2. What is Waste?
A material, substance, or by-product which is
eliminated or discarded as no longer useful or required
after the completion of a process.
TYPES OF WASTES
Solid wastes: Domestic , commercial and industrial wastes especially
common as co-disposal of wastes
Examples: Plastics, bottles, cans, papers, scrap iron,
and other trash
Liquid Wastes: wastes in liquid form
Examples: Domestic washings, chemicals, oils, waste
water from ponds, manufacturing industries
and other sources
5. Types of Liquid Wastes
Polluted water body Household Waste Water
Industrial Waste Water
6. MSW principally includes:
Domestic Waste: Kitchen waste, plastic, wood, rag/cloth and any other household
garbage, Street sweeping waste, Construction and demolition debris and Sanitation
About 46 million ton of MSW is generated annually (as per census 2001)
Approx. 30,000 tones/day is generated by 23 Metro Cities in India
50,000 Tones/day are generated by Class I cities(5,00,000/-
7000 Tones of plastics waste is generated every day
Municipal Solid Waste in India:
7. MSWM in India is driven by Municipal Solid Waste (Management &
Handling) Rule, 2000 which envisages segregated storage of waste at
source, collection from source, protected transportation to the treatment
facility, establishment environmentally safe treatment system and its
operation and maintenance and safe disposal of inert rejects.
Rules are under revision and CPHEEO is also preparing revised Manual on
MSWM for urban local bodies in India
Municipal Solid Waste in India:
25. Open windrows composting:
Process: Composting is done through windrow composting method for 30 to 40
days. very popular, cheaper and Practiced in many Indian city as one of the
Limitations: Out of total mixed MSW only 10 to 15 % is converted into
compost, vvery high land requirements and 40 to 50 days of operation cycle.
Maximum part of waste goes t landfilling as rejects are more
26. CLOSED VESSEL COMPOSTING
Generally describes a group of methods that which confine
the composting materials within a building, container, or vessel.
Closed vessel composting systems can consist of metal or concrete bunkers in
which air flow and temperature can be controlled, using the principles of a
Generally the air circulation is metered in via buried tubes that allow fresh air
to be injected under pressure, with the exhaust being extracted through a bio
filter, with temperature and moisture conditions monitored using probes in the
mass to allow maintenance of optimum aerobic decomposition conditions.
27. 1st week of composting
2st week of composting
CLOSED VESSEL COMPOSTING
Well known technology for domestic sewage and organic wastes treatment, but not
for mixed MSW.
Biological conversion of biodegradable organic materials in the absence of oxygen
at temperatures 55 to 75oC.
Residue is stabilized organic matter that can be used as soil amendment after
Digestion is used primarily to reduce quantity of sludge for disposal / reuse.
Methane gas generated used for electricity / energy generation or flared.
30. The process of conversion of garbage into fuel pellets involves primarily drying,
separation of combustibles from garbage, size reduction and pelletization after
mixing with binder and additives as required.
The reduction in moisture is very crucial and can be done artificially or by natural
sun drying. Sun drying is preferred when adequate land is readily available.
However, during periods of heavy rainfall, alternate arrangements for drying will
have to be made.
Many plants in Indian cities e. Hyderabad, Kochi, Nashik etc. funded under
JnNURM but most of them are not working due to various reasons.
Considerable energy inputs required for moisture reductions, shredding,
segregation and pelletization and which is not economical.
If properly designed and segregation achieved at source can be very economical
and suitable for industrial use
REFUSE DERIVED FUEL (RDF):
32. This is an emerging technology for energy/resources recovery from organic
wastes. The system basically uses a Plasma Reactor which houses one or
more Plasma Arc Torches.
A high voltage discharge and consequently an extremely high temperature
environment (above 3000 degree Celsius).
Non-commercial has been proven technically (pilot scale) but not
commercial scale / financially in India.
Organic materials are converted to syngas composed of H2, CO.
Inorganic materials are converted to solid slag.
Syngas can be utilized for energy production or proportions can be
condensed to produce oils and waxes.
Very less land required, landfilling is also minimum.
Plasma Arc Technology/Plasma Pyrolysis Vitrification
34. Combustion of raw MSW, moisture less than 50%, Sufficient amount of
oxygen is required to fully oxidize the fuel
Combustion temperatures are in excess of 850oC
Waste is converted into CO2 and water concern about toxics (dioxin,
Any non-combustible materials (inorganic such as metals, glass) remain
as a solid, known as bottom ash (used as feedstock in cement and brick
Fly ash APC (air pollution control residue) particulates, etc
Needs high calorific value waste to keep combustion process going,
otherwise requires high energy for maintaining high temperatures
Combined technologies available for power generation
Not on commercial scale in India, some projects are in pipeline..
36. Pyrolysis involves an irreversible chemical change brought about by the action of
heat in atmosphere devoid of oxygen. Synonymous terms are thermal
decomposition, destructive distillation and carbonization.
Pyrolysis is carried out at temperature between 500 and 1000OC to produce
three component streams.
Byproducts from pyrolysis are char, liquids and gas have a large calorific value.
Certain amount of excess heat still remains which can be commercially exploited.
Many international and national companies are interested but successful model is
not available in country.
39. SANITARY LANDFILLS (ACCOMMODATE 57% OF
TOTAL MUNICIPAL SOLID WASTE):
Each day trash is spread in
Covered with a soil layer
Graded for drainage
Sanitary landfills have largely
replaced open dumps.
42. PROBLEMS WITH LANDFILLS…
Landfills require space
Produce methane gas (can be used for energy, or can cause climate
Leachate must be collected and treated
Potential for water pollution
NOT a long-term remedy