Integrated solid waste management

Integrated Solid Waste Management

By Ms. Jini Rajendran

World Environment Day 2015 – Seven Billion Dreams. One Planet. Consume with care.

Definition

• Integrated Solid Waste Management (ISWM) is a comprehensive waste collection, treatment, recovery and disposal method that aims to provide environmental sustainability, economic affordability and social acceptance for any specific region.

• Municipal Solid Waste (MSW): As per the Municipal Solid Waste (Management and Handling) Rules 2013, MSW Includes the commercial and residential waste generated in a municipal or notified area in either solid and semi-solid form excluding industrial hazardous waste, e-waste and bio-medical waste.

ISWM - Planning Process

Education

Public participation

Outreach

Identify Needs

Review Existing System

Review existing regulations

Organize Decision making framework

Establish Objectives

Identify Potential Components

Compare options

Develop ISWM plan

Implement the plan

Evaluate the Waste Management System

Lessons learned

Top level political commitment as well as interest and commitment of local authorities is crucial to the success of project.

Baseline data is usually not available and requires considerable time and resource.

Local project team is very essential for the success of ISWM project.

Stakeholders consultation provides vital information and greatly improve local ownership.

Benefits of proper waste management should be looked not just from the environmental perspective but economic and social benefits should also be factored.

Assessment of Current MSW Management Practices Assessment of policies, regulations and laws governing MSW and

authority level of the local in the ISWM.

Assessment of population of the City/Town/Municipality:- Must Consider the design period (25 – 30 years).

Identify sources of Municipal Solid Waste (MSW) generation:- Household, commercial, street sweeping and cleaning, hotels, hospitals, institution, parks and gardens, market temples, cinema and function halls.

Estimate quantity of MSW generated

Characteristics of MSW (Physical and Chemical).

Assessment of current practices of the municipality.

Regulations and Laws Governing MSWLatest regulation governing MSW in India is Municipal Solid Waste (Management and Handling) Rules 2013.

Every Municipal Authority (MA) shall be responsible for the implementation of the provisions of these rules and for necessary infrastructure development for collection, storage, segregation, transportation, processing and disposal of MSW directly or by engaging agencies or groups working in waste management including waste pickers.

MA or operator of the facility shall obtain EC from SEIAA for setting up MSW P&D facility including landfill and the site for such facility shall be incorporated in the land-use plan of the Town Planning Authority and buffer zone shall be specified by SEIAA on a case to case basis.

MA or operator of the facility shall obtain authorization, consent to operate and consent to establish from SPCB for setting up and operating P&D facility including landfill.

SPCB shall be responsible for monitoring the progress of implementation of action plan and compliance of standards regarding ground water quality, ambient air, leachate quality, compost quality including incineration standard.

MA shall encourage use of MSW by adopting suitable technology which may include composting, vermi-composting, anaerobic digestion with or without energy recovery, co-incineration or a combination of such technologies.

MA or operator who intend to use any new technology shall approach SPCB to get standard laid down and seek authorization to ensure compliance.

Management of MSW shall strictly comply with following regulation: Safe collection and segregation of MSW into bio-degradable and non-

biodegradable waste.

Horticultural, construction and demolition waste and dairy waste shall be collected and disposed of in accordance of local bye law and not mixed with MSW.

Storage facility shall have three bin system, green for biodegradable, white for recyclable and black for others.

Manual handling of MSW shall be prohibited, except in case of unavoidable circumstances under proper precaution using adequate PPE measures.

Landfill shall be permitted for non-usable, non-recyclable, non-biodegradable, non-reactive inert waste only.

Bio-medical waste, industrial hazardous waste and e-waste shall not be mixed with MSW and shall be handled separately as per the separate specific rules for the purpose.

Existing dumpsites which are not engineered landfill sites shall be closed and properly capped.

Specification for landfill site is provided in Schedule 1 of the MSW Rule.

Regulations and Laws Governing MSW

Typical Sources of MSW in Indian Cities

Domestic household

waste; 37.18%

Commercial Es-tablishment

Waste; 6.95%

Hotels and Restaurants; 13.24%Institutional Waste; 2.48%

Parks and Gardens;

1.38%

Street Sweeping Waste; 6.47%

Waste from Drains; 3.47%

Markets; 9.52%

Temples; 0.70%

Chicken mutton beef, fish stalls;

3.26%

Cinema Halls; 0.30%

Function Halls; 1.74%

Hospitals; 0.69%

Construction and Demolition

Waste; 12.62%

Quantity and Quality of MSW in Indian Cities

Per capita waste generated in Class 1 Indian cities has increased from 440 gm/capita/day to 500 gm/capita/day in last decade. This is fuelled by lifestyle changes and purchasing power of urban indians.

Including construction waste which will be around 600 – 700 TPD, the per capita waste generated will workout to be around 550 to 600 gm/capita/day.

The Composition of MSW in Indian cities will be 51 % organic, 17.5 % recyclables and rest 31% will be inert.

The average calorific value of MSW will be around 1750 Kcal/Kg and the average moisture content is 47%.

S. No Physical Characteristics Average (%)1 Organic Waste 48.222 Paper and Cardboard 7.263 Plastics 8.614 Metals 0.525 Glass & Ceramics 1.666 Rags/Cloth/Cotton 5.77 Rubber and Synthetics 1.828 Leather 1.299 Garden Waste 2.9710 Stone Debris and boulders 0.811 Bio Medical Waste 0.5712 Sand Silt and Earth 11.6213 Coconut Shell 0.0914 Others 8.87

Typical Physical Characteristic of MSW in Indian Cities

Typical Chemical Characteristic of MSW in Indian Cities

S. No Chemical Property Range1 pH 6.24 – 7.15

2 Moisture Content (%) 31.73 – 59.24

3 Carbon Content (%) 7.6 – 15.6

4 Nitrogen mg/Kg 4,500 – 7,200

5 Zinc, mg/Kg 132 - 272

6 Lead, mg/Kg 10 – 25

7 Nickel, mg/Kg 1 - 6

8 Calorific Value, Kcal/Kg 1,250 – 2,550

Importance of MSW Collection and Transportation

Organic waste bio-degrades quickly and releases pungent odours. Organic waste attracts flies, rodents and pest.

Organic waste if not collected efficiently can lead to epidemic diseases such as cholera and typhoid.

Air, water and physical environment gets affected due to bad management of MSW. Leachate from MSW pollutes surface and ground water .

Improper MSW management affects the aesthetic of the cities/towns.

Cleaner cities are better able to attract private investment and tourists and thus create more jobs in the locality.

Source Segregation at

Household level

Primary Door to Door

Collection

Secondary Collection

Points

Secondary

Transportation

Transfer Stations

Tertiary Transportation

Processing and

Disposal Site

Collection and Transportation System

Street sweeping and

drain cleaning

Bulk Waste from

Hotels institutions and

function halls

Source Segregation is significant to improve the waste quality and subsequent improvement in the waste processing facility.

Source segregation shall be encouraged at household level to store dry and wet waste separately.

Wet waste include food and green waste such as cooked/uncooked food, vegetables, fruits, meat, bone, fish waste, leaves and grasses.

Dry waste include recyclable and non-biodegradable waste such as paper, plastic, glass, metal, ceramic, rubber, leather, rags, used cloths, wood, stone, sand, ash, thermocol, straw and packing material.

Inert (construction debris) and hazardous (used lead batteries, infected cotton, medicines, dried paint and dry shoe polish.) waste also needs to be segregated

Source segregation shall be achieved with the help of public awareness campaign programs.

Source segregation increases the value of MSW and promotes cost recovery schemes in addition to prolonging the life of the Landfill.

Source Segregation and its Significance

Primary collection and Transport

Door to door primary collection is achieved with the help of collection crew using tricycles or auto tippers.

Auto tipper are advanced system and provides a better coverage and efficiency. They have provision to store the waste separately into wet waste and dry waste.

Urban Local bodies can charge a user fees from the residence and other generators.

Total requirement of auto-tippers can be calculated considering density of MSW as 400 kg/m3 and capacity of tipper (0.85 m3) and no of trips by each auto-tippers. This will give the no of house holds covered and the requirement of auto-tippers.

Primary collection and Transport

Street sweeping shall be conducted by sanitary workers. Average road length covered will vary from 0.2 – 2.8 km per worker.

Drain cleaning is also a major activity to be conducted as part of primary collection. The drains are cleaned for silt and sand and the dumped on the road sides.

Refuse swept from the street and drain silt and sand shall be directly send to secondary transport system.

ULB may enter into appropriate contractual agreement with private operators for carrying out such activities.

Bulk waste from hotels, institutions and commercial establishments are collected separately tractors or tippers and are directly transported to the processing facility.

For calculating the requirement of bulk waste transportation vehicles, total quantity of bulk waste needs to be assessed, the bulk density of waste considered shall be 500 kg/m3 and distance to be covered by each vehicle and no of trips shall be assessed based on traffic study.

Secondary Collection and Transport

MSW collected from primary door to door collection shall be temporarily stored in secondary collection points prior to transportation to Transfer Stations.

Bins are of 3.5 m3 capacity type or 1.1 m3 dumper bins can be used for secondary collection of MSW. Secondary collection bins shall have color code, Eg. Green for collection of organic waste and blue/yellow for collection of inorganic waste.

Such bin location shall be strategically located so that the dumper placer vehicles can easily maneuver and lift these dumper bins and place it back.

Dumper placers or vehicle compactors can then transport the waste to Transfer stations.

Transfer Stations

Waste transfer station facility are designed to received MSW secondary transportation vehicles, where the waste is compacted and loaded to larger vehicles.

The primary reason for using a transfer station is to reduce the cost of transporting waste to disposal facility. It reduces the fuel consumption, vehicle maintenance cost and produces less traffic, air emission and road wear.

At some transfer stations workers screen the incoming wastes on conveyor system or tipping floors or in receiving pits. Screening is done for recyclables or waste inappropriate for disposal.

Screening for inappropriate waste is more efficient at transfer stations than in landfill.

Decision to have a transfer station will have to be studies in detail based on planning, siting, designing and operating cost against the saving the transfer station might generate from reduced hauling cost.

Although cost effectiveness will vary, transfer stations generally become economically viable when the hauling distance to the disposal facility is greater than 15 – 20 miles.

One of the main component of the transfer station is the tipping floor, one approach to estimate the tipping floor space is to begin with a base area of 4000 sft and add to it 20 sft for each ton of waste received in a day assuming that waste will be temporarily piled 6 ft high on the tipping floor.

Transfer stations shall have the following components Unloading platforms, lower operation area, ramp facility, Hopper, weighbridge, office building, service area, Compound wall, green belt, landscaping and roof cover.

Tertiary Transportation

Tertiary transportation is conducted with the help of 18 m3 hook loader container vehicles to transport MSW from Transfer station to Processing and disposal sites.

The requirement will be calculated based on density of waste (500gm/m3), number of trips to be performed by each tertiary vehicles. Traffic assessment study is required to identify the no of trips.

Process Flow in Typical ISWM P&D Site

Waste Receiving Platform

(Pre-engineered covered shed and

RCC Platform with drains for

collection of leachate)

Moisture Loss (5%)

Removal of tyre, boulders and

other bulk materials (6%)

Pre-Sorting Plant (100 mm rotary

screen)



collection of leachate)

Recyclables (5%)

Refuse Derived Fuel (35%)

Composting (Windrow Composting – 3

mx2mx1.5m Turning after every week

for 3 weeks) (44%)

Sanitary Landfill for disposal of Inert from MSW (5%+14%)

Compost (11.5%)

Rejects

Rejects Rejects

Rejects

Moisture Loss (18.5%)

Composting

The process of degradation of organic mater by microorganism (bacteria, actinomycetes and fungi) in a controlled condition to a stable substance is called composting and the stable product is called compost.

The compost so generated is an organic manure which contain plant nutrients and improve the physical, chemical and biological characteristics of soil.

Composting is considered as a sustainable practice. it reduces 50% load of the landfill since around 50% of the MSW comprise of organic matter. Compost is considered as a natural solution to increase soil fertility than chemical fertilizers.

Many organizations and institutions are considering composting of their organic waste as part of their sustainability practice.

Composting

Monsoon Shed (15 days for

stabilization)


RCC Platform with drains for collection

of leachate

Primary and Secondary Screening

with 35mm and 16 mm screen. (Pre-

engineered covered shed and RCC

Platform with drains for collection of

leachate

Curing (15 days for further

stabilization and moisture control)

(Pre-engineered covered shed and RCC

Platform with drains for collection of

leachate

Fine Screening with 4mm screen



collection of leachate

Composting (Windrow Composting –

3 mx2mx1.5m Turning after every

week for 3 weeks) (base – concrete or

compacted clay 50cm thick permeability

coefficient less than 10-7 cm/sec with

drains to collect leachate and surface

run-off)Packing Bagging and Labeling of

Compost

Composting

Parameters Concentration not to exceed (mg/kg dry basis, except pH and C/N ratio)

Arsenic 10.00

Cadmium 5.00

Chromium 50.00

Copper 300.00

Lead 100.00

Mercury 0.15

Nickel 50.00

Zinc 1000.0

C/N 20-40

pH 5.5 – 8.5

In order to ensure safe application of compost, MSW rules 2013 stipulates the following specification of compost quality must be met. Compost exceeding the below mentioned concentration limit shall not be used for food crops.

Micro-organism required for composting are indigenously present in MSW (bacteria, fungi and actenomycetes). Inoculum or enzymes may be added to hasten the process but not necessary in Indian condition.

The optimum moisture content required for composting will be 50 – 60%.

Temperature in the aerobic compost can rise beyond 700 C, however the activity of cellulose enzymes reduces above 700 C. A temperature range of 50 – 600 C is optimum for 5 – 7 days. This will also ensure destruction of pathogen and parasites.

C/N ratio of 30:1 is most favorable for composting. When C/N ratio is low carbon sources such as straw, saw-dust, paper are add and if C/N ration is to high nitrogen sources such as sewage sludge, slaughter house waste etc. is add.

During composting the oxygen get depleted and has to be continuously replenished. This can be achieved by turning windrows at ever 5- 7 days. (Artificial aeration to the tune of 1-2 m3/ day/Kg of volatile solids will be required in case of enclosed composting).

Composting is normally considered as complete when the C/N ratio reaches 20, excess carbon tend to utilize nitrogen decreasing soil nitrogen content and low C/N ratio will not help to improve soil structure.

Refuse Derived Fuel

Secondary

Shredding

Primary shredding of

Combustibles

Screening of

combustibles

Air Density Separator

Fluff

Combustibles from the presorting

shed (MSW particle size more than

100 mm size)

Bales

Packing and dispatch

Typical Characteristics - RDF

S. No. Parameters Value

1 Moisture Content % 17.195

2 Ash Content % 16.795

3 Volatile Matter % 66.01

4 Chloride % 0.615

5 Carbon C % 46.7

6 Hydrogen H % 3.5

7 Nitrogen as N % 1.345

8 Sulfur as S % 0.5025

9 Fixed Carbon % 0.725

10Net Calorific value Cal/g

3244

11Gross Calorific Value Cal/g

3848.5

Combustible components of MSW are paper, cardboard, plastics, textiles, rubber, leather and wood.

RDF is mostly used in cement kilns, in cement kilns combustion takes place under a very high temperature of about 14500 C and relatively longer residence time. These conditions are favorable for burning RDF.

RDF quality for cement industry are : Particle size - < 30 mm

Sulfur content < 1%

Chlorine content < 1%

Moisture Content < 30%

Hg content < 3 mg/Kg

RDF Components % C % H % O % N % S % Cl % H2O % Ash

Paper 34.4 4.72 32.4 0.16 0.21 0.24 21 4.62

Plastic 56.4 7.79 8.05 0.85 0.29 3 15 8.59

Wood 41.2 5.03 34.5 0.02 0.07 0.09 16 2.82

Textile 37.2 5.02 27.1 3.1 0.28 0.27 25 1.98

Leather, rubber 43.1 5.37 11.6 1.34 1.17 4.97 10 22.5

Recyclables – Coconut Shell Shedding and Coir Making

Sanitary Landfill Sanitary landfills are sites where waste is isolated from the environment until

it is safe. Waste is buried underground or in large piles Different types of landfill include Above ground landfill, below ground landfill,

slope landfill and valley landfill. Landfill section will be arrived at keeping in view the topography, depth of water table and availability of daily cover material.

The essential components of a landfill are : A liner system at the base to prevent migration of leachate or gas to surrounding soil.

A leachate collection system which collects and extract leachate from within and from base of the landfill and then treat leachate.

A gas collection system which collects and extract gas from within the landfill and then treat it or use for energy recovery.

A final cover system at the top of the landfill which enhances surface drainage and prevent infiltrating water and supports surface vegetation.

A surface water drainage system which collects and removes all surface runoff from landfill sites.

Environment monitoring system which periodically collect and analyses air, surface water, soil and ground water samples around the landfill.

A closure and post closure plan for long term monitoring and maintenance of the completed landfill.

Sanitary Landfill

Landfill capacity is determined by the volume of waste and volume occupied by the liner system. For planning purpose the a density of 0.85 kg/m3 is considered for biodegradable waste and a higher value of 1.1 t/m3 is considered for inert waste.

Landfill is operated in a phased manner, so that at a given time a part of the site may have a final cover, a part being actively filled, a part being prepared to receive waste and a part undisturbed.

Each phase is typically designed for a period of 12 months. It must be ensured that each phase reaches the final cover level at the end of its construction period and that it is covered before the onset of monsoons.

The term cell is used to describe the volume of material placed in the landfill during one operational period, usually one day. A cell includes the solid waste deposited and the daily covering material usually consisting of 15 – 30 cm of native soil at the end of each operating period.

The purpose of daily cover is to control blowing of waste material, to prevent rats, flies and other disease vectors entering into the landfill and to prevent entry of water into the landfill.

Sanitary Landfill

Sanitary Landfill

Compacted earth

Compacted clay liner 900 mm thick with permeability 1 x 10-7 cm/sec

1.5 mm thick HDPE liner

285 gsm geo-textile

300 mm thick drainage media with 160/200 OD HDPE pipes

285 gsm geo-textile

Waste dump in thin layers compacted

Waste dump in thin layers compacted

100 mm thick soil cover

500 mm thick clay layer

150 mm drainage media

450 mm soil with grass beeding

Gas vent to atmosphere

Bottom LinerTop Cover

Leachate collection system consist of drainage layer of permeability of greater than 0.01 cm/sec. Perforated pipes are laid at a slope of 2%.

Usually PVC or HDPE pipes are used with perforation separated at 1200.

Estimation of pipe diameter and spacing is on the basis of estimated leachate quantity and maximum possible head.

Factors that influence leachate generation are precipitation, ground water intrusion, moisture content of the waste, daily cover during filling period and final cover design.

Leachate generated is collected at sumps, which are depression in liner filled with gravel to accommodate collected leachate.

Sumps are accessed by side slope raiser pipes that follow the landfill slope. Leachate is extracted by pumps that often run intermittently using level sensing switches.

Sanitary Landfill

Sanitary Landfill

Landfill gas results from the biodegradation of waste. The major components of landfill gas are methane and carbon dioxide (typically in the ratio of 3:2).

There are two type of landfill gas collection system, namely passive and active collection system.

Passive system relies on pressure and concentration gradients to function. This includes a vertical vent and gravel trenches.

Active system includes a prime mover that creates a vacuum on the landfill. This includes vertical gas wells and horizontal collectors.

If the gas quantity is too low for use then it can be flared. A flare system may also be used to burn off excess gas.

Wells are typically drilled to 75% of refuse depth or until leachate is reached. Boreholes are typically 24 to 36 inch in diameter. Casing ill be of PVC, HDPE or carbon steel. Perforated with slots, holes or screens. Typically perforated with slots for bottom 1/3 to 2/3 height.

Gravel pack enhances LFG extraction and reduces screen plugging.