Solid Waste Management
Praveen Kumar Singh
M. Sc. Environmental Science
Central University of Rajasthan
What are Wastes?
Waste (also known as rubbish, trash, refuse, garbage, junk, litter, and ort)
is unwanted or useless materials. In biology, waste is any of the many
unwanted substances or toxins that are expelled from living organisms,
metabolic waste; such as urea and sweat.
Basel Convention Definition of Wastes
“substances or objects which are disposed of or are intended to be disposed
of or are required to be disposed of by the provisions of the law”
“any operation which may lead to resource recovery, recycling, reclamation,
direct re-use or alternative uses (Annex IVB of the Basel convention)”
Kinds of Wastes
wastes in solid forms, domestic, commercial and industrial wastes
Examples: plastics, Styrofoam containers, bottles, cans, papers, scrap iron, and
wastes in liquid form
Examples: domestic washings, chemicals, oils, waste water from ponds,
manufacturing industries and other sources
Classification of Wastes according to their Properties
can be degraded (paper, wood, fruits and others)
cannot be degraded (plastics, bottles, old machines, cans, Styrofoam containers and
Classification of Wastes according to their Effects
on Human Health and the Environment
Substances unsafe to use commercially, industrially, agriculturally, or
economically and have any of the following properties- ignitability,
corrosivity, reactivity & toxicity.
Substances safe to use commercially, industrially, agriculturally, or
economically and do not have any of those properties mentioned above.
These substances usually create disposal problems.
Classification of wastes according to their origin
Municipal Solid wastes: Solid wastes that include household garbage,
rubbish, construction & demolition debris, sanitation residues, packaging
materials, trade refuges etc. are managed by any municipality.
Bio-medical wastes: Solid or liquid wastes including containers,
intermediate or end products generated during diagnosis, treatment &
research activities of medical sciences.
Industrial wastes: Liquid and solid wastes that are generated by
manufacturing & processing units of various industries like chemical,
petroleum, coal, metal gas, sanitary & paper etc.
Agricultural wastes: Wastes generated from farming activities. These
substances are mostly biodegradable.
Fishery wastes: Wastes generated due to fishery activities. These are
extensively found in coastal & estuarine areas.
Radioactive wastes: Waste containing radioactive materials. Usually these
are byproducts of nuclear processes. Sometimes industries that are not
directly involved in nuclear activities, may also produce some radioactive
wastes, e.g. radio-isotopes, chemical sludge etc.
E-wastes: Electronic wastes generated from any modern establishments.
They may be described as discarded electrical or electronic devices. Some
electronic scrap components, such as CRTs, may contain contaminants such
as Pb, Cd, Be or brominated flame retardants.
Sources of Wastes
Commerce and Industry
MAGNITUDE OF PROBLEM: Indian scenario
Per capita waste generation increasing by 1.3% per annum.
With urban population increasing between 3 – 3.5% per annum.
Yearly increase in waste generation is around 5% annually.
India produces more than 42.0 million tons of municipal solid waste
Per capita generation of waste varies from 200 gm to 600 gm per capita /
day. Average generation rate at 0.4 kg per capita per day in 0.1 million
Affects our health
Affects our socio-economic conditions
Affects our coastal and marine environment
Affects our climate
GHGs are accumulating in Earth’s atmosphere as a result of human
activities, causing global mean surface air temperature and subsurface
ocean temperature to rise.
Rising global temperatures are expected to raise sea levels and change
precipitation and other local climate conditions.
Changing regional climates could alter forests, crop yields, and water
This could also affect human health, animals, and many types of
Deserts might expand into existing rangelands, and features of some of our
national parks might be permanently altered.
IMPACTS OF WASTE IF NOT MANAGED WISELY
TECHNOLOGIES AVAILABLE FOR PROCESSING,
TREATMENT AND DISPOSAL OF SOLID WASTE
Composting is the decomposition of organic matter by microorganism in warm,
moist, aerobic and anaerobic environment.
Composting of MSW is the most simple and cost effective technology for treating
the organic fraction of MSW.
Main advantages of composting include improvement in soil texture and
augmenting of micronutrient deficiencies. It also increases moisture-holding capacity
of the soil and helps in maintaining soil health.
It is simple and straightforward to adopt, for source separated MSW. It does not
require large capital investment, compared to other waste treatment options. The
technology is scale neutral.
Composting is suitable for organic biodegradable fraction of MSW, yard (or
garden) waste/waste containing high proportion of lignocelluloses materials, which
do not readily degrade under anaerobic conditions, waste from slaughterhouse and
This method, however, is not very suitable for wastes that may be too wet and
during heavy rains open compost plants have to be stopped. Land required for open
compost plants is relatively large. Also, issues of methane emission, odor, and flies
from badly managed open compost plants remain.
At the operational level, if waste segregation at source is not properly carried out
there is possibility of toxic material entering the stream of MSW.
Vermi-compost is the natural organic manure produced from the excreta of
earthworms fed on scientifically semi-decomposed organic waste.
Normally, vermi-composting is preferred to microbial composting in small towns
as it requires less mechanization and it is easy to operate. It is, however, to be
ensured that toxic material does not enter the chain which if present could kill the
Waste to Energy
Even though the technology of waste to energy (WTE) projects has been proven
worldwide, its viability and sustainability is yet to be to be demonstrated and
established in the country.
The main factors that determine the techno-economic viability of WTE projects are
quantum of investment, scale of operation, availability of quality waste, statutory
requirements and project risks.
Anaerobic Digestion and Biomethanation
Biomethanation is a comparatively well-established technology for disinfections,
deodorization and stabilization of sewage sludge, farmyard manures, animal
slurries, and industrial sludge.
It leads to bio-gas/power generation in addition to production of compost (residual
sludge). This method provides a value addition to the aerobic (composting) process
and also offers certain other clear advantages over composting in terms of energy
production/consumption, compost quality and net environmental gains.
This method is suitable for kitchen wastes and, other putrescible wastes, which
may be too wet and lacking in structure for aerobic composting.
This plant is free from bad odor, rodent and fly menace, visible pollution, and
social resistance. It has potential for co-disposal with other organic waste streams
from agro-based industry. The plant can be scaled up depending on the availability
of the waste.
This method is suitable for only the organic biodegradable fraction of MSW; it
does not degrade any complex organics or oils, grease, or ligno-cellulosic materials
such as yard waste.
This method, commonly used in developed countries is most suitable for high
calorific value waste with a large component of paper, plastic, packaging material,
pathological wastes, etc.
It can reduce waste volumes by over 90 per cent and convert waste to innocuous
material, with energy recovery. The method is relatively hygienic, noiseless, and
odorless, and land requirements are minimal. The plant can be located within city
limits, reducing the cost of waste transportation.
This method, however, is least suitable for disposal of chlorinated waste and
aqueous/high moisture content/low calorific value waste as supplementary fuel may
be needed to sustain combustion, adversely affecting net energy recovery.
The plant requires large capital and entails substantial operation and maintenance
costs. Skilled personnel are required for plant operation and maintenance.
Emission of particulates, SOx, NOx, chlorinated compounds in air and toxic metals
in particulates concentrated in the ash have raised concerns.
Pyrolysis/Gasification, Plasma Pyrolysis Vitrification
(PPV)/Plasma Arc Process
Pyrolysis gasification processes are established for homogenous organic matter
like wood, pulp, etc., while plasma pyrolysis vitrification is a relatively new
technology for disposal of particularly hazardous wastes, radioactive wastes, etc.
Toxic materials get encapsulated in vitreous mass, which is relatively much safer to
handle than incinerator/gasifier ash. These are now being offered as an attractive
option for disposal of MSW also.
In all these processes, besides net energy recovery, proper destruction of the waste
is also ensured. These processes, therefore, have an edge over incineration.
This process produces fuel gas/fuel oil, which replace fossil fuels and compared to
incineration, atmospheric pollution can be controlled at the plant level. NO and SO
gas emissions do not occur in normal operations due to the lack of oxygen in the
Sanitary Landfills and Landfill Gas Recovery
Sanitary landfills are the ultimate means of disposal of all types of residual,
residential, commercial and institutional waste as well as unutilized municipal solid
waste from waste processing facilities and other types of inorganic waste and inerts
that cannot be reused or recycled in the foreseeable future.
Its main advantage is that it is the least cost option for waste disposal and has the
potential for the recovery of landfill gas as a source of energy, with net
environmental gains if organic wastes are landfilled. The gas after necessary
cleaning, can be utilized for power generation or as domestic fuel for direct thermal
Highly skilled personnel are not required to operate a sanitary landfill.
Major limitation of this method is the costly transportation of MSW to far away
Down gradient surface water can be polluted by surface run-off in the absence of
proper drainage systems and groundwater aquifers may get contaminated by
polluted leacheate in the absence of a proper leacheate collection and treatment
An inefficient gas recovery process emits two major green house gases, carbon
dioxide and methane, into the atmosphere. It requires large land area. At times the
cost of pre-treatment to upgrade the gas quality and leacheate treatment may be
There is a risk of spontaneous ignition/explosion due to possible build up of
methane concentrations in air within the landfill or surrounding enclosures if proper
gas ventilation is not constructed.
Reuse corrugated moving boxes internally.
Reuse office furniture and supplies, such as interoffice envelopes, file folders, and
Use durable towels, tablecloths, napkins, dishes, cups, and glasses.
Use incoming packaging materials for outgoing shipments.
Encourage employees to reuse office materials rather than purchase new ones.
excess building materials
old equipment to local organizations
Develop an “office recycling procedures” packet.
Send out recycling reminders to all employees including environmental articles.
Train employees on recycling practices prior to implementing recycling programs.
Conduct an ongoing training process as new technologies are introduced and new
employees join the institution.
education campaign on waste management that includes an extensive internal web
site, quarterly newsletters, daily bulletins, promotional signs and helpful reference
labels within the campus of an institution.