Solid Waste
Management
Dr. Roli Misra
ASAS, AUM
Solid Waste Pollution
Solid Waste
• Any unwanted or discarded material from residential, industrial, commercial, mining
and agricultural activities that cause environmental problems may be termed as soli
d waste.
• Solid waste can be broadly define as those wastes which have been rejected for furt
her use and which can neither be transported by water into stream nor can readily e
scape into the atmosphere.
Classification and Origin
Solid Waste
Domestic Municipal Industrial Agricultural
Special Waste
waste Waste Waste Waste
Domestic waste
These includes waste from household preparation, cooking and serving of food; waste paper a
nd plastics; cloth; rags; etc.
Municipal waste
• These include garbage and rubbish from households, offices, hotels, markets, etc. and als
o street refuse such as street sweepings, dirt, leaves, contents of litter receptacles, etc.
• The term garbage is generally used to putrescible or biodegradable food wastes while the
term rubbish is used to denote non putrescible or nonbiodegradable solid waste which inc
ludes combustible (paper, cloth, plastics, tyres etc.) as well as non combustible materials (
broken crockery, metals, glass, masonry waste, used metal cans and containers, etc.).
• Apart from these ashes, cinders, dead animals, abandoned vehicles, construction and de
molition wastes, septic tank sludges, pipes, wires, conduits, insulations, etc.
Industrial waste
Industrial processes, construction activities and power plants produce a wide range of
solid by products and residues.
• Non process waste – office and criteria wastes, packaging wastes, etc. which are co
mmon to al industries.
• Process waste – like tannery waste, food processing waste, plastic waste, rubber, m
etal waste, mineral waste from mineral processing units etc.
Agricultural waste
• Agricultural wastes arise from waste materials generated from animal manure, crop,
and farm remains. The solid wastes like the animal manure and other agricultural by
products are collected and dumped in the landfills.
• Waste from farms, feed lots and livestock yards.
• Agricultural waste includes paddy husk, bagasse from sugarcane, tobacco and corn r
esidue,
Special waste
This include hazardous waste from different sources waste from farms, feed lots an
d livestock yards. e.g.
A. Radioactive waste from nuclear power plants, laboratories, hospitals etc.
B. Toxic substances such as heavy metal sludges, pesticides, pharmaceuticals, etc.
C. Biological products such as enzymes, antibiotics, pathogenic and pathological
wastes, etc.
Composition of Solid waste
Apart from variations in quantity, wide variations in the composition of domestic and
municipal solid wastes may also occur depending on the following factors-
✓ Degree of urbanization and industrialization of the area
✓ Per capita income
✓ Social custom
✓ Climatic condition of the area
✓ Acceptability of packaged foods
✓ Frequency of collection by municipality, etc.
Increasing urbanization and population growth rate is considerably accountable for the i
ncreased number of landfills across the world. With the increase of population and urb
an growth, the demand for manufactured products and materials increases. As the dem
and increases, so does the increase of solid wastes.
Municipal solid wastes heap up on the roads due to improper
E disposal system. People clean their own houses and litter their
F immediate surroundings which affects the community including
F
themselves.
E
C
T
S
This type of dumping allows biodegradable materials to decompose under
uncontrolled and unhygienic conditions. This produces foul smell and breeds
various types of insects and infectious organisms besides spoiling the
aesthetics of the site.
EFF E C TS
1. Industrial solid wastes are sources of toxic metals and
hazardous wastes, which may spread on land and can
cause changes in physicochemical and biological
characteristics thereby affecting productivity of soils.
2. Municipal solid wastes heap up on the roads due to improper disposal system. It
produces foul smell and breeds various types of insects and infectious organism.
Various types of wastes like cans, pesticides, cleaning solvents, batteries (zinc, lead
or mercury), radioactive materials, plastics and e-waste are mixed up with paper,
scraps and other non-toxic materials which could be recycled. Burning of some of
these materials produces dioxins, furans and polychlorinated biphenyls, which
have the potential to cause various types of ailments including cancer.
EFF E C TS
Methods of Solid Waste Disposal
There are different methods of solid waste management. The following
are some of the recognized methods:
i. Sanitary Landfill
ii. Incineration
iii. Composting
iv. Pyrolysis
1. Sanitary Landfill
This is the most popular solid waste disposal method used today.
Garbage/rubbish is basically spread out in thin layers, compressed
and covered with soil at the end of the disposal of the waste everyday
.
1. Sanitary Landfill
Landfills are designed in such a
way that the bottom of the landfill
is covered with an impervious line
r, which is usually made of several
layers of thick plastic and sand. Th
is liner protects the ground water
from being contaminated because When the landfill is full, it is covered with
of leaching or percolation. layers of sand, clay, topsoil and gravel or
plastic foam to prevent seepage of water.
• In a sanitary landfill, complex organic waste are slowly degraded by soil m
icrobes, primarily by aerobic bacteria and fungi. Since air can not enter thro
ugh a compacted land fill, the aerobic bacteria decompose the organic solid
waste by utilizing whatever oxygen present inside the landfill. The decomp
osition by anaerobic microbes begins and this accounts for the degradation
of most of the solid waste present in landfill.
• The bacteria and fungi present in the soil aerobically metabolize these acids
into CO2 and water.
• Occasionally, anaerobic methane bacteria accumulate in landfill systems an
d generate appreciable quantities of methane gas. Most of the methane is es
cape into the atmosphere and may pose a potential fire hazards.
An ideal sanitary landfill site satisfy the following criteria-
1. It should be cheap, accessible, and at a reasonable distance.
2. It should be at least 1.5 km downwind from the commercial and residential
neighboring area.
3. It should be reasonably levelled, clear and well drained, with capacity of
use for at least 3 years.
4. Its soil should be of low permeability so that it can be used as satisfactory
cover material.
5. It should be well above the ground water table so that the underground
water supplies are not polluted.
Problems with landfilling
1- Economic Problems
The land used as landfill can not used in future as a productive farm land. Even after c
losure of the landfill site, its further use should be restricted only to some type of open d
evelopment such as a park or recreational area. Building construction in the site must be
controlled.
2- Aesthetic problems
Poorly operated landfill operations may cause problems due to bad odours, insects, bl
owing papers, rats, and scavenger birds, apart from the dust and noise from waste trans
porting vehicles and compacting operations.
3 – Environmental problems
• During landfilling operations, aerobic and anaerobic degradation takes place, liquid f
rom waste, rain water and surface runoff percolates through the refuse. This produce
s a contaminated liquid called, “leachate” which can contaminate ground water.
• Further methane and CO2 are generated during anaerobic decomposition.
2. Incineration
This method involves the burning of solid wastes
at high temperatures until the wastes are turned
into ashes. Incinerators are made in such a way
that they do not give off extreme amounts of heat
when burning solid wastes.
The good thing about this method is the fact that it
reduces the volume of waste up to 20 or 30% of the
original volume.
Advantages
• The volume of the waste is reduced to more manageable levels thereby red
ucing the transportation costs to the ultimate disposal site.
• It reduces land requirement to one-third of that required if the refuse is to
be landfilled.
• Residue after incineration, if properly carried out, is free from any degrada
ble materials and hence is no longer a source of pollution.
Disadvantage
• These waste-to-energy systems are
more expensive to set up and operate co
mpared to landfilling because they requir
e special equipment and controls, highly
skilled technical personnel.
• Possibility of air pollution if not carrie
d out properly
3. Recovery and Recycling
Recycling of resources is the
process of taking useful but
discarded items for the nex
The three R's – reduce, reuse and recycle – all t use. Plastic bags, tins, glass
help to cut down on the amount of waste we and containers are often recy
throw away. They conserve natural resources cled automatically since, in
, landfill space and energy. Plus, the three R's many situations, they are
save land and money communities must use likely to be scarce commodi
to dispose of waste in landfills. ties.
Resource recovery is a method to turn wastes into resources by recovering
usable products –both material and energy.
About 70% by weight of municipal solid waste from domestic and commer
cial areas is combustible. One ton of such a waste is approximately equal to
9 million British Thermal Units (BTU) of heat or 65 gallons of fuel oil or 900
0 cubic feet of natural gas.
4. Composting
Due to a lack of adequate space for landfills
biodegradable yard waste is allowed to
decompose in a medium designed for the
purpose. Only biodegradable waste
materials are used in composting.
Composting is environmentally friendly as well as beneficial for crops.
It requires intensive management and experienced personnel for large scale
operation.
It is a biological process in which aerobic micro-organisms, specifically fu
ngi and bacteria, convert degradable organic waste into substances like h
umus.
This finished product, which looks like
soil, is high in carbon and nitrogen.
Good quality environmentally friendly
manure is formed from the compost
that is an excellent medium for
growing plants and can be used for
agricultural purposes.
The reaction taking place during the composting generate heat and hence the c
ompost temperature raise during the process.
Depending upon the composition and nature of the waste, the waste volume is
reduced by about 30 to 60%.
The criteria for optimum composting operation
Temperature – 40 to 50*C
pH - 4.5 to 9.5
Moisture - 40 to 70%
Particle Size – 0.63 to 2.54 cm
Air - 0.5 to 0.8 cubic meter per day per kg
Carbon to Nitrogen Ratio – (35 to 50) : 1
Carbon to Phosphorous ratio – 100 : 1
Process of composting
• In natural system, the garbage is mixed with a nutrient source (e.g., sewage sludge, a
nimal manure) and a filter (e.g., wood chips) which permits the air to enter into the p
iles. The mixture which is maintained at about 50% moisture content, is kept in wind
ows having a width of about 2.5m The mixture is turned over a twice a week. Within
about 4 to 6 weeks, the temperature falls, the color darkens and a musty odour deve
lops. This indicated the completion of the process.
• The filter may then be removed and remaining humus lie material is used as soil cond
itioner.
• With mechanical system, the composting time is reduced to half of that required in na
tural systems, because of continuous aeration and mixing.
5. Vermi- Composting
Vermicomposting is the process by which worms are use
d to convert organic materials (usually wastes) into a hu
mus-like material known as vermin-compost.
Vermicomposting is a method of preparing
enriched compost with the use of earthworms. It is
one of the easiest methods to recycle agricultural w
astes and to produce quality compost. Earthworms
(Eisenia fetida, Lumbricus rubellus) consume biomass
and excrete it in digested form called worm casts.
6. Pyrolysis
This is a method of solid waste management where
by solid wastes are chemically decomposed by hea
t in low oxygen or an oxygen free environment.
In this process, the combustible constituents of the
solid waste are heated in special retort like chambe
r known as pyrolysis reactor at 600 to 1000*C.
This is an endothermic process and thus differs fro
m the conventional incineration.
This will keep the environment clean and reduce health and settlement problems.
Advantages
• Volume reduction by about 90%.
• Possibility of handling potentially hazardous
plastics e.g., PVC in a safe way.
• Absence of pollution problem.
Disadvantages
The systems that destroy chlorinated organic molecules
by heat may create incomplete combustion products,
including dioxins and furans. These compounds are
highly toxic in the parts per trillion ranges. The residu
e it generates may be hazardous wastes, requiring prop
er treatment, storage, and disposal.
Solid Waste Management Rules
• Present scenario of MSW in urban India needs to be clearly understood before lookin
g at the Municipal Solid Waste (MSW) rule.
• According to the reports of Central Pollution Control Board (CPCB), the average wast
e collection in India ranges from 50 to 90 percent. Around 94 percent of the collected
waste is disposed of in open areas in an unacceptable manner without considering th
e engineering principles.
• This has resulted in severe degradation of groundwater and surface water through le
achate, along with degradation of air through uncontrolled burning of waste.
• Since 1960’s, the government of India has been sanctioning loans for setting composti
ng plants to encourage the proper management of MSW. Despite taking many initiati
ves and implementing new technologies and methods, the rapid urbanization has co
mpounded the problem of MSW in India.
Focused attention to solid waste management however gained momentum only after the
outbreak of plague in Surat in 1994. Further due to increased public awareness of MSW
M, a public litigation was filed and resulted in the Municipal Solid Waste (Management a
nd Handling) Rules, 2000.
The MSW rule of 2000 provides detailed guidelines on various aspects of Solid Waste Ma
nagement. Central Pollution Control board (CPCB) and the State Pollution Control boa
rds (SPCB) are the nodal agencies to monitor its implementation directly in the various st
ates and Union territories of India. Rest details are in separate PDF format……..
