What is Solid Waste Management?

Solid Waste Management is all the activities and actions required to manage waste from its inception
to its final disposal. This includes amongst other things, collection, transport, treatment and disposal
of waste together with monitoring and regulation.

Solid Waste Collection Systems:

Door-to-Door : Involves the LA labourers entering the premises, collecting garbage from a storage
area and emptying it into the collection vehicle.

Building-to-Building: Collecting garbage from outside/adjacent to buildings, along streets or

Bell Collection: Music based collection method, where garbage collection vehicles play special music
or callers shout "dustbin" as they collect garbage.

Kerbside Collection: Closed containers placed on roadside for collection. Containers are returned to
pick up point after emptying.

Handcart Collection: Handcart collection is a type of a kerbside collection system. Labourers collect
waste stored in containers, bags of waste left at the kerbside or collect waste directly from the
resident. Handcarts must transfer their loads to a tractor, lorry or compactor for transportation to the
disposal site. In areas of the town/city that have narrow or congested roads, handcarts are often used
for collection.

Waste Pooling Sites: A centralized collection point typically located on public property no more than
a specified distance from any waste generator.

Options for Improving Collection

Some of the common methods used in waste pooling sites in

1. Public Bin Collection

Public Bin Collection: Involves people carrying their garbage to a public concrete bin. The garbage
should be discharged into the bin in a closed disposable container (e.g. plastic bag).

Stationary Trailer Collection: Similar to the public bin collection system, except that in this case, a
stationary trailer is parked at a particular location on specified collection day(s) and/or times. People
are required to discharge their waste into the trailer. LA will subsequently come and remove the trailer
for emptying.

Dumpster Collection: Similar to stationary trailer but smaller in size. Used to transfer waste
hydraulically or by means of forklift to the collection vehicle.

Public Litter Baskets/Bins: “Mini” version of waste pooling sites. Helps to reduce waste scattering
and collection, street sweeping and drain cleaning workload. For litter – e.g. lunch packet leftovers,
lottery tickets, food packaging, etc. – not for garbage.
Methods of Solid Wastes Disposal:

i. Sanitary Landfill
ii. Incineration
iii. Composting

i. Sanitary Land Filling: In a sanitary landfill, garbage is spread out in thin layers, compacted and
covered with clay or plastic foam. In the modern landfills the bottom is covered with an impermeable
liner, usually several layers of clay, thick plastic and sand. The liner protects the ground water from
being contaminated due to percolation of leachate.

Leachate from bottom is pumped and sent for treatment. When landfill is full it is covered with clay,
sand, gravel and top soil to prevent seepage of water. Several wells are drilled near the landfill site to
monitor if any leakage is contaminating ground water. Methane produced by anaerobic decomposition
is collected and burnt to produce electricity or heat.

Sanitary Landfills Site Selection:

i. Should be above the water table, to minimize interaction with groundwater.

ii. Preferably located in clay or silt.

iii. Do not want to place in a rock quarry, as water can leech through the cracks inherent in rocks into
a water fracture system.

iv. Do not want to locate in sand or gravel pits, as these have high leeching. Unfortunately, most of
Long Island is sand or gravel, and many landfills are located in gravel pits, after they were no longer
being used.

v. Do not want to locate in a flood plain. Most garbage tends to be less dense than water, so if the area
of the landfill floods, the garbage will float to the top and wash away downstream.

A large number of adverse impacts may occur from landfill operations.

These impacts can vary:

i. Fatal accidents (e.g., scavengers buried under waste piles).

ii. Infrastructure damage (e.g., damage to access roads by heavy vehicles).

iii. Pollution of the local environment (such as contamination of groundwater and/or aquifers by
leakage and residual soil contamination during landfill usage, as well as after landfill closure).

iv. Off gassing of methane generated by decaying organic wastes (methane is a greenhouse gas many
times more potent than carbon dioxide, and can itself be a danger to inhabitants of an area).

v. Harbouring of disease vectors such as rats and flies, particularly from improperly operated landfills.

ii. Incineration: The term incinerates means to burn something until nothing is left but ashes. An
incinerator is a unit or facility used to burn trash and other types of waste until it is reduced to ash. An
incinerator is constructed of heavy, well-insulated materials, so that it does not give off extreme
amounts of external heat.

The high levels of heat are kept inside the furnace or unit so that the waste is burned quickly and
efficiently. If the heat were allowed to escape, the waste would not burn as completely or as rapidly.
Incineration is a disposal method in which solid organic wastes are subjected to combustion so as to
convert them into residue and gaseous products. This method is useful for disposal of residue of both
solid waste management and solid residue from waste water management. This process reduces the
volumes of solid waste to 20 to 30 per cent of the original volume.

Incineration and other high temperature waste treatment systems are sometimes described as “thermal
treatment”. Incinerators convert waste materials into heat, gas, steam and ash. Incineration is carried
out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid,
liquid and gaseous waste. It is recognized as a practical method of disposing of certain hazardous
waste materials. Incineration is a controversial method of waste disposal, due to issues such as
emission of gaseous pollutants.

iii. Composting: Due to shortage of space for landfill in bigger cities, the biodegradable yard waste
(kept separate from the municipal waste) is allowed to degrade or decompose in a medium. A good
quality nutrient rich and environmental friendly manure is formed which improves the soil conditions
and fertility. Organic matter constitutes 35%-40% of the municipal solid waste generated in India.
This waste can be recycled by the method of composting, one of the oldest forms of disposal. It is the
natural process of decomposition of organic waste that yields manure or compost, which is very rich
in nutrients. Composting is a biological process in which micro-organisms, mainly fungi and bacteria,
convert degradable organic waste into humus like substance. This finished product, which looks like
soil, is high in carbon and nitrogen and is an excellent medium for growing plants.

The process of composting ensures the waste that is produced in the kitchens is not carelessly thrown
and left to rot. It recycles the nutrients and returns them to the soil as nutrients. Apart from being
clean, cheap, and safe, composting can significantly reduce the amount of disposable garbage.

The organic fertilizer can be used instead of chemical fertilizers and is better specially when used for
vegetables. It increases the soil’s ability to hold water and makes the soil easier to cultivate. It helped
the soil retain more of the plant nutrients.

Vermi-composting has become very popular in the last few years. In this method, worms are added
to the compost. These help to break the waste and the added excreta of the worms makes the compost
very rich in nutrients. In the activity section of this web site you can learn how to make a compost pit
or a vermi-compost pit in your school or in the garden at home.

To make a compost pit, you have to select a cool, shaded corner of the garden or the school
compound and dig a pit, which ideally should be 3 feet deep. This depth is convenient for aerobic
composting as the compost has to be turned at regular intervals in this process. Preferably the pit
should be lined with granite or brick to prevent nitrite pollution of the subsoil water, which is known
to be highly toxic. Each time organic matter is added to the pit it should be covered with a layer of
dried leaves or a thin layer of soil which allows air to enter the pit thereby preventing bad odour. At
the end of 45 days, the rich pure organic matter is ready to be used.

Composting: some benefits

i. Compost allows the soil to retain more plant nutrients over a longer period.

ii. It supplies part of the 16 essential elements needed by the plants.

iii. It helps reduce the adverse effects of excessive alkalinity, acidity, or the excessive use of chemical
fertilizer.

iv. It makes soil easier to cultivate.

v. It helps keep the soil cool in summer and warm in winter.

vi. It aids in preventing soil erosion by keeping the soil covered.

vii. It helps in controlling the growth of weeds in the garden.

Mass burn Incinerator: Mass-burn systems are the predominant form of MSW incineration. Mass-
burn systems generally consist of either two or three incineration units ranging in capacity from 50 to
1,000 tons per day; thus, facility capacity ranges from about 100 to 3,000 tons per day.

Fluidised Bed Incinerator: In a fluidised-bed incinerator, the stoker grate is replaced by a bed of
limestone or sand that can withstand high temperatures, fed by an air distribution system. The heating
of the bed and the increasing of the air velocities cause the bed to bubble, which gives rise to the term
‘fluidised’.

Fixed-Hearth Incinerators: Fixed-hearth incinerators are used extensively for medical and
municipal waste incineration. Fixed hearths can handle bulk solids and liquids. A controlled flow of
"under fire" combustion air (70 to 80 percent of the theoretical air required) is introduced up through
the hearth on which the waste sits. Bottom ash is removed by dumping into a water bath.

Rotary Kiln Incineration: Solid wastes as well as liquid wastes generated by industry are destroyed
by on-site and commercial-site rotary kiln incinerator systems. The rotary kiln is a
cylindrical refractory -lined shell that is rotated to provide a tumbling and lifting action to the solid
waste materials. 

Liquid Injection: The chemical industries generate liquid wastes that contain toxic organics. These
liquids are atomized through nozzles, exposed to high temperature fuel burner flames, vaporized,
superheated, and when combined with air in a turbulent zone attain temperature levels from 1,800 to
3,000°F thus burning the waste.

Sludge Incineration: The disposal of sewage sludge along with the incineration of household rubbish
can be integrated both in newly planned plants as well as retrofitted in older plants.

3 ‘R’ (Reduce, Reuse, Recycle)

Reduce, reuse and recycle (3R) are the three essential components of environmentally-responsible
consumer behaviour.

The concept behind the first R, reduce, is that you should limit the number of purchases that you make
in the first place.

The concept behind the second R, reuse, is that you should reuse items as much as possible before
replacing them.

The concept behind the third R, recycle, is that you should ensure that items or their components are
put to some new purpose as much as possible.