SOLID WASTE
MANAGEMENT
136 - 140
WHAT IS WASTE & WHY IS IT A HEALTH HAZARD
Solid waste is the unwanted or useless solid materials generated from human activities in residential,
industrial or commercial areas
Solid waste is a health hazard because:
it decomposes and favours fly breeding
it attracts rodents and vermin
the pathogens which may be present in the solid waste may be conveyed back to man's food through
flies and dust.
water and soil pollution
and creates nuisance from bad odours.
SOURCES OF SOLID WASTE
1. Street refuse
2. Market refuse
3. Stable litter
4. Industrial refuse
5. Domestic refuse( rubbish, garbage,ash)
SOLID WASTE MANAGEMENT
SORTING
STORAGE
COLLECTION
DISPOSAL
SORTING
The waste generated by them in three separate bins as follows:
Biodegradable waste: These wastes are organic material that can
be degraded by micro-organisms into simpler stable
compounds. The green colored bins or bags are used to dump
biodegradable waste. Green garbage, food waste, paper waste,
and biodegradable plastics are all common examples of
biodegradable waste that can be found in municipal solid
waste.
Non-biodegradable: Also known as "dry recyclable waste," these wastes are those
waste that cannot be degraded by microorganisms into simpler stable compounds.
Blue bins are used for the disposal of non-biodegradable wastes such as plastic
materials like wrappers, packing plastics, bottles, cans, etc. Examples of non-
biodegradable garbage include polystyrene, metal, aluminum cans, tires, paint,
poisonous chemicals, and plastics. According to the Solid Waste Management Rules
(SWM) Rules, 2016, used sanitary napkins, diapers, condoms, tampons,
incontinence sheets, and any other similar waste are classified as sanitary waste,
and should be disposed of properly with dry waste.
Domestic hazardous wastes: These are wastes which are generated from residential
households and include discarded paint drums, pesticide cans, CFL bulbs, tube
lights, expired medicines, broken mercury thermometers, used batteries, used
needles and syringes and contaminated gauge, etc. These hazardous wastes are
stored in black bags, as and when produced.
STORAGE
Galvanized steel dust bin with close fitting cover
Paper sac: Refuse is stored in the paper sack, and the sack itself is removed with the contents for
disposal and a new sack is substituted.
Public bins :
Public bins are useful for a larger number of people( usually without cover) ,kept on a concrete
platform raised 2- 3 inches above ground level to prevent flood water entering the bins.
In bigger municipalities, the bins are handled and emptied mechanically by lorries fitted with cranes.
COLLECTION
House to house collection of refuse.
Open refuse carts should be replaced by enclosed vans.
Mechanical transportation is more practical and economical.
METHODS OF WASTE DISPOSAL
Dumping
Controlled tipping or sanitary land-fill
Incineration
Composting
Manure pits
Burial
DUMPING
The refuse collected from the cities and municipal areas dumped
in the low-lying areas or open tracts of lands.
Disadvantage :
Waste lying in the open, getting dispersed by the wind to nearby
places, attracting rodents, insects, and birds, causing a risk of
transmission of diseases, and encouraging breeding of flies.
Drainage from these dumps contributes to the pollution of water
and land.
CONTROL TIPPING
Material is placed in a trench or other prepared area, adequately compacted, and covered with earth at the
end of the working day.
3 methods are used in this operation: the trench method, the ramp method and the area method
1. The trench method: Where level ground is available, the trench method is usually chosen. A long trench
is dug out 2 to 3 m deep and 4 to 12 m wide, depending upon local conditions. The refuse is compacted
and covered with excavated earth. Where compacted refuse is placed in the fill to a depth of 2 m it is
estimated that one acre of land per year will be required for 10,000 population
1. The ramp method: This method is well suited where the terrain is moderately sloping. Some excavation
is done to secure the covering material.
2. The area method: This method is used for filling land depressions, disused quarries and clay pits. The
refuse is deposited, packed and consolidated in uniform layers up to 2 to 2.5 m deep. Each layer is
sealed on its exposed surface with a mud cover at least 30 cm thick.Such sealing prevents infestation by
flies and rodents and suppresses the nuisance of smell and dust. This method often has the disadvantage
of requiring supplemental earth from outside sources.
INCINERATION
Method of disposal by burning the refuse.
It is the method of choice where suitable land is not available.
not a popular method in India because the refuse contains a fair proportion of fine ash which makes the
burning difficult.
disposal of refuse by burning is a loss to the community in terms of the much needed manure.
Expensive
COMPOSTING
Composting is a method of combined disposal of refuse and nightsoil or sludge. The organic matter breaks down under bacterial action
resulting in the formation of humus.
Methods of composting
1. Bangalore method(anaerobic)
2. Mechanical method(aerobic)
Bangalore Method:
Trenches are dug 90 cm deep, 1.5 to 2.5 m broad and 4.5 to 10 m long
First a layer of refuse about 15 cm (6 in) thick is spread at the bottom of the trench. Over this, nightsoil of 15cm(2in) is added. Then
alternate layers of refuse and nightsoil are added in the proportion of 15 cm (6 in) and 5 cm (2 in) respectively, till the heap rises to 30
cm (1 ft.) above the ground level. The top layer should be of refuse, at least 25 cm (9 in) thickness.
Then the heap is covered with excavated earth.
Within 7 days the intense heat required for the decomposition and destruction of the pathogens is formed.
Decomposition is completed in 4-6 months.
Recommended for population above 10,000.
Mechanical:
Refuse cleared of salvageable materials.
Powdered in a pulverizer .
Mixed with human night soil in a rotating machine
Incubated for 4-6 weeks.
(Entire process of composting is complete by the action of temperature,
moisture, pH and aerobic bacteriae)
MANURE PITS
The daily domestic refuse is dumped and covered with earth
after each day’s dumping.
After about 4-6 months, the refuse is converted into compost,
which can be used to the field as manure.
Burial
suitable for small camps. This is also the same as trench
method, but in the trenches, only the refuse is dumped and not
the human excreta. At the end of each day, the refuse is
covered with earth. When the trench is filled, new trench is dug
out. After 4 to 6 months, the compost is removed and used as
manure.
E – Waste Management
Toxic ingredients posing threat to occupational health
of rag pickers and environment.
Generation of E-waste at an alarming rate.
Lack of awareness and appropriate skill.
Lack of legal framework, legislature and logistics.
Burden
50 mil tons each year , increasing rate of 3-5 %
23,000 tons shipped to developing nations.
5 % of all municipal solid waste.
Only 20 % recycled, rest to landfill and incineration.
INDIA – dumping ground for developed countries – 2012 – 8,00,000 tonnes
Sources
Individual and small businesses : computers discarded mainly due to upgradation of
newer technologies.
Large Businesses, Institutions, and Establishments : waste goes to lease
companies , take old ones and send it for reuse/recycling/export markets.
Original Equipment Manufacturers : Production does not meet quality, export to
developing companies in name of free trade.
Hazards
Environmental :
Landfilled computers produces contaminated leachates – groundwater pollution. Cd –
phone battery , Pb – CRT
Incineration – toxic fumes and gases
To recover Cu , PVC cables and plastic casings burnt – toxic dioxins and furans released.
Melting computer chips – acid and sludge – acidification of soil and water contamination
Disturbance of aquatic ecosystems.
Hazards
Due to regulations , cost of waste disposal
increased.
Toxic traders and Toxic Links
Basel Convention
Geneva , Switzerland
Aim : control and reduction if trans boundary movements of hazardous wastes.
Minimise generation , environmentally sound management , active promotion and
transfer and use of technologies.
The European Parliament recently passed legislation that will
require manufacturers to take back their electronic products
when consumers discard them. This is called "Extended producer
responsibility."
Waste Minimization Techniques
Inventory Management : Improved operating , Maintenance procedures, Employee
training
Production Process Modification : Replace to Non hazardous materials, more
efficient and upgradable equipment.
Volume Reduction : Segregation , Concentration methods – RO, freeze vaporisation,
vacuum filtration
Recovery and Reuse : RO , Centrifugation, Condensation, Electrolysis, Filtration
Management
Government : District wise regulatory agencies , Strict legislation enforcements ,
Research
Industries : qualified waste handlers , adopt waste management techniques , reverse
production system , recycling and disposal.
Citizens : reusing donated and working electronics , proper disposal , NGOs
Disposal
Recycling : assembling , developing , promoting or buying of new products from
waste. Dismantle —> Remove hazardous materials and valuable materials —> Proper
disposal of hazardous and retrieval of valuable materials —> New equipments
developed.
Landfilling : dumping and/or burial of e-waste. Cd,Hg – leaches
Reusing : Direct use or use after slight modification , volume reduction
Incineration : complete combustion , reduces volume and made less hazardous.
DISPOSAL OF COW DUNG
Tight packing of cowdung under earth cover in manure pits is quite hygienic and the
prevailing practice of drying cowdung into dry cakes for fuel should be replaced by
this method. The contents of the pits afford a nitrogenous manure.
Digestion of cowdung in cowdung gas plants
Recycling
All reusable materials are separated from the refuse and used.
Paper and rags are used for paper production. Plastics are
sorted out by type and recycled separately for the manufacture
of plastic buckets, pots, mugs, etc. Glass, rubber, aluminum,
copper, iron, brass, etc. are melted and put to their respective
uses. Discarded tubelights are used for the manufacture of
laboratory glassware. Garbage and plant wastes are used for
composting. Animal excreta are separated and used for
producing biogas.
LEGISLATIVE MEASURES
ENVIRONMENT PROTECTION ACT,1986
MUNCIPAL WASTES RULE,2000( revised 2016)
