Ce2039 Municipal Solid Waste Management Lecture Notes

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CE2039 MUNICIPAL SOLID WASTE MANAGEMENT

LECTURE NOTES

By

G.BASKAR SINGH M.E.

Assistant Professor/Civil Engineering Department

S.VEERASAMY CHETTIAR COLLEGE OF ENGINEERING AND TECHNOLOGY

(NBA* NAAC* Accredited)

PULIYANGUDI,TIRUNELVELI(DIST)-627 855


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MUNICIPAL SOLID WASTE MANAGEMENT

CE 2039

LECTURE NOTES


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TABLE OF CONTENTS

UNIT TITLE PAGE

1 Sources and Types of Municipal Solid Wastes 120

2 On-Site Storage & Processing 2130

3 Collection and Transfer 3161

4 Off-Site Processing 62 - 101

5 Disposal 102 - 122

References

Glossary

Anna University Question Paper Nov-Dec 2012

Informations to knowMunicipal Solid Waste

Management


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Municipal Solid Waste Management

UnitI

Sources & Types of Municipal Solid Waste

Syllabus:

Sources and type of solid wastes Quantity Factors affecting generation of

solid wastes Characteristics Methods of sampling & characterization Effects of

improper disposal of solid wastes Public health effects Principle of solid waste

management

Social & economic aspects

Public awareness

Role of NGO &

Legislation

1.Principles of Municipal Solid waste Management

- Municipal Solid waste Management involves the application of Principle

of Integrated Solid waste Management (ISWM)

-

ISWM is the application of suitable techniques, technologies and

management programmes covering all types of solid wastes from all

sources.

-

ISWM has two objectives:

o Waste Reduction

o Effective management of waste still produced after waste reduction

- Waste Reduction: Itcan be done by following the policy, More with less

(i.e.) more goods / services with less use of Worlds resources (raw

materials & energy) and less pollution & waste. Waste reduction can also be

achieved by using internal recycling of materials (or) On-site energy

recovery.

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-

Ef fective Management of Soli d wastes:Effective solid waste management

systems are needed to ensure better human health and safety. They must be

safe for workers and safeguard public health by preventing the spread of

disease.

-

An effective management system must be both environmentally and

economically sustainable.

(a)Environmentally Sustainable: It must reduce as much as possible, the

environmental impacts of waste management.

(b)

Economically Sustainable: It must operate at a cost acceptable to the

community

- An effective waste management system includes one (or) more of the

following options

(a)Waste collection & Transportation

(b)Resource recovery through sorting & recycling (through separation)

(c)Resource recovery through waste processing (through bio / thermal process)

(d)

Waste transformation (without recovery of resources)

(e)Disposal on land (i.e.) environmentally safe and sustainable disposal in

landfill

2. Functional Elements of MSWM

The activities associated with the management of municipal solid wastes

from the point of generation to final disposal can be grouped into 6 elements as

follows:

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Waste Generation:

-

Waste generation contains activities in which materials are identified as

no longer being of value (no usefulness) and are either thrown away (or)

gathered together for disposal.

- Waste generation is at present, an activity that is not very controllable. In

the future, more control is likely to be exercised over the generation ofwastes.

Waste Handl ing, Sorting, Storage & Processing @ sour ce:

- The 2nd

of 6 functional elements in the solid waste management.

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-

Waste handling and sorting involves the activities associated with

management of wastes until they are placed in storage containers for

collection.

-

Sorting of waste components is an important step in the handling and

storage of solid wastes at source.

- On site storage is of primary importance because of public health

concerns and aesthetics consideration.

-

Processing at the source involves activities such as backyard waste

composting.

Collection:

- The functional element of collection, includes not only the gathering of

solid wastes and recyclable materials, but also the transport of these

materials after collection to the location where collection vehicle is emptied.

Sorting, Processing & Transformation of soli d wastes:

-

Its the 4th

of MSWMs functional elements.

- Sorting of mixed materials recovery facility (MRF), transfer stations,

combustion facilities and disposal sites. It includes the separation of waste

components (by size), separation of ferrous & non-ferrous materials.

- Waste processing is undertaken to recover, conversion products &

energy. The commonly used thermal processing is incineration.

- Waste transformation is undertaken to reduce volume, weight (or) size

(or) toxicity of waste without recovery. It can be done by mechanical,

thermal, chemical techniques.

Transfer & Transport: This involves two steps.

- The transfer of wastes from the smaller collection vehicle to the larger

transport equipment.

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- The subsequent transport of wastes, over a longer distances to processing

disposal site.

Disposal:

-

The final functional element in the solid waste management system is

disposal.

- A municipal solid waste landfill plant is an engineered facility used for

disposing of solid wastes on land without creating nuisance (or) hazard to

public health (or) safety.

3.

Sources of solid wastes

Sl. Wastes Sources Examples

No

1 Residential Single & multifamily Food wastes, paper,

dwellings card board, plastics,

textiles, leather, yard

wastes, metals, ashes,

etc.,

2 Industrial Light & heavy House keeping wastes,

manufacturing, packaging, food

fabrication, wastes, hazardous

construction sites, wastes, etc.,

power & chemical

plants

3 Commercial Stores, hotels, Paper, cardboard,

restaurants, markets, plastics, wood, glass,

office buildings. metals, etc.,

4 Institutional Schools, hospitals, Same as commercial

prisons, govt. centres

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5 Construction & New construction Wood, steel, concrete

Demolition sites, road repair,

renovation sites,

demolition o

buildings

6 Municipal Street cleaning, Industrial process

Services landscaping, parks, wastes, scrap

beaches, etc., materials, off-

specification products,

slag tailings

4. Types of Solid wastes

In order to plan, design and operate a solid waste management system, a

thorough knowledge of the quantities generated, the composition of wastes and

its characteristics are essential. Based on the source, origin and type of waste,

types of solid wastes is given below:

Domestic and Residential Wastes

- These are originated from single & multi-family household units.

- These are generated as a consequence of household activities such as

cooking, cleaning, repairs, hobbies, redecoration, empty containers,

packaging, clothing.

Municipal Wastes

-

It includes wastes resulting from municipal activities and services such

as street waste, dead animals, market waste & abandoned vehicles.

- This term is commonly applied in a wider sense to incorporate domestic

wastes, institutional wastes & commercial wastes.

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Commercial Wastes

- It includes wastes produced from offices, wholesale and retail stores,

restaurants, hotels, markets, warehouses.

I nstitutional Wastes

-

These are arising from institutions such as schools, universities, hospitals

& research institutes.

- It includes wastes which are classified as garbage & rubbish.

Garbage

-

Its the term applied to animal & vegetable wastes resulting from the

handling, storage, sale, preparation, cooking & serving of food

- These wastes contains putrescible organic matter, which produces strong

odor, so requires quick attention in its storage

Rubbish

- Its a general term applied to solid wastes generating in house holds,

commercial establishments & institutions, excluding garbage & ashes.

Ashes

- Ashes contains of a fine powdery residue, cinders & clinker often mixed

with small pieces of metal & glass.

-

Ashes are the residues from the burning of wood, coal, charcoal, coke &

other combustible materials

Bulky Wastes

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-

These are house hold wastes which cannot be accommodated in the

normal storage containers of house holds. So, they require special

collection.

-

This includes large household appliances such as cookers, refrigerators,

washing machines, furniture, crates, vehicle parts, tyres, wood.

Street Sweeping

-

This term indicates that are collected from streets, walkways, alleys,

parks & vacant lots.

- Street wastes includes paper, cardboard, plastic, dirt, dust, leaves & other

vegetable matters.

Dead animals

- This term applied to dead animals that die naturally (or) accidentally

killed. These are divided into 2 groups; large & small.

-

Large animals are horses, cows, goats, sheep. Small animals are dogs,

cats, rabbits & rats.

Construction & demoli tion Wastes

I ndustrial Wastes

Hazardous Wastes

Sewage Wastes

5.Quantity of Solid Wastes

-

The measurement of quality of solid wastes generated is becoming

significant in accessing thepayload capacityof the collection equipment.

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- Also important in designing and planning a solid waste management

system.

6. Factors affecting Generation of Solid wastes

Ef fect of source reduction

- Waste reduction may occur through the design, manufacture and

packaging of products with minimum toxic content, minimum volume of

material, source reduction can also be achieved by:

-

Decrease unnecessary (or) excessive packaging- Develop & use products with greater durability

-

Use fewer resources ( e.g: 2 sided copying)

- Increase the recycled materials content of products.

Extent of Recycling

- The existence of recycling programmes within a community definitely

affects the quantities of wastes collected for further processing (or) disposal.

Ef fect of Publ ic attitudes & Legislation

- Public attitudes ultimately, does significant reduction in the quantities of

solid wastes generated.

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-

A programme of continuing education is essential in bringing about a

change in public attitudes.

- It depends upon the willingness of people to change their own volition,

habits & lifestyles.

-

Legislation perhaps the most important factor affecting the generation of

certain types of wastes such as package & beverage container materials.

Geographic Location

-

Physical factor that affects the quantity of waste generated including

location, season of the year, the use of kitchen waste food grinders, waste

collection frequency.

-

Different climate influences both the amount of certain types of solid

wastes generated & the time period over which the wastes are generated.

- (e.g.) substantial variations in the amount of yard & garden wastes

generated in various parts of the country are related to climates.

Season of the year

- The quantities of certain types of solid wastes are also affected by the

season of the year. (e.g.) Festivals of India is totally a various thing overall.

Depending upon the type & change of festivals, waste generation is

different.

Frequency of Coll ection

- In general, where unlimited collection service is provided, more wastes

are collected. It does not mean that wastes are generated in more quantity.

But, it means the tendency of throwing away the wastes respective of

frequency of collection.

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Character istics of Service Area

- Peculiarities of the service area can influence the quantity of solid wastes

generated. (e.g.) Quantities of yard wastes generated on a per capita basis

are considerably greater in many of the wealthier neighborhood than in

other parts of town.

7. Characteristics of Solid Wastes

7.1 Physical Characteristics

Density (Mass per unit volume)

-

Knowledge of the density of a waste is essential for the design of all

elements of SWM, such as community storage, transportation and disposal.

- A reduction of volume of 75% is frequently achieved with normal

compaction equipment, so that an initial density of 100 kg / m3will readily

be increased to 400 kg /m3.

-

Density is an critical in the design of a sanitary landfill as it is for thestorage, collection & transportation of waste.

- Measurement of Density: The solid wastes should be taken in thesmaller

0.028 m3box to give a composite sample, from different parts of heap of

wastes.

-

After weighing, this smaller box (0.028 m3) is emptied in bigger 1m

3

box.

- Continue the process until bigger box is filled to the top. The waste

should not be compacted by pressure.

-

Fill 1m3box three times, and take the average. Thus weight per m

3 is

obtained.

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Moisture Content

- Moisture content of solid wastes is usually expressed as the weight of

moisture per unit weight of the wet material.

- A typical range of moisture contents is 20 - 45 %, representing the

extremes of wastes in an arid climate.

-

Moisture content is a critical determinant in the economic feasibility of

waste treatment plants.

- Apart climatic conditions, moisture content is generally higher in lower

income countries because of the higher proportion of food & yard wastes.

Size of waste consti tuents

- The size distribution of waste constituents in the waste stream is important

because of its significance in the design of mechanical separators and

shredder & waste treatment process.

Calorif ic Value

- Its the amount of heat generated from combustion of a unit weight of a

substance, expressed as Kcal / kg.

-

This value is measured experimentally using Bomb Calorimeter in

which the heat generated at a constant temperature of 25 C from the

combustion of a dry sample is measured.

7.2

Chemical Characteristics

Knowledge of chemical characteristics of waste is essential in

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determining the efficacy of any treatment process. Chemical characteristics

includes (i) Chemical (ii) Bio-chemical (iii) Toxic

Chemical

- It includes pH, Nitrogen, Phosphorous & Potassium (N-P-K), Totalcarbon, C/N Ratio, Calorific value.

Bio-Chemical

- It includes carbohydrates, proteins, natural fibers & biodegradable factors.

Toxic

- It includes heavy metals, pesticides, insecticides, toxicity test for leachates(TCLP)

8. Methods of Sampling

8.1

Collection of Samples of solid wastes

- When collecting samples of municipal solid waste, major collection sites

are identified which are covering a large size of population?

- Based on the type of area such as residential, commercial, and industrial,

market, slum etc., sampling points are distributed uniformly over the study

area.

-

About 10 kg of Municipal Solid waste (MSW) is collected from ten

points from outside & inside of the solid waste heap.

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-

Ground water contamination by the leach generated by the waste dumb.

-

Surface water contamination by the run-off from the waste dumb.

- Bad odor, pests, rodents and wind-blown litter in and around the waste

dumb.

-

Generation of inflammable gas (methane) within the waste dumb.

-

Bird menace above the waste dumb which affects flight of aircraft.

- Fires within the waste dumb.

- Erosion & stability problems relating to slopes of the waste dumb.

- Epidemics through stray animals.

-

Acidity to surrounding soil & release of greenhouse gas.

9.2 Impact on Public Health

-

Exposure to hazardous waste can affect human health, children

being more vulnerable to these pollutants. Also, it leads to chemical

poisoning due to chemical mix in the wastes.

-

Direct handling of solid wastes contains Organic domestic wastes in

various types of infectious and chronic diseases with the waste workers &

the rag pickers.

- Waste from agr iculture and industr ies can also cause serious

health risks such as chemical & radioactive hazards.

- Waste treatment & disposal sites can also create health hazards for

the neighborhood. Improperly operated incineration plants cause air

pollution & improperly managed & designed landfills attracts all types of

insects and rodents that spread diseases.

- Recycling too carries health risks if proper precautions are not taken.

Workers working with waste containing chemical & metals may experience

toxic exposure.

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11. Role of Legislation and NGO on MSWM

11.1 Role of Legislation

- River & Harbours Act, 1899 regulated the dumping of debris in

navigable waters and adjacent land. The idea was to protect the navigation.

- Solid Waste Disposal Act, 1965. The intention was:

o To promote solid waste management & resource

recoveryo To promote technical & financial aid

o To promote national research

- Public Util ity Regulation & Poli cy Act ( PURPA) 1981, it directs public

& private utilities to purchase power from waste to energy facilities.

- Comprehensive Environmental Response, Compensation & Liabil i ty

Act, (CERCLA), 1980, it gives response to uncontrolled hazardous waste

disposal sites.

- Resource Conservation & Recovery Act (RCRA), 1976

o Its theLegal basis for implementation of guidelines and standards

for solid waste storage, treatment & disposal.

o RCRA was amended in 1978, 1980, 1982, 1983, 1984, 1986 & 1988.

The 1980 and 1984 versions emphesized with hazardous waste.

-

National Environmental Policy Act (NEPA), 1969

- Resource Recovery Act, 1970.

-

MSW Rules 2000 (India), these rules lay down the steps to be taken by

all municipal authorities to ensure management of solid waste according to

best practice.

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11.2 Role of Non-Governmental Organizations (NGO)

- Non-Governmental organizations (NGOs) are yet another set of

participants in waste management operations.

-

NGOs are often commissioned to improve the environment of the quality

of life of poor marginalized populations, and may stimulate small-scale

enterprises and other projects.

-

Since waste materials often represent the only growing resource stream,

these organizations frequently base their efforts in extracting certain

materials.

-

The some locations with insufficient collection (or) whereneighborhoods are underserved, community based organizations play an

active role in waste management operations.

- These small-scale organizations (or) local NGOs are formed primarily as

self-help (or) self-reliance units, which may evolve into service

organizations that collect fees from their collection clients and from the sale

of recovered materials.

-

NGOs working with informal workers and community based

entrepreneurs often seek recognition for these organizations as part of the

waste management systems.

-

12. Public Awareness and Training

-

Public Awareness is an important activity in solid wastemanagement to keep the system sustainable. The information related to

public awareness is necessary for creating a sustainable system.

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12.1Partnership Role for Public Awareness

-NGO

-

CBO

12.2Mode of Implementing Public Awareness Programmes

1.

Audio & Video program

2.

IEC program

3.Child to child education

4.School education

12.3Public Participation

- Total number of sweepers allotted for door to door waste collection

work in each ward.

-

Number of sweepers getting good response from citizens in the matter of

doorstep collection.

- Number of sweepers not getting response from the public.

- Percentage of public participation.

-

Improvement of the area than the previous month.

13.

Economic Aspects of MSWM

-

Presently a large proportion of the total expenditure is incurred oncollection, a bit lesser on transportation & ameagre amount on disposal.

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-

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Unit II

On-Site Storage & Processing

Syllabus:-

On-Site storage methods Materials used for containers On-Site

segregation of solid wastes Public health & economic aspects of storage

Options under Indian conditionsCritical evaluation of options.

1. Introduction

-The handling, storage and processing of solid wastes at the source

before they are collected is the 2nd

of 6 functional elements of MSWM.

-

It is important to understand, what this element involves? This unit

includes a description and discussion of the Handling, Storage and

Processing of waste materialsat the sour ce.

2. On-Site Handling

-On-Site handling methods and principles involves public attitude,

individual belief and ultimately affects the public health.

-Its an activity associated with the handling of solid waste until they

are placed in containers.

2.1 Importance of On-Site Handling

(a) Reduce volume of waste generated

(b) Alter physical form (c) Recover usable material

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2.2 On-Site Handling Methods

(a) Sorting

(b) Shredding

(c)

Grinding

(d) Composting

3. On-Site Storage

- The first phase to manage solid waste is at home level. It requires

facilities for temporarily storing of refuse on the premises.

-

Individual house holders (or) businessman have responsibility for on-

site storage of solid waste.

-Four factors that should be considered in the on-site storage of solid

waste are: type of containerto be used, the location of containers, publi c

health, coll ection method / time.

3.1

Storage Container

-Garbage and refuse generated in kitchens and other work areas should

be collected and stored in properly designed and constructed water-proof

garbage cans ( waste bins ).

-The cans can be constructed from galvani zed i ron sheets(or) plastic

materials.

-

They should have tightly fitting covers. They must be of such size

that, when full, can be lifted easily by one man.

-They should be located in a cool place over platforms, at least 30 cm

above ground level.

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-The bins must be emptied at least daily and maintained in clean

conditions.

-A typical example of garbage can, constructed from galvanized iron

sheet, dimensions: 45 cm diameter, height 75 cm.

-

An adequate number of suitable containers should be provided with

proper platforms with stand.

-Suitable containers shall be water tight, rust resistant, tight f itt ing covers,

fi re resistant, enough size, li ght in weight, side handle & washable.

3.2 Storage containers as per Indian Conditions

- The segregation of garbage at source isPrimarily meant to keep the

two broad categories of solid waste generated separately in different

containers (i.e.) bio degradable waste in one container (GREEN)and non-

bio degradable waste in another container (RED).

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- The storage of garbage used by pedestrians (or) the floating

populations, bins should be located at regular intervals. The bins should be

placed on TWO BINS BASIS

-

Some types of receptacles presently used for storage are:

(a) Buckets

(b) Plastics / HDPE / MDPE bins

(c)

Plastic bags

(d)

Metal bins with (or) without lids.

-The MSW Rules, 2000 describes, The litter ing of municipal soli d

waste shal l be prohibited in citi es, towns and in urban areas noti fi ed bythe State Government

3.3 Container Size ( Capacity )

Considerations should be given for the size of the loaded container

that must be hauled to the collection vehicle (or) to the disposal site.

Therefore, container size for:

-

Ash up to 80 to 128 lit

-

Mixed refuse up to 120 to 128 lit

- Rubbish up to 200 lit

- Office waste is 10 to 20 lit

- Kitchen waste is 40 lit

-

Garbage is 48 to 80 lit

-Plastic liners for cans and wrapping for garbage reduce the need for

cleaning of cans and bulk containers. It avoids bad odors, rat and fly

breeding.

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-

Galvanized metal is preferable for garbage storage because it is

resistant to corrosion.

- Bulk containers are recommended where large volumes of refuse are

generated such as hotels, restaurants, apartment houses, shopping centres.

4. On-Site Processing / Segregation

On site segregation is intended:

(a) To improve disposal options

(b)

To recover valuable resources(c) To prepare materials for recovery as new products (or) energy

4.1 Objectives of On-Site waste Processing / Segregation

- Compound Separation ( Hand sorting, screening )

- Volume reduction ( baling, shredding )

-

Size reduction ( shredding, grinding )- Resource recovery ( composting )

4.2 Critical Evaluation of Options

- In case of On-Site processing of solid wastes, there are more number

of methods may be available.

-

But, one engineer should know to evaluate the various methods and

should be able to pick up a better and better solution suitable to the local

conditions.

-

The various factors that enters in, when deciding the best suitable

method are:

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(a)

Systems impact on local & global environment

(b)

Reliability

(c) Safety to workers and to local community

(d)

Ease of operations

(e)

Efficiency

(f)

Economics & aesthetics (noise, odors. Litter, increased traffic)

- A number of processing technologies have been developed for solid

waste management and one of the jobs of an engineer is to select and

design the most sustainable and cost effective methods for a given

community.

5.

On-Site Segregation, Storage & Processing Options under

Indian Conditions

Over all process of MSWM is shown here:

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5.1 Definition of Segregation

- Segregation indicates separation and storage of individual constituents

of waste materials on site.

Fig: On-Site Storage containers located in Tindivanam (2011)

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5.2 Segregation at Dwellings

There are three classifications most often used,

(a)Low rise buildings ( < 4 stories )

a.

Single family detached

b. Single family attached

(b)Medium rise buildings ( 4-7 stories )

(c)High rise buildings ( > 7 stories )

5.2.1 Low rise detached dwelling

-

Here, the residents are responsible for placing the solid waste and

sorting out recyclables.

- In many communities, the decisions have been made, not to require

the residents to separate the waste.

- But, it should be mandated.

- The equipments & facilities required are, household compactors, large

wheeled containers, small wheeled hand carts.

5.2.2 Medium size apartments

-

The collection and sorting process differs according to location and

type of waste generated.

-

Some of the solid waste storage locations are:

Basement Storage / Curb Storage

Outdoor / Mechanized Storage

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5.2.2.1 Basement Storage

- Usually owner provides basement storage rooms and the

recycling containers located near (or) next to solid waste storage.

-

The residents are responsible for storing waste in the curb side.

- The maintenance staff is responsible for curb side collection to

the street collection.

5.2.2.2 Outdoor Storage

-

Here, the large containers are located at the outdoor (or) near

the apartments.

- The residents are responsible for disposing their waste in the

containers.

- The collection vehicles with unloading mechanism are always

preferred here

.

5.2.3

High rise Apartments

- Wastes are picked up by building maintenance personnel (or)

porters from the various floors and taken to the basement (or) service

area.

- Wastes are taken to the basements by tenants.

- Wastes discharged in chutes (or) collected in large containers,

compacted in to large containers.

- In many high rise apartments, solid waste chutes are used with

large compactors.

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6. Public health & Economic Aspects of On-Site Storage

6.1 Problems related to On-Site Sorting, Storage

The main problems of sorting of waste as it is carried out manually at

various stages are listed below:

(a) Waste gets scattered at the bins.

(b)

Some types of waste does not get recycled, since it is not

currently recyclables.

(c) Toxic (or) hazardous waste does not get collected and ends up

either in landfills (or) in composting operation. Both cause other

contamination such as of groundwater.

(d)

Recycling takes place in very poor health and environmentally

unsafe conditions

.

6.2 Desirable Changes to be happened

The following long-term changes are desirable:

(a)

Organized colony-wise collection systems involving rag pickers,with proper gear and protection.

(b) Investments in the recycling sector to ensure that the units are

safe and operate at economic scales.

(c) Development of recycling laws for specific types of wastes.

(d)

Promotion of simple disinfection techniques and devices such as

needle cutter for infectious waste to be pre-treated before disposal.

(e) Pre-sorting of waste for composting operations, through

mechanical means.

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Unit III

Collection & Transfer

Syllabus:-

Methods of collection Types of vehicles Manpower requirement

Collection routesTransfer StationsSelection of locations, operations &

maintenanceOptions under Indian conditions

1.Introduction:

-

In the Municipal Solid waste Management system, Collection is an

important aspect.

- It is carried out in 5 different phases as discussed below:

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Phase 1: The individual house owner must transfer whatever is

considered as waste to the refuse can, which may be inside (or) outside the

home.

Phase 2: The movement of the refuse can to the truck, which is usually

done by the collection crew, called backyard collection.It the can is moved

to the street by the home occupant, the system is called, curbside collection

Phase 3: More & more separated materials and yard wastes are collected

separately either in same truck (or) in separate vehicles from house to

house.

Phase 4: This phase is known as truck routing. The trucks must collectthe refuse from many homes in the most efficient way possible.

Phase 5: The fifth phase of the collection system involves the location of

the final destination (e.g: MRF, disposal site, transfer station)

2. Collection Components:

Components of a solid waste collection system can be listed as below:-

Collection Points

-

Collection Frequency

- Storage Containers

- Collection Crew

-

Collection Route

-

Transfer Station

Collection Poin ts :It depends on the locality that may be residential, commercial

(or) industrial. It has the deciding factors such as size & storage which ultimately

affect the cost of collection.

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Collection Frequency:

-

Climatic conditions and requirements of a locality as well as

containers and costs determine the collection frequency.

- In hot and humid climates, solid wastes must be collected atleast

twice a week because the decomposing solid wastes produce bad

odour & leachate.

- In residential areas (food & other putrescible wastes), frequent

collection is desirable for health & aesthetic reasons.

- While deciding the collection frequency, following factors must be

kept in mind; cost, storage space, sanitation.

Storage Containers:

- Proper container selection can save the collection energy, increase

the speed of collection and reduce crow size, while evaluating

residential waste containers, the following factors must be kept in

mind.

- Efficiency: The containers should help to maximize the over all

collection efficiency.

- Convenience: The containers must be easily manageable both for

residents and collection crew.

- Compatibility The containers must be compatible with collection

equipment.

-

Public Health & Safety: The containers should be securely covered

and stored.

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Transfer Station:

-

A transfer station is an intermediate station between final disposal

option and collection points in order to increase the efficiency of

the system, as collection vehicles and crew remain closer to routes.

- A centralized sorting and recovery of recyclable materials are also

carried out at transfer station.

- The unit cost of hauling solid wastes from a collection area to a

transfer station and then to a disposal site decreases when the size

of the collection vehicles increases.

3. Methods of Primary Collection of wastes

3.1 Door step Collection through Containerized Hand carts:

- A bellmay be affixed to the handcart given to the sweeper

(or) a whistle may be provided.

- Each sweeper maybe given a fixed area (or) stretch of

houses for the collection of wastes.

Area Allotment / Sweeper

(i) Thickly Populated - 250 to 350 RMT

(ii) Less Populated - 400 to 600 RMT

(iii) Low density - 650 to 750 RMT

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3.2 Role of Sweeper:

- The sweeper should ring the bell (or) blow the whistle indicating his

arrival at the place of his work and start sweeping the street.

- On hearing the bell (or) whistle, people should deposit their

domestic biodegradable waste into the handcart of sweeper.

- No sweeper may be expected (or) directed to do house-to-house

collection by asking for waste at the door steps, as this will affect his energy &

productivity.

3.3 Collection through Motorized Vehicles:

- Local bodies, as an alternative to door step collection through

containerized handcarts may deploy motorized vehicles having unconventional

horn for doorstep collection of waste.

- Driver of vehicle should blow the horn to indicate his arrival, and

householders should deposit their domestic wastes directly into the vehicle without

loss of time.

3.4 Primary Collection of waste from Societies / Complexes:

- It is made compulsory for the management of the societies,

complexes and multi-storied builders to keep community bins (or) containers in

which dry & wet wastes may be stored separately by their residents.

- To facilitate collection of waste from societies (or) complexes, the

local bodies should act by a rule, make it obligatory for them to identify an

appropriate site within their premises for keeping such bins for waste storage.

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3.5 Collection of waste from slums:

- Local bodies should collect waste from slum by bell ringing /

whistle system along their main access-lanes.

-

Residents should bring their wastes from their houses to handcarts.

-

Performance certification by a Mohalla (Local level) Committee

may be insisted upon in such cases.

3.6 Collection-at-the doorstep in Posh Areas:

- In posh residential areas where the residents as a whole might not be

willing to bring their wastes to the municipal handcart, system of collection from

the doorstep on full cost recovery basis may be introduced.

4.Types of Collection Vehicles

- Almost all collections are based on collector and collection crews,

which move through the collection service area with a vehicle for collecting the

waste material.

-

The collection vehicle selected must be appropriate to the terrain, type

and density of waste generation.

-

The most commonly used collection vehicle is the dump truck fittedwith a hydraulic lifting mechanism. A description of some vehicles types

follows:

(i) Small-Scale Collection & Muscle-powered Vehicles

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(ii) Non-Compactor Trucks &

Compactor Trucks

4.1

Small-scale Collection & Muscle Powered Vehicles:

- These are common vehicles used for waste collection in many countries

and are generally used in rural hilly areas.

- These can be small rickshaws, carts, (or) wagons pulled by people (or)

animals, and are less expensive, easier to build and maintain compared to

other vehicles.

-

They are suitable for densely populated areas with narrow lanes, andsquatter settlements, where there is relatively low volume of waste

generated.

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4.2 Non-Compactor Trucks:

- Non-Compactor trucks are efficient and cost effective in small cities

and in areas where wastes tend to be very dense and have only little potential

for compaction.

- When these trucks are used for waste collection, they need a dumping

system to easily discharge the waste.

-

It is generally required to cover the trucks in order to prevent residue

flying off (or) rain soaking the wastes.

-

Trucks with capacities of 10-12 m3 are effective, if the distance

between the disposal site and the collection area is less than 15Km.

-

Non-compactor are generally used when labour cost is high.

4.3 Compactor Trucks:

- Compactor vehicles are more common these days, generally having

capacities of 12-15 m3due to limitations imposed by narrow roads.

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-

The advantages of the compactor collection vehicles include the following:

(a)

Container are uniform, large, covered and relatively visually inoffensive.

(b)

Waste is set out in containers so that the crew can pick them up quickly.

( c ) Health risks to the collectors and odor on the streets are minimized.

(d) Waste is relatively inaccessible to the waste pickers.

5. Collection Vehicle Routing

- Efficient routing and re-routing of solid waste collection vehicles

can help to decrease the cost by reducing the labour expended for collection.

- Routing procedures usually consists of the following two separate

components:

(a)Macro RoutingDefining size of routes

(b)Micro RoutingDefining exact path of each route

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- Results of micro-routing analysis should also be done by the

review of experienced collection drivers.

5.3 Deciding Factors for Collection Vehicle Routing:

- The heuristic (trial & error) route development process is a

relatively simple manual approach that applies specific routing patterns to blockconfigurations.

- The map should show collection, service locations, disposal (or)

transfer sites, one-way streets, natural barriers and the area of heavy traffic flows.

- Then, routes should be traced out onto the tracing paper using

the following factors:

(a)

Routes should not be fragmented (or) overlapping.

(b)Total collection (+) Hauling time reasonably constant for each route in

the community.

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( c ) The collection route should be started as close to the garage (or) motor pool as

possible.

(d)

Heavily travelled streets should not be visited during rush hours.

(e)

In case of one-way streets, it is best to start the route near the upper end of

the street.

(f)

In case of dead-end streets, wastes must be collected by walking down,

reversing the vehicle (or) taking a U-turn.

(g)

Higher elevations should be at the start of the route.

(h)For collection from one side of the street at a time, it is generally best to route

with many anti-clockwise turns around the blocks.

Based on the above rules, a typical vehicle routing is illustrated below:

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6.Transfer Stations

-When the waste disposal unit is remote to the collection area, a transfer

station is employed.

-

A transfer station is an intermediate station between final disposal option

and collection point in order to increase the efficiency of the system, as collection

vehicles & crew remain closer to routes.

-

In some situations, the transfer stations serves as a pre-processing plant,

where wastes are dewatered & compressed.

-A centralized sorting and recovery of recyclable materials are also

carried out at the transfer station.

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6.1 Basic Transfer Technologies:

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-

Selecting sites that have direct access to truck routes, highways and

rail terminals.

-

Providing adequate space within the facility site so that customers

waiting to use the transfer station do not interrupt traffic on public roads.

-Arranging the site so that traffic flows are not adjacent to properties

that are sensitive to noise.

-The site should large enough to accommodate all required functions and

possibly future expansion should be centrally located in the area where waste is

generated.

6.5Operation & Maintenance of a Transfer Station

-Six categories can be finalized and can be explained under Operation &

Maintenance of a Transfer Station. They are:

(i)Operation & Maintenance plans

(ii)Facility Operating Time

(iii)Interacting with the

people (iv)Waste Screening

(v)Emergency Situation

(vi)Record Keeping

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Operation & Maintenance Plans:

- Although a transfer stations basic function as a waste consolidation and

transfer facility is straightforward, operating a successful station involves properly

executing many tasks.

-They should be written specifically for a particular facility and include

the following elements:

-

Facility operating schedules, including days of the week, hours each day

& holidays.

-

Staffing plan that lists duties by job title, minimum staffing levels

and typical work schedules.

-

Description of acceptable & unacceptable wastes.

-

Operating methods for each component of the facility & description of

maintenance procedure for each component.

- Employee training - Safety rules & regulations

- Recordkeeping procedures - Emergency Procedures

Facil ity Operating Hours:

- A transfer stations operating hours must accommodate the

collection schedules of vehicles delivering wastes to the facility.

- Operating hours need to consider the local setting of the transfer

station, including neighboring land uses, as well as the operating hours of

disposal sites collecting wastes from the transfer station.

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Record Keeping:

-Medium & large transfer stations typically record the following

informationas part of their routine works.

-Incoming Loads:date, time, company, driver name, truck number, origin

of load, fee charged.

- Outgoing Loads:date, time, company, driver name, truck number, type of

waste.

- Facility operating log:Noting any unusual events during the operating

day.

-Complaint Log: Noting the date, time, complaining party, nature of

thecomplaint.

-Accidents (or) releases: Details of any accident (or) waste releases into

the environment.

-Maintenance Records: For mobile and fixed equipments.

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Unit IV

Off Site Processing

Syllabus:-

Processing techniques & Equipments Resource Recovery from solid

wastes Composting Incineration Pyrolysis Options under Indian

conditions.

1.Processing Techniques & Equipments

1.1 Purpose of Processing

- The processing of wastes helps in achieving the best possible benefit

from every functional element of the solid waste management (SWM) system and,

therefore, requires proper selection of techniques and equipment for every element.

- Essentially, the purposes of processing are:

(a)Improving efficiency of SWM system (e.g.) Shredding

(b)Recovering material for reuse

( c ) Recovering conversion products & energy

1.2

Various Techniques & Equipments:

(a)Mechanical Volume & Size reduction

(b)Component Separation

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-

Air Separation

-

Magnetic Separation

-

Screening

( c ) Drying & Dewatering

1.3 Mechanical Volume & Size Reduction

- Mechanical volume and size reduction is an important factor in the

development and operation of any SWM system.

- The main purpose is to reduce the volume and size of waste, as

compared to the original form, and produce waste of uniform size.

1.3.1 Volume Reduction (or) Compaction:

- Volume reduction (or) compaction refers to densifying wastes in

order to reduce their volume. The benefits of compaction are:

(a)

Reduction in the quantity of materials to be handled at the disposal site

(b)Improved efficiency of collection and disposal of wastes

( c ) Increased life of landfills

(d) Economically viable waste management system

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- The rejected material passes down a chute that is connected to a

bucket elevator, while the solid slurry passes out through the bottom of the

pulper tank and is pumped to the next processing operation.

1.4 Component Separation

- Component separation is a necessary operation in which the

wastecomponents are identified and either manually (or) mechanically to aid

further processing.

1.4.1 Air Separation

This technique has been in use for a number of years in

industrial operations for segregating various components from dry mixtures.

- Air separation is primarily used to separate lighter materials from

the heavier ones.

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Equipments used for Magnetic Separation

Suspended Magnet:

- In this type of separator, a permanent magnet is used to attract the

ferrous metal from the waste stream.

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- When the attracted metal reaches the area where there is no

magnetism, it falls away freely.

- This ferrous metal is then collected in a separate container.

Magnetic Pul ley:

- This consists of a drum type device containing magnets (or)

electromagnets over which a conveyor (or) a similar transfer mechanism carries

the waste stream.

- The conveyor belt conforms to the rounded shape of the magnetic

drum and the magnetic force pulls the ferrous material away from the falling

stream of solid waste.

1.4.3 Screening

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3. Composting

Composting is one of the important technologies for solid waste

management.

- Any organic material that can be biologically decomposed is

compostable.

- Today, composting is a diverse practice that includes a variety of

approaches, depending upon type of organic materials being composted and the

designed properties of final product.

The overall composting process can be explained as follows:

Organic matter + O2+ Aerobic bacteria Co2+ NH3+ H2O + other end products + Energy

3.1 Principles of Composting

- Decomposition and stabilization of organic waste matter is anatural phenomenon.

- Composting is an organized method of producing compost

manure by adopting this natural phenomenon.

- Composting can be carried out in two ways, aerobically

& anaerobically.

3.1.1 Aerobic Composting

- During composting, aerobic micro-organisms oxidize organic

compounds to Co2, Nitrite and Nitrate

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3.2Methods of Composting

-Manual composting was systemized by Howard and his associates.

-It was further developed by Acharya & Subramanyam and the

methods are conventionally referred as Indore and Bangalore methods of

Composting.

3.2.1

Bangalore Method

-This is an anaerobic method conventionally carried out in pits.

-

Formerly the waste was anaerobically stabilizes in pits where

alternate layers of MSW and night soil were laid.

- The pit is completely filled and a final soil layer is laid to prevent fly

breeding, entry of rain water into the pit and for conservation of the released

energy.

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- The material is allowed to decompose for 4 to 6 months after which

the stabilized material is taken out and used as compost.

3.2.2 Indore Method

- This method of composting in pits involves filling of alternate

layersof similar thickness as in Bangalore method.

- However, to ensure aerobic condition, the material is turned at

specific intervals for which a 60 cm strip on the longitudinal side of the pit is

kept vacant.

- For starting the tuning operation, the first turn is manually

given using long handled rakes 4 to 7 days after filling.

- The second turn is given after 5 to 10 days. Further turning

is normally not required and the compost is ready in 2 to 4 weeks.

Comparison of the methods:

- The Bangalore method requires longer time for stabilization of

thematerial & hence needs larger load space.

- The gases generated in this anaerobic process also pose smell &

odour problems.

- The Indore method on the other hand stabilizes the material

in shorter time & needs lesser land space.

- As no odourous gases are generated in this process, it is environment

friendly & hence commonly preferred.

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3.2.3 Windrow Composting

- The organic material present in Municipal Waste can be converted

into a stable mass by aerobic decomposition.

- Aerobic micro-organisms oxidize organic compounds to carbon

di oxide and oxides of Nitrogen and carbon from organic compounds is used as

a source of energy, while Nitrogen is recycled.

-Due to exothermic reactions, temperature of mass rises.

-In areas / regions were higher ambient temperatures are available,

composting in open windrows is to be preferred.

- In this method, refuse is delivered on a paved / unpaved open space

but leveled and well drained land in about 20 windrows with each window 3m

long x 2m long x 1.5m high with a total volume not exceeding 9.0 m3

- Each windrow would be turned on 6th

& 11th

days outside to

the centre to destroy insects larvae and to provide aeration.

- On 16th

day, windrow would be broken down and passed

through manually operated rotary screens of about 25mm square mesh to

remove the oversize contrary material.

- The screened compost is stored about 30 days in helps about 2m

x 1.5m high and up to 20m long to ensure stabilization before sales

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I ndian Standards for compost:

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3.2.4 Mechanical Composting

- Though manual methods are preferable in countries where labouriscomparatively cheap, processes are preferred where higher labour costs and

limitations of space exist.

- Mechanical composting plant is a combination of variousunits which perform specific functions.

- Solid waste collected from various areas reaches the plant site at avariable depending upon the distance of collection point.

- As the compost plant operates at a constant rate, a balancing storagehas to be provided to absorb the fluctuations in the waste input to the plant.

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- It is hence stored in large sized windrows for 1-2 months either at

the plants (or) farms.

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3.3Factors affecting Composting

(i)

Organisms

(ii)Use of cultures

(iii)Moisture

(iv)

Temperature

(v)C/N Ratio

(vi)Aeration

(vii)Addition of sewage & sewage sludge

Organisms:

- Aerobic composting is a dynamic system where in bacteria,actinomycetes, fungi and other biological forms are actively involved.

- The relative preponderance of one species over another depends

upon the constantly changing food supply, temperature and substrate conditions.

- When the temperature drops, actinomycetes & fungi are confinedto 5 to 15 cm outer surface layer.

- Thermophilic actinomycetes and fungi are known to grow well

in the range of 45 to 60C

Use of Cul tures:

- During the development of composting process, various innovatorscame forward with inoculum, enzymes claimed to hasten the composting process.

- Investigations carried out by various workers have shown thatthey are not necessary.

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- Under proper environment conditions, the indigenous bacteria

adopted to MSW rapidly multiply as compared to the added cultures.

- However, such inoculum will be required during composting of

industrial and agricultural solid waste which do not have the large mix ofindigenous bacterial population.

Moisture:

- The moisture tends to occupy the free air space between the

particles.

- Hence, when the moisture content is very high, anaerobic conditionset in.

- The composting mass should have a certain minimum moisturecontent in it for the organisms to survive.

-The optimum moisture content is known to be between 50 to 60%

-Higher moisture content may be required while composting straw

and strong fibrous material which is often the fibre and fills the large pore spaces.

Temperature:

-The aerobic decomposition of a gram mole of glucose releases 484to674 kilo calories energy under controlled conditions, while only 26 kcal arereleased when it is decomposed anaerobically.

- Under properly controlled conditions, temperatures are known to rise

beyond 70C in aerobic condition.

- This increased temperature results in increased rate of biologicalactivity and hence result in faster stabilization of materials.

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- The temperature range of 50C - 60

C is optimum for

nitrification and cellulose degradation.

- Thus, if the process is so controlled that the temperature is kept

between 50

C to 60

C for 5 to 7 days, destruction of pathogens and parasitescan be ensured.

Carbon to Ni trogen Ratio:

- The organisms involved in stabilization of organic matter utilizesabout 30 parts of carbon for each part of nitrogen and hence an C/N ratio of 30 ismost favorable.

- It has reported that optimum value to range between 2631 depending upon other environmental conditions.

- Whenever the C/N ratio is less than the optimum, carbon source

such as straw, sawdust, paper are added while if the ratio is to high, the

sewage sludge, slaughter house waste, blood are added as a source of nitrogen.

Aeration:

- It is necessary to ensure that oxygen is supplied throughout themassand aerobic activity is maintained.

- During the decomposition, the oxygen gets depleted and has tobe continuously replenished.

- This can be achieved either by turning of windrows (or) bysupplying compressed air.

- In case of artificial supplying, the quantity of air supply is normallymaintained at 12 cu m / day / kg of volatile solid.

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- It have shown that the optimum turning interval which will reduce

the cost and simultaneously maintain aerobic conditions in 5 days.

Addition of sewage & sewage sludge:

-The optimum C/N ratio for composting is 25-30.

-MSW in developed countries has a C/N ratio of nearly 80.

-To bring it down to the optimum value and to reduce the cost of

sewage sludge treatment, it is mixed with sewage sludge.

-MSW in India, has an initial C/N ratio of around 30 which does notneed blending.

4. Incineration

4.1 Definition

- Incineration process can be defined as an engineered process

using controlled flame combustion to thermally degrade waste materials inpresence of oxygen.

4.2Necessity of Incineration

-Waste volume reduced to less than 5%

-At sufficiently high temperature, and residence time, any

hydrocarbon vapour can be oxidized to carbon di oxide and water.

- Relatively simply devices capable of achieving very high removalefficiencies.

-

Heat can be recovered

-Most gases are burntwell designed systems

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- Solid as well as pasty and liquid materials can be fed into the furnace

for incineration at the same time.

- Through a high excess of air and through the constant addition of

supplemental fuel, thorough incineration is guaranteed.

-The hazardous waste and the incineration air is introduced into thesystem from the front side of the rotary kiln.

-

From the opposite end the slag and flue gas is being discharged.

-The following incineration temperatures are achieved:

Maximum furnace temperature in rotary kiln: 1050 degrees C

Maximum post-combustion temperature: 1300 degrees C

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-

Filtered out recyclable materials make for 15-20% of the initial amount of

waste, depending on its composition, and can be sold to the market, providing a

significant source of revenue.

-

The remaining waste stream is chipped into small pieces up to 50mmin diameter. In the dryer its moisture content is reduced down to 20% in order

to provide higher conversion results.

-

The properly prepared waste is finally collected in the storage bin.

Step 2: Pyrolysis of waste

-

The high-temperature pyrolysis process takes place in an indirectly heatedpyrolytic chamber (a retort) at 700-750%C in an oxygen-free environment, allowing

conversion of the waste into synthesis gas (90-98%) and a solid cocking residue, or

carbon char (2-10%), without any liquid tar fractions being formed.

-The specific temperature regime, continuously maintained in the process

chamber, eliminates any dioxins or furans in the carbon char residue thereby

allowing further use of this byproduct. Dioxins are contained in syngas only.

Step 3: Thermal Oxidizer

-

Syngas is mixed with air in the main burner and directed to the oxidizer for

combustion at 1200C.

-

Specific controlled conditions in the oxidizer ensure complete destruction of

dioxins and furans contained in the syngas and prevent their re-formation.

-The oxidized gasses have high thermal capacity and are partly utilized

by the system to maintain the temperature in the pyrolytic chamber, thereby

decreasing outside energy consumption (natural gas, or propane-butane) by 60%.

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Step 4: Energy Generation.

-

As oxidized gas leaves the thermal oxidizer, its high temperature is heatexchanged to a waste heat boiler.

-

Thermal energy captured from the oxidized gas is converted into high

temperature steam supplying energy to turbine generators which in turn

produce clean electric power

.Step 5: Pollution Control System.

-The cooled (flue gasses are passed through a multi-stage pollution control

system to be cleaned of harmful impurities and safely released into the

environment.

-

Waste off gasses utilized for pyrolysis reactor heating are also directed

to the waste heat boiler, and, after being cooled, pass through a similar

depuration system.

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Unit V

Disposal

Syllabus:-

Dumping of solid waste; sanitary landfills Site selection, design and

operation of sanitary landfills Leachate collection & treatment

1. Introduction

- The term landfill can be treated as synonymous to sanitary

landfill of Municipal Solid Waste, only if the latter is designed on the principle of

waste containment and is characterized by the presence of a liner and leachate

collection system to prevent ground water contamination.

- The term sanitary landfill has been extensively used in the past to

describe MSW disposal units constructed on the basis of dump and cover but

with no protection against ground water pollution.

- Such landfills do not fall under the term municipal solid waste

landfills

2. Sanitary Landfill

-The term landfill is used to describe a unit operation for final

disposal of Municipal Solid Waste on land, designed and constructed with the

objective of minimum impact to the environment by incorporating eight essential

components.

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4. Essential Components of a Landfill

The seven essential components of a MSW landfill are:

(a)

A liner system at the base and sides of the landfill which prevents migration of

leachate or gas to the surrounding soil.

(b)

A leachate collection and control facility which collects and extracts leachate

from within and from the base of the landfill and then treats the leachate.

(c)

A gas collection and control facility (optional for small landfills) which collects

and extracts gas from within and from the top of the landfill and then treats it or

uses it for energy recovery.

(d)A final cover system at the top of the landfill which enhances surface drainage,

prevents infiltrating water and supports surface vegetation.

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(e)

A surface water drainage system which collects and removes all surface runoff

from the landfill site.

(f)

An environmental monitoring system which periodically collects and analyses

air, surface water, soil-gas and ground water samples around the landfill site.

(g)A closure and post-closure plan which lists the steps that must be taken to close

and secure a landfill site once the filling operation has been completed and the

activities for long-term monitoring, operation and maintenance of the completed

landfill.

5. Site selection for Landfill

Selection of a landfill site usually comprises of the following steps, when a

large number (eg. 4 to 8) landfill sites are available:

(i)Setting up of a locational criteria

(ii)Identification of search area

(iii)Drawing up a list of potential sites;

(iv)

Data collection

(v)Selection of few best-ranked sites

(vi)Environmental impact assessment and

(vii)Final site selection and land acquisition.

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(f)

Public parks: No landfill should be constructed within 300 m of a public park.

A landfill may be constructed within the restricted distance if some kind of

screening is used with a high fence around the landfill and a secured gate.

(g)

Critical Habitat Area: No landfill should be constructed within critical habitat

areas. A critical habitat area is defined as the area in which one or more

endangered species live. It is sometimes difficult to define a critical habitat area. If

there is any doubt then the regulatory agency should be contacted.

(h)

Wetlands: No landfill should be constructed within wetlands. It is often difficult to define a wetland area. Maps may be available for some wetlands, but in

many cases such maps are absent or are incorrect. If there is any doubt, then the

regulatory agency should be contacted.

(i) Ground Water Table: A landfill should not be constructed in areas where

water table is less than 2m below ground surface. Special design measures be

adopted, if this cannot be adhered to.

(j) Airports: No landfill should be constructed within the limits prescribed by

regulatory agencies (MOEF/ CPCB/ Aviation Authorities) from time to time.

(k)Water Supply Well: No landfill should be constructed within 500 m of any

water supply well. It is strongly suggested that this locational restriction be abided

by at least for down gradient wells.

(l)Coastal Regulation Zone: A landfill should not be sited in a coastal regulation

zone.

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(m)

Unstable Zone: A landfill should not be located in potentially unstable zones

such as landslide prone areas, fault zone etc.

(n)

Buffer Zone: A landfill should have a buffer zone around it, up to a distance

prescribed by regulatory agencies.

(o)Other criteria may be decided by the planners.

I I Search Area

- To identify the potential sites for a landfill a search area has to bedelineated. The search area is usually governed by the economics of waste

transportation.

- It is usually limited by the boundaries of the municipality. Typically search

areas are delineated on a map using a search radius of 5 to 10 km, keeping the

waste generating unit as the centre.

-

Alternatively, the search area may be identified by adopting a range of 5

km all around the built-up city boundary. One should start with a small search area

and enlarge it, if needed.

I I IDevelopment of a l ist of Potential Sites

-After demarcating the search area, as well as after studying the various

restrictions listed in the locational criteria, areas having potential for site

development should be identified.

- A road map may be used to show the potential sites that satisfy the

locational criteria. Preliminary data collection should be undertaken with an aim of

narrowing the list of sites to a few best-ranked sites.

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- In areas where land availability is scarce, degraded sites such as abandoned

quarry sites or old waste dump sites can be considered. Special design measures

are required for such sites.

I V Data Coll ection

Several maps and other information need to be studied to collect data within

the search radius. Some are discussed below.

(a)

Topographic Maps: The topography of the area indicates low and high areas,

natural surface water drainage pattern, streams, and rivers.

(b)Soil Maps: These maps, primarily meant for agricultural use, will show the

types of soil near the surface.

(c) Land Use Plans: These plans are useful in delineating areas with definite

zoning restrictions. There may be restrictions on the use of agricultural land or on

the use of forest land for landfill purposes.

(d) Transportation Maps: These maps, which indicate roads and railways and

locations of airports, are used to determine the transportation needs in developing a

site.

(e)

Flood Plain Maps: These maps are used to delineate areas that are within a 100

year flood plain. Landfill siting must be avoided within the flood plains of major

rivers.

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(f) Ground Water Maps: Ground water contour maps are available in various

regions, which indicate the depth to ground water below the land surface as well as

regional ground water flow patterns. Such maps should be collected from Ground

Water Boards or Minor Irrigation Tube well Corporations.

(i)

Rainfall Data: The monthly rainfall data for the region should be collected

from the Indian Meteorological Department.

(j)

Wind Map: The predominant wind direction and velocities should be collected

from the Indian Meteorological Department.

(k)Seismic Data: The seismic activity of a region is an important input in the

design of landfills Seismic coefficients are earmarked for various seismic zones

and these can be obtained from the relevant BIS code or from the Indian

Meteorological Department.

V Site Walk-over & Establ ishment of Ground Truths

-

A site reconnaissance will be conducted by a site walk-over as a part of the

preliminary data collection. All features observed in various maps will be

confirmed.

-

Additional information pertaining to the following will be ascertained from

nearby inhabitants:(a) Flooding during monsoons

(b) Soil Type

(c) Depth to G.W. Table (as observed in open wells or tube wells)

(d) Quality of groundwater and (e) Depth to bedrock.

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VI Prel iminary Boreholes and Geophysical I nvestigation

-At each site, as a part of preliminary data collection, one to two boreholes

will be drilled and samples collected at every 1.5m interval to a depth of 20m

below the ground surface.

-The following information will be obtained:

(i)Soil type and stratification

(ii)Permeability of each stratum

(iii)

Strength and compressibility parameters (optional)

(iv)

Ground water level and quality and

(v)

Depth to bedrock.

VI I Assessment of Publ ic Reaction

-

The public/nearby residents should be informed of the possibility of siting

of a landfill in a nearby even as soon as a list of potential sites is developed. A

preliminary assessment of public opinion regarding all the sites in the list is

essential.-

Public reaction is less hostile if landfilling is done in an area already

degraded by earlier municipal waste dumps or other activities such as quarrying,

ash disposal etc.

VI I I Selection of Few Best-Ranked Sites

- From amongst a large number of sites, the selection of a final site will

emerge from a two -stage approach.

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(a)

Selection of a few best-ranked sites (usually 2 sites, sometimes 3) on the basis

of pathway and receptor related attributes.

(b)

Selection of final site on the basis of environmental impact assessment, social

acceptance and cost of disposal.

I X Environmental Impact Assessment (EIA)

-Wherever feasible, environmental impact assessment will be conducted for

two alternate sites (in exceptional circumstances up to 3 sites)

-

The impact of the landfill on the following will be quantified: (a) Ground

water quality;

(a)Ground water quality; (b) Surface water quality; (c) Air quality gases, dust,

litter; (d) Aesthetics visual, vermin, flies; (e) Noise; (f) Land use alteration; (g)

Traffic alteration; (h) Drainage alteration; (i) Soil erosion; (j) Ecological impacts

X F inal Site Selection

- The final selection of the site from amongst the best-ranked alternatives

should be done by comparing:

(a)

The environmental impact;

(b)Social acceptance; and

(c)Transportation and landfilling costs.

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- The total landfill area should be approximately 15% more than the

area required for landfilling to accommodate all infrastructure and support

facilities as well as to allow the formation of a green belt around the landfill.

- There is no standard method for classifying landfills by their

capacity. However the following nomenclature is often observed in literature:

Small size landfill : less than 5 hectare area

Medium size landfill : 5 to 20 hectare area

Large size landfill : greater than 20 hectare area.

Landfill heights are reported to vary from less than 5 m to well above 30 m.

6.3 Layout

- A landfill site will comprise of the area in which the waste will be

filled as well as additional area for support facilities.

- Within the area to be filled, work may proceed in phases with only a

part of the area under active operation.

-

The following facilities must be located in the layout:

(a)Access roads

(b)Equipment shelters

(c)Weighing scales

(d)

Office space

(e)

Location of waste inspection and transfer station (if used)

(f)Temporary waste storage and/or disposal sites for special wastes

(g)

Areas to be used for waste processing (e.g. shredding)

(h)

Demarcation of the landfill areas and areas for stockpiling cover material and

liner material

(i)Drainage facilities

(j)Location of landfill gas management facilities

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(k)

Location of leachate treatment facilities; and

(l)

Location of monitoring wells.

A typical site layout is shown below

- It is recommended that for each landfill site, a layout be designed

incorporating all the above mentioned facilities

7. Operation of a Landfill

- To secure public acceptability, landfill operations require careful

planning and determination of the extent of environmental effects.

- The basic factor influencing the planning of site operations is the

nature and quantity of incoming waste.

- The various aspects of operation of a landfill are as follows

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7.1 Methods of Filling

- Trench M ethod: This involves the excavation of a trench into which

waste is deposited, and the excavated material is then used as cover.

- Area Method:Wastes may be deposited in layers and so form terraces

over the available area. However, with this type of operation, excessive leachate

generation may occur.

- Cell Method: This method involves the deposition of wastes within pre-

constructed bounded area. It is now the preferred method in the industrialized

world, since it encourages the concept of progressive filling and restoration.

- Canyon / Depression: This method refers to the placing of suitable

wastes against lined canyon or ravine slide slopes. Slope stability and leachate gas

emission are critical issues for this type of waste placement.

7.2 Refuse Placement

- The working space should be sufficiently extensive to permit

vehicles to man oeuvre and unload quickly and safely without Impeding refusespreading, and allow easy operation of the site equipment.

- Depositing waste in thin layers using a compactor enables a high

waste density to be achieved.

- Various systems for monitoring the leachate level are in use, and are

mostly based on pipes installed prior to land filling.

- Placing pipes within a column or tyres may, however, offer some

protection.

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- At an early stage of site preparation, therefore, a number of

monitoring boreholes need to be provided around the site.

- However, the location, design and number of boreholes depend on

the size of the landfill, proximity to an aquifer, geology of the site and types of

wastes deposited.

8. Leachate Collection & Treatment

8.1 Leachate Control

-Leachate control within a landfill involves the following steps:

(a)

Prevention of migration of leachate from landfill sides and landfill base to the

subsoil by a suitable liner system

(b)Drainage of leachate collected at the base of a landfill to the sides of the landfill

and removal of the leachate from within the landfill.

-

Three types of liner systems are usually adopted and these are describedhereafter:

(a) Single Liner System: Such a system comprises of a s

Ce2039 Municipal Solid Waste Management Lecture Notes

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