and initially 1000 worms put into the pit do not need to be replenished again for initiation of another cycle in the start. This activity can also be organized at community level. The vermi compost is very good for vegetable and fruit gardens. In some urban centres this is organized as an industry and there is high demand of vermi compost by the city dwellers for growing flowers in earthen pots of terrace gardens.

Two practical methods have been discussed which are being adopted at individual as well as small commercial levels. Any centralized system such as sanitary landfill (which also includes disposal of inorganic matter, could be practiced at urban community level and village community level also. Sanitary landfills need activities such as separation of recyclable material, control of fly and odour nuisance by covering the daily fillings with sand. The sanitary landfill also needs to have necessary infrastructure so as to prevent pollution of water sources through leachate of the sanitary landfills.



13.3.3.3. Bio Gas Plant

All bio degradable organic solid waste could be converted under anaerobic decomposition into a gaseous mixture of methane and carbon dioxide known as Biogas. The decomposition occurs under the fermentation process which is carried out by different groups of microorganism like bacteria, fungus, actinomycetes etc. The anaerobic digestion of the organic waste matter occurs in three different stages: Hydrolysis Acidogenesis Methanogenesis

The biogas technology can be used for management of bio degradable solid waste (portion) generated from: Household – Kitchen waste, cattle dung, garden waste, leaves etc. Community – Cattle dung from gaushalas, garden waste, and agriculture waste.

The Gas production varies from 0.29 cu.m per kg of volatile solids added per day to 0.19 cu.m 0.16 cu.m per kg added per day in different seasons. The volatile solids destruction ranges from 40 to 55%. The sludge has good manorial value of nitrogen, phosphorous, potassium (NPK ratio is 1.6: 0.85: 0.93). The process gives a good performance at a retention time of 30 to 55 days varies as per season. Design and Construction of Biogas Plant There are many designs and models of biogas plants in operation with each one having some special characteristics and each popular model having some basic components. The biogas plants have following components for proper functioning of these designs: Digester or fermentation chamber Gas holder or gas dome Inlet (pipe or tank) Outlet (pipe or tank) Mixing tank Gas outlet pipe



Inlet and Outlet displacement chambers (for fixed dome biogas plant) Inlet and Outlet gates

Following are the two groups of biogas plant designs: Floating gas holder plant e.g. KVIC, water jacket, Pragati etc. Fixed dome plant e.g. Janata, Deen Bandhu etc.

Floating Gas Holder Plant This type was developed in India and is usually made of masonry. It runs on a continuous basis and uses mainly cattle dung as input material. The gas holder is usually made of steel although new materials such as Ferro cement and bamboo cement have already been introduced. The original version of this floating gas plant was a vertical cylinder provided with partition wall except for small sizes of 2 and 3 cum of gas per day. The main characteristic of this type is the need for steel sheets and welding skill. The mode of functioning of these plants is depicted in the following Figure:

Figure 13-2: Floating Gas Holder Plant

A. Fixed Dome Plant

This plant runs on a continuous or batch basis. Accordingly, it can digest plant waste as well as human and animal waste. It is usually built below ground level hence it is easier to insulate in a cold climate. The plant can be built from several materials, e.g. bricks, concrete, lime concrete and lime clay. This facilitates the introduction and use of local materials and manpower. The available pressure inside the plant doesn’t cause any problems in the use of the gas.

In the floating dome type plants the gas holder moves while in the fixed dome plants the slurry moves. The mode of functioning of the fixed dome plant is depicted in the following Figure:



Figure 13-3: Fixed Dome Biogas Plant

In the semi-continuous feed type system, a predetermined quantity of feed material mixed with water is charged into the digester from one side (inlet) at specified interval of time; say once a day and the digested material (effluent) equivalent to the volume of the feed, flows out of the digester from the other side (outlet). The digestion volume remains always constant.

This type is best suited for household or family size biogas plants. In practice, it is only this type which has been adopted for all categories of biogas plants, viz. family size, large size (institutional) and community size (village level).

B. Design Criterion for a Biogas Plant

Volume of digester – which is interalia dependent on quality or quantity of feed and its hydraulic retention time

Storage capacity of the gas holder - which is dependent on the requirement of gas and the intervals at which substantial quantity of gas is required

Delivery pressure of the gas Volume of mixing tank which is dependent on the quantity of daily feeding

and proportion of water to be mixed Arrangement of heating and insulation The unit should be strong to have a long life, using local raw materials and

labour for construction/ installation and it should be leak proof for liquid and gas

Another very important aspect is that the cost should be as minimum as possible.

C. Advantages

Biogas plants help not only in decomposing the solid waste but also produce good amount of clean fuel and environment friendly organic manure. Biogas is a



clean fuel which does not make cooking vessels dirty and does not produce smoke to irritate eyes and lungs.

D. Limitations

High cost for lower middle and low income group in rural areas Lack of availability of required technical infrastructure in rural areas.

13.4. Liquid Waste Management

There are two type of liquid wastes: Grey Water

Water which carried bathroom and kitchen wastes along with washings are classified is as grey water. This can be carried out to the disposal points through open or close drains. Its treatment could be carried out through forestry, disposal in filter beds or into village ponds. The drains will carry part of the storm water also. The remaining water will flow over the pavements discharging into the ponds.

Black Water

Water used for flushing of human excreta which has high B.O.D is termed as black water.

13.4.1. Sanitary Latrines and Safe Disposal of Human Excreta/Waste Water Disposal

A. VIP Latrines

This consist of a squatting platform over a pit with a hole plug to be placed after defecation. In the improved design a ventilating pipe with cowl at the top covered with net is provided for preventing fly and odour nuisance. For proper functioning, liquid waste as urine and ablution water must not be discharged into the pit and sand covering after each defecation be done by pouring handful of sand or ash into the pit. Considering the inconvenience for separate entry of liquid waste it is not in much use.



Figure 13-4: VIP Latrine

B. Twin Pit Pour Flush Latrines

This is the most versatile design developed by the UNDP Global Technology Mission and is widely adopted by the Government of India under its Total Sanitation Campaign (now Swachha Bharat Mission).

It consists of a squatting pan, a trap with water seal. The trap is then connected through a pipe or a cover drain to a small shallow junction chamber. This chamber has properly shaped cunnette dividing the flow into two outlet openings each leading to one leach pit dug into nearby ground. To start with one opening of the shallow chamber is closed while the other opening which has connection to one of the two pits is kept open so that the flushed contents from the squatting pan through shallow junction chamber flows into this pit. This pit is used for almost one and half to two years and gets filled. On filling of this pit its opening in the shallow junction chamber is closed and the other opening leading to second pit is opened such that now the flow of water along with excreta is diverted into the second pit.



Each pit has the capacity to take waste discharged for about one and a half year so that the first pit will be required to be connected again after its closure only after this period. By this time i.e. about one and a half to two years most of the pathogens present in the human excreta will die off and the mass is converted into sludge. This could be conveniently emptied since by this period the excreta get digested and the waste water leaches out into the surrounding underground. The digested sludge is very good manure and can be used in the fields. Thus the two pits can be used for 3 years continuously alternatively at one and half to two year’s interval each with one getting the flow and the other is emptied and allowed to rest. The principle is that small quantity of water used for flushing the toilet leaches easily into the surrounding soil thereby leaving the solid alone for digestion. The squatting pan is of special design with steep bottom slope of 25 to 28 degree with a trap having 20 mm water seal set on a cement concrete floor. The slope of the toilet pan is such that by pouring small quantity of water (about 1.5 to 2.0 litre per use) can flush human excreta into the pit. Twin pit pour flush water seal latrine is a very satisfactory and hygienic system of disposal of human waste and could be located even inside the house yards since the water seal prevent odour and insect nuisance.

Ø1000 Ø1000

1000

800

Figure 13-5: Lay out Plan of Twin Pit Pore Flush Latrine



Figure 13-6: Details of Shallow Junction chamber

70

425

320

Plan

Junction Chamber

CC700125

475

4070

Squatting Pan

54

50

280

Brick Drain

BB

From Latrine Pan

249

80°

85° Water Seal

All dimension in mm

AA

250

To Leach Pit

To Leach Pit

115

250

115

480

75 mm A.C.or P.V.C. NonPressure Pipe

115115480

To Leach Pit To Leach Pit

From Latrine Pan

Section C-C

Trap

Section B-BSection A-A

Plan

Plan

R.C.C. Slab1:2:4

Slope 1:10

Cement Concrete1:6:12

12mm Cement Plaster1:4 Finished with

Brick Work in Cement Mortar1:6

115 250 115480

25mm or 1:2:4Finished Smooth

Brick Work in Mud Mortar

12mm Cement Plaster 1:4Finished with Cement Punning Brick Work in Cement

Cement Concrete 1:3:6

75

40

150

75

350

12

1275

75

75

Mortar 1:6

or Cement Mortar 1:12

Cement Punning

25

R 17

2.8

16°

Channel

Chapter-

-13

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C. L

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ure 13-7: S

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Managemen

Page 13‐21

de the innering in areas Depending

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the likely flood water or sub soil water level. Raising the pipe will necessitate raising the latrine floor also.

In pits located in water logged or flood prone areas, earth should be filled and well compacted all around the pits in 1000 mm width up to the top. It is not necessary to raise the pit by more than 300 mm above the plinth of the house because if water rises above the plinth, the residents will in any way vacate the houses.

In high sub soil water areas, about 300 mm filling all around the pits may be done depending upon the site conditions.

In all such conditions the pit bottom should be sealed to stop leaching through it. The pit dimensions be designed taking the long term infiltration capacity of the soil as 20 litre/day/sq. meter of the pit surface area subjected to leaching.

Pits in Rocky Strata

In rocky strata having soil layers in between, leach pits are designed on the same principle as those for low sub soil water level taking the long term infiltration capacity of the soil as 20 litre/sq.meter/day. However in rocks with fissures & Chalk formation, pollution can flow over a long distance, hence these conditions demands careful investigation and adoption of pollution safeguards.

Since there will be no infiltration of liquid in totally impervious rocky strata the pits will function as holding tanks. In such a situation pour flush latrine with leaching pit is not a suitable system.

Pit in Soils with Low Infiltration Capacity (Clayey Soils)

Leaching capacity tends to be the limiting factor when the infiltration capacity of soil is low. In these circumstances there are two options; construct a larger pit, or increase the leaching area. Construction of a larger pit is a costly option while the critical leaching area could be increased by back filling and compacting with brick blast, gravel, sand etc. in the required width all around the pit. This will increase the leaching area, since the leaching area is the vertical surface of the excavation of the pit rather than of the external wall of the pit.

Pits in black cotton soil are designed on the basis of whether the pit is wet or dry, taking the infiltration rate as 10 litre per sq. meter per day. However a minimum 300 mm vertical fill (envelope all around the pit) of sand, gravel or ballast of small sizes should be provided all around the pit outside the pit lining to separate the soil and the pit lining thereby increasing the infiltration surface area.



Latrine Size and Super Structure

The overall plan area dimension of the latrine as proposed by UNDP in their design is 750x900 mm, though for convenient sitting the plan area dimension of 800x1000 mm has been found to be more acceptable. The latrine super structure should be such that it could ensure all weather uses as well as privacy. This means provision of proper roofing and doors as per availability of local material and economics in cost of construction. Proper ventilation by providing C.C. Jali work near the roof is necessary to avoid suffocation during defecation. The Rural Latrine Pan (used without cistern) with steep gradient are available in the market. The squatting pan and the trap can be of ceramic, glass fibre, reinforced plastic/HDPE/PVC with inner surface glazed and smoothly finished. Cheap latrine pan with locally made cement concrete, mosaic are also available which are not very smooth and needs intensive cleaning.

Site Selection and Pollution Safeguards

As the leach pits stores the excreta and flush water, it is necessary to select the site for location of twin pits in such a way that there is no chance to cause sub soil water pollution. Extensive studies carried out during Technology Mission14 in India and other countries have established:

(i) That there is no risk of bacterial pollution when the pit is in alluvial soils with predominance of silt mixed with clay and fine sand, if the pit bottom is at least 2 m above the maximum sub soil water level

(ii) Even under unfavourable conditions such as coarse sand, high water table and where the soil depth beneath the water table is less than 2m, the twin leach pit pour flush latrine system can be used with one or more following modifications as necessary: Providing all around minimum 500 mm thick envelope of fine sand

of average size of 0.6 mm sieve Sealing the bottom of the pit by any impermeable material such as

puddle clay or any polythene sheet Keeping the inlet of the pit at least 1 m above the maximum

ground water level in high water table conditions.

Detailed investigation for geological /hydro geological conditions of the site where pits are to be located and the locations of drinking water sources their size etc. are the prerequisite in planning designing and construction of twin pit pour flush latrine as a onsite low cost sanitation system. This is necessary to ensure that the pollution risk to ground water and water distribution mains is minimal. Faulty construction and wrong data/information gathering regarding hydro geological condition may lead to pollution of drinking water sources. To ensure that the risk of polluting ground water and drinking water sources is minimal, following safeguard should be taken, while locating the pits:

14 UNDP Mission in India in 1980s



Drinking water should be obtained from another source or from the same aquifer but at a point beyond the reach of any faecal pollution from the leach pits

If the soil is fine (effective size 0.2 mm or less) the pits can be located at a minimum distance of 3.0 m from the drinking water sources, provided the maximum ground water level throughout the year is 2.0 m or more below the pit bottom. If the water table is higher i.e. less than 2.0 m below the pit bottom, the safe distance should be increased to 10.0 m

If the soil is coarse (effective size is more than 0.2 mm) the same safe distance as specified above can be maintained by providing a 500 mm thick sand envelope of fine sand of 0.2 mm effective size all around the pit and sealing the bottom of the pit with an impervious material such as puddle clay, a plastic sheet, lean cement concrete or cement stabilized soil

If the pits are located under a footpath or a road and if a water supply main is within a distance of 3.0 m from the pit, the invert of the pipes or drains connecting the leach pits should be kept below the level of water main or 1.0 m below the ground level. If this is not possible due to site consideration, the joints of the water main should be encased in concrete.

Limitations of Pour Flush Latrine

Out of two systems of onsite disposal of human excreta, twin pit pour flush latrine have been found to be most acceptable because of low cost, simple technology and suitability for adoption in all types of geological and hydro geological conditions. However, some limitations and adverse observations have been reported, which are as below: i) Non availability of space in quite a few households especially of low

economic and socially depressed sections of the community ii) Pit emptying is a cultural problem requiring some agency to carry it

out on demand and at nominal cost iii) Pit porosity of leached pit on subsequent uses have been reported to

get reduced resulting into pits getting filled earlier in further usages well before the design period of one and a half to two year

iv) Chances of ground water getting polluted in case of lack of supervision in ensuring the suggested measures under different conditions such as high sub soil water level, floods etc.

To ensure open defecation free condition in the village The Total Sanitation Campaign of the Govt. of India has included construction of community latrines for household not having space to build and at market places. Community latrines, if not properly managed could become serious nuisance instead of the solution of the problem. These have to be managed on the pattern of Sulabh Sauchalaya as available in some cities on the basis of “Pay and Use” facility with disposal of waste through septic tank and soak pits or into the city sewer.



13.4.2. E – Toilet

E –Toilets are widely used in Kerala and are developed by Eram Scientific. The first prototype E –toilet was constructed in the year 2010 and by now the number of such toilets is more than 400. Some of the important features of the E-toilet are:

Automated Main Door Coin Validator Toilet status indicator lights Automated floor wash Floor wash on request Auto and Manual flush Platform cleaning Inbuilt water tank Water Low Indication Internal / External Speakers Exhaust Fan Health Faucet LED lights Auto shutdown on AC power failure or no water Power Backup USB Voice Guide Instructions WEB Connectivity / Updation Self-Checking Capabilities.

The waste generated in these toilets is taken care of by bio digester developed on Defence Research and Development Organisation Technology, Anaerobic STP, by connection to existing sewer lines and septic tanks. CPU control valve flushes 4 to 6 litres depending on usage time and 5 litres for floor washing after every 5 uses. 1 service vehicle for 25 machines and trained personnel for maintenance as per plan are used. E- Toilets are available in different models and broadly the dimensions of the cubicle are:

Length – 2.3 m Width – 1.25 m Height – 2.8 m Overall Area requirement – 32 Sq. Meters.

These units are widely used as individual house toilets, school toilets and at various public places as pay and use facility. The Model IHHL (Sanitation) facilities shall be provided as per guidelines suggested in Swachch Bharat Mission (Web site under MoDWS).

13.4.3. Bio – Toilets

Bio toilets are based on bio-digester technology developed by Defence Research Development Organization for high altitude military establishments like Siachen. This technology has been commercialized by Banka Bio Loo Pvt. Ltd located at Orissa state. This consists of four chambers such that the waste water enters into the first chamber which has charged bacteria colonies. The process continues in chamber 2 and 3 and clear water rich in nutrients is delivered in Chamber number 4 along with sludge formation. There is a provision for gases to be let out through vent pipes and the water collected in



chamber 4 could be disposed off through soak pit or land irrigation. A sketch diagram is given below:

Figure 13-8: Bio-Toilet

This technology is now being used by Indian railways for intercepting the human waste from the toilets in train coaches which at present is discharged directly on the railway tracks. Based on this technology bio digester tanks are fitted in toilets of the railway coaches. Night soil degradation occurs through microbial reaction which converts it into bio gas. On the basis of dry waste weight, 90% of the waste is reduced and the gaseous effluent is continuously let out to the atmosphere. Liquid effluent from the tank is discharged into soak pits without causing any environmental hazard or can also be used for irrigation. This technology is being applied on bio-toilets constructed in rural Odisha.

13.4.4. Septic Tanks

In some villages a few affluent household have constructed septic tanks which are in fact a system of primary treatment of raw sewage i.e. human excreta flushed with water prior to its final disposal. The liquid wastes from bathrooms and kitchens can also be sent into the septic tank without endangering its normal operation, though excessive use of detergents flowing into the tanks should be avoided. The effluent from the tank should not be discharged into open street drains as it contains pathogenic bacteria, cysts and worm eggs since the anaerobic decomposition occurring in the septic tank does not provide complete treatment. Septic tanks are the most satisfactory units for disposal of excreta from houses, institution, colonies, camps, school and hospitals, where proper sewerage system does not exist.

The Indian Standard IS:2470, Code of Practice for Design and Construction of Septic Tank Part-II recommends following parameters-

(i) Plan dimension shall be based on surface loading at peak discharge. Length shall be 2 to 3 times the width. Surface area is designed on the basis of 0.83 sq. m. for flow of 9 lpm



(ii) Per capita contribution of dry solid be assumed as 70 grams per day (iii) Detention period should be within 24 to 48 hours on an average daily flow of

sewage (iv) Load may be taken in terms of fixture units, sanitary appliances taking flow from

each fixture as 9 lpm (v) Each household having 5 members be considered to have 2 fixtures units each (vi) Peak discharge is worked out on the basis of 60% of fixture units discharging

simultaneously (vii) Average temperature of the septic tank is assumed as 25˚C (viii) Capacity required for sludge digestion on the basis of assumption taken in ii) &

vii) of the above, is 3.3 cum/100 persons (ix) Capacity required for storage digested sludge on the basis of assumption at ii) is

7.67 cum for 100 persons per year (x) Minimum depth of septic tank is considered to be 1.0 m (xi) The baffle wall should project 30 cm. above liquid level while the overall free

board should be 45 cm. above liquid level.

Prior to putting new septic tank into operation it is necessary to seed the tank with some quantity of ripe sludge or cow dung which is fairly in an advance stage of decomposition so as to provide bacteria and fungi for rapid fermentation. Turbulence in the tank should be avoided as it may cause complete failure of the functioning of septic tank.



Recommended sizes and capacities of septic tank for equal and less than 50 users as per I.S. Code 2470 are as below:

Table 13-4: Salient Details of Septic Tanks for User up to 50

No. of users

Length (L)

Breadth (B)

Liquid depth D for Cleaning interval Of

Liquid capacity For cleaning

Sludge to be removed for cleaning interval of

Depth of sludge to be withdrawn for cleaning interval of

6 Mths.. 1 Yr. 2 Yr. 6 Mths. 1 Yr. 2 Yr. 6 Mths. 1 Yr. 2 Yr. 6 Mths. 1 Yr. 2 Yr.

m M M M M M3 M3 M3 M3 M3 M3 m m m 5 1.5 0.75 - 1.0 1.05 - 1.12 1.18 - 0.36 0.72 - 0.32 0.64 10 2.0 0.90 - 1.0 1.40 - 1.80 2.52 - 0.72 1.44 - 0.40 0.80 15 2.0 0.90 - 1.3 2.0 - 2.34 3.60 - 1.08 2.16 - 0.60 1.20 20 2.3 1.10 1.1 1.3 1.80 2.53 3.30 4.55 0.72 1.44 2.88 0.28 0.57 1.14 50 4.0 1.40 1.0 1.3 2.00 5.60 7.28 11.2 1.80 3.60 7.20 0.32 0.64 1.28

Note: A provision of 30 cm. should be made for free board.

Figure 13-9: Septic Tank



13.4.4.1. Soak Pits

Effluent from the septic tank should be disposed into the soakage pit. A soakage pit is of diameter 1-2.5 m and depth of 2–5 m below ground. The walls of the pit are lined with brick or stone masonry without mortar. The pit is filled with stone or over burnt brick bats as filter media. The pit soil has to be fairly porous so that it can last for about 5 years. The location of pit should be on downhill side and at least 10 m away from the water source. This is necessary since on choking of pours of the soil with passage of times or due to over loading of pits, overflowing has been observed. As such the construction of soakage pits needs to be discouraged in the thickly populated area especially where the ground water is the source of water supply.

13.4.4.2. Septage and Its Disposal

Septage is the sludge consisting of solids or settled contents of pit latrines and septic tanks. It is different from the sludge obtained in the conventional sewage treatment plants. Its characteristics varies widely from household to household and are influenced by the duration of storage, temperature, intrusion of ground or surface water in tanks / pit , performance of tank and tank emptying technology and pattern.

Septic Tank should be emptied every year or when the tank is ⅓ (one third) full. Normally at almost all the places except for bigger towns, these are emptied manually and hardly any safety of the environment or of the worker is considered. The septic tank are of capacity 1 to 4 m3 in most of the household and taking ⅓ (one third) of sludge being retained in the tank the quantity of sludge to be emptied works out as @230 litre per m3 per year of tank capacity. The sludge quantity which has to be taken out at the time of emptying after one year in a 4 m3 capacity tank works out as 920 litre say one meter cube.

Tank emptying should be done mechanically with vacuum pumps mounted on the waste water carrying tankers. Small machines of capacity 200 litre with vacuum pumps are available which can go inside the narrow lanes. Large machines of capacity up to 2000 litres truck mounted are also available; On an average one machine can empty three to ten septic tanks per day. As such depending upon the number of tanks and taking one year as the emptying interval, the no of machines and their schedule could be planned out which should include details such as location of all tanks, procedure for emptying, post emptying site control, safety of workers, repair of equipment’s and disposal arrangements. The procedure for emptying the septic tank is to lower the tank water level below outlet point, breaking of scum and sucking contents through vacuum pumps into the tanker. Some sludge around 10 cm thick at the bottom of tank should be left.

The Septage could be disposed of:

Into the existing sewage treatment plant, where available At the plant set up to treat the septage, a separate plant for septage disposal By mixing with organic refuse including agricultural waste for composting.

In villages, composting is the feasible option considering cost of new plant and operation & maintenance problems at existing sewage treatment plant nearby. Composting is carried out by putting septage along with organic refuse into stacks as



windrows which are trapezoidal or triangular stacks of height 1 to 2 meters and width at bottom of about 2 to 4.5 meters. Anaerobic and aerobic decomposition takes place with moisture content 40 to 60 %, oxygen 5 to 15 % and temperature 55 to 600c, in the stacks, pH-6 and carbon nitrogen (C.N) ratio 30 to 1. These stacks are overturned after one week every time such that the inside material is brought out on stack and the outside material gets inside of the stacks. After three to four turnings the wastes turns into compost which could be screened and stacked properly. This compost can be used as manure in the field for farming.

13.4.5. Small Bore Sewer Systems

(For black water)

Figure 13-9: Schematic diagram of a small bore sewer system

13.4.5.1. Small Bore Sewers System

Small bore sewer systems are designed to receive only the liquid portion of household wastewater for off-site treatment and disposal. Grit, grease and other troublesome solids which might cause obstruction in the sewers are separated from the waste flow in interceptor tanks installed upstream of every connection to the sewers. The solids which accumulate in the tanks are removed periodically for safe disposal at offsite treatment plant. Advantage: - Collecting only settled wastewater in this manner has four principal advantages:

Reduced water requirements – Since large quantities of water are not needed to carry solids



Reduced excavation costs - With solids removed, the sewers do not need to be designed for self-cleansing velocity

Reduced materials costs – Peak flows are lower as interceptor tanks provide some storage which attenuates peak flow

Reduced treatment requirements – Since primary treatment is performed in the interceptor tanks.

Disadvantage: - The principal disadvantage of the small bore sewer system are following:

Need for periodic evacuation and disposal of solids from each interceptor tank in the system

Need for a strong organization for maintenance and for effective control over illegal connections to the system as they may not provide interceptor tank.

13.4.5.2. Components

Small bore sewer systems consist of: (a) house connections; (b) interceptor tanks; (c) sewers and their appurtenances; and (d) sewage treatment plant.

House connection. Storm water must be excluded in house connection Interceptor tank. The interceptor tank is a buried watertight tank with baffled

inlet and outlet. The tank should have capacity to store Liquid flow for 12 to 24 hours and ample volume for storage of the solids, which are periodically removed through an access port.

Figure 13-10: Typical solids interceptor tank

Sewers. The sewers are small bore plastic pipe (minimum diameter of 100 mm) which is trenched into the ground at a depth sufficient to collect the settled wastewater from most connections by gravity. Sewer alignment may curve to avoid natural or manmade obstacles



Cleanouts and manholes. These are required for inspection and maintenance. Cleanouts are preferable to manholes because they cost less and can be more tightly sealed to eliminate most infiltration and grit

Figure 13-11: A typical small bore sewer cleanout

Vents. The sewers must be ventilated to maintain free-flowing conditions. For this vents within the household plumbing are sufficient

Lift stations. Lift stations are necessary where elevation differences do not permit gravity flow from interceptor tank to sewer. Preferably these should be avoided.

13.4.5.3. Need for Small Bore Sewer System

i. The purpose of the sewers is to remove liquid effluents from interceptor tanks that cannot otherwise be disposed of onsite - and so forms a natural link to the most likely application of small bore sewers in developing countries: to upgrade on-site disposal systems such as pour-flush latrines when changes in water use, housing densities or other conditions lead to difficulties in on-site effluent disposal.

ii. There are situations when, due to adverse ground conditions such as low soil permeability, shallow rock, on-site systems are technically infeasible. In such circumstances, Small bore sewer systems are suitable in developing countries in the following situations.

Pour-flush toilet systems with Sewer: When the effluent from pour-flush

toilets and household sullage cannot be disposed of on-site, as soil becomes unable to absorb because of rise in subsoil water level and increased water usages

Septic tank systems with Sewer: Improvements in the water supply distribution system resulting into increased waste water flows or from increased housing densities, the septic tank effluent could not be absorbed in soaking pit/ trenches.



13.4.5.4. Design Considerations

1. Flows I. Considerable care has therefore to be exercised by the design engineer in

estimating the design flow, as often the factors are difficult to evaluate precisely since with improvement in water supply and subsequent increase in consumption of water higher waste water flows are observed. Over estimation of the flow usually results in the interceptor tank and small bore sewers being overdesigned and under-estimation results in a system prone to failure

II. Small bore sewer system are suitable for installation in low- to middle-income areas on the peripheries of towns in developing countries, where very high rates of urban population growth will probably result in considerable changes in settlement patterns and in provision of water supply service resulting into need for more waste water carrying capacity in small bore sewer system. This could be done at less cost by duplication of this system which with conventional sewer system may not be physically possible.

2. Design Considerations for Interceptor Tanks The preferred shape of interceptor tank is rectangular with a length to breadth

ratio of 2 to 1 or higher, in order to reduce short-circuiting of the raw wastewater across the tank

For equal volumes, shallow tanks are preferred to deep tanks, to ensure good removal of settable solids; the liquid depth of the tank should be at least 0.9 m but not more than 2 m

To prevent blockages in the small bore sewers, the tank outlet should be smaller than or equal to the diameter of the sewer

The baffle should extend 150 mm above the liquid level to rise above the scum layer, and down to approximately 30 to 40% of the liquid depth. A curtain, or hanging, baffle is not recommended on the inlet because scum is able to build up behind it and so plug the inlet

The outlet invert should be at a sufficient level below that of the inlet to provide some surge storage and prevent stranding of solids. A drop of 75 mm is recommended

A minimum freeboard or space above the liquid level of 300 mm should be provided for scum storage and ventilation

The inlet and outlet baffles should be open above the scum layer to provide adequate ventilation

An access hole 300 to 600 mm dia. in the roof of tank is common. 3. Sewer System Layout. Selection of sewer routes must consider the following:

Interceptor tank location and elevation Rights-of-ways and easements Vertical and horizontal alignment lift stations if required Future development Site restoration Resident and traffic disruption.

The location and outlet elevation of the interceptor tanks together with the local topography will establish the routes and necessary depths of the sewers in most cases.



Use of existing rights-of-way and easements should be assessed but if excavation costs can be reduced significantly by some other route special easements may be necessary.

4. Peak flow & Hydraulic Formula Until more field data are available it seems prudent to adopt a design flow

peak factor of 2 Wastewater flows for sewer dia. design should include estimates of

groundwater infiltration and surface water inflow ideally, the addition of any such "clear" water should be zero but conservative estimates of clear water inflow would be 20 m3/ha/day for vitrified clay pipes and 10 m3/ha/day for PVC pipes

Manning formula given below be used for hydraulic design of sewers:

푉 =1푛 ∗ 푅

/ 푆 /

V = velocity of flow, m/s n = pipe roughness coefficient R = hydraulic radius, m S = slope of the hydraulic grade line, m/m

Values of ‘n’ range from 0.011 to 0.015 but for most pipe materials a value of 0.013 is suitable

In order to facilitate cleaning of the sewer, a minimum diameter of 100 mm is recommended in developing countries where the specialized equipment for cleaning smaller pipes is not generally available

The design must ensure that an overall fall does exist across the system and that the hydraulic grade line during estimated peak flows does not rise above the outlet invert of any interceptor tank

High points where the flow changes from pressure flow to open channel flow and points at the end of long flat sections are critical locations where the maximum elevation must be established above which the sewer pipe cannot rise.

13.4.5.5. Appurtenances

Cleanouts and manholes provide points of access for cleaning and maintaining the sewers. Since hydraulic flushing is sufficient to cleanse the lines of accumulated organic solids, cleanouts are recommended in lieu of manholes, except at major junctions, because the latter are more costly and are a source of infiltration, inflow and grit. Cleanouts should be located at all upstream termini, intersections of sewer lines, major changes in direction, high points, and at intervals of 150 to 200 m in long flat sections. Lift stations are used to overcome adverse elevation conditions either at individual service connections or to raise collected wastewater from one drainage basin to another basin.



13.4.6. Waste Water Treatment - DEWATS

DEWATS is the process through which waste water could be treated at comparatively less capital and operation maintenance cost by employing treatment system based on simple technology, not requiring electrical and mechanical equipment, such that it could be operated and maintained by the community having minor basic primary skills.

DEWATS is based on four treatment systems:

sedimentation and primary treatment in sedimentation ponds, septic tanks, fully

mixed digesters or Imhoff tanks Secondary anaerobic treatment in baffled reactors (baffled septic tanks) or fixed-bed

filters Secondary and tertiary aerobic/anaerobic treatment in constructed wetlands

(subsurface flow filters.) Secondary and tertiary aerobic/anaerobic treatment in ponds.

Treatment system components are combined in accordance with the wastewater influent and the required effluent quality.

13.4.6.1. Components

Septic tanks (see para 13.4.4 of this Chapter)

Fully mixed digesters provide anaerobic treatment of wastewater with higher organic load, while serving as a settler in a combined system. In the process, biogas is produced as a useful by-product.

Anaerobic baffled reactors or baffled septic tanks function as multi-chamber septic tanks. They increase biological degradation by forcing the wastewater through active sludge beneath chamber-separating baffles. All baffled reactors are suitable for all kinds of wastewater, they are most appropriate for wastewater with a high percentage of non-settle-able suspended solids and narrow COD/BOD ratio.

Horizontal gravel filters are sub-surface, flow constructed wetlands, which provide effective, facultative treatment and filtration, while allowing for appealing landscaping. Constructed wetlands are used for wastewater with a low percentage of suspended solids and COD concentrations below 500 mg/l.

13.4.6.2. Treatment Systems – Advantages & Disadvantages:

The advantages and disadvantages of various type of treatment has been furnished as below:



Table 13-5: Advantages & Disadvantages of various type of Treatment System

Type Kind Of Treatment

Used For Type Of Wastewater


septic tank sedimentation, sludge stabilization

wastewater with settleable solids, especially domestic

simple, durable, little space because of being underground

low treatment efficiency, effluent not odourless

fully mixed digester

sedimentation, sludge stabilization

concentrated organic wastewater – e.g. agroindustrial – with settleable solids

access to renewable source of energy (biogas)

less simple than septic tank; special skills needed for gas-tight dome construction

anaerobic baffled reactor

anaerobic degradation of suspended and dissolved solids

pre-settled domestic and industrial wastewater with narrow COD/BOD ratio, suitable for strong industrial wastewater

simple and durable, high treatment efficiency, little permanent space required because of being underground, hardly any blockage, relatively cheap compared to anaerobic filter

requires larger space for construction, less efficient with weak wastewater, longer start-up phase than anaerobic filter

horizontal gravel filter

aerobic-facultative anaerobic degradation of dissolved and fi ne suspended solids, pathogen removal

suitable for domestic and weak industrial wastewater where settleable solids and most suspended solids are already removed by pre-treatment

high treatment efficiency when properly constructed, pleasant landscaping possible, no wastewater above ground, can be cheap to construct if filter material is available at site, no nuisance of odour

high permanent-space requirement, costly if right quality of gravel not available, great knowledge and care required during construction, intensive maintenance and supervision during first 1-2 years

anaerobic pond

sedimentation, naerobic degradation and sludge stabilization

strong and medium industrial wastewater

simple in construction, flexible in respect to degree of

wastewater pond occupies open land, there is always some odour, can even be stinky, mosquitoes



Type Kind Of Treatment

Used For Type Of Wastewater


treatment, little maintenance

are difficult to control

aerobic pond

aerobic degradation, pathogen removal

weak, mostly pre-treated wastewater from domestic and industrial sources

simple in construction, reliable in performance if proper dimensioned, high pathogen removal rate, can be used to create an almost natural environment, fish farming possible when large in size and low loaded

large permanent space requirement, mosquitoes and odour can become a nuisance if undersized near residential areas, algae can raise effluent BOD

13.4.6.3. Space Requirements

Depending on the total volume and the nature of the wastewater and its temperature, the following values may indicate permanent area requirements for setting up a treatment plant: Septic tank, Imhoff tank: 0.5m²/m³ daily flow Anaerobic baffled reactor, anaerobic filter: 1m²/m³ daily flow Horizontal gravel filter: 30m²/m³ daily flow Anaerobic ponds: 4m²/m³ daily flow Facultative aerobic ponds: 25m²/m³ daily flow Land use can be minimized if closed anaerobic systems are applied, as they are usually constructed underground. The area for sludge-drying beds may require an additional 0.1 to 10 m²/m³ daily flow, depending on the wastewater quality and de-sludging intervals.

13.4.6.4. Performance

Treatment quality depends on the nature of the influent and boundary conditions like temperature

BOD removal rates are generally within 70 to 90% for anaerobic baffled reactors and anaerobic filters. 70 to 95% for horizontal gravel filter and pond systems

Assuming a discharge limit of 50mg/l BOD, for discharge in land the anaerobic filter in combination with a septic tank may treat wastewater of 300mg/l BOD without further treatment

Phosphorus removal in DEWATS is limited – as in most treatment plants.



13.4.6.5. Pathogen Control

Transmission of worm infections is the greatest risk associated with wastewater Worm eggs or helminthes are removed from effluent by sedimentation and

accumulate in the bottom sludge The long retention times in septic tanks and anaerobic filters of 1 to 3 years

provide sufficient protection against helminthes infection Frequent sludge removal is discouraged due to increased health risks.

13.4.6.6. Septic Tank

The septic tank is the most common, small scale and decentralised treatment plant, worldwide. It is compact, robust and extremely efficient when compared with the cost of constructing it. It is basically a sedimentation tank in which settled sludge is stabilised by anaerobic digestion. Dissolved and suspended matter leaves the tank more or less untreated requiring further treatment of effect. For details (Refer Figure no. 13-9 of this Chapter)

13.4.6.7. Fully Mixed Digester

The fully mixed anaerobic digester (also called bio-digester) is suitable for rather “thick” and homogenous substrate like sludge from aerobic-treatment tanks or liquid animal excreta.

“Thick” viscous substrates of more than 6% total solid content do not need stirring. To avoid Scum formation still at the inlet and outlet pipes should be placed at middle height. In fixed-dome digesters, the outlet should be made of a vertical shaft with the opening starting immediately below the zero line; this will allow some of the scum to discharge.

Figure 13-12: Fully Mixed Digester (Bio-Digester)

The main parameter is the hydraulic retention time, which should not be less than 15 days in a hot climate and not less than 25 days in a moderately warm climate; a HRT of more than 60 days is required for highly pathogenic substrate. The gas-storage volume depends on daily gas use in relation to daily gas production. The storage



capacity of gas for household use should exceed 65% of the daily gas production. Gas production is directly related to the organic fraction of the substrate which based on field experience could be taken as 40 litre biogas per mm kg of fresh cattle dung diluted with are litre of water.

13.4.6.8. Anaerobic Baffled Reactor

The anaerobic baffled reactor is ideal for DEWATS because it is simple to build and simple to operate. Hydraulic and organic shock loads have little effect on treatment efficiency.

Figure 13-13: Anaerobic Baffled Reactor

The anaerobic baffled reactor consists of at least four chambers in series. And treatment efficiency does not increase with more than six chambers. Equal distribution of inflow, and extensive contact between new and old substrate are important process features. The fresh influent is immediately mixed – and, thereby, inoculated – with the active sludge in the reactor, to begin digestion. The wastewater flows from bottom to top with the effect that sludge particles settle against the up-stream of the liquid, providing intensive contact between resident sludge and newly incoming liquid. A settling chamber is used to separate the larger solids before the wastewater continues to a series of up-flow chambers. Between chambers the water flow is directed to the bottom of the next chamber by baffle walls that form a down-shaft, The wastewater that enters a tank should be distributed over the floor area as evenly as possible. This is facilitated by relatively short compartments (length < 50% to 60% of the height) The outlet of each chamber (particularly the last one) should be placed slightly below the water surface to retain possible scum. The anaerobic baffled reactor is suitable for treating all kinds of wastewater its efficiency increases with higher organic loading; it is also well-suited for domestic wastewater. Treatment performance is in the range of 65% to 90% COD (70% to 95% BOD) removal. However, three months are required for maturation.



13.4.6.9. Starting Phase and Maintenance

Treatment performance depends on the availability of active microbial mass. Inoculation with old sludge from septic tanks shortens the start-up phase. In principle, it is advantageous to start with only a quarter of the daily flow and with a slightly stronger wastewater. The loading rate should increase slowly over three months. This provides micro-organisms with enough time to multiply before suspended solids are washed out. Starting with the full hydraulic load from the beginning severely delays maturation.

13.4.6.10. Calculating Dimensions

The up-flow should not exceed 1.0m/h. This is the most crucial parameter for dimensioning, especially with high hydraulic loading. The organic load should be below 3.0kg COD/m³×d. Higher loading rates are only possible at higher temperatures and for easily degradable substrate. The HRT of the liquid fraction (i.e. above the sludge volume) should not be less than eight hours. Sludge-storage volume should be provided for 4l/m³ BOD (4 litre/cube meter) inflow to the settler and 1.4l/m³ BOD removed in the upstream tanks.

Figure 13-14: Anaerobic Baffled Reactor

13.4.6.11. Planted Soil Filters

Horizontal filters comply with DEWATS criteria, as they are simple in principle and require almost no maintenance – if well-designed and constructed. Planted horizontal gravel filters – also referred to as subsurface flow wetlands (SSF) or root zone treatment plants – provide natural treatment for pre-settled waste water of a maximum COD content of 500mg/l. They are ideal, therefore, as tertiary treatment for wastewater, which has already undergone secondary treatment in units, such as baffled reactors, anaerobic filters or biogas digesters. They are also appropriate for treating pre-settled grey water directly.



13.4.6.12. Horizontal Gravel Filter

The treatment process in horizontal ground filters is complex and not yet fully understood. The rules of safe design are: large and shallow filter-bed wide inlet zone reliable distribution of inflow over the full width of the inlet zone round, coarse gravel that is nearly the same size as the filter medium.

Figure 13-15: Horizontal Gravel Filter

In order to utilize the full filter, the front part of the bed must have voids that are small enough to retain some of the SS, while being large enough to allow further SS removal in later parts of the bed. Round, uniform gravel of 6-12 mm or 8-16 mm is best.

Removing fine soil from gravel by washing is more important than ensuring the exact grain size. If the length of the filter-bed is more than 10 m, an intermediate channel for redistributing cross-flow should be provided.

The relation between organism load and oxygen supply reduces with length. It is most likely, therefore, that anaerobic conditions prevail in the front part, while aerobic conditions reach to a greater depth in the rear part. However, only the upper 5 to 15 cm can really be considered an aerobic zone.



Filter clogging normally results in surface flow of wastewater. This is usually not desired, although it hardly reduces the treatment efficiency if flow on the surface maintains the assumed retention time inside the filter

Figure 13-16: Horizontal Filter Details

Knowledge of the amount of void space within the filter material is essential for calculating the retention time and planning the treatment process. The details are given below:



Table 13-6: Porosity Details

Filter medium

Diameter of grain mm

Pore volume Coarse Total

Gravel 4 - 40 30% 35%- 40% Sand 0.1 - 4 15% 42%

For high conductivity, large pore size is more important than total pore volume. The filter-bed should not be deeper than the depth to which plant roots can grow (30–60 cm), as water will tend to flow faster below the dense cushion of roots. However, treatment performance is generally best in the upper 15 cm because of oxygen diffusion from the surface. Shallow filters are more effective, therefore, than deeper beds of the same volume. Uniform distribution of wastewater throughout the filter requires an equally distributed supply of water at the inlet and equally distributed reception at the outlet side. Trenches filled with rocks 50 to 100 mm in diameter are provided at both ends to serve this purpose. A perforated pipe, which is connected to the outlet pipe, lies below the strip of rocks that form the collection trench. While the top of the filter is kept strictly horizontal to prevent erosion, the bottom slopes down from inlet to outlet ideally at 1%. The percolation of wastewater into the ground is not desirable so the bottom of the filter must be sealed. While solid-clay packing might be sufficient, heavy plastic foils are more common. Whenever possible, trees should not be planted directly beside the filter; this will avoid the structural problems caused by the roots and the unwanted sealing of the filter surface by fallen leaves. The filter is changed every eight to 15 years. Weaker wastewater, lower loading rates and larger gravel size generally increase the lifetime of the system. The plants are not normally harvested. Phragmites australis (reeds), found almost anywhere, are considered to be ideal because their roots form horizontal rhizomes that guarantee a perfect root-zone filter bed. At least two clumps of plants or four sprouted rhizomes should be placed per square meter when planting is started.



13.4.6.13. Starting Phase and Maintenance

Young plant seedlings may not grow on wastewater. So it is advisable to start feeding the plant with plenty of fresh water and to let the pollution load grow parallel to plant growth. Replacement of the filter media might be necessary when treatment efficiency declines. Since there is no treatment during the time that the filter media is being replaced, it is advantageous to install several, parallel filter-beds.

To prevent clogging of the filter with fine soil, storm water should neither be mixed with the wastewater before the treatment step, nor should outside storm water be allowed to overflow the filter bed.

13.4.6.14. Calculating Dimensions

As a rule of thumb, 2.5 square meter of filter should be provided per capita for domestic wastewater. This would mean a hydraulic loading rate of 30 litre per square meter and an organic loading rate of 8 gm BOD per square meter per day.

13.4.7. Sullage Stabilization Ponds

In this system, the collected grey water is stabilized by natural processes involving algae, bacteria and natural oxidation processes. Hot climate is very suitable, solar radiation and light is intense for efficient functioning of this system. Advantage

1. The process is a natural process. The GP only provides suitable piece of land where ponds are established

2. Capital cost is very low 3. O&M cost is also very low & affordable.



4. The system can be managed by unskilled manpower 5. Stabilized water pollution due to untreated grey water is avoided 6. Surface water pollution, due to untreated grey water is avoided.

Description The system has three or more components:

a) Anaerobic pond b) Facultative pond c) Maturation pond one or more. These components are usually placed in series. Maturation ponds can be more than one. The following description and measurements are applicable only for grey water (not black water) i.e. waste water without human excreta.

13.4.7.1. Anaerobic ponds

The grey water reaching the pond via drain usually has high solid content. In the anaerobic pond, these solids settle at the bottom, where these are digested anaerobically. Thus, the partially clarified liquid is discharged onwards in to a facultative pond for further treatment.

The solids are expected to settle in this pond, and would be anaerobically digested at the bottom of the pond. Hence, this pond should have a depth of 8 – 10 ft. The length and width or the diameter of this pond should be such that the volume of pond would provide hydraulic retention time of 1- 2 days for the incoming grey water i.e. the water remains in the pond for 1-2 days. The pond may have brick lining. If the soil permits, the sides and bottom may be compacted to make it less pervious and stable. If the soil is very permeable, plastic sheeting topped with soil may be laid at bottom.

13.4.7.2. Facultative pond

The partially clarified water is led to facultative pond. In this pond oxidation of grey water takes place. It is called ‘facultative’ because in this pond in the upper layer aerobic conditions are maintained while in the lower layer, anaerobic conditions exist. In this pond solids are generally taken care of by three mechanisms.

Aeration from air through the surface (however this is limited) Oxidation due to oxygen liberated through photosynthetic activity of algae growing

in the pond because of the availability of plant nutrients, from bacterial metabolism in water and the incident light energy from sun.

The pond bacteria utilize the algal oxygen to metabolize the organic solid content of grey water.

13.4.7.3. Maturation pond

The stabilized water from facultative pond is led to a maturation pond. The main function of the maturation period is destruction of pathogens. This pond is wholly aerobic.



13.4.8. Waste Water Treatment through Duckweed Pond:

Waste water specially the sewage is treated in special treatment plants involving high capital cost and requires high annual expenditure for their operation and maintenance. In the treatment plants for sewage the bacteria, fungi and protozoa are used to decompose the organic matter present in waste water into simpler, less toxic compounds. This decomposition takes place in both aerobic and anaerobic environments. The objective of all waste water treatment plants is to decompose the organic matter contained in waste water and to destroy any pathogens present, thereby preventing the spread of disease.

This objective could be achieved specially in small communities where waste water generation is in small quantity and does not contain more complex industrial wastes by treatment in lagoons( ponds ) covered by Duckweed. The floating mat of Duckweed effectively reduces the growth of phytoplankton (algae) and submerged aquatic plants by competing for nutrients dissolved in the waste water and creating shade, which also prevents the growth of these plants. The floating Duckweed mainly consists of Lemna obscure. Since Duckweed is forty percent protein by weight and grows so quickly, it can serve as an excellent feed supplement for poultry, livestock, and fish. Thus an integrated system can be developed where waste water is treated and also provide income through employment to local residents who sell the produce raised on Duckweed.

Such projects are ongoing in Bangladesh and some countries of Middle East (Palestine, Israel) etc. In Bangladesh most communities have their own village ponds where all waste water generated in the community is gathered and these ponds are converted into Duckweed ponds by properly seeding them with Duckweed .Duckweed harvesting and it’s drying for use as chicken or other animal feed is done by the local people. In India at Bhubaneswar in Orissa Duckweed ponds are followed by ponds developed for fisheries as the effluent from these ponds have adequate food material for healthy growth of fishes .Some of the findings about Duckweed are as below:

1. Duckweed thrives around 30 degree Celsius; in temperatures much higher or lower than this the plant will not grow to cover the ponds

2. Duckweed is to be harvested twice in a week 3. Average weight of chickens fed by Duckweed is 17 % higher than other chickens and

has whiter meat 4. In addition to reducing the biological oxygen demand and Total suspended solids

levels Duckweed efficiently reduces nitrogen and phosphorus levels in waste water.

It is said that the operation of Duckweed systems is an art rather than a science, and while plants flourish in some locations, it is difficult to grow them in others.

13.4.9. Waste Water Treatment through Forestry

The Central Soil Salinity Research Institute Karnal carried out detailed study on treatment and disposal of waste water through its application on land. At present in most of our local bodies it is observed that the waste water carried out of town is being utilized for irrigation and growing vegetables and other crops. Irrigation with sewage makes the plant more succulent and thus more vulnerable to attacks by insects and pathogens to control the farmers use more insecticides and fungicides. These contaminate the vegetables thereby exposing people to severe health hazards.



For safe utilization of sewage following points needs to be given due attention:

1. No stagnation of sewage to avoid foul smell and mosquito breeding 2. Sewage should not percolate into ground to avoid ground water pollution and as such

should evaporate or be consumed by the plants 3. It should not make the land unproductive by increasing the salinity of land and/ or due

to accumulation of toxic elements 4. No vegetation grown on lands with sewage irrigation should be consumed raw by any

being.

Considering all these constraints a technology based on growing trees on ridges one meter wide and fifty centimetre high and disposing sewage in furrows { shallow trenches ) two meters wide, as shown in figure enclosed . The discharge into the trenches is so regulated that it is consumed in 12 to 18 hours and there is no standing water left in the trenches. It is possible to dispose of five to fifteen centimetre depth of sewage which is equal to 0.5 to 1.0 million litters of sewage per day per hectare of land. Forest plants use water and nutrients of sewage for their growth. Each tree acts as small Bio-Pump absorbing water from the soil and releasing it in the environment through transpiration. There is no adverse effect of sewage disposal on land either on account of toxicity or deficiency of nutrients or due to salinity. It builds up the soil fertility with respect to availability of N (Nitrogen), P (Phosphorus), K (Potassium) and O (Oxygen) and micronutrients. lt decreases the soil pH from the highly alkaline to neutral levels . Further there is no chance of pathogens entering into human food chain system as forest plants produce fuel wood or timber.

The tree species chosen for this arrangement should be fast growing, can transpire high amount of water and are able to withstand high moisture content in the root environment. Such species are Eucalyptus, Leucaena and Poplar .Out of these three species Poplar is most responsive in utilizing sewage, however in winter it remains dormant and cannot Bio-drain the effluent. Depending on the area available and the volume of effluent a combination of Poplar and Eucalyptus have been suggested.

Figure 13-17: Root Zone Treatment System



13.4.10. Drainage and Grey Water Treatment

13.4.10.1. Design Guidelines and Improvement of Drainage System

The waste water from the household coming out of kitchen, bath and washing is called sullage. It consists of some organic matter ashes and other material used for cleaning of kitchen utensils as well as soap and other ingredients used during bathing and washing etc. This liquid waste needs to be properly discharged and dispose of otherwise it spreads all around the village lanes creating slush over unpaved streets and water pools thereby making movement on foot in village lanes difficult and becomes breeding places for mosquitoes at stagnating pools. With the supply of more quantity of water, more liquid waste is generated and it is common to hear complaints usually faced on introduction of pipe water supply in the villages. In villages where adequate natural ground slopes are not available the water spreads all around the village and as such drains are required to carry this water for collection and proper disposal. The water coming out of the houses during rains includes water falling in courtyards and roofs and is known as storm water. The quantity of storm water coming out of the house and flowing in lanes depends upon the intensity of rain fall in the area. Compare to sullage water the quantity of storm water is quite large thereby requiring big drains to carry it. Considering the village lane width mostly being narrow it may not be possible to construct large sized drains. As such in the villages the drains/small bore sewers are designed for dry weather flow while the storm water flow is allowed into free board capacity of drain and otherwise flows on street pavements. The drain should full fill the following conditions: It should develop self-cleansing velocity (Minimum 0.60 m/s) with the minimum

dry weather flow It should have free board of at least 15 cm even during Peak flow/ maximum

discharge of the drain. Free board is the depth between the top of drain i.e. ground level at the place and the maximum flow level of waste water into the drain

It should be such that it can be cleaned easily. Narrow deep drains are difficult to clean as compared to wide drains

It should be structurally safe and stable In case of single drain provided on one edge of the street the cross connecting

drain from the other side should have inlet into the main drain at higher level during maximum dry weather flow discharge.

13.4.10.2. Catch Pits

Catch pits prior to outflow of sullage water from the houses must be provided so as to entrap any solids and other gritty material getting into the drains. It consists of a small chamber with screen at a top so that the floating material is entrapped at the screen. Further the sediments flow along the water gets settled in the kitchen pit chamber bottom as the outlet from the chamber bottom is kept around 6-9” above the bottom of the chamber there by providing some settling space for the gritty material. Thus the catch pit entrap most of the sediment and floating material which if allowed to flow onto street drain will deposit in the drain restricting the smooth flow. These catch pits should be kept clean by occasionally taking out the sediments deposited in the chamber and removing the screens blocking the flow into the chamber. No flow from



the house should be allowed without the provision of catch pits before it flows into the drains. It has also been observed that if the catch pits are provided inside the house, these are kept clean as against those where these are provided outside the household premises.

13.4.10.3. Layout of Drains

Depending upon the topography of the village settlements the layout of the drain has to be so planned that the deep drains are avoided. This is possible only if the drains are laid mostly at ground slopes. As such detail surveys of village its layout with lane width, ground levels and natural gradients (ground slopes) should be carried out. At places it may not be possible to provide drains on both sides of the street pavement along the houses. As such shallow covered cross drain to collect the waste from house or group of houses have to be constructed to collect the waste discharge by the houses on the other end of the pavement. The layout of drain has to be so planned that all waste water is collected preferably at one lowest level point usually the village pond. In some villages it may not be possible and the final out fall of the drains have to be connected to more than one point so as to avoid deep drains.

13.4.10.4. Drain Sections

Depending upon the dry weather flow main width and availability of ground slope drains in various sections have been designed and described as below:

U- Shaped Section: The bottom is of semicircular shape with side walls vertically straight along the length. These drains are provided for small discharges, are quite stable and easy to clean as these are mostly shallow drains

V- Shaped Section: The drain section has the advantage that it can develop self-cleansing velocity with small discharges and at the same time it can carry large amount of flow during rains. The drain requires more wide area at top which may not be available in village lanes

Rectangular Section: These types of drains are suitable for large quantities of flow. Cleaning of these drains is difficult. To ensure better flow hydraulic the bottom of the drain is kept as U –shaped

For standardized section of drain as shown in Figure 13-18, the permissible slopes and corresponding quantity of flow are given in the table below. Depending upon the requirement the drain section could be altered for which necessary calculation be done.

Table 13-7: Typical Details of Hydraulic Section for Various Types of Drains

Type of Drain

Cross sectional area of flow sq. m.

Hydraulic mean depth m.

Gradient of the drain For velocity 0-6 m/sec.

For velocity 0-75 m/sec.

For velocity 0-9 m/sec.

I 0.0091 0.00381 1 in250 1 in 150 1 in 100 II 0.0251 0.06401 1 in 450 1 in 300 1 in 200 III 0.0464 0.08230 1 in 650 1 in 400 1 in 300 IV 0.0706 0.09754 1 in 800 1 in 550 1 in 350 V 0.0947 0.11582 --- 1 in 650 1 in 450 VI 0.1375 0.13106 --- 1 in 800 1 in 550



Figure 13-18: Typical Sections of Drains

13.4.10.5. Kerb and Channel Drains

These are provided at both the edges of the edges of the pavement all along its length. Since small elevation (raising central portion slightly higher) all along its length of pavement. Most of the water falling on the pavement drains towards the edges into the K&C drains. Along the side edges of the pavement most of the village houses are located and the waste water from the houses also discharges into these. In cases where ground slopes are steep these drains carry most of the water discharged from the houses but at times adequate capacity drains have to be constructed. However to keep the pavement dry and to carry the storm water falling on the pavement K&C drains are provided all along the street length. In villages where streets are paved provision of K&C drains are necessary. These drains are triangular sections. Now a days precast kerb sections are available in the market and have replaced the brick masonry constructed especially along highways and city pavements where these are provided at both the sides along the footpaths. These have small converging capacities but their provision is necessary for long life of pavements.

400200

640

400200

135 255 135525

TYPE 1 DRAIN SECTION

430

TYPE II DRAIN SECTION

TYPE III DRAIN SECTION

TYPE IV DRAIN SECTION

TYPE V DRAIN SECTIONTYPE VI DRAIN SECTION

CONCRETETILES OR CC

CONCRETETILES OR CC

CONCRETETILES OR CC

290

400200

133 375 133

190

485

CONCRETEIN LINE120

290

135 215 135585

290

38

100

CONCRETEIN LINE

SIDE SLAB

CONCRETEIN LINE

6 mm JOINT6 mm JOINT

6 mm JOINT

6 mm JOINT

7550

133 500 133766

483

130 440 130700

7550

200 200

CONETTESIDEREVETMENTBRICK - ON EDGEREIMSURSEMENT

115

CC 1:7:20 ORLIME CONCRETE

38

100

7550

7550

75

501 IN 10 1 IN 10

5080

75

60 150 60270

Note-ALL DIMENSIONS ARE IN MM UNLESS SPECIFIED



Figure 13-19: Kerb and Channel Drains

13.4.10.6. Covered/Open Drains

For proper maintenance and cleaning drains are mostly kept open. At crossings or where the lane width is small drains are covered. Covering of drains has the advantage that the household cannot be able to throw solids and house sweepings into the drain but have the disadvantage that encroachment over the drains occurs and the maintenance including cleaning of drains becomes difficult. At some places underground PVC pipe laid in the centre of village lane to avoid traffic load are also used as drains. In such cases waste should flow through single outlet from the house with proper catch pit provided in the house which should be kept clean. Pre cast concrete drain with two circular halves of pipe diameter to be joined by placing top half over the bottom half have also been used as piped drain laid at the centre of the lane.

13.4.10.7. Hydraulic Design of Drain

Drains in different section are laid at such gradients that self-cleansing velocity at minimum dry weather flow is generated in them. The self-cleansing velocity occurs during non-peak hours and the flow is minimum, while the flow during peak hours is almost 6 to 8 times the non-peak flow. Considering that the waste water from the household also carries some suspended solids the self-cleansing velocity during non-peak hours could be 0.60 m/sec. which with peak flow could be around 0.90m/sec so that any sediments deposited during non-peak hours may get flushed during peak hours. The drains laid at very steep gradients may result into velocities up to 1.5- 2 m/sec. which may erode the invert of the drain. Most of the village panchayat with the funds available under the State or Central grant have constructed street pavements with rectangular drains without any proper design and layout of the drainage system. Most of these drains do not generate sufficient cleansing velocity and are being found

PCC: 1:4:8

BRICK WALL IN 1:6 C.M

PCC: 1:2:4

300

115

FOOTPATHIN P.C.C:1:2:4

200

DRAIN

KERB STONE230

G:LG:LG:L

BRICKPAVEMENT

BULL NOSE BRICKSAT TOP OF WALL

WELL COMPACTEDEARTH

PCC: 1:4:8

100

PLASTER IN SIDE: 1:4 C.M PLASTER OUT SIDE: 1:6 C.M

NEED CEMENTFINISH

BRICK WALL IN 1:4C.M

100

230

KERB & CHANNEL DRAIN WITH FOOTPATH(with precast kerb stone)

KERB & CHANNEL DRAIN RECTANGULAR DRAIN

75

115

115

50

A

Note-ALL DIMENSIONS ARE IN MM UNLESS SPECIFIED



mostly clogged with only in the top few inch portions of drain water flows down. It is suggested that when natural ground slope are not available as per requirement for self-cleansing flow then at least the minimum slope of 1:240 for 200 mm dia. / bottom width and 1: 315 for drains of diameter / invert width of 250 mm be provided.

13.4.10.8. Treatment of Waste Grey Water

Layout of drain be so planned that all waste water of the village flows to the lowest level where mostly village ponds are available. Preferably one single out fall at a pond be provided where some pre-treatment in the shape of grit chamber with screen could be constructed. Pumping of waste water into the pond should be avoided and if necessary more than one out fall discharging into more number of ponds could be provided. The treatment at the out fall for the waste water could be as below:

Root Zone Treatment System-Community waste can be treated efficiently Stabilization Pond – most of our existing village ponds function like stabilization

pond and with slight modification their performance could be improved Duckweed Ponds – Weeds grown in such ponds are useful food material for

ducks and this method is widely practiced in Bangladesh. Tree Plantation/ Forestry – Some varieties of trees have the capacity to treat waste

water and grow rapidly such trees are eucalyptus, poplar etc.. Forestry based on plantation of such trees with rotational cutting and generation of new trees can be done around the outfall area close to the pond.

At household level the waste could be disposed of through soak pits. Such soak pits have been found to be constructed in quite a few household of some villages. It is observed that the design of these pits is not based on the infiltration capacity of soil and for proper design percolation test for assessing the infiltration capacity is necessary. In areas where the infiltration capacity is low soak trenches have to be provided. Details of soak pit and soakage trenches are already given in. In villages having dense habitation such household treatment and disposal of waste water is not advisable.

13.4.10.9. Root Zone Treatment System

Pond Systems

Pond systems are the ideal form of treatment – if the required space is available. Anaerobic ponds are deep and highly loaded with organics. Depending on the retention time, digestion of sludge only or the complete wastewater is possible. Facultative and anaerobic ponds may be charged with strong waste water, however, bad odour cannot be avoided reliably with high loading rates. Aerobic ponds are large and shallow – they provide oxygen via the pond surface for aerobic treatment. Wastewater for treatment in aerobic ponds should have a BOD5 content below 300mg/l. Pond systems can be combined with certain types of vegetation, creating aquatic plant systems with additional benefits. Existing village ponds with some modifications could be used for treatment of grey water which has very low BOD content as it mainly consists of water from the bath rooms and kitchens besides rain water. The modification could be by providing screen and grit removal chambers prior to their inlet into the tank. Some of the methods described earlier viz Forestry,



Duckweed pond and Gravel filters could also be used depending upon the availability of land and the drainage system proposed in the village.

Root Zone System

The community waste water can be treated and reused by adopting Root Zone Treatment System. The mechanisms followed in this system are:

The functional mechanisms in the soil matrix that are responsible for the mineralization of biodegradable matter are characterized by complex physical, chemical and biological processes, which result from the combined effects of the filter bed material, wetland plants, micro-organisms and waste water

The treatment processes are based essentially on the activity of microorganisms present in the soil. Smaller the grain size of the filter material and consequently larger the internal surface of the filter bed higher would be the content of microorganisms. Therefore the efficiency should be higher with finer bed material. This process however is limited by the hydraulic properties of the filter bed; finer the bed material, lower the bed hydraulic load and higher the clogging tendency. The optimization of the filter material in terms o hydraulic load and biodegradation intensity is therefore the most important factor in designing RZTS

The oxygen for microbial mineralization of organic substances is supplied through the roots of the plants, atmospheric diffusion and in case of intermittent wastewater feeding through suction into the soil by the out flowing wastewater. The roots of the plants intensify the process of biodegradation also by creating an environment in the rhizosphere, which enhances the efficiency of microorganisms and reduces the tendency of clogging of the pores of the bed material caused by increases of biomass

RZTS contain aerobic, anoxic and anaerobic zones. This, together with the effects of the rhizosphere causes the presence of a large number of different strains of micro-organism and consequently a large variety of biochemical pathways are formed. This explains the high efficacy of biodegradation of substances that are difficult to treat



The filtration by percolation through the bed material is the reason for the very efficient reduction of pathogens, depending on the size of grain of the bed material and thickness of filter, thus making the treated effluent suitable for reuse.

The main components of the root zone system are:

Sedimentation tank for settlement of solids Inlet pipe (PVC non pressure pipe to be used) Inflow collection system Space effective root zone treatment module(gravel filtration: horizontal flow or

vertical flow as per soil condition and topography) Outlet collection system Outlet pipe (Non-pressure PVC) Polishing pond.

Figure 13-20: Root Zone Treatment System

Construction Management


14. Construction Management

14.1. Background

Construction of Water Supply and Sanitation works is an important and integral part of the implementation phase of project. The responsibilities at different level of technical personnel for various activities are mentioned in the engineering responsibility matrix which is appended as Annexure-2 (Volume-2) in this manual, for details refer PIP Annexure-27 . Desired supervision and quality control are the main features to achieve the objective of water supply and sanitation schemes. These actions are primarily taken by site engineer and his superiors.

14.2. General Strategy of Supervision

The basic job of a site engineer is to ensure:

1) Compliance with the plans and specifications as per applicable national codes and standards

2) Safety regulations in construction 3) Environmental and social safeguards. The site engineer can be Junior / Assistant Engineer of the State Technical Department / Agency or Support Organisation on behalf of Gram Panchayat (GP).

The site engineer normally acts with limited authority as agent of the owner who may be either GP or State Technical Department, thus he reports to the owner or his Project Manager (Engineer). Site Engineer uses measuring devices and test equipment, takes photographs, keeps a daily log and keeps the record of all maps and drawings. He writes reports on the progress of the construction and also keeps records of the work performed with the materials used, so that proper payment can be made.

14.3. Requirements of Site Engineer

The site engineer works under the orders of his superior and is guided by the requirements of contract, plans and technical specifications. As he observes the activities of the contractor’s daily works, he should have the following technical knowledge and skills to achieve results:

1. Knowledge It is essential for the site engineer to have knowledge of the work he is supervising. The site engineer’s background and knowledge should include, among others, the following:

Knowledge of all the Technical Specifications, National Building Codes and IS standards



Knowledge of applicable engineering terminology and familiarity with the construction materials and equipment

Knowledge regarding the use of all types of Tools and Plants and equipment.

2. Skills

Site Engineer should have the following skills:

Read and interpret engineering drawings and specifications for construction Plan and schedule inspections and related activities to accommodate emergencies

or changing situations and the needs of the owner and the Contractor Use computer databases for reporting and record keeping Monitor and observe objects to determine compliance with prescribed

specifications or safety standards Communicate well verbally and using written communication and contractor staff

including labour Perform physical tasks that require climbing, stooping, kneeling, crouching and

has good eye sight Ability to work in team.

14.4. The Site Engineer’s Report:

The site engineer’s report is a proximate record of present events that serves as a future reference when these events need to be reviewed. It is often an important document and sometimes the only source of clues on how these present events might have contributed to malfunctions and failures that have to be investigated. The site engineer’s reports should contain all information pertaining to the work being inspected. Any information/item should be recorded in sufficient detail to make it fully understandable.

14.5. Construction Management of Work

14.5.1. Civil Works

The levels at site shall be checked from the source point to service reservoir and ascertained that the levels taken are same as mentioned in the drawings proposed during planning and preparation of DPR. If any variation is noticed the necessary action shall be taken to redesign the pumping main and pump machinery in accordance with the working levels now obtained.

Civil works construction will start once contract procurement process is over and work orders are issued. Once the adequacy of source in terms of quantity and quality is assured transmission line and reservoir works with procurement of pipe material can be taken simultaneously and immediately. As per experience, distribution pipe line works are likely to deviate from the original plans due to change in alignment on community demand accordingly procurement of distribution pipes can be phased out suitably.

Ground water recharging works should be taken up after rainy season and be completed before the next rainy season or completed to a safe level so that it once withstands the impact of the floods. Sanitation work can commence simultaneously such that water supply should be available by the time sanitation works are completed and put to use.



Splicing of reinforcement bars and its bending & cranking shall be as per bar bending schedule/ drawing or as detailed or indicated. Laps and welding of reinforcement shall be in accordance with IS Specifications. Welding shall be done during day time only.

The specifications are intended to generally describe the quality of materials and workmanship to be used for the finished work. They are not intended to cover minute details; it is assumed that only the best quality of materials and workmanship shall be used on the proposed work and that the work shall be executed in accordance with the best engineering practices and as per the instructions and directions of the engineer who is supervising the work.

The works envisaged in the proposed project shall, unless otherwise stipulated, be carried out as per the various Indian Standard Specifications/Code of Practice as may be applicable. To ensure the quality of construction works, construction checklists have been appended (refer Annexure-04, Volume-2).

14.5.2. Construction of Over Head Service Reservoirs (OHSR)

A. Site Requirement

The following precautions should be taken before selecting the site for construction of OHSRs at the identified / selected site.

• The selected site should not be in made up soil or loose earth • Trial pits have to be dug up to the depth of 1 m below the foundation level to

assess the nature of soil met • If soil met with is loose or black cotton or soft clay the SBC of soil should be got

tested again from soil mechanics laboratory. If SBC is found to be less, the design should be modified suitably.

B. Procedures to be followed during Construction of OHSR

Centering and Shuttering/or strutting • Formwork for concrete shall be rigidly constructed of approved materials

and shall be true to shape and dimensions described on working drawings • Proper check should be made for the verticality of the formwork of columns

and side walls with plum-bob during execution • Apply non staining oil or grease to column moulds, shuttering of beams,

side walls and slabs etc., to prevent absorption of water from concrete • Provide tight joints between shuttering sheets and moulds to prevent

leakage of cement slurry • Steel moulds and shuttering should be used for columns, braces, side walls,

floor slabs and roof slabs • Mango planks should not be used • Shuttering made out of bamboo with mud plaster on top should not be

entertained • Centering may be removed after two days for sides of slab, beam and

columns to aid curing • The strutting floor slab should be independent without touching the other

components of the structure. It should not be supported over the braces



• The struts should be firmly fixed on firm ground • The level of formwork for braces, floor slab and roof slab provided should

be checked for any deviations prior to and during concreting. Checking of Reinforcement and Cover

• The diameter, type and spacing of reinforcement may be verified with reference to drawings and agreement specifications thoroughly

• Proper cover of 5cm, 4 cm, 2.5 cm may be provided for footings, columns, beams and slabs respectively with cement concrete cover blocks (for details see IS: 456)

• Stone chips or similar pieces of bricks etc., should not be used for maintaining cover

• Concrete spacer blocks or concrete rings of required cover preferably tied with rods, by binding wire should be used to prevent their displacement

• Rusted steel reinforcement or reinforcement coated with mud, oil, and grease should not be used

• Cut length rods should not be used for main reinforcement to minimize the laps • The reinforcement should be tied properly with binding wire • Stirrup hooks should be cranked inside for proper binding.

Mixing of Concrete

• Only after testing and satisfying to the required quality standards, the aggregate, sand, cement, steel and water may be permitted for use in the work.

• Mixer machine should be used for mixing concrete • Bulkage of sand should be checked and the same quantity should be allowed. • Slump cone test should be done for assessing the water cement ratio as

mentioned IS: 456 • Only machine mixed concrete allowed. For small petty works where necessary

hand mixing if done should be on platform and not on ground • Minimum 3 Nos. of concrete cubes (02 nos. are to be tested) of 15 cm x 15 cm

x 15 cm must be casted at during concreting for each component of OHSR and tested on 7th day and another on 28th day in the nearby laboratory at site

• Vibrator should be used for better compaction. Curing of concrete

• Exposed surfaces of concrete shall be kept continuously in a damp or wet condition by ponding or by covering with a layer of sacking canvas or similar materials and kept constantly wet for 21 days from the date of placing the concrete. If admixture is used then if can be reduced depending on the admixture

Admixtures • Sometimes the admixtures are added in concrete to improve the concrete with

respect to its strength, hardness, workability, water resisting power

Depending upon their respective activities in the concrete mix, the admixtures can be classified in the following five categories:

• Accelerators • Air entraining admixtures • High range of water reducers or super plasticizers • Normal range of water reducers or plasticizers



• Retarders.

Some admixtures may have the combined effect of the above individual activities. The popularity of various types of admixtures in concrete is increasing rapidly because of the following advantages available from their use:

• Adjusting the final setting times of concrete • Higher early and ultimate strengths • Higher slump and self-levelling concrete • Increasing durability of concrete • Lesser water-cement ratios • Reducing quantity of cement • Reduction in the permeability of concrete • Time savings in terms of repair and maintenance, etc.

Precautions to be Taken • After laying of foundation concrete, the disturbed soiled watered and

consolidated for at least 10 days • Centering sheets should be smooth enough to get smooth finishing. Finishing

should be such that further finishing is not warranted • Before laying concrete for floor slab and roof slab the props should be checked

properly to avoid any disturbance in formwork • Polyethylene cover sheets may be spread over the centering sheets of floor slab

and roof slab to prevent leakage of cement slurry and for attaining smooth finish

• The top level of PCC, ground level, brace, middle brace, floor slab, and roof slab should be checked with tube level during concreting for any disturbance in formwork

• Floor slab, stride wall, roof slab diameter should be checked perpendicularly and diagonally, in four direction to obtain uniform size.

Miscellaneous Works of OHSR

• Tank inside ladder, manhole frame and cover should be provided as per specifications and drawings and to be fixed properly

• Gate/Sluice valves bearing ISI Mark, Batch No. Trade Mark should be fixed for outlet, scour, inlet, overflow pipe etc

• The MS angles of ladder from balcony to reservoir roof may be extended horizontally for 0.6m on roof slab and fixed with concrete rigidly at top. Handrail of 16 mm dia. MS rods welded with both angles of MS ladder should be provided on both side of ladder and be extended for 0.60m above roof level, cranked to 0.60 m horizontally, then bent downward and welded with MS angle suitably

• Support angle of 50 x50 x 6 mm should be strutted with MS ladder at middle to avoid buckling of ladder

• MS door of 2.0 meter height with locking arrangements be provided at staircase for safety

• MS ladder, metallic pipes and specials connected to pump sets and water retaining structures should be painted with anticorrosive paint.



• Separate feeder outlets may be provided in the floor slab of OHSR for separate zone when separate zoning is done in the distribution systems due to ground level variation

• The gate valves should be fixed at a convenient height from ground level for each operation within the reach.

• Relevant IS codes latest version of: 3370 (Part 1 to 2) : 3370 (Part 3 to 4) : 11682 (for staging) may also be consulted.

14.5.2.1. General Guidelines for all type of Civil works

Excavation: The excavation shall be of the width and length necessary for the construction of foundations or other works below ground. The depth of all excavation shall be decided by the engineer-in-charge depending upon the bearing capacity and other requirements. Excavation for building work shall generally be left open taking all safety measures such as display sign, barricading. The bottom shall be cleaned and any loose or disturbed ground shall be well rammed

Preparation of Ground below Permanent Construction: Plain concrete in foundation shall not be placed in direct contact with earth soil of excavation. The top of excavation is covered with a ‘blinding’ layer or screed of (1:3:6) or M-10 concrete not less than 50 mm thick with smooth surface. The required cover of concrete under the reinforcement shall be entirely above the blinding layer. A sliding layer of bitumen paper or other suitable material to destroy the bond between screed and floor concrete shall be provided (IS: 3370).

Bending of Reinforcement: Bars shall be bent cold. No reinforcement shall be bent when in position in the works. Bends shall comply with dimensions given in Bending Schedule. Refer to IS:2502 for details

Fixing Reinforcement: Reinforcement shall be accurately fixed and maintained in a position as described in the drawing. Bars crossing each other shall be securely wired together at all such points with No. 16 gauge soft iron annealed tying wire. Reinforcement projecting from work being concreted or already concreted shall not bend out of its correct position for any reason. Refer to IS:2502 for details

Proportions of Concrete: The proportion of cement and aggregate shall be as taken in design. Only sufficient water shall be added to cement and aggregate during mixing to produce a concrete having sufficient workability to enable it to be well consolidated, to be worked into the corners of formwork and around the reinforcement, to give the specified surface finish and to have specified strength throughout the work. Slump test shall be conducted from time to time to ensure the maintenance of desired consistency. Refer to IS:456 for details

Placing of Concrete: Before proceeding to place the concrete, the formwork shall be realigned if necessary and water and rubbish therein shall be removed. Immediately prior to the placing of concrete, the formwork shall be well wetted except in frosty weather. Each layer of concrete while being placed shall be consolidated by mechanical vibration and tamping to form a dense material, free from honey combing, free from water and air holes. Concrete shall be placed in a single operation to a full thickness of slab, beams etc and shall be placed in horizontal layers not exceeding 1 m deep in walls and columns etc., If stopping of concrete operation is unavoidable elsewhere, a construction joint shall be made where the concrete work is stopped



Sealing Mortar: The sealing mortar for packing of recesses, seal grooves and form holes shall consist of one part of cement and 1 ½ parts of the sand by weight. For tie holes and pipe seals, the mortar shall be packed tightly into place.

Seal around Pipes: Pipes shall not be run through the wall except where absolutely necessary. Grooves shall be provided around each pipe where it intersects exposed surface, and shall be filled with sealing mortar

Placing of Concrete Joints: Construction joints shall be vertical and horizontal, as required and shall be at right angle to the axis of member. Construction joints shall be in a position described on the drawings and where not so described shall be in accordance with the following: A joint shall be formed horizontally at the top of a foundation 75 mm below

the lowest soffit of the beams meeting at the head of a column. A joint shall be formed in the rib of a large T- beam and L- beam 25 mm

below the soffit of the slab. Concrete in the beam shall be placed without a joint. Before placing new concrete against the concrete that has already hardened,

the face of the old concrete shall be cleaned and roughened and scum and loose aggregate removed. The face shall be thoroughly wetted and coating of neat cement grout applied thereto immediately before placing the new concrete

Spring of Formwork: Formwork shall be removed by gradual easing. Removal of formwork shall proceed only in the presence of competent person. A complete record of the dates upon which the concrete is placed in each part of the work and the date upon which the formwork is removed there from, shall be maintained. Before the bottom forms and posts are removed, the concrete surface should be exposed in order to ascertain that the concrete has sufficiently hardened.

In normal circumstances (generally where temperatures are above 200C.) where ordinary cement is used, forms may be removed after expiry of the following periods.

a) Walls, columns and verticals 24 to 48 hr. b) Slabs (props left under) 3 days c) Beams soffits (props left under) 7 days d) Removal of props to slabs:

1. Spanning up to 4.5m 7 days 2. Spanning over 4.5 m 14 days

e) Arches 1. Spanning up to 6m 14 days 2. Spanning over 6 m 21 days

Procedure of Removal of Formwork

All formwork shall be removed without such shock or vibration as would damage the reinforcement and concrete. Before the soffit and struts are removed the concrete surface shall be exposed where necessary, in order to ascertain that the concrete has sufficiently hardened. Proper precautions shall be taken to allow for the decrease in the rate of hardening that occurs with all cements in the cold weather:



Finishes: Honey combed surfaces shall be made good immediately upon removal of formwork and superficial water and air holes shall be filled in. No other finish to the concrete shall be given unless it is inspected by the engineer-in-charge

Water Tightness Test for Hydraulic Structures

After completion of the hydraulic structure, it is tested for water tightness. If there is more than one compartment, initially all of them are filled in simultaneously. This ensures uniform settlement all over the area. The filling operations are also carried out gradually and full supply level is reached in a period of not less than 72 hours IS: 3370 (Part-I General requirements) ‘Code of Practice for the Concrete Structures for Storage of Liquids’ specifies water tightness test at full supply level

Brick Work

Bricks which absorb water more than 1/5th of their own weight when dry shall be used. Bricks shall be clean well wetted or soaked in fresh water for at least twenty-four hours before use on the work and no brickbats or broken bricks shall be used except where absolutely necessary to complete the bond. Entire cut bricks wherever specified shall be used and shall be of the first quality. (For details refer to IS: 2212)

Preparing Surfaces for Plastering

Immediately prior to the application of the plaster, the joints of the brickwork shall be raked out to a depth of at least 12 mm and the surface cleared and thoroughly saturated with water before the plastering is commenced

Cement Plaster

Cement plaster shall be of the specified composition cement and sand. Plaster shall be laid in a single coat of somewhat more than the required thickness and shall be levelled with a flat wooden straight edge and smothered with proper trowels to the precise thickness required. The plastering shall be kept thoroughly wet for seven days from the date it is done. The entire finished plaster work shall be to perfect plumb. For more details, IS:1661 may be referred

Curing of Plaster

The plaster shall be thoroughly cured for 15 days. Any cracks, which appear in the surface and all portions which sound hollow when tapped or are found to be soft or otherwise defective, shall be cut out in rectangular shape and redone.

14.5.2.2. Pipelines

Pipe Handling

The proper handling, moving, and storing of pipe materials should assure the integrity of the materials regardless of size, type or classification.



Inspection of Delivered Pipe Materials

Normally pipes undergo inspection at the factory before being delivered to the job site. The engineer must check for the following before accepting the delivery:

1) Damage on any of the pipe before or during unloading 2) Randomly pipes be checked physically with magnify callipers 3) Conformity of all piping materials (e.g., pipes, rings, gaskets and fittings) against

a tally sheet for quantity and correct sizes and class.

Loading/Unloading

The site engineer must see to it that the pipes are not damaged while being loaded or unloaded. The following practices are prescribed:

1. If possible, pipe should be loaded/unloaded using some form of mechanical lifting equipment. Whatever the method used, it should prevent abuse and damage to the pipe materials

2. In handling the pipes, no hooks, chains, or similar metal devices should contact the pipe at any failure points

3. Single slings should not be used. Pipes should be lifted with 2 slings (minimum) at their third points to avoid bending them and cracking their lining or coating

4. At the jobsite, pipes should be unloaded as near as possible to where they are to be used, so as to avoid excessive handling

5. Pipes should never be dragged along the ground or road.

Stacking/Storage

Generally, pipes, fittings and gasket materials should be stacked and stored in accordance with the manufacturer’s recommendations. The Site Engineer must also ensure compliance with the following:

1. All pipes, fittings and gasket material should be kept as clean as possible and be protected from any contamination

2. Pipe stockpiles should be built on a flat base, above the ground to minimize contamination. (See Figure 14-1)

3. The bottom layer should be supported uniformly along the barrel of the pipes to prevent bending

4. Pipes of the same size and classes should be stacked together 5. When stacking pipes, the bell ends should project beyond the end of the barrel in

alternate layers 6. Stacks should be kept within the limits of safety and practicality. Generally, a stack

should not be more than 1.5 m high 7. The stacked pipes should be secured against rolling down 8. PVC pipes should be protected from sunlight. The stockpiles should be covered with

opaque material in a way that permits adequate air circulation above and around the pipe and prevents the excessive accumulation of heat

9. The interior of the pipes, as well as all end surfaces, should be kept free from dirt and foreign matter from the time they are delivered to their actual installation

10. Coils may be stored stacked one on top of the other, but they should be kept away from hot surfaces



11. Short pipes, fittings, adapters and gaskets should be placed in separate piles 12. When issuing pipes, fittings, adapters and gaskets, the principle of “first in first out”

should be followed.

Stringing

Pipe stringing means the unloading of pipes along the line of the trench. If pipes are to be strung, the Site Engineer must ensure that the proper practices are applied:

1. Pipes should be laid as near to the trench as safely possible to avoid excess handling 2. The pipe should be laid on the side opposite the excavated material or equipment, or,

if trench is not yet opened, opposite where these will be positioned 3. Pipes should be secured against rolling into the trench and kept safe from traffic and

heavy equipment 4. The bell end of the pipe should be placed towards the direction of the work, as during

the installation the spigot end will enter the bell end of the previously laid section 5. Lifting equipment should be used to lower larger pipes; for which a webbing sling

should be attached to the pipe 6. The pipe ends should be covered to prevent contamination and entry of any object.

Figure 14-1: Arrangement of Stacking of Pipe



Laying of Pipe Lines

Depth and width of trench required for laying the pipe lines, hydraulics testing have been discussed in Chapter 6 on “Technical Guidelines-Water Supply Components (Volume-1)” in this Manual. However for further details refer CPHEO Manual on Water Supply and Treatment

14.5.2.3. Tube Well

Tube well construction should be done as described in IS: 2800 (Part –I) and it should be tested as per IS: 2800- Part–II.

A tube well is to be developed according to the IS: 11189 either by over pumping or with compressor as mentioned in Chapter – 6- “Technical Guidelines – Water supply Components”.

For rehabilitation of tube well guiding principle is adopted as per IS: 11632.

14.5.2.4. Construction of Slow Sand Filters:

Some of the important considerations that need attention during construction are:

I. the type of soil and its bearing capacity, II. the ground water table and its fluctuation, III. the availability and cost of construction material and labour. IV. Water tight construction of filter bed should be guaranteed, especially when

ground water table is high. This will prevent loss of water through leakage and contamination of filtered water. The top of the filter box should be at least 0.5 m above the ground level in order to keep away flood water, dust, animals and children. The pipe drainage system for collection of filtered water should be carefully laid as it cannot be inspected, cleaned or repaired without complete removal of the filter sand and gravel.

14.5.2.5. Surface Water Treatment Plant:

It will be constructed as per design and specifications elaborated in the contract document and approved by the competent authority. The site Engineer will supervise accordingly.

Refer Chapter – 8 on Water Treatment (Volume-1)-and IS specification for more details.

14.5.2.6. Pump Sets Installation:

1) Installation of Submersible Pumps: It should be procured and installed as per Chapter 7 (Volume-I) on “Pumping Stations-Electro-Mechanical Appliances/ Equipment’s” of this manual.

Normally the submersible pumps are installed at 1.5 m-2.0 m below the lowest safe yield level (water level after drawdown) for continuous operation during summer; Hence, it is necessary to install electronic water level indicators to read the water level



in the bore well ensuring the required minimum sub-mergence (1.5 m) also to avoid drawing of the silt/sand from the bottom. It is preferable that the lowest part of the pump is at least 3m above bottom of the well. Performance guarantees shall be based on laboratory tests corrected for field performance.

Following precautions to be taken for proper installation of submersible pumps:

1) Do not pull the pump with the electric cable. 2) Do not tamper with the important assembly settings carried out at workshop like

axle play of motor and pump since these have been done under expert supervision with proper tools. In case pump set is required to be disassembled at site, it should be carried out by factory-trained mechanic of the manufacturer.

Commissioning and Start-up

During the initial start-up pump should be run for 10 minutes with discharge valve slightly open because powerful suction might cause the large amount of sand to be entangled with the water and damage the pump. Do not keep the pump idle for more than 2 weeks. It is ideal to run pump at least five minutes in a week. Always ensure that the pump is not running dry.

Installation of Centrifugal Pumps

Centrifugal pumps shall be installed for intake well/Clear water pumping stations such that the motor assembly is fitted in pump room and the suction point is fitted in water at collection level and delivery point to feeder or conveyance main.

The bottom of suction pipe is fitted with foot valve and strainer.

Horizontal centrifugal pump is most commonly available pump as it is extensively used in water supply schemes. Centrifugal pumps are supplied with electric motor fitted on the common base frame. Pump shall be installed as per the instructions of manufacturer. Proper installation of pump is of utmost importance for satisfactory and trouble free working of the pump.

Normally pumps are supplied with a matching electrical motor. Pump and motor are mounted on a common base frame and coupled by a coupling. This assembly is required to be properly secured on a cement concrete foundation and then connected with suction and delivery pipeline. (refer IS: 6595: part-2).

Foundation: Refer Para 7.8 and 7.8.1 of Chapter-7 (Volume-1) of this Manual.

14.5.2.7. Suction and Delivery Lines

After foundation is completed place the equipment in the order. Suction and delivery pipe size should be of bigger size than suction and delivery ports of the pump. Both piping must have independent support to avoid the undue strain on the pump nozzle. Suction and delivery pipe strain may result in wearing of the ball bearing and bending of the pump shaft. Suction line should be correctly laid out. Foot valve is provided in proper working condition and dust free. The suction piping should be leak proof to facilitate the trouble free priming. On delivery line a non-return valve and gate valve



should be installed to protect the pump from excessive back-pressure. Pressure gauge with the valve to be provided before the delivery valve.

14.5.3. Electric Motor

Electric motor if supplied with pump should be decoupled from the pump and no load test and trial be carried out before connecting to pump. Generally pumps and motors are tested at the manufacturer place as the facility for such test and trial are available there. Direction of motor shall match the direction of rotation of pumps, (as marked on the pump casing). Recoupling of motor at no load trial shall be done with proper alignment. Motor shall be provided suitable earthing.

14.6. Inspection and Testing

Inspection and testing of various components of pump sets as well as testing of complete pump set after assembly will be done by the engineers deputed. The result achieved during testing should tally with the data/specification furnished by the supplier in the tender/Agreement.

The guidelines for the inspection procedure will be as follows: i) Manufacturer should submit test certificate on the casting for physical and chemical

properties for each and every pump set. The inspecting authority on their discretion may take samples of raw materials of casting for due verification of the composition and ascertain whether the materials supplied conform to the relevant standard

ii) Dynamic balancing certificate for the impellers and the result should be submitted for verification

iii) Manufacturer should test each and every pump set for hydraulic performance and submit the result for verification

iv) Manufacturer should carry out no load test for each and every motor and full load test for every 5 motors and temperature rise for every 20 motors and submit the result for verification

v) The inspection authority will see the performance of motor, type of tests of motors, including temperature rise test, torque test, hydraulic performance test and dynamic balancing on random samples. Necessary facilities also be provided to inspecting authority for checking every individual component of the pump set

vi) All the pump sets which are approved for delivery by the inspecting authority shall bear the inspection marking as stipulated in general forms and conditions of contract.

vii) The pump test should be done taking into consideration of pipe friction losses using orifice plate.

14.7. Testing and Inspection at Manufacturer’s Work site:

The manufacturer shall conduct all tests required to ensure that the equipment furnished shall conform to the requirements of the specifications and in compliance with requirements of the applicable codes. The buyer’s (GP) representatives shall be given full access to all tests. Prior to pump performance tests, the manufacturer shall inform the Buyer allowing adequate time so that if the buyer desires his representatives can witness the test. All materials and casting used for the equipment shall be to tested quality. The test certificates shall be made available to buyer. The pump casing shall be hydraulically tested at 200% of pump rated head or at 150% of shut-off head, whichever is higher. The test pressure shall be maintained for at least half an hour. The pump rotating parts shall



be subjected to static and dynamic balancing tests. All pumps shall be tested at the shop for capacity, head efficiency and brake horsepower and cavitations. The tests are to be done according to the requirements of the “Hydraulic Institute” of U.S.A., ASME Power Test Code PTC-8.2 (latest edition) and Indian Standards as applicable. The pumps accessories e.g. the thrust bearing, the motor pump shaft coupling etc. will be subjected to tests as per manufacturer’s standard. The combined vibration of pump and motor should be restricted to the limits specified by Hydraulic Institute Standard, USA, when the pump in operation at any loads singly or in parallel. Tests on motors shall be conducted as per electrical specification. The reports and certificates of all the above-mentioned tests to ensure satisfactory operation of the system shall be submitted to the buyer before dispatch. Cast heat marks to be provided on castings for casing and impeller.

Accessories

(a) Switches: A main switch of adequate capacity to disconnect power supply shall be provided after the meter. This will enable to disconnect the service immediately in case of any emergency or for maintenance purpose.

(b) Starter: Starter with over load relay is provided to start and stop the motor and to protect it against any over load. Over load may be either electrical or mechanical

(c) Capacitor: Installation of capacitor of suitable rating in the motor circuit will improve the power factor and reduce energy consumption. The running cost of the motor will also be reduced. The recommended capacitor ratings are shown in Table 14-1.

Table 14-1: Capacitor Ratings

Sl. No. Range of Motors Starter

Type Cables Capacity

or KVAR

MCB Amps

Volt meter Ammeter

1 Up to & Inclusive of 3 HP

Direct on Line 2.5 Sq.mm 1 20 0 to 500 V 0-15 A

2 Above 3 HP up to 5 HP Direct on Line 2.5 Sq.mm 2 20 0 to 500 V 0-15 A

3 Above 5 HP up to 7.5 HP Star Delta 4 Sq.mm 3 32 0 to 500 V 0-30 A

4 Above 7.5 HP up to 10 HP Star Delta 4 Sq.mm 4 40 0 to 500 V 0-30 A

5 Above 10 HP up to 12.5 HP Star Delta 6 Sq.mm 5 40 0 to 500 V 0-60 A

6 Above 12.5 HP up to 15 HP Star Delta 6 Sq.mm 5 63 0 to 500 V 0-60 A

(d) Single phase preventer: In three phase circuit, three fuses are provided (one for each phase). If in any one phase were to blow or any one phase is disconnected from service during running of the motor, the motor keeps running drawing excess current from the two lines and hence causing damage to the motor. If a single phase preventer is provided in the circuit, it will sense the operating coil and trips the starter and protects the motor from burning.

(e) Voltmeter and Three Phase Ammeters: These meters will indicate whether system voltage is within permissible range for the motor or to know whether motor is



drawing current equally on all three phases. The functioning of Voltmeter is very important, voltage being low in villages damaging the motors.

(f) Selector Switch: Selector switches of adequate capacity shall be used wherever more than one pump is installed. The selector switches will enable to operate any one of the pump or both the pumps from a single switchboard.

14.7.1. Electrical Connections

Refer Para 7.15 Chapter-7 (Volume-1) of this Manual.

14.8. Solid and Liquid Waste Management

Sanitation Materials:

The squatting pan can be of ceramic, glass fiber reinforced plastic (GRP), high density polyethylene (HDPE) or polyvinyl chloride (PVC), polypropylene (PP), cement mosaic. However, the ceramic pans are favored in this project due to their better non-sticking and non-staining properties.

The superstructure of latrine cubical could be brick or stone in mud or in cement mortar. The superstructure could be of very low cost if constructed with bamboo matting with mud plaster outside and inside with thatched or tiled roof.

Care to be taken during construction of Latrine and Leaching pit

During construction, one should check whether the following conditions have been met:

• The depth of the pit below the invert level of connecting pipes or drain shall be as given in relevant drawings

• The minimum distance between the two pits shall be equal to the effective depth (depth of the pit below the invert of incoming pipe or drain) of the pits

• The pits shall not be located in a depression where water may stagnate over the pits or in a drainage line which allows the flow of rain water over the pits

• The bottom of the leach pit is left in a natural condition except where it is necessary to seal it to prevent pollution

• The RCC cover is as per designs • The top of the pit cover is about 50 mm above the natural ground level and the earth

fill is well compacted all around the cover sloping to avoid a step being formed • The drains is “U” shaped, cross-sectionals and is inner surface is smooth. Drains with

benching are properly provided in the junction chamber to divert the flow to one of the two pits

• A minimum gradient of 1:15 is provided in the connecting drains or pipes. The mouth of the drains or pipes is projecting nearly 75 mm past the pit lining in the pits

• The flow has been restricted to one pit by blocking the mouth of one of the drains or pipes

• The materials used are of the quality specified in the design, or relevant standard specifications and the workmanship is good

• The specifications laid down have been followed and the work has been finished nearly



• The floor surface is smooth and sloping slightly towards the pan • The foot-rests have been fixed at the proper place and at an angle, as in the drawing • 50 mm wide holes have been provided in the pit lining in alternate layers up to the

invert of the pipe or drain, and the lining above is in solid brick work (no holes). If the soil is sandy, or if a sand envelope is provided, or there are chances of damage by field rats, the width of the holes is to be reduced to 12 to 15 mm. If the foundation of the building is close to the pits, holes are not to be provided in the portion of lining facing the foundation. In element concrete ring lining, rings below the invert of pipes or drains should have 50 mm circular holes staggered about 200 mm apart

• The covers over the pits, drains, and junction chamber are placed properly • The pan and trap used are of a design specified for pour flush and these are fixed

properly so as to provide a 20 mm water seal, and that the joint is water tight and the top of the pan is flush with the latrine floor

• No vent pipe has been provided • A well-ventilated superstructure has been provided to enable use of the latrine • All surplus materials have been removed and the site cleared and dressed • The users have been educated on these and maintenance of PF latrines.

Septic Tanks

Construction Care: Only that material shall go into the construction of a septic tank which offers guaranteed strength and water tightness. The masonry is done in rich cement mortar and plastered inside (with 1:3 cement-sand mixture). In bed C.C. M-15 should be used. In case of small tanks one manhole cover above the inlet serves the purpose but in case of large tanks, two manhole covers of water tight and double seal design depending upon the expected load should be used. Staggered M.S. steps are provided to facilitate access to the manhole.

Ventilating pipes are provided in every septic tank. On the top of ventilating pipe is provided a suitable cover of mosquito proof wire mesh. The height of ventilating pipe should extend to at least 2 m above the top of the highest building within a radius of 20 m.

14.9. Public Safety

General

During preconstruction meetings and in monthly meetings during construction, the job-site safety issues should be discussed with all parties involved in the project.

The discussions should put specific focus on hazards peculiar to the upcoming phase of construction, as well as keep the discussants alert to the more general, continuing ones that are features of any such constructions. They should address any problems that need to be corrected and set reminders on potential health and environmental hazards. In addition, the Inspector should routinely check first-aid supplies weekly, and continuously check the job site for debris and hazards.

Construction Safety and Social Safeguard

The need for safety precautions in any specific project area must be recognized and observed before and during construction activities. Following care should be taken:



1. Any construction will draw on-lookers, especially children. Onlookers should be kept away from the operating equipment and from the edges of excavations

2. Traffic must be diverted and or controlled at all times unless permission has been received from the proper authority to completely close a road

3. When a pipeline trench crosses any road intersection, steel plates should be put in place to allow traffic to cross the trench. The Engineer, Contractor, and all workers should be alert to situations when these are dislodged from their proper placement

4. Emergency vehicles must not be delayed 5. Vehicular access to homes and places of business should be maintained. If this is not

possible, the occupant should be apprised of the situation by the Contractor or the Engineer. It is an absolute necessity that good relations be maintained with the general public

6. When leaving the project at night, no unnecessary obstructions to traffic should be left behind, such as earth lumps from the trench excavation or sections of pipe that encroach on the roadway

7. All necessary barricades for the construction close to traffic need to be made 8. Provision of warning signs 150 meters in advance of any place on the project where

the operations interfere with the use of the road by crosses or coincides with an existing road

9. Provide a sufficient number of watchmen 10. The construction area of the project should be properly lightened 11. Deploy traffic flagmen as needed. In case only alternating one-way traffic control

needs to be imposed, the contractor shall furnish flagmen to direct traffic through the section of road under one-way control.

Signs, Signals and Barricades

It should be ensured that signs, signals and barricades are properly used.

1. Barricade

This is an intentionally placed obstruction to deter the passage of persons or vehicles.

a) Types Permanent – A large surface area barrier at the limits of the work area Temporary – Smaller barricade used for work area protection or as portable

bases for temporary warning or directional signs. b) Placement

Should be placed so that there is no gap large enough for a vehicle to pass. Should be facing traffic and must be illuminated or reflectorized at night. Should never be placed in a moving lane of traffic without an advance

warning sign.

2. Delineators

These are markers which aid the driver in determining the locations and alignment of the traffic lane.

3. High-Level Warning Devices (Flag Standards)



These are devices, which provide advance warning of a work area. These should be at least twelve (12) feet high with three flags for daytime and three flashers for nighttime use.

4. Flagmen

Flagmen in sufficient number should be provided.

14.10. Trial Run & Commissioning

The following procedures should be ensured like:

(i) Designed Quantity of the water reaches all households (ii) Desired residual chlorine levels are maintained in the system (iii) Water treatment plants produce the required quality and quantity of water and (iv) Efficiency of pumping machinery is as per design (vi) Pumping hours are adjusted to provide the reduced/present service level for present population since the scheme is designed for ultimate population.

14.11. Exit Strategy

Following activities to be covered as part of the exit strategy

(i) Proper contract closure and follow-up with social and technical audits will form part of exit strategy. For more details para 15.3.8 of Chapter-15 (Volume-1) may be referred.

14.12. Implementation Schedule

While preparing the implementation schedule, following aspects shall be considered:

(i) Time period for technical and financial sanction (ii) Implementation period of the project (iii) Testing and Commissioning Period

14.13. Institutional Responsibilities

Following agencies shall be involved at different stages of the project:

(i) Concerning State Department – Project preparation, Technical sanction, Appraisal, Implementation (Execution), to provide technical knowhow and training for maintenance and monitoring

(ii) World Bank, GOI Government – World Bank and Government of India financing the project

(iii) Gram Sabha – Project Users, beneficiaries, maintenance through GPWSC (iv) State Electricity Board – Power Supply

14.14. Completion Plan & Reports

When a project is completed, commissioned and handed over, the history of the project is to be maintained .The advantages of the keeping records is It will be helpful while carrying out the O&M.



It will act as a guide for future projects It will examine the mistakes committed and study to avoid mistakes in future projects

Completion Drawings

On execution of scheme it is required to prepare drawings of all components as per the work done called completion drawings. These are modified from working drawings. The completion drawings should indicate all changes made during execution. The list of drawings required is : Site plan or location plans Village map Plan showing bore well/open well with cross sections Plan showing pumping main, showing alignment, distance and position of valves.

Size of pipes and type of pipes should be marked Plan showing intake well with cross sections Plan showing service reservoirs with all designs Plan showing details of treatment units Plan showing distribution system, showing alignment, distance, position of valves

and position of public stand posts. Size of pipes and type of pipes should be marked For all civil works the material of construction, classification, and foundation details

should be shown For all plans dimensions should be marked Permanent bench marks should be marked Levels at which components taken up should be marked.

Completion Reports

The completion Report shall contain all the text information of the project that may be required in future reference. This will be useful for carrying out O& M activities and for upgrading scheme. The completion Report shall have the following information. General information Name of the work Estimate cost Administrative Sanction No, Date and authority. Technical Sanction No, Date and authority. Work order No, Date and authority Name of the agency executed the wok Name of the Implementing office Date of Commencement of work Time scheduled for completion of work Date of completion of work Date of hand over to GPWSC. Final payment made.

General Abstract:

The general abstract of the scheme is to be prepared along with comparative/completion Statement showing the deviations. The completion Proforma should also be prepared for each of the sub work, clearly indicating all the details of work. Performance of key agencies, activities should be informed in reports Performance of contractors



Performance of key agencies Performance of GPWSC/Community. Difficulties faced during construction. Coordination required with other organizations.

14.15. Environmental & Social Impact

a) Environmental impact may be defined as the sum of the short term and long term effects of any proposed action (of absence of action) on man himself and on physical, biological and socio-economic environment, including the effects of policies. Legislature proposal, programmes, projects and operational practices, attention needs to be paid significant adverse effects on the quality of man’s life including both those that affect him directly and those that affect him indirectly through adverse effects on the environment.

b) Several studies both at national and international levels have concluded that most of the diseases are either water borne or water related. Consumption of safe and clean drinking water will help to control all these infectious diseases which are caused by pathogens. Some of the important infectious diseases related to consumption of infected water are fluorosis, typhoid, cholera, dysentery, diarrhoea, and gastro-enteritis. Viral hepatitis and amoebiasis etc.

c) It is imperative to mention that there are a numerous invisible savings that are caused as a result of clean and safe environment to be provided by the proposed service of piped water supply. Such savings or benefits cannot be fully quantified in terms of monetary gains, but their impact can be well perceived in form of good health, longevity of life, reduction in cost of hospitalization for fighting diseases and consequently extra working days / years and improved socio-economic conditions. These benefits are not apparently visible but cost heavily on exchequer and national economy.

d) As stated earlier, the project needs deliberate and sincere endeavours for prompting health and sanitary environment. Introduction of piped water supply scheme in project area’s Gram Panchayats shall have a significant impact on the aforesaid direct and indirect benefits. It may also be pointed out that this project does not include any such proposal / activity, which at any stage might have adverse effect either on environment or on natural resources in the project area. The project is thus eco-friendly.

In absence of pipe water supply, the Women used to bring the water from the remote places. The implementation of pipe water supply shall facilitate them to save the time. This time may be utilized by them in: (i) Look after their children (ii) To explore the other income source like farming, animal husbandry, carpet weaving. Hence social impact of the project is positive.

14.16. Environment & Social Management Framework

Refer Annexure 22 (PIP) for Environment Management Frame work and Annexure 24.1 (PIP) for Social Management Frame work.

| Operation & Maintenance


15. Operation& Maintenance

15.1. General

The objective of an efficient operation and maintenance of a Water Supply System is to provide safe and clean drinking water in adequate quantity and of desired quality, at adequate pressure at convenient location and time and as economically as possible on a sustainable basis. Operation refers to timely and daily operation of the components of a Water Supply System effectively which is a routine function. The term maintenance is defined as the art of keeping the structures, plants, machinery and equipment and other facilities in an optimum working order. Maintenance includes:

Preventive maintenance: regular effective follow up of schedules for operations Corrective maintenance: Based on problems faced ascertain reasons and take

corrective measures.

Efficient and effective operation depends upon sound village water supply strategies made up of: (a) Water safety plans to ensure good quality water (b) Standard operating procedures (c) Service improvement plans.

These simple templates allow villagers to assess the condition of their assets, the true costs of operations, their current performance, to identify operational and infrastructure remedies and how they propose to finance these.

The templates can also be used to guide development of training modules for local operators, field facilitators, Gram Panchayats, and Block Resource Centre and District Water and Sanitation Mission staff. Any water supply system, how well engineered it may be, can give satisfactory service to the community only when it is properly and effectively maintained. The operation refers to the art of handling the system in such a manner that designed quantity and quality of water can be produced. The scope of maintenance of water system will vary depending upon the particular situation. Following consideration need to be undertaken for the effective and efficient O&M activities:

Availability of Detailed Plans, Drawings and O & M Manuals:

All these sets must be corrected and updated whenever any additions / alterations / deletions are done to any of the structures and equipment.

Schedule of Daily Operations:



For each of the activity where operators are employed, a detailed scheme and schedule of unit operations should be worked out and a copy of the same should be available with each operator. This schedule of unit operators may have to be altered to suit changes in raw water quality, hours of availability of power, breakdowns and upset conditions etc.

15.2. Operation & Maintenance of Various Components for Water Supply Schemes

15.2.1. Intake Works

a) Sanitary Survey Sanitary surveys at regular intervals at field management levels and inspections at supervisory management level should be conducted. The catchment area of the source should be located on the maps. Potential sources of pollution observed in the catchment should be marked. The type of pollution e.g. industrial / domestic waste discharges, wastes of animal origin and agricultural run-offs should be determined. The quality of such discharges has to be ascertained and its likely effect on water being drawn at source should be mentioned. Reports of such surveys should be promptly sent to the Pollution Control Authorities as well as water works authorities to promote corrective action. Procedure for monitoring of preventive action taken should be laid down and observed. An instant action plan for providing chlorination of raw water should be available and brought into effect under such circumstances.

b) Measurement of Flow

In case of surface sources such as springs, rivers, canals, etc., there should be a permanent arrangement for recording daily flows near the intake works. Appropriate records in the form of graphs showing variation of flows in the source for each month in a year and for each year shall be maintained. Rain gauge stations should be established to record daily rainfall in their service catchments and appropriate rainfall records should be built up and compared with discharges / storages available. In cases of reservoirs, the regime tables for refilling and emptying of storages should be maintained for each year.

c) Maintenance of Intakes

It should be ensured that sufficient water level is maintained at headworks in order to ensure withdrawal of required quantity of water into intake works without vortex formations

All intake strainers should be cleaned at frequent intervals particularly during monsoon to prevent entry of fish or floating matter into intake works

All damages to structural components of intake works particularly during floods should be promptly repaired

Sufficient stocks of rubble should be maintained at intake works site for use to temporarily overcome the problems of scours at spillways and other places

A schedule of painting of steel and other structural parts of the intake works should be prepared and followed scrupulously to avoid damages to the structures

All raw water holding structures such as intake wells should be desilted during and immediately after monsoon to remove settled silt.



15.2.2. Tube Well

Table 15-1: Trouble shooting procedure for tube wells

Sl. No. Observations Investigations Causes Actions 1 Reduced yield

and loss of pressure

a) Check water level while pumping

b) Check pump shut off head

c) Check motor for overhauling and rotation

d) Check static water level (min 8 hours recovery)

i) Motor overheating, rotation slow, low voltage, pump overheating

ii) Pump efficiency low pump worn out

iii) Pump not performing on curve, pump water level down

i) Check motor, pull pump, check for worn out bearing Replace worn out part

ii) Check water static level. If SWL is lowered, modify pump to new position.

iii) If SWL is normal pill pump and rehabilitate well

2 Sand in discharge , loss of pressure , surface subsidence around the well

a) Check well design for conformity to geological conditions

b) Check pump for worn out impellers

c) Check well construction for conformity to design

i) Design is inadequate

ii) Well is being over pumped

iii) Pump is worn out

iv) Casing failed

i) Correct faulty construction (repair casing or screen)

ii) Repair or replace pump

iii) Revaluate option for new well and reduce yield of repaired well

3 Well is surging, pump is cavitied, breaking suction, excessive drawdown

a) Check pump discharge Vs. design inlet

b) Check condition of well conduct pump test

c) Check water levels in nearby wells

i) Pumping in excess of design rate

ii) Drawdown in pumping well excessive, whereas SWL in observed wells is normal

i) Reduce pumping rate

ii) Increase chemical quantities, repeat treatment, adopt vigorous surging. If still does not improve abandon well

Source: APRWSSP-Tech Manual 15.2.3. Clear Water Sump &Reservoir

Roofing should be periodically checked to ensure that no leakages are there. Ventilator outlets should be regularly checked and cleaned to guard against mosquito breeding and bird droppings. Cleaning of the sump and reservoir should be done regularly. Level recorder should be kept in working order at all times.



The total capacity of clear water reservoirs should be adequate for storage of treated water, especially during low supply periods at night when reservoirs become full. Instances are reported, where water from the filters have backed up into the inspecting galleries, thus reducing the rate of filtration. The remedy lies in having additional clear water reservoir in the plant, or arrangement for the final water to be automatically pumped to the balancing reservoirs.

15.2.4. Balancing Reservoirs and Elevated Reservoirs

Important aspects to be considered during maintenance are: I. Measurement of inflows and outflows: Whenever measuring devices are provided, it

should be seen that discharge at inlets and outlets fairly tally. It should be seen that water level indicators and recorders are in proper working order

II. Structural Leakages: All structural damages and leakages should be promptly repaired III. Preventing External Pollution: The manhole opening, ventilating shafts and overflow

pipes should be properly closed and protected from external pollution IV. General cleanliness in and around the reservoirs should be maintained and observed.

A garden around the reservoir structure may be provided V. A programme for periodical cleaning of the reservoirs at least once in a year should

be undertaken. During such cleaning process there should be facility to bye pass the supply to distribution system

VI. Appropriate safety measures to prevent climbing of unauthorized persons should be provided. All the railings provided shall be maintained in a safe and firm condition.

15.2.5. Treated Water Quality

The quality of the water before distribution may be controlled by adjusting the calcium carbonate balance in the water to safeguard against corrosion or excessive scale formation in pipes. The periodical analysis of the water can also indicate if there is any biological growth in the main and if any further chlorination is needed to check it. The samples of water collected from several points should be routinely examined for residual chlorine and other chemical and bacteriological parameters.

15.2.6. Water Treatment Plants

The engineer-in-charge responsible for maintenance of water treatment plants should have complete knowledge of the working of various components of the treatment system. Major problems in the treatment unit arise because of the fluctuation in quality and quantity of water, improper functioning of several units and mechanical and electrical equipment.

For proper and sufficient maintenance of treatment plants it is imperative to take timely action to avoid unexpected break downs. For effective maintenance the following points are to be observed: 1) Complete set of drawings of the components of treatment plant unit should be readily

available. These drawings should indicate the location and sizes of all pipes and appurtenances

2) The drawings of important parts of plant should be displayed inside the building of plant for ready reference



3) A systematic routine schedule for inspection of various components of the plant and equipment installed in it, should be drawn and proper record should be maintained in respect of machinery and lubricants used

4) A log book should be maintained keeping complete record of various units and equipment regarding their cleaning, repairs, break-downs of particular component and the time taken for its repair

5) Analysis of water, Jar test records and the quantity of chemicals used should be maintained regularly and methodically.

15.2.6.1. Water Treatment Components

a) Chemical Feeders: Alum tanks should be painted annually. Stock for spares, mixing devices should always be available

b) Flocculation System: The flocculation equipment should be checked up prior to monsoon once a year for overhauling and maintenance. The parts moving under water shall be dried, loose rust or scale removed and equipment should be thoroughly checked up to avoid break down during service, sludge lines should be kept free from choke. The traction wheel should be checked for alignment

c) Sedimentation Tanks: The tanks should be checked up once a year and any minor repairs if required should be carried out. The walls and floors of the tanks should be thoroughly cleaned to remove algae growth or other loose material and dirt and then tank should be disinfected. Algae grown on walls of sedimentation tanks can be controlled by coating the wall portion from FSL to a point 0.6 m below with a mixture of copper sulphate and lime. The sludge can be removed by opening the scour valve provided in the bottom of the tank. Sludge will flush with discharge of water with sufficient force. The sludge at the distant corners should be flushed towards the drain with the help of 65 mm dia hose streams with a pressure of 3.4 to 4 kg/cm2

d) Slow Sand Filter: At start up, filters are filled with water by introducing it from the bottom. First, close the outlet valve and charge the filter with clear water from the bottom to remove the air bubbles from the filter bed. This method of filling should be continued till the water comes above the media at least up to 500 mm. This will prevent disturbance of bed that may be caused by turbulence on admission of raw water. Now open the inlet valve and start filling up the filter from the top up to the supernatant level. Open the outlet valve and waste the effluent. Continue wasting at a rate of approximately one quarter of the normal filtration rate till the filter gets mature.

The new filter takes some time to “mature” (to build up the “schmutzdecke”15) a thin layer formed on the surface of the filter bed which contains algae, plankton, bacteria and other forms of life and the sticky layers round the sand grains). Till maturing, the effluent quality is not expected to be satisfactory hence it is to be wasted. For several weeks during “schmutzdecke” development the filter should be operated with the regulating valve only slightly open or fully closed. Subsequent to maturing the valve is gradually opened a little each day; to compensate for the choking of the filter and to maintain the required rate of flow. In the early part of the filter run the daily build-up will be almost negligible; Calling for little valve adjustment but towards the end of the

15 It is a German word to define naturally occurring gelatinous layer of living biological matter on a sand based water filter.



resistance will increase more rapidly, necessitating a more positive opening of the valve.

Regular Operation

After maturing filter will run without requiring much attention. Daily activities that an operator will have to pay attention are listed below in table:

Table 15-2: Daily Activity Chart for Slow Sand Filter

Activity Procedure Regulation of supernatant water level

Manipulate inlet valve to maintain a constant supernatant water level and to avoid overflow

Removal of scum and floating matter

Allow temporarily the supernatant with the scum to overflow or manually remove using long handled wire net

Checking the filtration rate Observe flow indicator and note the rate, if flow indicator is not provided try to calculate flow by recording the time taken in filling up the filtered water sump

Regulation of filtration rate

Manipulate filter outlet valve to maintain desired constant rate

Shutting 0ff the filter Closing the outlet valve and inlet valve after days requirement of water is filtered

Source: APRWSSP-Tech Manual

Cleaning of Filter

To clean the filter bed, (whenever required, normally once in two or three year) the raw water inlet is first closed, allowing the filter to continue to discharge to the clear water well as long as possible. Then by opening the waste valve on the effluent outlet pipe, the water level in the filter bed is lowered until it is 100 mm or more below the surface. Then a 10-20 mm thick sand layer containing the “schmutzdecke” is removed using flat nosed shovels.

After the removal of the scrapping the bed should be smoothed to a level surface and restarted with sand topping up. The quicker the filter bed is cleaned the less will be disturbance of the bacteria and the shorter the period of re-ripening.

Filter units should be cleaned one by one. When one unit is cleaned others can be operated at higher rate to avoid shortfall of filtered water.

e) Rapid Gravity Filters: Washing of filters is done using different methods such as High Velocity Wash Water System, Surface Wash System, Air Wash System, Application and Operation of filters, filter appurtenances such as rate of flow controller, such expansion gauges, care of sand in filter beds, chemical treatment etc. The rate of flow gauges and loss of head gauges usually get out of order. Necessary spares for these gauges should be kept in stock for carrying out minor repairs quickly.

f) Chlorinators: Whenever chlorinator goes out of order it should be repaired immediately and commissioned. It is necessary to dismantle gas piping and feeders once a year to clean the accumulate impurities to avoid unscheduled breakdown.



15.2.6.2. Records

The format of records for the purpose of treatment would depend upon the size and type of treatment plant. The record should be kept systematically and regularly. Where the plants are large, each operator of the plant should maintain record of his own shift of 8 hours, recording hourly the chemical doses and volume of water treated etc. This information should be transferred to daily forms.

The laboratory assistant shall maintain records of laboratory tests indicating the volume of each sample, volume of reagent used supported by details of computations so that it can be rechecked by the engineer in charge in case of any variation. The record of chlorine equipment should indicate the volume of water treated, dosage of chlorine, loss of weight of chlorine cylinder (i.e., the actual amount of chlorine consumed) residual chlorine determined at specific intervals with column for remarks for indicating any particular observation or events.

15.2.7. Distribution System

Important aspects of operation and maintenance of distribution system are detection and prevention of wastage due to leakage. The object is to control the waste within reasonable limits.

The O&M of a water distribution system is directed at the following general objectives:

To ensure adequate pressure in the system To minimize Non Revenue Water (NRW) To ensure that the water delivered is potable.

The distribution system consists of four components, whose O&M requirements are based on their unique characteristics as well as their function and contribution to the total system. They are:

1. Distribution pipelines 2. Storage tanks or reservoirs 3. Service connections 4. Valves and other appurtenances.

Distribution pipelines must be able to convey quality water reliably and efficiently to the consumers and keep it from being contaminated along the way. Properly constructed, pipelines can provide years of trouble-free operations. However, sound operation practices need to be observed, both to ensure water quality and to prevent the deterioration of pipeline efficiency.

15.2.7.1. Sound Operation Practice

Sound operation practice can be summarized as follows:

1. Always maintain positive line pressure. Negative pressure could result in backflow from private storage and the intrusion of foreign water/matter that may pollute or contaminate the system



2. Always open and shut off valves gradually. Abruptly opening or shutting off a valve can cause sudden surges, changes in water velocity, and reversals of flow that might produce water hammer effects that could stir up sediments, making the water dirty, and damage valves and weaken the pipe joints

3. Implement an appropriate flushing program to clear sediments from the system. Such a program should institute the regular, periodic flushing of the pipes, as well as prescribe the maintenance measures for those sections of the system that are more prone to sediment build-up, such as dead-end pipes and low sections. These sediment-prone sections should be pre identified and, if needed, provided with additional scour and hydrants to facilitate flushing and disinfection.

15.2.7.2. Preparation for Repairs

Regardless of their construction and the best operational and maintenance practices, pipes are subject to the aging process, to accidents, and to other adverse factors including force majeure. Since water main breaks need to be repaired with as little delay as possible, it is important to have contingency plans in place, and the maintenance personnel are trained to work with minimal delay based on the plans.

The following tasks should be done in advance in order to eliminate delays in getting the needed repair work started:

1. Post the phone numbers of key maintenance personnel conspicuously in the pumping station or office

2. Keep the following items available and ready for use at all times: valve keys, hand tools, digging tools, pavement breakers, trench-shoring material, a portable centrifugal pump, floodlights, an emergency chlorinator, and calcium hypochlorite

3. Keep a stock of split-sleeve and mechanical-joint repair fittings in sizes that fit critical mains.

15.2.7.3. Locating Water Mains

The exact location of pipes can be determined by referring to records or as-built plans of the water supply system. In cases where records are inadequate or lost, underground pipes might be pinpointed by

Asking old residents who witnessed their installation; Trial excavation:

1. In the vicinity of the reported problem, select a primary reference point that you can use to establish the position of the problem pipeline. An exposed pipe section would be a good primary reference point

2. Where there is no exposed pipe section, select any point one side of the road; Identify household having house connection, the owner of the house will inform which side of the road and at which approximate distance the pipe line exists. Then excavate and locate the pipe line

3. If a water main is not found at the first point excavated, try again at another point based on gathered information and continue the trial and error process until a water main is located

4. Using the water main just located as reference point, select a second point in line with the first 50 to 100 meters from it and make another excavation



5. Once a second excavation point reveals the water main, draw an imaginary line connecting the successful excavation points 1 and 2. The connection of the two points is the exact position of the buried pipe

6. Repeat the above process using the identified points as reference until all pipelines are pinpointed.

15.2.7.4. Cleaning Pipelines

Water going through the pipelines may sometimes carry sand, sediments, and organic and other objectionable matter. When water velocity is low, these tend to get deposited and build up inside the pipes. The built-up deposits decrease the carrying capacity of the pipes and increase internal friction, making the pipelines less efficient. Less water can be delivered per given time, pumping costs increase, and the added and uneven pressure within the pipelines increases the likelihood of breaks and leaks. These effects are complicated when magnesium and calcium salts are present in the water (hard water), as their precipitation results in scaling inside the pipes. Likewise, when organic matter is present in the deposits, bacteria proliferate, causing undesirable odours, and an of-taste and colour in the delivered water.

The method for removing solids which are not cemented to the inside surface of pipes is to flush with water at high velocity. Annual flushing is generally sufficient to maintain the pipelines clean. (But note that different water and pipe materials may need a different schedule.) Dead- end pipes should be flushed and disinfected at least once a year. Furthermore, whenever mains are opened for repair, they should also be flushed and disinfected. The flushing procedure is as follows:

1. Isolate the water mains to be cleaned by closing the appropriate control valves 2. Empty the water mains by opening the scour valve or other temporary outlet at the

lower end of the pipeline. In some cases, to expedite the emptying of water mains without pumping, compressed air may be introduced at the highest point of the isolated system

3. Inject water at high-induced velocity (1.0 meter per second or higher) until the objectionable materials are expelled

4. As needed, disinfect the pipelines. After disinfection, flush the pipeline with clean water until the chlorine-odour is hardly detectable

5. Put pipelines back to operation.

15.2.7.5. Repairing Pipe Leaks

Leaks in water mains should be fixed as soon as they are detected. Once the leak is pinpointed, the water in the isolated main must be removed the repair job then consists of sealing the leaks and/or replacing the defective pipe section. The different methods of fixing leaks are as follows:

1. Using Epoxy (for Small Leaks) a) Dry the surface of the area to be repaired b) File the surface to make it rough, and slightly enlarge the crack or hole c) Apply the epoxy, forcing some of it into the crack or hole to produce a seal



d) Normally, the epoxy will set in 2 to 4 hours before the pipe can be disinfected and put back into service, However, be sure to check the directions for use of the epoxy as some types may require more or less time.

2. Using Sleeve Type Coupling /Repair Clamps Put a split sleeve/repair clamp around the leak opening.

3. Using Strips from the Inner Tube (“Interior”) of a Rubber Tire In emergency work when no other repair materials are available, cut a discarded inner tube of a rubber tire into strips and wind the strong, flexible rubber strips tightly around the pipe to cover the leak and its surrounding surfaces.

4. After the Leak Is Repaired a) Open the control valve to allow water to flow into the repaired section b) Observe carefully to verify if the leak is completely sealed c) After sealing, backfill the excavation and restore the surface to its former

condition d) Apply the disinfection procedures.

5. Replacing Damaged Sections of Pipelines

When the damage in a certain section of a water main is extensive, repair may involve cutting off and replacing the damaged section. The procedures for repairs are as follows.

For Galvanized Iron (G.I.) Pipes

a) Isolate the defective section by closing appropriate control valves b) Excavate the water main c) Determine the exact location of the leak d) Cut the defective portion of the water main e) If a nipple of appropriate length is not available, prepare a substitute nipple

using a short pipe of the same kind, diameter and length as the cut off defective pipe

f) Thread the ends of pipe to be joined g) Install G.I. coupling and union parts h) Assemble them i) Open the control valve to allow water to flow into the repaired section j) Observe carefully if the repaired section is not leaking k) If there is no more leak, backfill the excavation and restore the surface to its

former condition l) Disinfect the repaired section.

For Polyvinyl Chloride (PVC) Pipes

a) Isolate the defective section by closing the appropriate control valves b) Excavate the water main c) Pinpoint the leak d) Measure and cut the defective portion of the pipeline. The length of the pipe

cut should have an equivalent commercially available threaded nipple e) Install the PVC socket and adaptor union



f) Join the two cut portions of the water main with the nipple in between

(In case PVC threaded nipple is not available, use the equivalent G.I. threaded nipple)

g) Open the control valve to allow water to flow into the repaired section and observe if it is not leaking

h) If there is no more leak, backfill the excavation and restore the surface to its former condition

i) Disinfect the repaired section.

15.2.8. Valves

Common problems observed in valves and corrective actions for the same are given below:

Table 15-3: General Problems in Valve Maintenance

Sl. No. Problems Problem Causes Remedies 1 Water passing in

closed valve position Valve may not close properly

Open the valve and again close it and check, if persists replace

2 Gland leaking through gland follower

Gland follower bolt must be loose

Tighten the gland follower bolt. Replace the gland packing.

3 Valve is stuck up and not opening and closing

Valve gate must have stuck up. Valve spindle damaged

Remove the valve from the line & check for break down change spindle if broken

4 Valve leaking through bonnet joint

Joint damaged Remove the valve and replace the bonnet joint

5 Valve while opening and closing slip down

Valve set nut or spindle threads are damaged

Remove the valve, check for break down and replace the spare parts


Procedure for Overhauling of the Valve

Disconnect the valve from the line Check for opening and closing Note the operation problem Dismantle the valve Check all the parts After dismantling clean all the parts properly If any part is damage then replace it with new one. After overhauling is complete, assemble the valve properly while doing so apply grease to the moving parts. Put new gasket between valve body and bonnet provide new gland packing. Check the valve opening & closing, take the trial by placing in line.



15.2.9. Meters

Accurate metering is the key to maximize the operational efficiency of water supply systems. It ensures accurate billing, helps identify leaks and provides consumption data which is vital for future planning. Water authorities all over the world are increasingly recognizing the importance of accurate metering for control, management and development of water supply. An effective maintenance of meters plays a vital role in the maintenance of distribution system. Meters indeed deserve a careful attention. These are perhaps the most delicate pieces of equipment and thus are most difficult to maintain. Skilled staff fully conversant with the maintenance of meters and necessary workshop is required to overhaul, repair and test water meter. A wilful damage to water meters is a common phenomenon either due to dishonesty of consumers or due to corrupt practices of meter readers. It is necessary to manage effective maintenance of meters otherwise revenue will suffer very badly. For first five years the maintenance will be done by the supplier/contractor. After that, a maintenance contract may be given.

15.2.10. Reservoir

1. Operation

Water for distribution is pumped from the water source to the system’s water tank or reservoir, from which it is delivered to the consumers through the pipelines. The reservoir is designed, based on the requirements of the system, to distribute the water by gravity or by pumping.

2. Cleaning

The quality of water coming from the reservoir must be maintained within the standards for potable water. To ensure the quality of the water supply, the reservoir must be cleaned and disinfected periodically. Failure to apply this routine will result in the accumulation of solids and proliferation of bacteria in the tank, making the water unsafe for drinking.

Cleaning is usually done once a year, but it always must be done whenever the water in the reservoir contains an appreciable amount of dirt.

3. Important Safety Precautions

When cleaning reservoirs workers must work in pairs – one to go down and the other to keep watch over the one inside the reservoir. Proper ventilation must be ensured at all times during the cleaning or repair operations.

Checking Sediment Levels a) Reduce the water level down to 15-20 cm above the bottom of the tank; b) Stir up the water c) If the bottom appears to be clean and sediments are either minimal or not

present, cleaning is not needed d) When the check confirms that an appreciable amount of sediments has

accumulated in the reservoir, cleaning should proceed



e) Brush the walls, column, ladders, and other parts of the reservoir to remove adhering dirt particles and algae, if any

f) Open the drain valve to drain the remaining water to waste. While draining, agitate the water to keep the dirt particles from settling, and sweep the sediments in the water towards the outlet

g) Disinfect the tank by any of the following methods: Fill the tank with 50-mg/l chlorine solutions and allow the solution to

stand for 24 hours before draining it to waste Alternatively, mix bleaching powder and water in a pail or bucket to form

a thin paste. Using a brush, apply the thin paste forcefully on the interior surfaces of the reservoir. Allow one hour to pass before rinsing the tank with clean water

h) Put the tank back into operation after rinsing it with clean water. 4. General Precautions

a) Storage facilities tend to attract children who like to play around the facilities,

climb the ladders, and play on top of concrete roof, oblivious of the serious hazards involved. All gates, access hatches and manholes of reservoirs should be locked. Never leave a storage facility for even a few minutes without locking all access openings

b) Vandals are known to intentionally damage storage facilities. Utilities should keep watch against vandalism to protect the stored water and the public from health hazards. If a covered storage facility is found to have been forced open, it must be assumed that the water has been contaminated. Therefore the reservoir should be drained to waste and disinfected before being refilled with new water. All fences should be maintained in good condition. Do not allow any materials to be staked out on fences, as these could aid trespassers to climb over

c) Keep reservoir roof ladders and walk ways free of dirt, debris and grease to prevent slipping and contamination

d) Never enter a closed reservoir alone without someone standing by to help if you get in trouble

e) Keep alert for cracks/leaks in the reservoir and repair these at once f) Never store un-chlorinated water in a reservoir for more than 72 hours g) The foundations of concrete reservoirs are subject to differential settlement when

the soil beneath one part of the foundation compresses more than the soil at another part. A differential of only 1- 2 cm can cause large stresses in the reservoir wall or legs. When differential settlement is discovered, corrective measures are urgent. These require the services of a soil engineer.

5. Detecting and Repairing Leaks in Concrete Reservoirs

Leaks in concrete reservoirs can be repaired with cement mortar. Concrete reservoirs may be elevated or installed at ground level. If the concrete reservoir is elevated, leaks can be detected visually. If it is at ground level, leaks can be detected by either of these methods:

Marking the Water Level in the Reservoir – Close the discharge pipe control valve. Fill the tank with water up to a certain level and mark the water level. After one or two days, check the water level. If there is an appreciable decrease in water



level, the tank has leaks. During the entire process, the outlet control valve should be closed

Checking the Discharge in the under drains – If the tank has under drains observe the discharge in them. An appreciable discharge indicates leaks in the tank.

6. Maintenance of Reservoir Appurtenances a) Monthly Maintenance Tasks

1. Lubricate float control pulleys. 2. Inspect float for leaks. 3. Check level indicator for free operation. 4. Sweep roof, catwalks and ladder landings.

b) Manholes Manholes should always be covered and locked to keep out foreign materials.

15.2.11. Machinery and Equipment

A regular schedule of inspection of machinery and equipment their lubrication and servicing program must be prepared and circulated and an effective supervisory control should be exercised. This schedule should follow the manufacturer’s recommendation for operation and maintenance procedure and should be drawn in simple language. Proper maintenance of pumping machinery needs a trained and skilled staff and should be well conversant with the equipment.

The spare parts required for routine maintenance shall be procured well in advance to avoid unnecessary delay in carrying out repairs and to be supported by the services of a nearby good workshop. Beside it the engineer-in-charge of maintenance shall keep readily with him the names and addresses of firms dealing in spare parts and other essential requirements.

The most important machine used in water supply scheme is pumps and motors.

15.2.11.1. Pumps

To keep the record of pumping hours, quality of water pumped and electric consumption are to be kept on format (logbook). The first page of the log book should contain detailed particulars, make and size of various components of the machinery installed along with date of installation with test results. These particulars are to be carried over to the subsequent log books so as to make the information always readily available.



Table 15-4: Daily Log Sheet of Pump


1) General Trouble Shooting, Problem and remedies in operation of pumps; It is given in following table which should be known to maintenance engineer.

Table 15-5: Trouble Shooting, Problem and Remedies in Operation of Pumps

Sl. No. Problem Probable Causes Remedies

1 Pump set does not deliver Water

1. Water Level has fallen below the level of Pump

2.1 Stop the unit until water level rises naturally

2.2 Ensure that the flow is not obstructed

2.3 If possible lower the unit further 2. Wrongly connected non return valve on delivery line

2.1 Check the flow direction arrow on the non-return Valve and connect it properly

3. Motor is not starting 3.1 Check for correctness of incoming power supply 3.2 Check for continuity in cable 3.3 Check for back-up protection

2 Pump set does not deliver sufficient quantity of Water

1 Motor running at lower than rated voltage

1.1 Ensure that the supply voltage is proper 1.2 Ascertain if there is voltage drop in the cable if so replace it with the cable of higher size

2. Strainer /Impeller / Stage Casing may be clogged

2.1 Check the piping joints for leakage 2.2 Clean the strainer and the flow passage of impeller and stage casing. If required replace them.

3. Increase in the internal clearances due to the wearing at impeller eye, periphery / Impeller/ worn out guide vanes

3.1 Replace the worn out component

Electric Consumption RemarksVacuam Delivery Date Wise

Hrs : mt Initial FinalConsumption KWH Kg/sqcm Kg/sqcm

Power shut down hours.Break down & Repairs Fuel ConsumptionAny other

1 2 4 5 6 7 9 10 11

Daily Logsheet of ______________ Pumping Station for the month of ___________

3 8

Quantity of Water Pumped

KLD

Reading of MeterPump

No.

Pumping Time

Guage Reading

Date Start Stop Volts Amp



Sl. No. Problem Probable Causes Remedies

and flow passages

3 Pump set consume excessive power

Motor may be running at a speed higher than the rated or Low voltage across the motor terminus or Pump set run outside the recommended range

• Check the supply voltage & frequency if necessary replace the cable with higher size.

• Ensure that pump set is operating nearer the best efficiency point • Consult the authorized dealer/service centre

4 Excessive Noise and Vibration

Excessive air intrusions in the water pumped.

Lower the unit further in the water Install a suitable NRV to minimize the effect of water hammering in the piping Improper piping system

OR Ensure proper support to piping and bend.

Chances of water hammering in the piping system

Replace the bearing

Improper Piping System Worn out and defective bearing in

motor

5 Motor Burns out

Defective motor protection device • Replace properly

Faulty back-up protection system Refer to pump manufacturer / Supplier Fault back-up protection system

• Refer to pump manufacturer/suppler Motor started without filling the water

Fill the motor with clean and fresh water before start up

Continuous operation of water at low voltage

Voltage in electricity supply to be corrected. Operate pump only , if the electricity supply is proper

Source: APRWSSP-Tech Manual 2)Safety Practices in O&M of Pump

While carrying out inspection/repair on pumps, main electric supply should be switched off and fuse removed. This will prevent unintended/accidental start of pump during inspection

Equipment should be covered with proper shed Ensure that coupling guard is in place before starting the pump Electric motor and cooling fan should also have safety guard All valves, main switch, emergency stop switch should be located at suitable height

to easy and safe access Electric cable should be properly clamped at loose end



Lifting of pump and electric motor should be done by using chain pulley block.

3) Inspection Schedule of the Pump a) Day to Day Checking Schedule

Clean the pump from the outside thoroughly Rotate the Pump & Motor by hand 2-3 turns. it should move freely Check the oil level of the pump bearing housing. (if the pump is oil lubricated) Pump bearing to be greased by turning the grease cup by half turn. Grease cup is

mounted on the pump bearing housing. (For grease lubricated pump).

b) Weekly Schedule

Clean the pump from outside. Check for any leakage Check the foundation bolts, if loose, tighten it Check the coupling pin and bush condition, if damaged replace it Check pump’s suction and delivery line, flanges, nut & bolts, if loose tighten it Check the gland leakages, if leakage is more, tighten the gland follower nut

slightly Check the pump suction delivery valve gland leakage, if it is more, tighten the

gland follower nut Check the value operating condition by opening and closing Lubricate the pump bearings by turning the grease cup 4 times If it is oil lubricated, top-up the oil level

c) Yearly Schedule

Decouple the pump Check the coupling fitment on the pump shaft if loose, try changing keys and grub

bolt still if it is loose replace the coupling halves having correct size bore and key way

Drain the lubricating oil from the bearing housing with fresh oil and fill fresh oil of proper grade as recommended by pump manufacturer ( For oil lubricated pumps)

Remove the bearing covers, clean the bearing grease, apply the fresh grease, fit the cover back (this is applicable in case of grease lubricated pumps).

d) General Checking

Check the pump shaft by hand, by turning, lifting up and down; if there is a play, the pump needs to be overhauled

Check the pump axial play by moving horizontally, if the play is more, pump need to be overhauled

Pump foundation bolts to be checked, if loose, tighten Check the grouting of the frame, if loosened, re grout it with cement concrete Pump Gland Packing to be removed and checked, if it is found damaged, pump

needs to be overhauled Replace joint packing between pump suction & delivery nozzles and lines



Check pump electric load, if it is less or more than specified, pump needs to be overhauled

By turning the pump shaft, bearing condition noise to be checked, if it is abnormal, pump needs overhauling

Check for pump and motor alignment, if it is disturbed, realign it Calibrate pump delivery line pressure gauge Get pump suction valve, delivery valve, NR valve, and foot valve overhauled

&hydraulically tested Provide fresh gland packing to pumps and valves Check line and valves supports. If it is not working overhaul or replace Paint pump, lines, and valves.

15.2.11.2. Maintenance of Electric Motor

There are following factors detrimental to the life of an electric motor:

a) Moisture in Electric Motors

Presence of moisture is not good for motor insulation. Motors should always be located in dry place. For moist locations drop proof, splash proof or totally enclosed motors should be used else the winding will be damaged. When motors are stored in unsuitable conditions where they can absorb moisture, it is essential to dry them thoroughly before commissioning. If the insulation resistance falls 1.0 mega ohm, the motor winding should be dried by any of the methods such as hot air blast, by means of hot stove or oven. Winding temperature should be maintained at about 900C.

b) Low Voltage Supply

Voltage lower than that specified on the name plate of the motor is detrimental to the motor in respect of performance and life expectancy. Low voltage will cause the winding to heat up even at low loads and the current drawn by the motor will be higher.

c) Dust

Dust has been cause for many motor failures. Its action is slow but sure. It is essential that preventive measures are taken to offset the dust accumulation and to blow it out occasionally from winding by a portable electric blower or with such other equipment.

d) Oil

Oil is very harmful to the winding insulation because once the winding is soaked with oil; It is in danger of immediate burn out or breaks down. It is, therefore, essential to ensure that oil doesn’t come in contact with the winding. To remove it, use non-inflammable solvent like carbon tetrachloride, but with caution because the latter has softening effect on the winding insulation.



e) Bearings

Bearings run well if properly lubricated. Insufficient or excessive supply of lubricants should not be resorted to, both being harmful to bearing life. Again correct grade and type of lubricant should be used.

f) Misalignment

Motor damages such as shaft being springing or broken, bearing getting worn-out or over load failure are often caused by misalignment. This defect can be in the motor or in pump and it should be carefully located and removed.

g) Vibrations

Misalignment is one of the important causes of vibrations. In order to locate the source of vibration disconnect the vibrating motor. If the motor operates far more smoothly when disconnected and if its alignment is found to be proper, the pump should be examined for the source of vibrations.

h) Overload To protect the motor from danger due to over load, various devices are incorporated in the starting mechanism of electric motors: (i) Electric motors are required to be protected against the hazards of current

fluctuation and overloading etc. during the operation by the use of certain devices which break the electric circuit when fluctuation is more than the predetermined value. The simplest device is the fuse to prevent excessive current to the motor, but the surges of power are not destroyed by the fuses or sometimes only one fuse blows off

(ii) Relays and circuit Breakers: The relays are used as automatic devices for breaking the circuit under fixed conditions. These devices are widely applicable and accurate. These are reliable in action and can be adjusted with precision to control the time of opening or closing of a switch. The circuit breakers are higher in initial cost but are preferable on circuits subject to frequent over loads. Standard relay can be adjusted for any current range and provides an instantaneous trip. Immediate repeat operation is possible. This works as single phase preventer also. Whenever an overload device operates, it has to be at rest before motor can restart. There setting may be automatic or manual. Whenever an over load device operates, the cause should be taken as warning. It may be due to low voltage, overload, Jammed or hard bearing, Single phasing etc.

15.2.11.3. Burn-out of New Motors

At times, brand new motors fail on the first switching or shortly after commissioning. Main reasons of this failure are:

(i) Occurrence of single phasing in the supply system (ii) Accumulation of water inside the motor.



It has been found in experiences that under certain circumstances, totally enclosed motors are highly susceptible to damage by the atmospheric moisture. Whenever totally enclosed motors have been standing idle for more than two or three weeks in an unheated building it will be a good practice to examine before putting them in operation. If the slightest trace of water is found inside the enclosure or if there be an indication like rust on the steel shaft or iron parts inside the machine, the safest rule would be to presume that the winding has absorbed moisture and to dry them before setting it to works.

Table 15-6: Faults in Motors and Their Diagnosis

Sl. No.

Problems Problem Causes Remedies

1 No Rotation 1. Supply failure (either complete or single phasing or reversed phase)

2. Control gear open circuited

1. Disconnect motor immediately or burn out may occur. Check all connections against diagram.

2. See that there is no break in cables and that terminal is clean and tight. Examine each section of all control gears for bad contact or open circuit

2 Motor starts but will not take load

Wrong setting of overload trips

Set over-load trips to approximately 150% of full load current

3 Sparking of brushes

Brush pressure too light Adjust to correct pressure. Also rub brushes and smooth out slip ring surface roughened by sparking.

4 Steady Electrical Hum

1. Running single phase 2. Excessive load

1. Check that all supply lines are live with balance voltage.

2. Compare line current with that given on the motor rating plate. Reduce load or change with higher rating motor.

5 Mechanical noise

1. Foreign matter in air gap

2. Bearing damaged

1. Check air gap, dismantle rotor and clean rotor and starter

2. Fit new bearing, check coupling gap and re-align

6 Vibration 1. Uneven foundation 2. Foreign matter in air

gap

1. Check level and re-align 2. Uncouple from driven machine,

remove coupling, run motor to determine whether unbalance is in the driven machine, pulley or motor Re-balance.

7 Over-heating of winding

1. Excessive load 2. Foreign matter in air

gap

1. Reduce the load or change to larger motor 2. Check air gap. Clean rotor and starter

8 Over-heating of brushes

1. Too much grease 2. Too little grease 3. Bearing overload Due to

1. Remove surplus grease 2. Wash bearing and replenish with grease.



Sl. No.

Problems Problem Causes Remedies

misalignment 3. Re-align and reduce the load and thrust.

9 Over-heating of bearings

1. Excessive load 2. Incorrect grade of brush 3. Brushes not bedding or

sticking in holders. Light brush pressure, hence sparking.

1. Excessive load Compare line current with that given on the motor rating plate. Reduce load or change to larger motor. 2. Use-correct grade of brush as per manufacturer’s recommendation 3. Carefully re-bed or clean brushes and adjust to correct pressure.

10 High starting current in slip ring motor

Due to interchange of cable leads of different phases in the motor circuit.

Identify cable leads of each phase at: a) Leads through shaft terminating a slip-ring collector b) Brush leads terminating at rotor terminal box. Re-adjust correctly.


15.2.11.4. Schedule

a) Daily Schedule Observe input supply. It should be 440 to 450 voltage. In case it is very

low/very high do not run the motor Check the working of pilot lamp/indicator lamp on switch board Working of ampere meter Check electric motor and fan by turning with hand 2-3 rotations. It should

rotate freely. Fan should also rotate and should not fowl with casing. Check that the coupling guard, motor fan end cover are in place Electric motor foundation bolts to be checked and tightened.

b) Monthly Schedule Decouple the electric motor, run electric motor alone, check no load current, it

should be Within specified limit. If in excess refer the matter to motor supplier Check for bearing running conditions; grease the bearings, if dry Check the electric motor foundation boards and tighten if loose Check coupling pin bush Electric motor terminal box if open to be fitted properly, if missing provide

new. c) Yearly Schedule

Note: This job is to be done only by qualified wireman under the supervision of a licensed supervisor. Check the main switch, pilot lamp, earthing connections, ampere meter and

volt meter conditions. Check the cable supply from main switch to electric motor. Take the over hauling of electric motor Dismantle the electric motor remove the rotor



Check the rotor at both ends and at bearing location Test the rotor winding. If it is damaged, get it repaired. Check rotor for dynamic balance. Check rotor shaft for trueness. Check shaft key way size Get the motor and motor cover painted After all test and repairs assemble the motor with new bearings.

15.2.11.5. Tools required for repair of Pumps and motor

Tools

Box spanner set mm size Box spanner set inches size fix spanner set inches and mm sizes Ring spanner set inches and mm sizes Hammer Allen key set Hack frame with blade Half round flat 12 inch 6 inch smooth and rough file Chisel Screw driver 8 inch 12 inch 18 inch Needle pliers Hand pliers Table vice Screw spanner Pipe range 12 inch, 18 inch Measuring tape 3m Filter gauge Outside and inside caliper Divider Hole punch Test lamp

15.2.11.6. Records

For each piece of equipment and machinery a record register should be maintained in which all records of the equipment such as servicing, lubricating, replacement of parts, operating hours (including cumulative) and other important data is entered.

15.2.12. Measures of Water Quality Control in field

(A) Using Field Water Testing Kit (FTK)

The field water testing kit is a simple device, which can be used for testing some critical water quality parameters in the field as it gives first-hand information on the quality of water. Whenever100% accuracy is needed then laboratory test shall be carried out. This water testing kit can be used for regular Water Quality Monitoring Programs to be conducted at Village level. Panchayat level functionaries, NGOs and students of even 7th and 8th standards can easily do the experiments using this kit. The details of water



sources and the quality of water in many villages can be collected and the data computerized at Panchayat level. The data will be much useful in planning and formulating various water supply schemes and will be useful for proper maintenance of rural water supply schemes. The kits can be used in schools to promote the knowledge on water quality and help to develop a good practice and scientific culture among the students.

(B) Water Testing Methodology

For testing water in the field, the following aspects have to be clearly understood:

Sampling procedures Testing procedures Reporting Procedure ( Refer para 3.9.1 & 3.9.2 of Chapter-3) Before sampling, the container should be flushed adequately For lakes, rivers and dams, the water should be collected near the off take

point The water should be collected after clearing the suspended and floating

matter Water for chemical examination should be collected in a clean white 250

ml capacity leak proof polythene container Before collection of sample the container should be washed, rinsed with

the water to be sampled for at least two to three times The water should be then filled completely in the container without

leaving any air space Place a polythene sheet (10x10cm) over the cap and tie it with a rubber

band or twine thread to avoid any leak Write the field code number (sample ID) on the container. The field code

number and related source details should be separately recorded in a note book

The testing of sample should be completed within 12 hours from the time of collection.

(C) Water Testing Procedure Physical Parameters

Pour 10-20 ml. of water into the 100 ml polypropylene/ titration cup. By observing the water in the cup, record qualitatively the appearance, odour and turbidity. - Appearance: Colourless & clear/ Brownish/ slightly brownish /

Greenish/ slightly greenish/ Blackish/ slightly blackish / slightly whitish / Turbid etc.

- Odour: Record odour as follows: None/ Soil Smell/ Algal Smell/ Objectionable Odour/ Slightly Objectionable Odour/ Rotten Egg Smell

- Turbidity: Record Turbidity as follows: No turbidity/ slightly turbid/Moderately turbid/Highly turbid



Chemical Parameters (i) Using the pH paper, record the pH value also.

- pH booklets have been provided to measure pH value of water. Tear a portion of the PH paper and hold it by your fingers. Using the ink filler add one drop of water sample on the paper. Wait for 10 seconds. The colour change taking place on the wet portion of the pH paper is observed and compared with the pH chart provided in the cover page of pH booklet. Record the pH value

(ii) Alkalinity: Using the measuring cylinder, measure 20 ml of water sample and pour it into the clean titration cup. Add 5 drops of 'A1liquid. The water turns bluish green. Using the '1 mL syringe' provided in the kit, add 'A2' liquid. At the end point, the colour of water changes into yellow or Orange. Record the number of divisions for which the 'A2' liquid has been consumed to reach the end point. Calculation: Alkalinity mg/L = No. of Divisions of 'A2' added x 10

(iii) Hardness: Using the measuring cylinder, measure 20 ml of water sample and pour it into the clean titration cup. Add 5 drops of 'H l' and then 5 drops of 'H2' liquids. The water in the titration cup turns Pink in colour. Using the '1 mL syringe' add 'H3' liquid in drops. At the end point, the colour of water changes into Bluish colour. Record the number of divisions for which 'H3' liquid has been consumed to reach the end point

(iv) Chloride: Using the measuring cylinder, measure 20 ml of water sample and pour it into the clean titration cup. Add 5 drops of 'C1' liquid. The water turns yellow in colour. Using the '1 mL syringe' add 'C2' liquid in drops. At the end point, the colour of water changes to slight reddish in colour. Record the number of divisions for which 'C2' liquid has been consumed to reach the end point. Calculation: Chloride mg/L = No. of Divisions of 'C2' liquid x 10

(v) Total Dissolved Solids (TDS):The approximate value of TDS can be arrived at by the following Calculation: TDS mg/L = (Alkalinity + Hardness + Chloride) x 1.2

(vi) Fluoride: In the 1.5 ml polypropylene tube, add 1.0 mL sample water. Add 5 drops of 'Fl' liquid. Mix. Gently. Compare the colour with "fluoride chart" provided and record the fluoride value

(vii) Ammonia: In the small glass bottle given, take 10 ml of water sample. Add 5 drops of' ammonia' liquid. Gently shake the bottle. If there is no ammonia, the colour will not change. If ammonia is present, the water turns yellow, Compare the ‘’yellow colour developed with the 'ammonia chart' provided and record the ammonia value

(viii) Nitrite: In the small glass bottle given, take 10 ml of water sample. Add 5 drops of 'N02' liquid. Gently shake the bottle. If there is no nitrite, the colour will not change. If nitrite is present, the colour of water will change into pink. Compare the 'pink' colour with the 'Nitrite (NO2) chart' provided and record the nitrite value

(ix) Nitrate: In the 10 mL measuring cylinder, take 1 mL of water sample. Add 9 mL distilled/ bottled/ mineral water and make up to 10 ml. Transfer this to the 10 mL glass bottle. Add 5 drops of 'NI'.



Add a small pinch of 'N2'. Mix. Add 5 drops of 'N3'. Wait for 2 minutes. If there is no nitrate, the colour will not change. If nitrate is present, the colour of water will change into pink. Compare the 'pink' colour with the 'Nitrate chart' provided and record the nitrate value

(x) Iron: In the 10 mL glass bottle, take 10 ml of water sample. Add 5 drops of 'fell' liquid and then 1 drop of 'Fe2' liquid. Mix. Add 5 drops of 'Fe3' liquid. Mix. Wait for 2 minutes. For turbid samples wait for 5-10 minutes till a persistent colour develops. If there is no iron, the colour will not change. If iron is present, the colour of water will change into orange red. Compare the colour with the 'Iron chart' provided and record the value

(xi) Phosphate: In the small glass bottle given, take 10 ml of water sample. Add 5 drops of 'PI' liquid. Gently shake the bottle. Then add 1 drop of 'P2' liquid. Again gently shake. If there is no phosphate, the colour will not change. If phosphate is present, the colour of water will change into blue. Compare the 'blue' colour with the 'Phosphate chart' provided and record the phosphate value

(xii) Residual Chlorine: In the small glass bottle given, take 10 ml of water sample. Add 5 drops of 'RC' liquid. Slightly shake the bottle. If there is no residual chlorine, the colour will not change. If residual chlorine is present, the colour of water will change into yellow. Compare the yellow colour with the 'chlorine chart' provided and record the residual chlorine value.

Bacteriological Parameters - E-Coli/Faecal Coliform: The test is conducted using H2S vials (H2S

vials have to be procured separately from the market). The water should be added up to the mark in the H2S vial. After screwing the cap, keep the vial for 24 hours. After 24 hours observe anyone of the following changes. a) Black colour = High level of contamination b) Turbid &; brownish = Moderate level of contamination c) No change in the honey brown colour = Absence of E.-Coli Faecal

Coliform.

(D) Reporting

The test results should be compiled in the following report form: Test Report: Source Details: Location and address of the source location and address of sampling point Name of village/habitation, Name of panchayat, Name of Block ,Name of District ,Type of source Type of scheme, Open well/ Bore well/ Infiltration well/ Lake/ Dam/ Hand pump/ Power pump Surface, water etc. Collected by (Name, designation & Office) Sample ID

1) Appearance 2) Odour 3) Turbidity 4) Total dissolved solids (maximum)



5) pH 6) Alkalinity as CaCO3, (maximurn) 7) Hardness as CaC03 (maximum) 8) Chloride as Cl (maximum) 9) Fluoride as F (maximum) 10) Ammonia as NH3 11) Nitrite as NO2 12) Nitrate as NO3, (maximum) 13) Iron as Fe (maximum) 14) Phosphate as PO4 15) Residual chlorine (minimum) as Cl2 - 0.2 mg/ L

No guideline value prescribed; however an ammonia level of greater than 1.0 mg/L indicates pollution taking place to the source

No guideline value prescribed; traces of nitrite and phosphate indicate pollution

To ensure effective disinfection, minimum residual chlorine of 0.2 mg/L should be present.

Report: The water shall be indicated as potable/non potable.

(E) Records of Quality of Water

Complete records of bacteriological and chemical analysis of water from source to the consumers tap point should be maintained and reviewed. Charts could also be prepared for the important characteristics of the water and any changes in these characteristics as compared to the standards must be taken note of.

15.2.13. Safety & Precautionary Aspects

(1) First Aid Boxes: These are simple boxes for use by the staff in case of an emergency. This contains wound and burn dressing. Disinfectants like iodine is provide for small cuts with cotton for application of disinfectant. It is useful to have two scissors available in the first aid box for getting out splinters. In case of a wound, it should be thoroughly washed under clean running tap water and after that the disinfectant should be applied. In case of all major injuries and something affecting the eye, immediate medical help should be obtained. The patient should be immediately taken to hospital in case of fracture of bones and unconsciousness etc

(2) Miscellaneous Items: Certain miscellaneous items like lamps with a stock of kerosene oil, cleaning rags, brooms, soap, detergent powder, three cell torch, emergency light, paint, paint-brushes, gardening tools and grass cutters are also required for carrying out maintenance job properly and effectively. Where bulk meters are used, daily and weekly charts and ink should be kept in stock for ready replacement. Other items usually required are red hurricane lamps for warning traffic of an open trench, torches, valve keys, portable stand pipe and a lockable hand cart for carrying these articles from one site to another

(3) General Cleanliness: Above all general cleanliness of plant is of vital importance. The equipment and the buildings where equipment is installed should be kept in neat and tidy conditions. This indeed speaks of the



responsibility and the interest of maintenance personnel in the discharge of their duties. It can be safely said that if external cleanliness is neglected the internal maintenance and up-keep of the equipment which is not seen is neglected still more

(4) Health and welfare of water works maintenance personnel: It is very necessary that the persons engaged in the operation and maintenance of water works, who come into contact with water supply works, who perfectly free from communicable diseases. Most of maintenance personnel come in direct contact with water such as labourer cleaning the filter boxes, cleaning tanks and wells, pipe fitters making repairs to the pipe line. So no labourer suffering from any disease should ever be employed on such maintenance jobs. It is important to get the water works maintenance personnel medically examined periodically

(5) The water works area should be properly fenced and entry should be restricted. Water works site should not be allowed to be a thoroughfare otherwise people will use tanks for bathing, washing of clothes etc. and start dumping refuse in the water works area.

Nearby the pump house facility of water tap and water closet should also be made available; otherwise the operating staff will get water for drinking and cleaning food containers by dipping their utensils in the water tank itself. In the absence of water closet, the staff will spoil the surroundings by indiscriminate urination. All these things take place if proper attention is not paid to provide necessary facilities to the operating staff.

15.2.14. Chlorine Safety

As generally chlorine is used for disinfection of water, health hazard may occur by careless handling.

15.2.14.1. Hazard of Chlorine

In both its liquid and gaseous form, chlorine is classified as a poisonous or toxic substance. When it gets into contact with moist body surfaces such as the eyes, nose, throat, lungs, and wet skin it reacts with the moisture, forming harmful acids that can cause severe damage to these organs and even be fatal.

1. Human Health; Repeated exposure to chlorine does not produce an immunity or tolerance. Long-term exposure even to low concentrations of chlorine may cause a gradual decrease in lung efficiency. A single exposure to a high concentration can cause permanent lung damage.

Following Table 15.716 presents the Toxic effects of the chlorine at different levels of concentration

16 Adapted from “Chlorine safe work practices, 2006” published by workers compensation board of British Columbia (Canada)



Table 15-7: Toxic Effect of Chlorine

Concentration Effects 1-3 mg/l May cause mild irrigation of the eye, nose and throat 3-5 mg/l Burning in eyes, nose and throat; may cause headache, watering eyes,

sneezing, coughing, breathing difficulty, bloody nose and blood-tinged sputum

5-15 mg/l Severe irritation of the eyes, nose and respiratory tract 30-60 mg/l Immediate breathing difficulty resulting in pulmonary oedema (fluid build-up

in lungs), possibly causing suffocation and death 430 mg/l Lethal after 30 minutes

Following Table 15-817 presents the human exposure limits to Chlorine.

Table 15-8: Chlorine Exposure Limits

Exposure Level Exposure Limit 0.5 mg/l Maximum allowable concentration averaged over an Eight-hour period 1.0 mg/l Maximum allowable short-term exposure (15 minutes) 10 mg/l IDLH “Immediately dangerous to Life and Health” (as published by the

United State National Institute for Occupational Safety and Health)

2. Fire and Chemical Reactions: Chlorine will not burn by itself, but will support combustion when it comes

into contact with many combustible materials, including acetylene, kerosene, most hydrocarbons like solvents, greases and oils, finely divided metals and organic matter, and materials containing potassium and phosphorous. It can explode when it reacts with high concentrations of ammonia or hydrogen peroxide Never store acetylene, solvents, and the other materials enumerated above in the same building or area as chlorine.

In both gas and liquid forms, chlorine reacts with almost all chemicals, usually releasing heat. At high temperatures, chlorine reacts vigorously with most metals. For instance, a chlorine reaction can cause stainless steel to catch fire or melt

Reaction to Water Chlorine reacts with water or moisture in the air to form highly corrosive acids. Every precaution must be taken to keep chlorine and chlorine equipment moisture-free.

Never use water on a chlorine leak. Most chlorine is more corrosive than dry chlorine and leak will worsen rapidly if water is applied to it.

15.2.14.2. Working Safety around chlorine gas

17 Adapted from “Chlorine safe work practices, 2006” published by workers compensation board of British Columbia (Canada)



1. General

Any water utility that uses chlorine should have written procedures for its chlorine system operation. Even the use of powdered chlorine should have written procedures. Before starting any chlorination process, take the following precautions:

(i) If a faucet with good flowing water is not available close by, make ready a 20 lit container of fresh water, but make sure it is away from the chlorine cylinder or storage area. This is to ensure that if the chlorine accidentally comes in contact with your eyes or skin, you can flush the affected areas with copious amounts of fresh water for at least 10-15 minutes

(ii) Flush the chlorine out. Do not just soak the affected surface. If you get some of the chlorine solution in your eyes, flush it out and immediately see your doctor

(iii)Wear the prescribed safety clothing and equipment, specifically: - Goggles to protect your eyes from contact with the chlorine in any form. - Rubber gloves and rubber boots certified for use around the chemical to

protect your hands and feet. - Waterproof suit, coveralls or a full-length apron.

2. Housekeeping/Chlorine Storage

a) Use signs to clearly identify all areas where chlorine is used or stored. Only qualified personnel should be permitted to enter these areas.

b) Do not store materials that may react violently with chlorine in the same room as chlorine. Put up visible warning signs prohibiting persons from taking these materials where the chlorine is stored.

c) Do not store chlorine near busy roadways or where vehicles operate. Chlorine reacts with carbon monoxide to produce phosgene, an extremely poisonous gas.

d) Store chlorine cylinders and containers in a cool, dry, and relatively isolated area, protected from weather and extreme temperatures.

• When storing cylinders and containers outside, shield them from direct sunlight.

• When storing chlorine containers inside, store the containers in a well-ventilated building, away from any heat sources.

e) Use cylinders and containers on a “FIRST-IN, FIRST-OUT” basis.

f) Clearly tag or mark empty cylinders and separate them from full cylinders.

g) Determine the most appropriate location for emergency equipment. Emergency equipment and a faucet should be available in a readily accessible location, but not inside the chlorine room because a worker (and emergency



response staff) trying to use the emergency equipment or faucet during a chlorine leak risks further exposure.

h) Store cylinders upright and secure them against tipping over and rough handling. Cylinders will discharge vapor when upright and discharge liquid when upside-down. Since chlorine gas tends to sink, provision should be made for low-placed ventilation near the floor that allows it to dissipate outward, as well as high-placed ventilation that allows the chlorine mist (the gas mixed with air) which tends to go upward, also to dissipate.

3. Handling Chlorine Cylinders

a) Handle containers with care while moving or storing them. Do not drop or allow containers to strike objects

b) Use new gaskets as recommended by the chlorine supplier each time a cylinder or container is connected

c) Follow the chlorine supplier’s recommended disposal procedures for leaking containers. Do not modify, alter, or repair containers and valves. Only the supplier should carry out these tasks

d) Ensure that cylinders have valve protection hoods in place when not connected to a system

e) Do not lift a cylinder by its valve protection hood. The hood is not designed to carry the weight of a cylinder

f) If possible, open valves by applying a steady force to a 200 mm (8 inches) wrench, without applying an impact force and without using an extension on the wrench. If this does not work, apply a light impact force by smacking the wrench with the heel of your hand

g) Do not use a wrench longer than 200 mm (8 inches) to open or close valves. To prevent valve damage that could cause leaks do not use tools such as pipe wrenches or hammers. Valves on cylinders are designed to deliver full volume after one complete counter clockwise turn. Valves may be damaged if turned beyond this point. Immediately return containers with damaged or inoperable (but not leaking) valves to the supplier

h) If the valve is very difficult to open, loosen the packing nut slightly. Tighten the packing nut after the valve is opened or closed.

15.2.14.3. Leak Detection (Chlorine) and Control

It is important to follow the right procedures in replacing an empty cylinder with a new one. Nonetheless, after the new cylinder has been installed, it is essential to ensure that there is no leak in the new hook up.



1. Detecting Leaks

Chlorine leaks can be determined by soaking a rag on the end of a stick in aqua ammonia (ammonium hydroxide, not pure ammonia) and holding it next to the pipes, cylinder or dosing equipment. (A plastic squeeze bottle containing the aqua ammonia can also be used.) A white cloud will show the location of the leak. This test is safe because ammonium hydroxide (ammonia dissolved in water or moist air) is used rather than pure ammonia. Chlorine reacts readily with ammonium hydroxide to form ammonium chloride, a relatively harmless compound. This reaction forms a visible white cloud, indicating a chlorine leak. The ammonia test is useful for pinpointing the exact location of a leak.

2. What to Do If a Leak Is Indicated After Installing a New Cylinder

a) Wear a respirator and immediately close the main cylinder valve

b) As long as the monitor reads less than 10 mg/l, the cylinder hook-up procedure may be repeated

c) Open (and close) the main cylinder valve and repeat the ammonia test

d) If a leak is still indicated, make a third and final attempt to get a good seal using a new lead washer

e) If the leak cannot be corrected after three attempts, remove the cylinder from service and contact the supplier. Ensure that there is no leak from this cylinder with the main valve closed. A different cylinder must be connected to the chlorination system

f) Leave the chlorine room and remain nearby to restrict access to the room or provide other assistance, as directed.

15.2.14.4. Repair and Maintenance of Chlorine System

Employers, in this case the water utility, are responsible for training and providing written operational, preventive maintenance and emergency procedures to any person who works on a chlorine system. Employers, in consultation with equipment manufacturers or suppliers, must ensure that all equipment are inspected regularly and replaced when necessary.

The utility’s management must make these written procedures readily available to all workers required to work on the chlorine system. Workers should not only understand but be thoroughly familiar with these procedures before carrying out repairs or maintenance on the chlorine system.

Only qualified workers must supervise the cleaning and repair of chlorine systems. All assigned workers must be familiar with all the hazards and adhere to the safeguards necessary to perform the work safely. Ideally, a chlorine container repair kit should be available on-site. If a container repair kits not available, the utility’s response team must be aware of the nearest readily available kit. There are three types



of repair kits (A, B, and C), each with materials specific to the type and size of the chlorine container.

15.2.14.5. Hazard Recognition

Written procedures for the repair or maintenance of chlorine systems must consider the following hazards and include procedures that will help workers avoid these hazards:

1. Moisture – Chlorine reacts with moisture to form corrosive acids. Every precaution must be taken to keep chlorine and chlorine equipment free of moisture, including the following steps:

• Close pipes, lines, valves, and containers tightly when not in use to keep moisture out of the system;

• Before starting repair, take the measures needed to prevent chlorine coming into contact with any residual material that may drip from the equipment when pipes or lines are being dismantled.

2. Foreign Material – Pipes, lines, and fittings must have all cutting oils, grease, and other foreign material removed from them before use. Trichloroethylene or other recommended chlorinated solvents may be used; however take special precautions because these solvents can produce serious health effects. Never use hydrocarbon or alcohol solvents for cleaning because they can react violently with chlorine

3. Heat – Because iron and steel will ignite in chlorine at about 230°C (450–500°F), all welding or burning must only be done after the chlorine equipment are completely emptied and purged with dry air.

15.2.14.6. Personnel Protective Equipment

Controlling exposure requires strict attention to the chlorine exposure effects (see Table 15-8). Appropriate eye, skin, and respiratory protection are essential. Workers must be familiar with their use and understand the equipment limitations or capacities.

a. Basic Protection

When chlorine gas is in the air, safety glasses and face shields will not protect the eyes and respiratory passages. Workers in an area where the concentration of chlorine may cause mild to moderate irritation must wear eye protection with a tight seal around the eyes as well as a respirator that prevents inhaling the gas. If a full face respirator is not available, a half-face respirator and vapour-tight chemical goggles should be worn.

b. Skin Protection

Emergency response workers who are engaged in controlling serious chlorine leak must have access to full-body protective suits.



c. Full-face Respirators

Full-face respirators, either with cartridges or canisters, may be used only if the chlorine concentration is determined to be below 10mg/l.

• With Cartridges – A worker must wear a full-face respirator fitted with acid gas cartridges during any hazardous work where there is a chance of a chlorine leak. Full-face respirators are also appropriate for leak control where tests show the chlorine concentration to be less than 10 mg/l. Workers required to use a respirator must be clean-shaven where the respirator seals with the face to ensure a proper fit.

• With Canisters – Although cartridges are preferable, a worker may use a full-face respirator fitted with an air-purifying canister for leak control and repair or maintenance procedures in chlorine concentrations less than 10 mg/l. Canisters with an indicator window must be replaced when the material in the window has changed colour. Canisters without an indicator window must be replaced after each use. In either case, canisters must never be used beyond the expiration date stamped on the label.

d. Self-contained Breathing Apparatus (SCBA)

A worker must use an SCBA when a chlorine leak is suspected and the airborne chlorine concentration is unknown or is measured at more than 10 mg/l. This means that an IDLH situation prevails in the area. A worker wearing an SCBA must not enter a contaminated atmosphere until a second, qualified person is present, also equipped with an SCBA, and ready to perform a rescue.

SCBA air cylinders should be refilled every six months or after each use, whichever comes first. Cylinders must have a hydrostatic test at least every five years. Since workers rely on this equipment in IDLH conditions, it is essential that maintenance and inspections be carried out according to the manufacturer’s instructions.

e. Person-check Radio or Telephone

Employers must establish a check system to ensure the continued well-being of workers who are working alone or at an isolated worksite. Where visual checks are not possible, the check system may require a radio or telephone. Workers who will need to use such a system must be trained in emergency procedures.

Figure 15-1: Self-Contained Breathing Apparatus (SCABA)



f. Emergency equipment

Emergency equipment includes eyewash and shower facilities, first aid kits, and container repair kits.

Workers must have immediate access to each of these items and must know how to use them in case of emergency.

15.2.14.7. Safe Work Practice

(A) First Aid

When someone is injured in a chlorine-related incident, first aid can help reduce the impact of their injuries and prevent further injuries from occurring. The following steps apply to any situation in which someone is injured:

1. Do not panic. 2. Ensure that there is no more danger to yourself or the victim. 3. Using appropriate safety gear, remove the victim from the contaminated

area. 4. Send for medical help.

(B) Chlorine Inhalation

A person who has inhaled chlorine may be unconscious, and may have difficulty in breathing or may have stopped breathing completely. Follow these steps when treating a victim of chlorine inhalation:

1. Assess the victim’s breathing. If breathing has stopped, begin artificial respiration and continue until the victim resumes breathing. Pocket masks are recommended for artificial respiration, although the mouth-to-mouth method may also be used

2. If the victim is having difficulty breathing (for example, gasping or coughing), place the victim in the most comfortable position, usually semi-sitting

3. If an oxygen therapy unit and trained personnel are available, administer oxygen at a 10-litre flow

4. Ensure that the victim is transported to hospital in case the victim suffers a delayed reaction in the form of pulmonary oedema. Any physical exertion, excitement, or apprehension increases the chance and severity of a delayed reaction. Keep the victim warm and completely at rest. Reassure the victim while waiting for assistance and transportation to hospital.

(C) Skin Contact Skin contact with chlorine can result in severe burns. Before attempting to flush a victim’s contaminated skin, make sure the victim is breathing properly. Follow these steps:



1. Assess the victim’s breathing. If breathing has stopped, begin artificial respiration and continue until the victim resumes breathing. Pocket mask is recommended for artificial respiration, although the mouth-to-mouth method may also be used. If the victim is having difficulty breathing (for example, gasping or coughing), place the victim in the most comfortable position, usually semi-sitting

2. As soon as the victim resumes breathing, flush the victim’s contaminated skin and clothing with large amounts of water for 30 minutes. Remove all contaminated clothing while flushing. Continue flushing until all traces of chlorine have been removed

3. Dress obvious burns with sterile gauze and bandage them loosely. Apply insulated cold packs to help reduce pain

4. Get the victim to hospital.

Take Note:

1. Do not attempt to neutralize the chlorine with other chemicals 2. Do not apply salves, ointments, or medications unless prescribed by a

doctor 3. Skin contact with liquid chlorine coming straight out of a cylinder can

result in frostbite.

(D) Eye Contact

Eye contact with chlorine (liquid or gas) for even a short period can cause permanent disability. Flushing must begin within 10 seconds. Follow these steps:

1. Flush the eyes immediately with large amounts of running water (preferably lukewarm) for 30 minutes. Hold the eyelids forcibly apart to ensure full flushing of the chlorine from the eyes and eyelids

2. After flushing has removed all traces of chlorine, cover both eyes with moistened sterile gauze pads and bandage, enough to keep light out

3. Apply insulated cold packs to help reduce pain 4. Get the victim to hospital.

(E) Unconscious Patients

1. As soon as an unconscious victim of chlorine inhalation resumes breathing, place the person in the drainage position (lying on one side, so fluids can drain from the mouth and airways). Never give an unconscious patient anything by mouth

2. Keeping the victim in the same position, flush the victim’s contaminated skin and clothing with large amounts of water for 30 minutes

3. Remove all contaminated clothing while flushing. Continue flushing until all traces of chlorine have been removed



4. Dress obvious burns with sterile gauze and bandage them loosely. Apply insulated cold packs to help reduce pain

5. Get the victim to hospital.

15.2.15. Records of key activities of O&M

For planning future augmentations and improvements of a water works in operations, it is advisable to maintain certain key records such as daily and cumulative supply over the years, number of connections of various sizes given and cumulative number of connections each month, water treated and the supply billed.

15.2.16. Staff Position

Appropriate charts indicating the standard staff for each of the unit of operations and maintenance and the staff actually in position (by names if possible) shall be maintained at each office for review. Table 15-9 below presents the skill requirements of personal for O&M Water Supply Scheme:

Table 15-9: Skill requirement for O&M of Water Supply Scheme

Applicability Scheme Component Skill Requirement For Operation and Maintenance

Remarks

Option 1 Tube well with Submersible / Centrifugal Pump

Person trained from ITI / Village Person trained by the Construction agency at the time of execution and maintenance

The person will be able to do day to day O & M however for repairs pumps and motors will be required to be sent to workshop.

Option 2 Service reservoir Elevated reservoir Distribution System

Qualified Plumber / Pipe Line Mistri / Village Person trained by the Construction agency at the time of execution and maintenance

For major Break down external help is required

Option 3 Intake / Jack well Infiltration Well Slow Sand Filter Rapid Sand filter

Trained person from ITI with experience

For major repairs external help will be required


15.2.17. Inventory of Stores

A reasonable assessment of the stores and spare parts of machinery required over a period of time say, for half a year one year or can be made and an inventory of the



same prepared. Issues and replacement of store articles could be watched and procurement procedures laid down and supervise. The aim should be that any material required for replacement is available at any time for the maintenance.

15.2.18. Guidelines to be Followed by the Village Panchayat/ GPWSC for Operation and Maintenance

Bylaws should be prepared for maintenance and got approved by the Gram Sabha Monitor the adherence to the water supply bylaws To fix water tariff for House Service Connections Open a separate bank account for O&M Prepare Annual Plan for the O&M Prepare Long Term Plan for future expansions Establish and maintain proper transparent revenue, collecting systems Maintenance of scheme in efficient and smooth manner To keep adequate spare parts in stock To monitor the functioning and status of water supply To check regularly that all water supply installations are functioning well To respond and take immediate action on the consumer's complaints To maintain cleanliness around water sources, pump room and OHSR locations to

avoid contamination To create awareness among beneficiaries about the benefit of the system and the

need for proper maintenance of it To maintain good public relations and rendering satisfactory service to the

consumers To maintain quality of water to desired standards To collect revenue for sale of water to private persons for functions etc. To maintain efficient administration and communication system To conduct monthly GPWSC meeting To check that the staff is performing the following duties The pump operator should check all the components periodically for better

maintenance of scheme Checking of quality and quantity of water supplied to all consumers (especially

tail end taps) Keep the pump room inside, outside and OHSR premises neat and clean Clean the panel board and the check the oil level in oil starter if provided

periodically Maintain a log book showing the hours of pumping, energy meter reading, voltage

meter and ammeter reading, Power Supply interruption, water meter reading and repair details clearly

Maintain a register of works/repairs carried out Operate the pump set regularly Replacement of gland rope and applying grease periodically Checking of gate valves, pressure gauge and reflux valves fixed at pumping

station and gate valves at OHSR Attend leaks in pumping main, distribution main valve pits and taps regularly Clean the OHSR periodically and chlorinate the OHSR water before distribution



Assist the GPWSC in protecting the water sources and carrying out water quality tests

Adhere to the instructions from the Village Panchayat/GPWSC Informing the problems then and there to the GPWSC Participate in the GPWSC meeting regularly for expressing the water supply

position and problems being faced.

To provide the License to ITI trained personnel for following functions: To effect house service connections as directed by the GPWSC for the consumer Should have proper tools Should not give connection from the existing stand post or on the pumping main Should not resort to undue favour in giving house service connections Should provide hole on top of distribution pipe to fix the saddle piece and should

not entertain to provide connection from bottom of pipe To refill the trench after finishing repair or installation works To attend the leaks and bursts occurred in pipe lines, valve pits etc. then and there

to avoid wastage of water and to refill the trench after finishing repair works To eliminate pit taps and to initiate action against the people who draw water

from public fountains without taps To check the water meter fixed to the house service connections To scour the pipe lines of both pumping main and distribution main periodically To check the valves and unauthorised house service connections regularly To obey the instructions of GPWSC.

15.2.19. Suggestions for GPWSC

1. Verify the certification of daily water supply and residual head by the ward member / sarpanch.

2. The persons identified by GPWSC, for running and maintenance of pumps / OHSR / Distribution Mains / Transmission Mains should be engaged on works with the executing agency at the time of construction for training purpose, so that later on they can take over the maintenance works without any difficulty.

3. For MVS schemes of surface water source, the maintenance of source, intake works and Pumps, Transmission lines, Raw Water Storage, Treatment Plant, CWR and upto OHSR should be maintaned by Concerning State Department, and from there the water should be supplied to intra villages through a bulk water meter. From onwards to this point the maintenance of distribution system, house water supply meters etc should be maintained by GPWSC and revenue should be collected by them. The agreed supplied water charges should be given to the department by GPWSC on monthly basis. This arrangement should be made under an agreement so that In the case of default in payment by GPWSC the amount could be recovered out of grants given to GP by the Government.

4. Based on income and expenditure statement as prepared in DPR, the GPWSC should fix the tariff for domestic and non domestic consumption so that proper maintainance can be performed. It is recommended that in addition to the annual O&M cost a provision to the extent of atleast 5% of the annual maintainance cost be provided while working out the tariff charges to meet out the major repairs.



15.2.20. Water Revenue (Billing & Collection)

Revenue management system is an important aspect of any Water supply System as it governs the financial sustainability to it. Besides fixing a tariff structure, billing and collection of revenue play an important part.

1. Tariff Fixation

The water charges to be fixed by the GPWSC with the assistance of concerned state department taking into account the ability of the system to meet the expenditure on the following heads: • O&M Cost (Recurring and non- recurring)/ Establishment Cost • Depreciation • Asset replacement fund.

Tariff structure should be revised annually.

2. Categories of Consumers

Among the different categories, the domestic consumers are the privileged class of people in terms of supply of water and collection of taxes mainly because they use water for their healthy existence. The other categories viz. commercial complexes, hotel/restaurant/ industries/ bulk consumers/ offices/ institutions etc. are usually charged with a higher tariff. Therefore, the distribution of cost incurred on the maintenance of such system to each class of consumers including un-privileged people should be logically and appropriately determined with reference to the level of service rendered.

3. Methods of Water Charges

The methods of levying water charges can be any one or more of the following: a) Metered consumption of water b) Non-Metered System

• Fixed charge per house per month (depending upon the size of the house) or per connection per month or fixed charge per family per month or per tap per month/per house or

• Percentage of rateable value of the property.

Note: Charges for APL and BPL family may be determined separately by GP/ GPWSC

4. Distribution of Bills to Consumer

In the case of the Multi Village Water Supply Scheme, the water agency / MVWSC / out sourced agency charged for O&M will raise the bill every month to each of the panchayat based on the GP bulk water meter reading. The panchayat will pay the water charges to the agency / GPWSC and in turn will collect the water charges from the consumers. In the case of Single Village water supply scheme, the panchayat / GPWSC will collect water charges from the consumers and utilized the revenue generated for the maintenance of the scheme.



The distribution of bills in rural area can be done by operators specially authorized for this purpose or meter readers and bills can be distributed at the time of meter reading along with the receipt for previous payment if collected in cash by him for the next round.

(This option saves effort/manpower but there is delay in one complete cycle in reading and distribution of bills).

5. Payment of Bills by Consumer

The payments can be accepted at any one or more ways of the following: • Counters at GPs. / VWSC office • At bank / banks authorized for accepting payments • Door to door/on the spot recovery by authorized person • By cheque through drop boxes.

6. Related Accounting

The billing section also carries out the accounting related to these receipts such as posting of receipts, generation of demand registers or ledgers on periodic basis. The complete accounting related to the billing may also be more efficiently carried out by the computerized system.

7. Delayed Payments

Since water is being treated as a commodity consumed the advance billing is generally not carried out. It is therefore ‘a must’ to levy penalty/interest on the delayed payments of the bills. To avoid delays in payments some discount/ incentive may be thought for the consumers who pay within the stipulated time.

15.3. Operation and Maintenance of Solid Liquid Waste Management

15.3.1. Operation and Maintenance of Sanitary Landfill

Refer Chapter 13 para 13.3.2.21 & 22 and for further details, refer CPHEEO Manual on Solid Waste Management.

15.3.2. Operation and Maintenance of Twin Pit Pour Flush Latrine

Generally the Twin Pit pour Flush Latrines are to be constructed in rural area, thus its main points for maintenance are given below: Diversion of flow from one pit to another is necessary as only one of the two pits is to be used at a time. It is very important to completely seal the entry to the pit that is not in use. This is done by blocking one of the openings in the junction chamber. When water does not flow out of the pan either there is blockage (chocked) or the pit in use is full. If by roding of the connecting pipe, the flow is not restored, it indicates that the pit in use is full and the flow needs to be diverted to the second pit. For this the opening of the second pit, which so far is not in use be opened and that of the pit which is filled up be blocked.



Keep cover on the drain from the junction chamber to the pit (in case of open drain connection) as well as on the junction chamber properly, so that foul smell is not emitted.

When the filled pit is allowed to rest for a minimum period of a one and a half year the pit contents are completely digested and are free of foul smell. The pit can then be safely emptied manually without being hazardous to health; by the householder himself or through the local authority or a private agency. However in cases of combined pits and pits located in water logged, high sub soil water areas desludging of pits should be done carefully; because the sludge might not be completely safe and dry to handle due to travel of pathogens from the pit in use to the pit to be desludged. After the pit is emptied the cover should be placed in position and the joint be made air tight. The sludge humus collected has rich manure value and is a good soil conditioner. The manure from dry pits can be used directly either in the kitchen garden or in the fields but from wet pits it can be used only after sun drying.

Do’s and Don’ts

For continuous sustainable uses of Twin Pit Pour Flush Latrines by all the members of the households certain actions for convenience of users as well as for long term use, following measures needs to be taken. Do’s

Keep a bucket full of the water outside the latrine Keep a 2.0 litre can in the latrine with water for pouring Before use, pour a little quantity of water to wet the pan so that excreta slid

smoothly into the pit Flush the excreta after the use Pour a little quantity of water say ½ a litre in the squatting pan after urination The squatting pan should be kept clean Use minimum quantity of water in washing the pan and latrine floor Wash hand using soap or ash after defecation at the assigned place If any construction defect is observed during the guarantee period, report the

matter to the local authority or the construction agency When the pit is in use is full, divert the flow to second pit If the trap gets choked, roding should be done from the pan side as well as from

the rear side by means of a split bamboo stick after removing the cover of the drain or junction chamber

Care should be taken when desludging the pit located in water logged or high sub soil water areas and in case of combined pits, as the humus may not be safe for handling

Don’ts Do not use both the pits at the same time Do not use more than 2.0 litre of water for each flushing (if the waste is not flush

with 2.0 litre pour more water at the specific spot for flushing waste) Do not use caustic soda or acid for cleaning the pan Do not throw sweepings, vegetable or fruit peelings, rugs, cotton waste and

cleaning material like corn cobs, mud balls, stone pieces, leaves etc. in the pan or the pits



Do not allow rain water, kitchen or bath waste to enter the leach pits Do not provide water tap in the latrine Do not throw lighted cigarette butts in the pan Do not desludge the pits before one and a half years of it being out of use.

15.3.3. Septic Tanks

(i) Withdrawal of septage from the tank should normally be done every year or in any case when it gets filled with sludge to one third of it’s depth. In case it is not done the effluent from the tank will carry lot of undigested organic matter having high BOD

(ii) Septage collection from the tank be carried out carefully with due consideration of the safety of workers and of the area environment

(iii) It is necessary that the water level in the tank is first lowered well below the tank outlet level and the scum is punctured for putting the suction of the pump

(iv) A layer of digested sludge of thickness around five to ten centimetres all through the bottom of tank be left over so that in subsequent loading of the tank with waste the process of sludge formation and waste digestion starts immediately.

15.3.4. Small Bore Sewers

(i) Small bore sewers require very little maintenance. The only routine maintenance which must be performed is the removal of sludge from each of the interceptor tanks. Routine flushing of the sewer mains has not been necessary in any of the systems currently in use. However, periodic flushing is recommended to insure against blockages.

(ii) Small bore sewer systems should be operated and maintained by the local agency (e.g., municipality, local water and Sewerage Company) responsible for waterborne sanitation. Its responsibilities should include all sewer appurtenances located on private property as well as those in the public right-of-way. Easements to any appurtenances should be obtained from each property owner to allow free access.

(iii) Interceptor tanks. Scheduled maintenance for the tanks is generally limited to yearly inspection and solids removal when necessary. If the sludge layer is within 300 mm of the bottom of either the inlet or outlet baffles, or if the bottom of the scum layer is within 75 mm of the bottom of the outlet baffle, the tank should be desludged. The sludge layer can be determined by wrapping a cloth (preferably toweling) on a stick long enough to reach the bottom of the tank. The stick is pushed to the bottom of the tank, twirled between the hands and held in the tank for about a minute. When the stick is withdrawn, a distinct black mark is left on the cloth recording the sludge depth. The scum layer can be checked by nailing a 75 mm square piece of wood on the bottom of the stick. This is pushed through the scum layer and slowly moved up and down to locate the bottom of the scum by feeling the change in resistance. The stick is marked using a convenient point for reference. With the same stick, the bottom of the outlet baffle is located and the stick marked again. The distance between the two marks is the distance between the bottom of the scum layer and outlet baffle.

(iv) Interceptor tanks are cleaned by pumping the contents to a truck-mounted tank for hauling to a suitable disposal site. All solids should be removed, although a small quantity may be left in the tank to act as a seed for the new sludge. At no



time should the tank be entered because of the danger of toxic gases. Land spreading or discharge to a treatment plant is the most common methods for sludge disposal.

(v) Sewer mains. Occasional hydraulic flushing of the sewer mains is required. This is usually sufficient to remove most solids accumulations. Flushing should begin at the upstream terminal ends of the sewers, and each section between cleanouts or manholes should be flushed successively downstream. Each cleanout or manhole is flooded with water from a tank truck to a depth sufficient to create a flow velocity of at least 0.5 m/s in the section. During flushing care must be taken not to surcharge the system excessively, so creating sewage backups at individual connections. The connections with the lowest elevation in each station should be noted to determine whether the flushing will create backup. Flushing rates and volumes should be adjusted accordingly.

(vi) If blockages occur, the connection at the lowest elevation upstream of the blockage should be located, the interceptor tank opened and a pump truck stationed there to remove all incoming sewage. The blockage can then be removed using hydraulic cutting tools snaked down the main through the cleanouts or by breaking into the pipe. If the pipe is broken into, a cleanout should be installed at that point for future emergencies

(vii) Flow monitoring at the wastewater treatment plant headworks is recommended to identify problems with inflow or infiltration. Both are detrimental to the system because of the grit which usually enters with the flow. If flows increase substantially during the wet season, the building sewers, interceptor tanks, sewer mains and appurtenances should be inspected for leaks.

15.3.5. Horizontal Flow Gravel Filter of DEWATS

(i) For proper growth of plants it is necessary to load the filter with fresh water only so that the seedlings planted attains rapid growth .The filter bed should thereafter be loaded gradually with waste water by increasing the contents of waste water till full load of waste water is attained and the plants attains full growth .Thereafter the waste water alone could be loaded on it

(ii) It is necessary that the inlet provides uniform distribution of waste water all through the cross section of the filter bed and the outlet also ensures equitable collection of the waste water all through from the cross section of bed. This is ensured by providing entry and outlet through the gravel mass at both ends of adequate porosity. It is necessary to ensure that at the two ends the gravel mass is not disturbed and if so it should be restored to as initially

(iii) The gravel sizes and shape provided are such that porosity of the gravel mass is as desired. For this it is necessary that all sand and dust is removed from the gravels before putting them at the inlet and outlet ends.

15.3.6. Anaerobic Baffled Reactor

(i) Before commissioning it is necessary that some quantity of fully digested sludge is put into the reactor such that the waste water flowing into the reactor gets in contact with the digested sludge thereby initiating the digestion reaction

(ii) The flow velocity in the chamber should not exceed one meter per hour and as such it necessary to control the flow of waste into the chamber



(iii) The entry at the first baffle is provided at its mid-depth and in subsequent baffles at the top end of the baffle wall

(iv) These openings of equal size are spaced at equal distances to each other all along the width of the baffle wall so that the waste flows smoothly all through the chamber uniformly under quiescent conditions.

15.3.7. Drainage System

(i) Catch pits provided in the house premises should be properly and regularly cleaned

(ii) Regular cleaning/de-silting is required for drains so that sufficient capacity is achieved. So that rain water shall not flow over pavement in case of occurrence of rain.

15.3.8. Exit Strategy

After trial-run and commissioning, joint inspection by both GPWSC/ Community and PHED/RWSD will be done to ensure: (i) water supply for all households (ii) bulk Flow meter and disinfection facilities installed (iii) distribution system covers the entire habitation, (iv) interconnection between new and existing system is provided, (v) saddle pieces are provided to all households, to take house connections (vi) water quality analysis reports are available (vii) construction quality records are available at the sites, (viii) GPWSC / Community is aware of O&M cost and tariff to be paid (ix).operator selected by community is trained (x) soft and hard copies of all financial details of the scheme are available; Completion plans and required contact numbers for effective complaint redressal are available and insurance of works provided in post implementation technical support to GPWSC. (xi) Arrangements are made for Periodic verification of service levels, social and sustainability audits of all completed schemes.

Provision for five year operation and maintenance of the schemes (DBO) shall be included in the scope of construction agency; while the provision of 01 year of O&M shall be kept for other schemes apart from DBO. After expiry of O&M period, the internal distribution system shall be handed over to gram panchayat, while common water source and reservoir will be maintained by the concerning state departments. Annexures are placed separately at Volume-2 of the Technical Manual.

Report No: ACS9385 Public Disclosure Authorized Republic...

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