Segregation of solid waste
•
Municipal waste is being generated in ever
increasing volumes in the urban areas.
•
The schematic diagram describes how
schematic diagram - segregation of municipal
solid waste
Municipal Solid Waste
Segregated at source
Recyclable dry waste Hazardous waste Inert debris Organic fraction Non Combustibles Combustibles Biological Treatment Low grade construction paving of roads
Hospital waste Others Glass, Metal Packing material, Paper Composting vermicomposting, biogas, landfill gas Recycling Industries Fuel pallets Incinerastion Planned according to the specific requirement
Segregation of solid waste
• Household waste should be separated daily into different
bags for the different categories of waste such as
wet
and dry waste
, which should be disposed of separately.
• One should also keep a bin for
toxic wastes
such as
medicines, batteries, dried paint, old bulbs, and dried
shoe polish.
•
Wet waste,
which consists of leftover foodstuff,
vegetable peels, etc., should be put in a compost pit and
the compost could be used as manure in the garden.
•
Dry waste
consisting of cans, aluminium foils, plastics,
metal, glass, and paper could be recycled. I
Waste can be segregated as
•
1. Biodegradable and
2. Nonbiodegradable.
•
Biodegradable waste
include organic waste, e.g. kitchen
waste, vegetables, fruits, flowers, leaves from the garden, and
paper.
Nonbiodegradable waste
can be further segregated into:
a) Recyclable waste – plastics, paper, glass, metal, etc.
b) Toxic waste – old medicines, paints, chemicals, bulbs, spray
cans, fertilizer and pesticide containers, batteries, shoe polish.
c) Soiled – hospital waste such as cloth soiled with blood and
other body fluids.
The role of the rag picker
• Rag pickers are the people who are actually going
through the garbage bins to pick out the ‘rags’.
• Rag pickers contribute a great deal to waste
The role of the rag picker
•
He sells all the material he picks to the whole
NGOs
•
Certain NGOs like Vatavaran in Delhi, CEE (Centre for
Environmental Education) in Bangalore and SNDT (Srimati
Nathibai Damodar Thackersey) Women’s University in Pune have
highlighted the cause of the rag pickers and have taken initiatives
to improve their lot.
•
In Bangalore, the
Waste Wise
project was initiated in 1990 with
the aim of improving the conditions of the rag pickers and at the
same time benefiting the society and the local authorities.
•
SEWA
,
Self Employed Women’s Association
in Ahmedabad has
What is a Hazardous Waste?
• Hazardous waste is a waste with properties that make it dangerous or
potentially harmful to human health or the environment
• Ignitability - Ignitable wastes create fires under certain conditions or are
spontaneously combustible, or have a flash point less than 60 °C (140 °F).
• Corrosivity - Corrosive wastes are acids or bases (pH less than or equal to 2 or
greater than or equal to 12.5) that are capable of corroding metal containers, such as storage tanks, drums, and barrels.
• Reactivity - Reactive wastes are unstable under "normal" conditions. They can
cause explosions, toxic fumes, gases, or vapors when mixed with water.
• Toxicity - Toxic wastes are harmful or fatal when ingested or absorbed (e.g.,
containing mercury, lead, etc.). When toxic wastes are disposed of on land, contaminated liquid may drain (leach) from the waste and pollute ground water. Toxicity is defined through a laboratory procedure called the Toxicity Characteristic Leaching Procedure (TCLP).
U.S. Scenario
•
4.6% of world population
•
50% of toxic wastes
•
1/3
rdof solid wastes
•
Mining (76%), agricultural (13%), industrial
(9.5%) = 98.5%
Benefits of Recycling
•
USA recycled 83 million tons of MSW.
•
This provides an annual benefit of 182 million
metric tons of carbon dioxide equivalent
emissions reduced,
•
comparable to removing the emissions from 33
million passenger cars.
•
But the ultimate benefits from recycling are
Municipal Waste
•
On-site (at home)
•
Open Dump
•
Sanitary Landfill
•
Incineration
Incineration
•
Solves space problem but:
–
produces toxic gases like Cl, HCl, HCN, SO
2–
High temp furnaces break down hazardous compounds but
are expensive ($75 - $2K/ton)
–
Heat generated can be recovered: % of waste burnt
•
Japan 67%, Switzerland 80%, USA 6%
–
North Little Rock, AK saving $50K in heating cost and
reducing landfill requirement by 95%
–
How many MSW combustors exist in the United States? In
Open Dump
•
Unsanitary, draws pests and vermin, harmful
runoff and leachates, toxic gases
•
Still accounts for half of solid waste
Sanitary Landfill
•
Sanitary Landfill
–
Layer of compacted trash covered with a layer of earth once
a day and a thicker layer when the site is full
–
Require impermeable barriers to stop escape of leachates:
can cause problem by overflow
–
Gases produced by decomposing garbage needs venting
–
1 acre/10,000 people: acute space problem: wastes piling
up over 150 million tons/year;
–
# of landfills down from 8000(1988) to 3091(1996)
–
NIMBY, NIMFYE, NIMEY, NOPE
Monitoring of Sanitary Landfills
•
Gases: Methane, Ammonia, Hydrogen sulphide
•
Heavy Metals: Lead, Chromium in soil
•
Soluble substances: chloride, nitrate, sulfate
•
Surface Run-offs
•
Vegetation: may pick up toxic substances
•
Plant residue in soil
Ocean Dumping
•
Out of sight, free of emission control norms
•
Contributes to ocean pollution
•
Can wash back on beaches, and can cause death of
marine mammals
•
Preferred method: incineration in open sea
•
Ocean Dumping Ban Act, 1988: bans dumping of
sewage sludge and industrial waste
