Disposal of

Municipal Solid Waste

We Use it

And we dispose it

as

?What would be the Future

3R for MSW

ReduceReuse

Recycle

The amount and toxicity of trash you discard

Containers and products; repair what is broken or give it to someone who can repair it

as much as possible, which includes buying products with recycled content.

Various functional elements of municipal solid waste management system

Storage • Movable bins - Type I: Bins with lid (5-20 litre), Type II: Bins

of 50 litre capacity, Type III: Bins of capacity from 50-200 litres, Type IV: M.S. Bins (4.5 cum)

• Fixed bins - Masonry bins of 3.6 cum capacity (Type V), Dustbins/Dalaos

Collection • (H/H (house to house) collection system, Community bin

systemTransportation • Hand cart (Type I), Hand cart with six containers (Type II),

Trycycle, Animal cart, Tipper trucks, Dumper placer, Bulk refuse carrier

Waste Transfer Stations (Relay Centre Facility)• Transfer station of same level type, Transfer station of split

level type

Processing Facility of Municipal Solid Waste

Source reduction• Reduce the amount and toxicity of trash you discard • Reusing items by repairing them, donating them to charity and

community groups, or selling them also reduces waste • Recycling to turn materials that would otherwise become

waste into valuable resources Composting • It is nature's way of recycling organic wastes into new soil

used in vegetable and flower gardens, landscaping, and many other applications

Energy recovery by incineration/pyrolysis• In addition to minimizing volume, combustors, when properly

equipped, can convert water into steam to fuel heating systems or generate electricity. A variety of pollution control technologies reduce the toxic materials emitted in combustion smoke.

Final Disposal Facilities/ Landfilling

• In MSW management, regardless of the method of processing, the final disposal called "Land fill" is mandatory. In India, most of the wastes (about 90 %) are directly dumped on the low lying area outside of the city/town limits which have no provision of leachate collection and treatment and landfill gas collection and use.

Waste disposal trends in India

Waste disposal methods1971 (40 cities)1 1991 (23

cities)2

Land dumping Almost all 89.8 %

Composting - 8.6 %

Others (pelletization, vermi composting)

Source: 1Nath, 1984, and 2EPTRI (draft), 1995

Common Problems Associated withUnsound MSW

• Careless and indiscriminate open dumping of wastes creates unsightly and unsanitary conditions within municipalities, e.g. along the roads and highways.

• Delay in delivery of solid wastes to landfills, resulting in nuisance dumps and unpleasant odours, which attract flies and other vectors. Such dumps also lead to pollution of land/soils, and ground and surface water through leachate as well as air through emission of noxious and offensive gases.

• Open solid waste dumps can also be a public health risk. Direct contact with refuse can be dangerous and unsafe to the public, as infectious diseases such as cholera and dysentery can be spread through contact with these wastes. In most municipalities, scavenging on refuse dumps is a common practice, and such people face danger of direct exposure to hazardous waste. Open solid waste dumps can also provide suitable breeding places for vermin and flies and other disease vectors, and can also contain pathogenic micro-organisms;

• Some categories of solid wastes block permeability of soils and drainage systems, including water courses, open drains and sewers, thus posing difficulties in the functioning and maintenance of such facilities;

• Due to the capital-intensive nature of solid waste handling and disposal operations, these can become an economic burden and constrain service delivery in other areas such as medical care, education and road construction.

Benefits of Municipal Solid Waste Reduction

• Resource ConservationRecycling reduces all categories of health risks and pollution from exploration, extraction, and processing activities associated with raw material production.

• EnergyIn US, products made from the 57 million tons of MSW recycled in 1996 used 408 trillion Btu’s less energy than would have been needed to make those goods from virgin materials. That is enough energy to supply 4 million households with energy for a year.

• Greenhouse Gas EmissionsIn US, use of the 57 million tons of recycled materials instead of virgin materials resulted in a reduction in greenhouse gas emissions equivalent to 33 million tons of carbon or the emissions saved from removing 25 million cars from the roads.These savings are because carbon emissions from making steel, copper, glass, or paper from virgin materials instead of recycled materials are 4 to 5 times higher. For aluminum, emissions are about 40 times higher for virgin ore when compared to making aluminum from used beverage containers.

• Landfill SpaceThe 57 million tons of municipal solid waste (MSW) recycled in 1996 represent 130 million cubic yards of landfill space or enough to require 64 additional landfills large enough to take the MSW from both Detroit and Dallas for a year.

Standard Processes for Managing Municipal Waste

• Incineration (increasing-reduces volume) – mostly by a few major hospital for managing clinical wastes;

• Composting• Landfill (most common and economical)• Recovery/recycling

Almost all categories of waste may be disposed to better managed landfills directly. However, those types of wastes which will destroy the microbiological degradation processes within the landfill are unwelcome i.e. the non-biodegradable wastes. Management of these could include: incineration, recycling and reusing.

Four Methods for Resource Recovery or Disposal of MSW

Recovery of materials : Recovered paper, plastic, metal, and glass can be re-used.

Recovery of energy : Energy is stored in chemical form in all MSW materials that contain organic compounds, i.e. which can be used to generate electricity and steam.

Bioconversion : The natural organic components of MSW (Food and plant wastes, paper, etc) can be composted aerobically to carbon dioxide, water, and a compost product that can be used as soil conditioner. Anaerobic digestion or fermentation produces methane, alcohol and a compost product.

Land filling : MSW materials that cannot be subjected to any of the above three method, plus any residuals from these processes (e.g. ash from combustion) must be disposed in properly desinged landfills.

Pathways for processing of Municipal solid waste

Processing Intermediate Products

Materials for Market

Conversion to Energy

Incineration

Compost

Anaerobic Digestion

Pyrolisis

Gasification

Combustion

Co - utilisation with Fossil Fuels

Glass, Metals, Aluminium etc.

Biodegradable Fr action

Secondary Raw material

Solid Recovered Fuels

Mechanical

Separation

MSW

Waste management / Thermal treatment trends

Dumping

Sanitary Landfill

Mass Burn

GasificationPyrolysis

Hydrogen

Economically the best Environmentally the best

Disposal Methods Incineration accounts for most of the remainder,

whereas Composting of solid wastes accounts for only an

insignificant amount. Selecting a disposal method depends almost entirely

on costs, which in turn are likely to reflect local

circumstances.

Landfill

• Sanitary landfill is the cheapest satisfactory means of disposal, but only if suitable land is within economic range of the source of the wastes; typically, collection and transportation account for 75 percent of the total cost of solid waste management.

• Gases are generated in landfills through anaerobic decomposition of organic solid waste. If a significant amount of methane is present, it may be explosive; proper venting eliminates this problem.

Overflowing Landfill

A volume that rapidly overflows local dumps. Cities running out of space for landfill often turn to incinerating their waste or transporting it to other areas, although up to 90 percent of the material might have been recycled.

Incinerators

• In incinerators of conventional design, refuse is burned on moving grates in refractory-lined chambers; combustible gases and the solids they carry are burned in secondary chambers.

• Combustion is 85 to 90 percent complete for the combustible materials.

• In addition to heat, the products of incineration include the normal primary products of combustion carbon dioxide and water as well as oxides of sulfur and nitrogen and other gaseous pollutants; nongaseous products are fly ash and unburned solid residue.

Composting

• Composting operations of solid wastes include preparing refuse and degrading organic matter by aerobic microorganisms. Refuse is presorted, to remove materials that might have salvage value or cannot be composted, and is ground up to improve the efficiency of the decomposition process.

• The refuse is placed in long piles on the ground or deposited in mechanical systems, where it is degraded biologically to a humus with a total nitrogen, phosphorus, and potassium content of 1 to 3 percent, depending on the material being composted.

• After about three weeks, the product is ready for curing, blending with additives, bagging, and marketing.

Resource Recovery

• These systems fall into two groups: combustion processes and pyrolysis processes. A number of companies burn in-plant wastes in conventional incinerators to produce steam.

• A few municipalities produce steam in incinerators in which the walls of the combustion chamber are lined with boiler tubes; the water circulated through the tubes absorbs heat generated in the combustion chamber and produces steam.

• Pyrolysis, also called destructive distillation, is the process of chemically decomposing solid wastes by heat in an oxygen-reduced atmosphere.

Recycling

• The practice of recycling solid waste is an ancient one. Metal implements were melted down and recast in prehistoric times.

• Today, recyclable materials are recovered from municipal refuse by a number of methods, including shredding, magnetic separation of metals, air classification that separates light and heavy fractions, screening, and washing.

• Another method of recovery is the wet pulping process: Incoming refuse is mixed with water and ground into a slurry in the wet pulper, which resembles a large kitchen disposal unit.

Recycling Newspapers

Thermal treatment facility at Stanislaus, California

The WTE industry is one of the most highly regulated in the US. PHOTO: AMERICAN REF-FUEL

Greenhouse Gases emission associated with the disposal of MSW

Greenhouse Gas Sources and Sinks Associated with the Material Life Cycle

Landfill GasCH4 emissions

CO2

Composting or other treatment

Landfill Gas Collection

CO2

Flaring ElectricityGeneration

CO2

Reducing greenhouse gas emission from waste:

The Role of Landfill Gas Management and Carbon Finance in Solid Waste Management

Energy from MSW

Land FillingLandfills include:• any site which is used for more than a year for the

temporary storage of waste; and,• any internal waste disposal site, that is to say a site where a

producer of waste is carrying out its own waste disposal at the place of production.

Landfills do not include:• any facility where waste is unloaded in order to permit its

preparation for further transport for recovery, treatment or disposal elsewhere;

• any site where waste is stored as a general rule for a period of less than three years prior to recovery or treatment; or,

• any site where waste is stored for a period of less than one year prior to disposal.

Criteria For Selecting and Managing a Landfill Site

1. Municipal Waste Collection:

i. Preferably, a site accessible within 30 minutes travel time (a function of road and traffic conditions) should be sought, because of the need to avoid adversely affecting the productivity of collection vehicles. At distances greater than 30 minutes travel, for collection operations to be economic, investment in either large capacity collection vehicles (5 tonnes per load or greater) would be necessary.

2. Municipal Waste Transportation:

i. The area should be accessible by a competent public road, which can accommodate the additional truck traffic without significant effect on traffic flow rates. From the public road into the site, the access road to be constructed should be less than 10 km for large landfills serving metropolitan areas and less than 1 km for small landfills serving secondary cities.

ii. Collection vehicles should have lids to avoid littering neighboring streets whilst transferring waste to disposal site.

3. Municipal Waste Disposali. Adequate land area and volume to provide the

landfill capacity to meet projected needs for at least ten years, so that costly investments in access roads, drainage, fencing and weighing stations are justifiable.

ii. The land area should not be in areas where adequate buffer zones are not possible, or in areas immediately upwind of a residential area in the prevailing wind direction(s).

iii. Areas characterized by steep gradients, where stability of slopes could be/are problematic.

iv. The seasonally high table level (i.e. 10 year high) of the groundwater should be below the proposed base of any excavation or site preparation to enable landfill development.

v. No environmentally significant wetlands of important biodiversity or reproductive value, sensitive ecological and/or historical areas should be present within the potential area of the landfill development.

vi. None of the areas within the landfill boundaries should be part of the ten-year groundwater recharge area for existing or pending water supply development.

vii. There should be no private or public irrigation, or livestock water supply wells down-gradient of the landfill boundaries because they are at risk from contamination - alternative water supply sources are readily and economically available, and the owner(s) gives written consent to the potential risk of well abandonment.

viii. Area should not be in close proximity to significant surface water bodies, e.g. watercourses or dams.

ix. No known environmentally rare or endangered species breeding areas or protected living areas should be present within the site boundaries.

x. No significant protected forests should be within 0.5 km of the landfill development area.

xi. No major lines of electrical transmission or other infrastructure (e.g. sewer, water lines) should be crossing the landfill development area, unless the landfill operation would clearly cause no concern or rerouting is economically feasible.

xii. There should not be underlying limestone, carbonate, or other porous rock formations that would be ineffective as barriers to leachate and gas migration, where the formations are more than 1.5 m in thickness and present as the uppermost geological unit.

xiii. There should not be underground mines that could be adversely affected by surface activities of land filling, or mining resources, which could be rendered less accessible by land filling unless the owner(s) gives explicit, consent.

xiv. No residential development should be adjacent to the perimeter of the site boundary. The waste disposal site should be at least outside a radius of one thousand meters away from a residential or commercial area and water sources.

xv. Landscaping and protective berms should be incorporated into the design to minimize visibility of operations from residential neighborhoods.

xvi. Unstable areas are not recommended – i.e. there should not be any significant seismic risk within the region of the landfill which could cause destruction of berms, drains, or other civil works, or require unnecessarily costly engineering measures.

xvii. There should not be fault lines or significantly fractured geological structure that would allow unpredictable movement of gas or leachate are within 0.5 km of the perimeter of the proposed landfill development.

xviii. The site should not be within 3 km (or legislated distance) of an airport or landing strip as the landfills attract birds, creating the danger of aircraft striking birds – for sites located more than 3km and less than 8 km from the nearest airport, no consideration is to be given unless the aviation authority has provided written permission stating that it considers the location as not threatening to air safety.

xix. Limited office facilities should be provided for use by the supervisor and other staff. Locating this office close to the entrance to the site will allow vehicle movements into the site to be monitored. The office should be provided with basic amenities including ventilation, toilet facilities, car park (in order to avoid interference with traffic flow); and, on large sites, as area where a weigh bridge (e.g. receiving over 500 tonnes/day) could be installed.

xx. To restrict access to the site, the entire perimeter should have a suitable animal pro of barrier. This could be in the form of a wire mesh fence, or, at the minimum, a ditch constructed such that excavated material is placed to form a bund on the site side of the ditch, on which may be planted indigenous species to form a hedge barrier. A distinctive buffer zone can be established between the site of the surrounding area by planting trees and shrubs. The entrance to the site should incorporate a cattle grid to deter entry of animals and an after hours disposal area just outside the gate.

xxi. A covered area should be provided, close to the landfill area where mobile plant (bull dozers, wheeled loaders, and trucks) can be maintained. A securely locked compound should be provided for secure storage of spare parts and lubricants and tools for routine maintenance and repair. A suitably lockable diesel fuel tank should be installed in this area, sized to accommodate perhaps a week’s supply of fuel.

xxii. The presence of scavengers on a landfill is highly disruptive and can prevent modern landfill operational techniques. Where their presence is inevitable then they have to be accommodated so they cause minimal disruption.

xxiii. Groundwater quality monitoring facilities need to be provided during the site development phase. Consideration has to be made for when there will be the need in the future to install a gas monitoring system near to buildings close to the site which may become at risk from gas migration once waste land filling has started.

Waste Decomposition• The decomposition process that naturally occurs when

waste material is buried is a principal driving force in the development, operation and closure of a landfill.

• MSW contains a large proportion of organic materials that naturally decompose when landfilled. This decomposition process initially is aerobic, but after the oxygen within the waste profile is consumed, it switches over to anaerobic processes.

• Both aerobic and anaerobic processes have byproducts. In the aerobic process, the main byproducts are carbon dioxide, plus contaminated water that flows toward the base of the landfill. In the anaerobic process, carbon dioxide and methane are produced as waste decomposes. Liquid byproducts contain a large concentration of various contaminants that naturally move toward the landfill’s base.

• The decomposition process continues for many years. As this takes place, in addition to the principal byproducts already mentioned, trace quantities of materials that may have significant impacts upon the environment can be contained in both the landfill gas and in the leachate. These trace materials are generated until the landfill becomes completely stabilized. Although it isn’t known long how this will take, some estimate between 300 and 1,000 years.

• It is hoped that new aerobic and anaerobic systems shorten the time necessary to stabilize the waste, therefore reducing the amount of byproducts that are released into the environment. In addition, it is anticipated that each of these processes significantly reduce volume. Thus, larger quantities of waste can be placed in the same area, and the eventual landfill profile is more compatible with the surrounding land uses.

Phases of Solid Waste Decomposition

References: Farquhar, G. J. and F. A. Rovers. 1973. “Gas Production During Refuse Decomposition,” Water, Air, and Soil Pollution, Vol. 2.; Stanforth, R., R. Ham, M. Anderson and R. Stegmann. 1979. “Development of a Synthetic Municipal Landfill Leachate,” Journal of the Water Pollution Control Federation, Vol. 51.

Landfill Gas Recovery • The waste deposited in a landfill gets subjected, over a

period of time, to anaerobic conditions and its organic fraction gets slowly volatilized and decomposed, leading to production of landfill gas which contains a high percentage of methane (about 50%).

• Typically, production of landfill gas starts within a few months after disposal of wastes and generally lasts for 10 years or even more depending upon mainly the composition of wastes and availability of mositure. As the gas has a calorific value of around 4500 Kcal/m3, it can be used as a source of energy either for direct heating/cooking applications or to generate power through IC engines or turbines.

Advantages of Landfill Gas Recovery• Reduced GHG emissions; • Low cost means for waste disposal; and • The gas can be utilized for power generation or as

domestic fuel. Disadvantages of Landfill Gas Recovery• Inefficient gas recovery process yielding only 30-40% of

the total amount of gas actually generated. Balance gas escapes to the atmosphere (significant source of two major green house gases, carbon-dioxide and methane);

• Utilization of methane may not be feasible for remote sites;

• Cost of pre-treatment to upgrade the gas may be high; and

• Spontaneous ignition/explosions may occur due to possible build up to methane concentrations in atmosphere.

Environmental Concerns of Land Fill• A landfill’s most noticeable concern is managing air

emissions. For example, while not significantly harmful to the environment, wind-blown paper is the most frequently cited concern of many landfill’s neighbors. While it is challenging to control wind-blown paper, the amount that escapes from a landfill can be minimized through management practices, such as having the operator pick up these materials or curtailing operations on high wind days.

• Odors also may escape from the land-fill. Odors generally result from decomposing waste and are difficult to entirely eliminate. To help, the amount of water that comes in contact with the waste can be minimized, and landfill operators should avoid accumulating ponds of water within the site. Good management practices, especially when recovering landfill gas, can minimize odors.

• Controlling dust also presents challenges for landfill operators. Dust can best be managed by limiting the amount of soil that is directly exposed and is not covered with vegetation or by dust control chemicals and spraying with water, as needed.

• Carbon dioxide and methane are natural byproducts of decomposition. Approximately half of the landfill gas is carbon dioxide with the remainder being methane. Carbon dioxide is only a concern because it is a greenhouse gas. Methane, however, presents a number of problems, particularly as it migrates underground before escaping into the atmosphere.

• Methane entering enclosed structures can cause an explosion. Care also must be taken when entering subsurface structures such as manholes that are located in or around the landfill. They very likely contain gases that can asphyxiate personnel who enter them. Standard procedures are available for testing, monitoring and venting these structures before landfill personnel enter.

• Methane emitting into the atmosphere also has been cited as a significant source of greenhouse gases. The global warming potential (GWP) of MSW is estimated to be 2.32 tons of carbon dioxide per ton of landfilled waste. One ton of methane is equivalent to 25 tons of carbon dioxide from a greenhouse gas potential. So controlling methane is important to consider in the global warming debate.

• Landfill gas also contains other organic compounds, generally in trace amounts. A number of these chemicals have been cited as having potential detrimental health effects to residents near the landfill.

• Noise may have a significant impact on the environment around the landfill. Operating equipment, alarm systems and blowers on gas recovery systems can be sources of noise. Good operation generally can minimize this.

• Waste entering the landfill contains moisture that naturally, as well as by the pressure of successive layers of waste being placed, squeezes water out of the waste. Additionally, rainwater that enters the landfill, or the surface runoff that enters the site, increases the liquid materials quantity that can reach the landfill base. This liquid is referred to as leachate and is highly contaminated. If it is allowed to escape from the landfill, the leachate can contaminate groundwater resources located below the landfill.

Groundwater Contamination by Leachate

Landfill Reclamation• A relatively new approach used to expand municipal solid

waste (MSW) landfill capacity and avoid the high cost of acquiring additional land.

• It is conducted in a number of ways, with the specific approach based on project goals and objectives and site specific characteristics.

• The equipment used for reclamation projects is adapted primarily from technologies already in use in the mining industry, as well as in construction and other solid waste management operations.

Steps in Landfill Reclamation• Excavation• Soil Separation (Screening)• Processing for Reclamation of Recyclable Material or

Disposal

Excavation

• An excavator removes the contents of the landfill cell. A front-end loader then organizes the excavated materials into manageable stockpiles and separates out bulky material, such as appliances and lengths of steel cable.

Soil Separation (Screening)• A trommel (i.e., a revolving cylindrical sieve) or vibrating

screens separate soil (including the cover material) from solid waste in the excavated material. The size and type of screen used depends on the end use of the recovered material. For example, if the reclaimed soil typically is used as landfill cover, a 2.5-inch screen is used for separation. If, however, the reclaimed soil is sold as construction fill, or for another end use requiring fill material with a high fraction of soil content, a smaller mesh screen is used to remove small pieces of metal, plastic, glass, and paper.

• Trommel screens are more effective than vibrating screens for basic landfill reclamation. Vibrating screens, however, are smaller, easier to set up, and more mobile.

Steps in Project Planning• Conduct a site characterization study.• Assess potential economic benefits.• Investigate regulatory requirements.• Establish a preliminary worker health and

safety plan.• Assess project costs.

Conduct a Site Characterization Study

• The first step in a landfill reclamation project calls for a thorough site assessment to establish the portion of the landfill that will undergo reclamation and estimate a material processing rate.

• The site characterization should assess facility aspects, such as geological features, stability of the surrounding area, and proximity of ground water, and should determine the fractions of usable soil, recyclable material, combustible waste, and hazardous waste at the site.

Assess Potential Economic Benefits• Increased disposal capacity.• Avoided or reduced costs of:

—Landfill closure.—Postclosure care and monitoring.—Purchase of additional capacity or sophisticated systems.—Liability for remediation of surrounding areas.

• Revenues from:—Recyclable and reusable materials (e.g., ferrous metals, aluminum, plastic, and glass).—Combustible waste sold as fuel.—Reclaimed soil used as cover material, sold as construction fill, or sold for other uses.

• Land value of sites reclaimed for other uses.

Thus, this step in project planning calls for investigating the following areas:

• Current landfill capacity and projected demand.• Projected costs for landfill closure or expansion of

the site.• Current and projected costs of future liabilities.• Projected markets for recycled and recovered

materials.• Projected value of land reclaimed for other uses.

Investigate Regulatory Requirements

• The municipal solid wastes (management and handling) rules, 2000.

Benefits of Landfill Reclamation

• Extending landfill capacity at the current site• Generating revenues from the sale of recyclable

materials• Lowering operating costs or generating revenues

from the sale of reclaimed soil• Producing energy at MWCs• Reducing landfill closure costs and reclaiming land

for other uses• Retrofitting liners and removing hazardous materials

Drawbacks of Landfill Reclamation

• Managing hazardous materials• Controlling releases of landfill gases and odors• Controlling subsidence or collapse

Excavation of one landfill area can undermine the integrity of adjacent cells, which can sink or collapse into the excavated area.

• Increasing wear on excavation and MWC equipment

IncinerationIt is the process of direct burning of wastes in the presence of excess air (oxygen) at high temperature (about 8000C) liberating heat energy, inert gases and ash. Net energy yield depends upon the density and composition of waste, percentage of moisture and inert materials, which add to the heat loss, ignition temperature, size, and shape of the constituents, etc. Combustion results in transfer of 65-80% of the heat content of the organic matter into hot air, steam and hot water.

Advantage of Incineration• Suitable for  high calorific value waste (paper), plastics,

hospital wastes etc; • Units with continuous feed and high throughput can be set

up; • Thermal Energy recovery for direct heating/power

generation;

• Relatively noiseless and odorless; • Low land area requirement; • Can be located within city limits, reducing cost of waste

transportation; and • Hygienic. Disadvantages of Incineration• Least suitable for high moisture content/low CV wastes and

chlorinated wastes • Excessive moisture and inert content in waste affects net

energy recovery; Auxiliary fuel support may be necessary to sustain combustion;

• Toxic metals may concentrate in ash; • In addition to particulates, SO2 and NOx emission, chlorinated

compounds, ranging from HCI to organo-compounds such as a dioxins and heavy metals are a cause for concern, which requires elaborate pollution control equipment; and

• High capital costs.

Treatment of organic MSW

After the separation of inorganic and organic MSW, the organic MSW are also treated for biogas production. There are two methods for biogas production

• Aerobic digestion • Anaerobic digestion/Biomethanation

Anaerobic digestion/Biomethanation• Anaerobic digestion is the bacterial decomposition of organic

matter that occurs in the absence of oxygen. • In this process, organic fraction of the wastes is segregated and

fed to a closed container (Biogas digester) where in the presence of methanogenic bacteria and under anaerobic conditions, it undergoes bio-degradation producing methane-rich biogas and effluent.

• Biogas mainly consists of methane (about 60-75%) and carbon dioxide (about 25-40%) besides small quantities of NH3 and H2S and have Calorific value of about 5000 kcal/m3.

• Depending upon the waste composition, the biogas production range from 50-150m3/tones of wastes.

• The biogas can be utilized either for cooking/heating applications or for generating motive power or electricity though dual gas engines, low-pressure gas turbines or steam turbines.

• The sludge from anaerobic digestion, after stabilization, can be used as a soil conditioner, or as manure depending upon its composition, which is determined mainly by the composition of the inout waste.

Advantages of Anaerobic Digestion/Biomethanation• Generation of gaseous fuel; • Can be done on a small-scale; • No external power requirement unlike aerobic treatment; • Enclosed system enables all the gas produces to be collected for; • Green house gases emission to the atmosphere is avoided; • Free from bad odor, rodent and fly menace, visible pollution and

social resistance; • Modular construction of plant and closed treatment needs less

land area; and • Production of biogas and high-grade soil conditioner. Disadvantages of Anaerobic Digestion/Biomethanation• In case of digesters operated under mesophilic temperature,

destruction of pathogenic organisms may be less than that in Aerobic Composting. However, several digester systems operated at high thermophilic temperature are also available;

• It is more capital intensive compared to composting and landfill; and not suitable for wastes containing less biodegradable matter.

MSW Management in India• The per capita of MSW generated daily, in India ranges

from about 100 g in small towns to 500 g in large towns.• The growth in MSW in our urban centres has outpaced

the population growth in recent years.

For example, the population of Mumbai grew from around 8.2 million in 1981 to 12.3 million in 1991, registering a growth of around 49%. On the other hand, MSW generated in the city increased from 3 200 tonnes per day to 5 355 tonnes per day in the same period registering a growth of around 67% (CPCB 2000).

• This trend can be ascribed to our changing lifestyles, food habits, and change in living standards.

• MSW in cities is collected by respective municipalities and transported to designated disposal sites, which are normally low lying areas on the outskirts of the city.

• The average collection efficiency for MSW in Indian cities is about 72.5% and around 70% of the cities lack adequate waste transport capacities (TERI 1998).

• The insanitary methods adopted for disposal of solid wastes is, therefore, a serious health concern. The poorly maintained landfill sites are prone to groundwater contamination because of leachate production. Open dumping of garbage facilitates the breeding for disease vectors such as flies, mosquitoes, cockroaches, rats, and other pests (CPCB 2000).

• The municipalities in India face the challenge of reinforcing their available infrastructure for efficient MSW management and ensuring the scientific disposal of MSW by generating enough revenues either from the generators or by identifying activities that generate resources from waste management.

Projected Trend in Generation of MSW

Cumulative Requirement of Land (baseyear 1997), for Disposal of MSW

Methane Emissions• Indiscriminate landfilling leads to deterioration of water

quality in neighbourhood areas of landfill sites due to contamination by leachates from the landfills. This has adverse health impacts on people living nearby, causes bad odours, and the people living nearby live in the constant fear of explosion of methane gas that can accumulate at the landfill sites. Landfill gas, which is 50%–60% methane, contributes significantly to global warming. It is estimated that in 1997, the landfills released about 7 million tonnes of methane into the atmosphere, which would increase to 39 million tonnes by 2047 under BAU (business as usual) scenario (Figure 3). Emissions have been calculated using Bingemer and Crutzen’s (1987) approach, which assumes that 50% of the carbon emissions in the landfills is transformed into methane.

Emission of Methane from Landfills in India

Means of MSW Disposal in INDIA • The growth in MSW (municipal solid waste) generation in

India has out paced the growth population in recent years. • The per capita generation of MSW in India range from

about 100g in small towns to 500g in large towns. The recyclable content of waste ranges from 13% to 20% (CPCB 1994/95).

• The survey conducted by CPCB puts total municipal waste generation from class 1 and class 2 cities to around 18 million tons in 1997 (CPCB 200b).

• Disposal of waste is a major issue of concern in India. Respective municipalities collect MSW in cities and transport it to designated disposal sites, which is normally a low-lying area on the outskirts of a city.

Targeting Waste Reduction at Source

• Fees and tax incentives to promote market-mechanisms to effect source reduction.

• Mandatory standards and regulations.

• Education and voluntary compliance with policies by business and consumers.

Market Actions For Waste Reduction

• By charging for the environmental and economic costs of production and disposal of waste upfront, market forces can be employed to improve the efficiency of waste management.

• By incorporating the cost of disposal also in the production cost, tendency to use less packaging or adoption of the recyclable/reusable packaging material would be promoted.

• At the consumer end also the tendency to reuse the material would be promoted.

Mandatory Standards For Waste Reduction

• Setting mandatory standards could make business responsible for the waste it generates. For instance, Germany has implemented a mandatory recycling programme in which, theoretically, the seller of consumer goods must take back all the package waste that is produced.

• In India the regulatory agencies should take the lead in setting up rules prescribing targets for waste reduction in various manufacturing sectors.

Education and Voluntary Compliance

• The alternative policy consists of a voluntary programme of consumer education and business initiatives. One of the tools to achieve this could be adoption of EMS (Environmental Management System) which is necessarily a voluntary initiative.

• The industries adopting EMS have achieved economic benefits also while achieving better environmental performance.

Revamp Waste Collection System• Revamp the existing collection service structure to

provide community with waste bins, conveniently placed for the people to deposit domestic waste, and door to door collection of waste.

• This along with separation of waste, at source, into biodegradable and non-biodegradable components would not only reduce the cost of transportation for final disposal but also provide segregated organic waste stock for waste to energy activities.

Treatment and disposal

• Proper segregation of waste would lead to better options and opportunities for its scientific disposal.

• Recyclables for example, could be straightaway transported to recycling units, which, in turn, would pay the corporations for it, thereby increasing their income.

• Finally, the inert material that will be required to be sent to landfill would be of much lower quantity compared to un-segregated waste, consequently increasing the life of our existing disposal facilities.

Efforts towards institutional and regulatory reforms• The financial constraints, institutional problems within the departments, fragile links with other concerned agencies, lack of suitable staff, and other allied problems prevent the urban local bodies from delivering and maintaining an efficient waste management system.

• Harness and integrate the role of three other emerging actors in this field - the private sector, NGO’s, and ragpickers.

• Private sector participation can help upgrade technical and managerial expertise, increase efficiency in operation and maintenance, improve customer services, apart from bringing in the capital to support the government in its efforts at waste management.

• Non-governmental organizations can play an important role in effectively projecting the community’s problems and highlighting its basic requirements for urban services.

Source Reduction: Plastic soft-drink bottles are now 25 percent lighter than in 1977. The weight of aluminium cans has been reduced by 35 percent since 1965.

MSW - REDUCTION AT SOURCE

• Consumer goods of low or long life • Reduction in the obsolescence of consumer goods

Plastic containers

Glass containers

Once usable

10-25 times reusable

Aluminium

Steel

Glass

15 million kcal/ton.

6.6 million kcal/ton.

4.4 million kcal/ton.

MSW - VOLUME REDUCTION

MSW - REDUCTION AT SOURCE

Separation at source (in the kitchen) – the first step in a strong recycling program.

MSW - RECYCLE/ SEGREGATION AT SOURCE / RECYCLE

Containers of Australian computer waste being impounded by Filipino authorities in Manila.

MSW - DISPOSAL (EXPORT)

Wandering Garbage : In 1987, a barge filled with garbage similar to this barge traveled from New York to Mexico looking for a place to dispose of its cargo. This practice of shipping unwanted garbage to other countries continues today throughout the world.

MSW - DISPOSAL (EXPORT)

The cargo ship Khian Sea, loaded with incinerator ash from Philadelphia, is approached by a boat carrying members of the American Bureau of Shipping ( a private inspection service) as it lies at anchor off Big Stone Beach, Delaware.

MSW - DISPOSAL (EXPORT)

Scavengers sort through the trash at “ Smoky Mountain ” one of the huge metropolitan dumps in Manila, Philippines. Some 20,000 people live and work on these enormous garbage dumps. The health effects are tragic.

Waste Recycle

Waste Recycle

MSW - Recycle

Reusing discarded products is a creative and efficient way to reduce wastes. This recycling center in Berkeley, CA, is a valuable source of used building supplies and a money saver for the whole community.

MSW - RECYCLE

Recycling: Even with the growth of recycling programs during the past several years, North Americans recycle only a small percentage of the municipal solid waste generated.

MSW - RECYCLE

This playground and park utilized 3000 recycled tires.

MSW - RECYCLE