solid waste part-i
Post on 16-Jul-2015
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1. INTRODUCTIONDefinition:-
‘Solid wastes are all the wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted’
* Solid waste may consist of organic and inorganic waste materials such as product packaging, grass clippings, furniture, clothing, bottles, kitchen refuse, paper, appliances, paint cans, batteries etc
Composition of Solid waste in India
The composition of municipal waste varies greatly from country to country and changes significantly with time.
Impacts of solid waste on human health
Chemical poisoning through chemical inhalation of toxic gases emitted from solid wastes
Uncollected waste can obstruct the storm water runoff resulting in local area flooding
Low birth weight Cancer Congenital malformations (Related to eyes) Neurological disease (Related to brain) Odour pollution
Nausea and vomiting because of foul smell.
Increase in hospitalization of diabetic residents living near solid waste disposal sites.
Mercury toxicity from eating fish with high levels of mercury.
Problem of flies, mosquitoes, rodents (rats etc) and related diseases (Malaria, plague etc.)
Impacts of solid waste on Environment.
Waste breaks down in landfills to form methane, a potent greenhouse gas
Change in climate and destruction of ozone layer due to waste biodegradable
Visual pollution, unpleasant sights Leaching: is a process by which solid
waste enter soil and ground water and contaminating them.
2. CLASSIFICATION OF SOLID WASTE
A] Source based
1) Residential
2) Commercial
3) Institutional
4) Municipal
5) Industrial
6) Agricultural
B] Type based classification1. Garbage:- Results from handling, sale,
storage, preparation, cooking and serving of food. Comprises of putresceble organic matter. Needs special attention in handling, storage and disposal
2. Ashes and residues:- remaining from burning of combustible materials.
3. Combustible and non combustible:- paper, wood, rubber etc are combustible materials while metals, glass etc are non combustible wastes
4. Bulky wastes:- out of service Refrigerators, ACs, Furniture are catagorised under bulky waste
5. Street wastes:- wastes resulting from different street activities such as cleaning, sweeping etc. Examples are paper, plastic, garden wastes
6. Bio-degradable and non biodegradable:Wastes capable of organic decomposition are
biodegradable wastes. Examples:- food waste Wastes not capable of organic decomposition are
non biodegradable wastes. Examples:- Ferrous metals, glass etc
7. Dead animals:- Dead bodies of animals such as rats, dogs, cats etc.
8. Abandoned vehicles:- Large abandoned vehicle after their utility. Cars, Vans etc
9. Construction and demolition waste:- Waste resulting from construction and demolition activities.
10. Farm wastes:- Waste resulting from farm yard activities. Agro waste
11. Hazardous wastes:- Wastes capable of posing danger to human health. Examples:- DDT, Petroleum waste
12. Sewage wastes:- Results from sedimentation and digester tanks of waste water plant
3. Sources of Solid wastesSolid wastes come from a variety of sources
including: Residential Commercial Institutional Construction and Demolition Municipal Services Treatment Plant Sites Industrial Agricultural
Source
Typical facilities, activities or locations
Types of solid wastes
Residential
homes, flats, apartment blocks, chawls , slums etc
food wastes, paper, cardboard, plastics, textiles, yard wastes, wood, glass, metals, special wastes (e.g. bulky items such as heavy goods, batteries, oil, tyres), household hazardous wastes
Commercial
Shops, restaurants, markets, office buildings, hotels, motels, print shops, service stations, auto repair shops etc
Paper, cardboard, plastics, wood, metals, food wastes, glass, special wastes (as above), hazardous wastes
Institutional
Schools, hospitals, universities, prisons, government centres etc
As above in commercial
Construction and demolition
New construction sites, road repairs, building demolition
Wood, steel, concrete, dirt etc
Municipal services (excluding treatment works)
Street cleaning, landscaping, parks and beaches, creek bed cleaning, litter bins
Special wastes, rubbish, litter, sweepings, debris, general wastes
Treatment plant sites
Water, wastewater, industrial treatment processes etc
Effluent plus residual sludges
Municipal solid waste (MSW)
All of the above All of the above
Industrial
Construction, fabrication, light and heavy manufacturing, refineries, chemical plants, power stations, demolition etc
Industrial process wastes, scrap materials etc. Non-industrial wastes including food wastes, rubbish, ashes, demolition and construction wastes, special wastes, hazardous wastes
Agricultural
Crops, dairies, feedlots, piggeries, farms etc
Spoiled food wastes, agricultural wastes, rubbish, hazardous wastes
Factors affecting generation of Solid waste
1. Geographic location
2. Seasons
3. Collection frequency
4. Population diversity
5. Extent of recycling and salvaging
6. Public attitude
7. Legislation
The type of litter we generate and the approximate time it takes to degenerate
Type of litter Approximate time it takes to degenerate the litter
Organic waste such as vegetable and fruit peels, leftover foodstuff, etc.
a week or two.
Paper 10–30 days
Cotton cloth 2–5 months
Wood 10–15 years
Woolen items 1 year
Tin, aluminium, and other metal items such as cans
100–500 years
Plastic bags one million years?
Glass bottles undetermined
4.Physical Properties of solid wastes
1. Density This is the weight per
unit volume and is expressed as kg/m3
Critical factor in design of landfills
Inert waste such as construction and demolition waste may have higher density.
COMPONENT DENSITY(kg/m3)
Food wastes 288
Paper 81.7
Plastics 64
Garden trimmings
104
Glass 194
Ferrous metals
320
Procedure for finding out density of solid waste
1. Cubical container of 60 cm x 60 cm x 60 cm (or any known volume) is taken and empty wt is recorded.
2. Solid waste is filled to overflow in the cubical container.
3. Compaction is done by tamping the container thrice.
4. For compaction container is lifted up 6cm above the ground and dropping down squarely.
5. The top of container is leveled with the help of a straight edge.
6. Finally container is weighed.
Density = (Wt of container filled with solid waste – empty wt of
container) / volume of container
2.Moisture Content•The ratio of the weight of water to the total weight of the wet waste.•Moisture increases weight of solid wastes•Plays important role in incineration.•Wastes should be protected from rain and other water.
M=[(w-w1)/w]x100M=Moisture contentw1=weight of sample after drying at 1050 Cw= initial weight of sampleAbove table shows moisture content of some common wastes
Type of WasteMoisture ContentRange (%)
Moisture ContentTypical (%)
RESIDENTIAL
Food wastes (mixed) 50 - 80 70
Paper 4 - 10 6
Plastics 1 - 4 2
Yard Wastes 30 - 80 60
Glass 1 - 4 2
COMMERCIAL
Food wastes 50 - 80 70
Rubbish (mixed) 10 - 25 15
CONSTRUCTION & DEMOLITION
Mixed demolition combustibles
4 - 15 8
Mixed construction combustibles
4 - 15 8
INDUSTRIAL
Chemical sludge (wet) 75 - 99 80
Sawdust 10 - 40 20
Wood (mixed) 30 - 60 35
AGRICULTURAL
Mixed Agricultural waste 40 - 80 50
Manure (wet) 75 - 96 94
3. Particle Size and Distribution•Important for the recovery of materials. •Important for design of mechanical separatorsSc= l Sc= [(l+w)/2]Sc= [(l+w+h)/3]Sc= Size of componentl= Length in mmw= Width in mmh= Height in mm
4. Field Capacity•The field capacity of MSW is the total amount of moisture which can be retained in a waste sample subject to gravitational pull.•Field capacity of residential and commercial sources are in the range of 50 - 60%.
5. Permeability of Compacted Wastes•The hydraulic conductivity of compacted wastes is an important physical property because it governs the movement of liquids and gases in a landfill. •Permeability depends on the other properties of the solid material include pore size distribution, surface area and porosity.
5. Chemical properties of solid wastes
1. Proximate AnalysisProximate analysis includes four tests –
1) Loss of moisture when heated to 105°C for 1 hour;
2) Volatile combustible matter (loss on ignition);
3) Fixed carbon; and
4) Ash (weight of residue after combustion).
TYPE OF WASTE
MOISTURE VOLATILES CARBON ASH
Mixed food 70.0 21.4 3.6 5.0
Mixed paper 10.2 75.9 8.4 5.4
Mixed plastics
0.2 95.8 2.0 2.0
Yard wastes 60.0 30.0 9.5 0.5
Glass 2.0 - - 96-99
Residential MSW
21.0 52.0 7.0 20.0
Typical Proximate Analysis Values (% by weight)
2. Fusing Point of Ash•This is the temperature at which the ash resulting from the burning of waste will form a solid (clinker) by fusion. •Typical fusing temperatures are from 1100 - 1200°C.
3.Elemental Analysis•This is also known as ultimate analysis and involves the determination of carbon, hydrogen, oxygen, nitrogen, Sulphur, and ash. • The results of this analysis is used to characterize the composition of the organic matter in wastes.• This is important for C/N ratios for biological decomposition.
4.Energy Content•The energy content of the components of waste can be determined using a boiler system, laboratory bomb calorimeter, or by calculation using elemental composition. •The SI unit of measurement is kJ/kg.
Objective Questions1. Pick out odd one
i. Paper, wood, cardboard, glass
ii. Paper, tree leaves, food waste, plastic
2. Paper waste requires _____ weeks to disintegrate.
3. Leftover Food items require _______ time to disintegrate.
4. In India ___ % of solid waste is biodegradable
Theory QuestionsQ1. Classify the solid wastes based on
a. Sources
b. Types
Q2. Write short notes on
1. Physical characteristics of solid waste
2. Chemical characteristics of solid wastes
Q3. Explain procedure for finding out density of solid waste.
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