Water Safety Plans for O&M Improvements Water Safety Conference Kuching, Malaysia 2- 4 November 2010...

Water Safety Plans for O&M Improvements

Water Safety Conference

Kuching, Malaysia2- 4 November 2010

Asoka Jayaratne Water Quality Specialist

Yarra Valley WaterMelbourne, Australia

April 21, 2023 2Yarra Valley Water Ltd

Outline

Linkage between Water Safety Plan (WSP) and operation & maintenance (O&M)

Lessons learned from poor O&M practices

WSP as a tool to drive O&M improvements

O&M framework for safe water


Why Do We Need Water Safety Plans?

Aim of water supply system• Provide safe drinking

water• Provide safe drinking

water 100% of the time

Does zero E coli mean safe drinking water?

System Assessment

Water Safety Plans

Health-based targets(National regulatory body)

Independent Surveillance(Surveillance agency)

Public health context and health outcomes

Linkage between WSP and O&M

WHO Framework

System Assessment

Operational Monitoring

Management

Plans


Linkage between WSP and O&M

Water Safety Plan Concepts

A documented plan that:• Identifies hazards, assesses risks from catchment to consumer• Prioritises risks focus on highest risks• Mitigates risks through control measuresMeaning:• Less output monitoring (final water)• More input monitoring (is the system working?)

Consumer system

Distribution system

Water resources &

sourcesTreatment

Linkage between WSP and O&M WHO Manual – WSP Components


The Link

Water Safety Plan

Good O&M Processes

Well developed O&M Procedures = Effective Water Safety Plan = Safe water 100% of time

Poor O&M Procedures = ineffective Water Safety Plan = Potentially unsafe water


Poor O&M = Unsafe Water Supply

Lessons from the past….

Gideon, Missouri, 1993


Hazard (contaminant): Salmonella

Hazardous event (cause):Pigeons nesting on a water tank roofTank roof was not sealed and pigeon faeces washed into the tankThere was a concentration of Salmonella bacteria in the water tank sediment and at the surfaceThe water tank rapidly drained into the distribution system during a flushing event and chlorine residual was not maintained

Effect~ 500 ill from town of 1,1047 Dead

MacKenzie et al, 1984; Corso et al, 2003

www.ionizers.org/images/cryptosporidium.jpg acd 2 March 2006

Milwaukee, Wisconsin, 1993 Hazard (contaminant):

• Cryptosporidium oocysts Hazardous event (cause):

• Runoff from heavy spring rains • Carrying sewage into Lake Michigan

(from which raw water was drawn)• Coagulation problems on the filtration

system in Milwaukee’s Southern water treatment plant

• Turbidity did not rise above 1.7 NTU Effect:

• 400,000 ill from 1.2 million in city• 100 dead• US$96.2 million


Oulu, Finland, 1998


Hazard (contaminant): Campylobacter

Hazardous event (cause):Water and sewer burst at the same time and placeThe water main was repaired and flushed out but traces of sewage remained in the water mainTraces of Campylobacter remained in the water main after it was reinstatedThe supply was not a chlorinated one

Effect~ 50 medically attended cases from town of around 15,000

O’Connor, 2002

Walkerton, Ontario, 2000

www.ehagroup.com/epidemiology/illnesses/images/e-coli-0157-h7-C.jpg acd 2 March 2006

www.cdc.gov/ncidod/eid/vol5no1/altek2b.jpg

Hazard (contaminant): E. coli O157:H7 Campylobacter jejuni

Hazardous event (cause):Heaving Spring rainsCow manure washed into the wellNo on line monitoringFailure to chlorinateWater supplied by local water utilityOperators, managers & government cutbacks found responsible

Effect2

,300 ill

7 Dead

$ C$155 million


32% of waterborne disease outbreaks in US are caused by microbial pathogens in the water

distribution system

Source: AWWA and Centres for Disease Control and Prevention

Distribution system re-contamination

April 21, 2023 Yarra Valley Water Ltd 16

The List goes on!!

400 + outbreaks in affluent countries


Water Safety Plans for

O&M Improvements


Driver for O&M Improvements

WSP Drives Improvements

• Structure to identify gaps in routine/emergency maintenance

• Identify gaps in operational procedures based on level of risks

• Infrastructure upgrades leading to improved operations

Benefits

• Longer term cost savings due to reduced incidents and events

• Improved operational efficiency


WSP for O&M ImprovementsAustralian Examples – Yarra Valley Water

Gaps in tank inspection and maintenance program

Improved spot chlorination method

Improved storage area security procedures


WSP for O&M ImprovementsAustralian Examples - YVW

Equipment calibration programs

Treatment chemical (hypochlorite) QA procedures• storage and shelf life• impurities• batch control

Water quality focus on water mains construction and replacement process – new industry Code

Incident and emergency management protocols


WSP for O&M ImprovementsExamples from India

Pilot WSP - Hyderabad Metropolitan Water Supply and Drainage Board

• Identified O&M issues based on level of risk funding requirements

• Leakage from sewers

• Infiltration from storm water drains

• Illegal sewer connection

21 April 2023 24Yarra Valley Water Ltd

WSP for O&M ImprovementsExamples from India

Pilot WSP - Hyderabad Metropolitan Water Supply and Drainage Board

• Treatment plant operational issues

• Non uniform dispersion of chlorine

• Inconsistent alum dosing

• Sand filter backwash not based on head loss

• Non representative lab sample program

• Inadequate chlorine residual monitoring


O&M Plan - Key Components

Standard Operating Procedures (SOP) for operation of water supply system from the catchment to consumer including Operational Manuals

Procedures for programmed and unscheduled (emergency) maintenance activities

Emergency and Incident Management Protocols and Manuals

Equipment calibration and maintenance programs

Asset information data capture and management systems


O&M Plan - Key Components

Key Performance Indicators (KPI)

Monitoring, reporting & review of KPI (government regulated/self regulated)

Long term asset management strategy and funding arrangements

Staff and contractor training programs

Quality Control / Quality Assurance systems, internal and third party Auditing (of WSP, O&M process and KPIs)


O&M Plan Examples - Storage

Reservoir water quality monitoring program off take levels• Normal operation• Events (floods, after fires, algal blooms)

Reservoir inspection program - security Algae management plan Contingency plan for high rainfall events


O&M Plan Examples - Treatment

Maintenance program – filters, equipment…..

Water treatment plant operational procedures

Operations and Emergency Response Manuals

Contingency plans for treatment plant failures

Treatment chemical quality control procedures


O&M Plan Examples - Distribution Storage tank operational procedures – taste and odour,

chlorine…. Storage tank structural inspection and cleaning program Valve and hydrant inspection programs Water main break repair procedures (flushing, disinfection,

shut down) Mains replacement program (prioritised based on risks) Backflow/cross connection prevention program Asset information system - data collection, analysis and

reporting


Time to develop a

Good O&M Plan

to deliver safe water

Water Safety Plans for O&M Improvements Water Safety Conference Kuching, Malaysia 2- 4 November 2010...

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