Solid Waste Management

SOLID WASTE MANAGEMENT SYED SAJID SOHAIL

CONTENTS• INTRODUCTION

• WASTE GENERATION

• COMPOSTING

• VERMICOMPOSTING

• ANEAROBIC DIGESTER

• MECHANICAL AND BIOLOGICAL TREATMENT

• WASTE TO ENERGY

• LAND FILL METHOD OF SOLID WASTE DISPOSE

• RECOMMENDATIONS

• REFERENCES

INTRODUCTION

Waste handling and separation Collection Transfer and transportSeparationProcessing Disposal

Ten factors to be considered in solid waste management :1. Geological hydrologic, and climatic circumstances, and the protection of ground

and surfacewaters2. Collection, storage, processing, and disposal methods3. Methods for closing dumps4. Transportation 5. Profile of industries 6. Waste composition and quantity 7. Political, economic, organizational, financial, and management issues8. Regulatory powers9. Types of waste management systems10.Markets for recovered materials and energy

Materials present in municipal solid waste:1. Paper and paperboard2. Glass3. Ferrous materials4. Aluminium5. Plastics6. Food wastes 7. Rubber and leather

Waste sorting or Waste segregation:

Separating the different elements found in waste streams is essential for enabling the recovery of useful materials, minimizing the amount of material sent to landfill and allowing recyclable materials to find a new incarnation. Companies sort and recycle materials in order to extract value.

1. Trommel separators/ drum screens

2. Eddy current separator

3. Induction sorting

4. Near infrared sensors

5. X-ray technology

COMPOSTINGSYED SAJID SOHAIL

“Composting is the biological decomposition of the biodegradable organic fraction of MSW under controlled conditions to a state sufficiently stable for nuisance-free storage and handling and for safe use in land applications.”

The organisms that are actively involved in composting can be classified into six broad groups. Named in order of decreasing abundance, the groups are: (1) Bacteria, (2) actinomycetes,(type of bacteria which resembles Fungi) (3) Fungi, (4) Protozoa, (5) Worms, and (6) Some larvae

Composting is carried out in two ways: • Aerobically (in presence of oxygen) • Anaerobically (in absence of oxygen).

Advantages of composting: 1. By proper decomposition, biodegradable waste gets converted into good quality organic manure whereby waste is turned into wealth. 2. Prevents vector breeding and breeding of rodents 3. In aerobic composting process considerable heat is generated, resulting in destruction of pathogens and weed seeds. 4. Insanitary conditions arising out of solid waste are removed and aesthetically, environment looks neat and clean.

The factors affecting the composting process are: (a) Micro-organisms (b) Moisture (c) Temperature (d) Carbon/ Nitrogen (C/N) ratio.

Types of composting: Backyard or Onsite Composting

Aerated (Turned) Windrow CompostingTurned Windrow AerationIn-Vessel CompostingComposting by organic waste converter machine:

WINDROW COMPOSTING

EXAMPLE: CALCULATION OF LAND REQUIRED FOR PRESENT CONDITION(KAKINADA TOWN):1. Volume of material to be composted = 7m3/day2. Composting period (detention time) = 45days3. Total volume of material on pad = 45 days × 7 m3/day = 315m34. Dimensions of windrow(ASSUMING)Length= 15 m Height= 1.8mWidth= 2.5m5. Volume of windrow: V = 2⁄3 × (1.8*2.5) × 15m3= 45m36. Number of windrows = total volume of material/volume of windrow = 315/ 45 = 77. Distance between windrows = 3m8. Space around perimeter of composting area = 3 m9. Length of composting area = windrow length and perimeter space = 15 m + 2(3) = 21m10. Width of composting area: width of windrows + distances between windrows + perimeter space = (7*2.4) + (6× 3) + (2 × 3) = 16.8 + 18 + 6 = 40.8m11. Area required = length × width = 40.8*21 = 856.6m2FOR KAKINADA : 857 m2 i.e. 0.212acres or 21.2( APROX 21.5) cents of land is needed

CALCULATION OF LAND REQUIRED IF PROPERLY SEGREGATED (ROUGH):1. Volume of material to be composted = 70 m3/day2. Composting period (detention time) = 45 days3. Total volume of material on pad = 45 days × 70m3/day = 3150m34. Dimensions of windrow (ASSUMING)20Length = 20 m Height = 1.8 mWidth = 2.5 m5. Volume of windrow: V = 2⁄3 × (1.8*2.5) × 20 m3= 60 m36. Number of windrows = total volume of material/volume of windrow = 3150/ 60 = 52.5=537. Distance between windrows = 3 m8. Space around perimeter of composting area = 3 m9. Length of composting area = windrow length and perimeter space =20m + 2(3) = 26 m10. Width of composting area: width of windrows + distances between windrows + perimeter space = (53*2.4) + (6× 3) + (2 × 3) = 127.2 + 18 + 6 = 151.2 m11. Area required = length × width = 151.2*26 = 3931.2m2FOR KAKINADA: 3931.2 m2 i.e. 0.9714acres or 97.14( APROX 97.5) cents of land is needed.

Composting by organic waste converter machine:Organic waste converter is an odorless, cost-effective and environmental friendly method to treat organic garbage. To convert the organic waste, other ingredients are spoonful’s of culture to convert the organic matter into manure, herbal pesticides to neutralize the odor and small proportions of dry materials such as sawdust, husk or wood peelings to absorb the moisture in the organic matter.

Potential User Groups of decentralize disposal options:Community Cluster of minimum 1000 families in 200 meter radius with availability of open public area for curing of treated material.1) Large Housing Complex 2) Building Cluster in lane 3) Institutional Campus 4) Markets

bulkwaste generators generating minimum 500kg of Segregated Organic Waste per day with availability of open Public area for curing of treated material. 1) Temples 2) Industrial 3) Canteen Clubs4) Resorts 5) Hospitals 6) Hotels

Infrastructure Resources required:Organic Waste Converter: OWC60 OWC130 OWC300Cabin Space for OWC: 3M x 4M 3M x 4M 3M x 4M Open Space for Curing: 40 sq.mt 60 sq.mt 150 sq.mt.

Operating Quantity: In India excel l.m.t is leading supplier of the owc and following are its models, Kakinada is presently using owc130.

Model: OWC 60 OWC130 OWC300Maximum Organic Waste load kg per day 500kg 1000kg 3000kg Estimate of Coverage (no.of families) 1000 2000 6000 Waste treatment per month 15000kg 30000kg 90000kg

Procedure: The organic waste is first shredded in to small pieces either in the shredding machine or any other proper shredder. In Kakinada OWC plant we have two types of shredders

After shredding the waste is taken in the organic waste converter for five minute. Add dry waste like sawdust to absorb moisture. For 35kg wet waste we add 15 kg dry waste. Add bioculumof 50 grams per 50 kg organic waste and switch on the OWC for 5 more minutes. The compost is collected in the tray provided at bottom and is sent to curing for 10 days.

VermicompostingSAJID SOHAIL. SYED

Look deep into nature, and then you will understand everything better.

Albert Einstein

Vermicomposting is the process by which worms are used to convert organic materials (usually wastes) into a humus-like material known as vermicompost.

Difference between vermi culture and vermicomposting:

Vermiculture is the culture of earthworms. The goal is to continually increase the number of worms in order to obtain a sustainable harvest.

Vermicomposting is the process by which worms are used to convert organic materials (usually wastes) into a humus-like material known as vermicompost.

ANECICENDOGEICEPIGEIC

Enemies of Worms: Rat/moles, Frog, Birds, Flatworms, Red ant, Ferficula, Centipedes, Protection from Rat --Use of Trap, Net, Cat and Rodenticides Protection from Frog/Toad -- Pick up manually Protection from Birds --Cover by Jute bags at vermi tank/container Protection from Flatworms -- Pick up manually, and kill Protection from Red ant/Ferficula/Centipedes -- Use of Neem and Bakaino Protection from Fly larvae -- Cover with soaked newspaper and jute bags in container.

The earthworm can be used as:a) Fish food b) Aquariumc) Poultry d) Piggery e) Human food and f) Medicine

Some biological information about earthworm: 1. Earthworm has one brain and fivehearts. 2. They have neither eyes nor ears. 3. They breathe through its moist skin. 4. They have no teeth but it has gizzard for grinding its food. 5. Worms are hermophrodic animals i.e each worm has both male and female reproductive organ and each produce cocoon. Reproductive rate is very fast. 6. Cocoon or egg case of redworm is round or oval shaped and small. Theychange color during their development, first white, becoming yellow, later brown. When new worms are ready to emerge, the cocoons are turning red. 7. Redworms reproduce very rapidly. A healthy, adult redworm can produce an egg capsule every seven to ten days under optimum condition. In one year, a breeder (earthworm) can produce 50 capsules.

8 ENVIRONMENT FOR WORMS:The Compost worms need five basic things: 1. An hospitable living environment, usually called “bedding”; 2. A food source;3. Adequate moisture (greater than 50% water content by weight); 4. Adequate aeration; 5. Protection from temperature extremes. 6. pH

Types of vermicomposting:There are three basic types of vermicomposting systems of interest to farmers:1)windrows,2)beds or bins,3) flow-through reactor.

Steps inVermi Composting : 1. Preparation :Waste collection, Sorting, Size reduction, Mixing.2. Aerobic Degradation: Box, bin, pile or chamber, Aeration, Addition of EM activator, Moisture control 3. Vermi Composting: Introduction of worms ,Monitoring, Harvesting .4. Maturation : Hatching of cocoons, Separation of vermin.5. Screening: 8 mm & 4 mm screens.7. Packaging:1kg, 5 kg, and 50 kg Bags.8. Storage9. Marketing: Nurseries, Farmers cooperatives, Fertilizer dealers, Department stores.

Vermic compost is very costlier than ordinary compost ( nearly 20 times )

5. ANEAROBIC DIGESTOR

FIG: FLOWCHART OF DEGRADATION

Fig: digestion process

a) Inlet tank for feedstock. b) Digester tank. c) Effluent tank. d) Effluent storage tank. e) Effluent pump. f) Gasholder drum.

The anaerobic digestion of the organic waste matter occurs in three different stages:• Hydrolysis• Acidogenesis• Methanogenesis

EXAMPLE: Design of Anaerobic digester with gas storage:

Per person contribution of organic waste is : 100 gram/day: 0.1 kg/day

Organic waste in Kakinada per day : 3,00,000*0.1 : 30,000kg/day

Organic waste in Kakinada per month : 30*30,000 kg/monthOrganic waste in Kakinada per month : 9,00,000 kg/ month

Organic waste in Kakinada per two month : 18,00,000kg/ 2 monthsSpecific gravity of organic waste : 1.377 to 1.530(taking ‘G’ as 1.4) Volume required for Kakinada : 18*105/ 1400

: 1285.71 Let the height be 6 meters for digester tank

Diameter for circular tank : 1285.71* 4/π* 1/6: 16.5 meters.

Height of digester tank and dome : 6 + 2.5 meters: 8.5 meters.

Area of the digester : πd2/4 : 214 sq. meters

There for the digester 5.28 cents of land is sufficient. Taking other structures required for efficient working including gas scrubber, inverter and other supporting structures the plant for Kakinada may need 30 to 50 cents of land( half acre).

Advantages: Biogas plants produce good amount of clean fuel and environment friendly organic manure Generation of biogas and fertiliser (almost complete retention of the fertiliser nutrients (N, P and K) Reduction of greenhouse gas emissions through methane recovery Combined treatment of different organic waste and wastewaters Reduction ofsolids to be handled (e.g. less excess sludge) Good pathogen removal depending on temperature

Disadvantages:• Small-and middle-scale anaerobic technology for the treatment of solid waste in middle-and low-income countries is still relatively new.• Experts are required for the design and construction, depending on scale may also for operation and maintenance.• Reuse of produced energy (e.g. transformation into, fire/light, heat and power) needs to be established.• High sensitivity of methanogenic bacteria to a large number of chemical compounds.• Sulphurous compounds can lead to odour.

Mechanical and Biological Treatment (MBT)

MBT is a term that covers a range of technologies to deal with residual municipal waste –i.e. waste that has not been collected for recycling or composting and has been left in wheelie bins or black bags.If the biological stage occurs before the mechanical treatment, it may be known as biological mechanical treatment (BMT).

The mechanical stage:The mechanical stage often has two main roles: in many (but not all) technologies, the waste is broken down into smaller parts,(e.g. by shredding removal of some recyclable material) and separate recyclable material.some approaches will use more energy than others, and some will separate recyclables more effectively than others.

The biological stage:In the biological stage the waste is either composted or digested, usually in an enclosed system. If an anaerobic digestion system is used, it should produce methane which can provide energy for the plant (and possible for export to the grid). Some systems take the composted waste and then remove more recyclables.

What happens to the non-recycled MBT outputs? MBT reduces the mass and volume of wastes, due to the removal of materials for recycling and both carbon and moisture losses. The amount of reduction is very dependent on the design and characteristics of each plant.

There are two main outputs for MBT residues, with the output type determining how the plant is operated: 1) As a low quality soil, or to landfill, also known as ‘biostabilisation.’ 2) )As a refuse derived fuel (RDF), for burning (sometimes called ‘bio drying’)

MBT can enable recovery of items that may not otherwise be collected in household systems (e.g. steel coat hangers, etc.) Potential hazardous waste contaminants of the waste stream, such as batteries, solvents, paints, fluorescent light bulbs etc, will not reach municipal landfill sites due to the sorting of the waste prior to treatment.

Potential disadvantages of MBT :Some local authorities see MBT as a means to meet recycling rates without the need for the separate collection of recyclables. These contracts may demand a fixed tonnage of waste that could undermine recycling and waste minimization efforts in the area. Some MBT plants are proposing to make RDF. If landfilled, the residue is subject to the landfill tax as well as gate fees.

Landfilling and Disposal of biodegradable waste to landfill contributes to climate change through the release of methane, a powerful climate change gas. It also makes no sense to dump recyclable resources in the ground.

Waste to energy

MSW includes commercial and residential wastes generated in municipal or notified areas in either solid or semi-solid form excluding industrial hazardous wastes but including treated bio- medical wastes. It consists of household waste, wastes from hotels and restaurants, construction and demolition debris, sanitation residue, and waste from streets.Incinerating municipal solid waste generates energy while reducing waste volumes by as much as 90% with ash disposal and air polluting emissions as the primary environmental impacts. Effective environmental management is needed to remove toxins prior to combustion to minimize pollutants.

MSW Generation in India

As per estimates more than 55 million tons of MSW is generated in India per year; the yearly increase is estimated to be about 5%. It is estimated that solid waste generated in small, medium and large cities and towns in India is about 0.1 kg, 0.3 –0.4 kg and 0.5 kg per capita per day respectively.The estimated annual increase in per capita waste generation is about 1.33 % per year.

Waste to energy path ways

Gasification and Pyrolysis (Partial or non-combustion)Gasification and pyrolysis are thermal conversion technologies that happen under different amount of air present in the system. Gasification occurs in the presence of limited amounts of air (or oxygen) that allows partial combustion of the material. Pyrolysis occurs in the complete absence of air (or oxygen). Gasification leads to combustible synthesis gas (syngas) as a final product. Syngas is a valuable commercial product used as an intermediate to create synthesis natural gas, methane, methanol, dimethyl ether and other chemicals. It can also be used directly to produce energy as a surrogate for natural gas. Pyrolysis leads to synthetic liquid fuel similar to crude oil and combustible synthetic gases. Liquid product can be mixed with crude oil and further refined to gasoline and other petroleum products.

The basic stages of the gasification process are shown in Figure

Types of Gasification        Ability to      

Operating

handle wide

Permissible Moisture

Gasifier Tar in Cold Gas variety of Dust

Design Syngas Efficiency

Energy

waste with

Particle Content

ContentRequirement Size (maximum)

        varying      

        composition      

Downdraft Low > 80% Low Moderate < 4 in ~ 40% Medium

UpdraftVery

> 80% Low Low < 2 in ~ 50% Low

High             

FluidizedHigh > 90% Moderate Very Low < 1/4 in ~ 10% High

Bed              

PlasmaVery

> 90% High Very High NA > 50% Low

Low             

Entrained Very> 80% Low Low < 1/25 in ~ 10% High

Flow Low            

PlasmaVery

Enhanced > 90% Moderate High < 4 in > 50% Low

Low

Downdraft

Typical heat values for Municipal waste components

Component Moisture present (Range)

Moisture present (typical)

Food wastes 50-80 70

Paper 4-10 6

Plastics 1-4 2

Textiles 6-15 10

Rubber 1-4 2

Leather 8-12 10

Wood 15-40 20

Estimated Heat Value for Kakinada TOWN

     Component Dry weight Heat Value(Kcal)Food Waste 16.5 18407

Paper 5.64 22415Plastics 7.35 57145

Rags/cloths/cotton 4.05 16870

Green waste , Coconuts 1 1555

Rubber & synthetics 1.37 5678.27

Leather 1.116 3725.38

TOTAL Heat Value   125799 Kcal     

Design for kakinadaThe heat value is, thus 1257 Kcal/Kg for the Kakinada waste and is amenable for combustion on a sustained basis without requiring supplementary fuel. The World Bank’s guide on ‘Incineration of Municipal Waste’ recommends that a min. Heat value (LCV) of 6000 KJ/Kg (1435 Kcal/Kg) during all the seasons for sustained combustion for adopting the Thermal treatment processTo design waste to energy plant the minimum amount of heat value must 1435 k cal/kg according to world bank guide on incineration of municipal solid waste to adopt the thermal treatment process . In Kakinada the heat value is1257 k cal/kg so the plant is not suitable in Kakinada

LANDFILL

LANDFILL

• A landfill site is a site for the disposal of waste materials by burial and is the oldest form of waste treatment. Some landfills are also used for waste management purposes, such as the temporary storage, consolidation and transfer, or processing of waste material (sorting, treatment, or recycling).

• SITE SELECTION

• The landfill site shall be large enough to last for 20-25 years.

• The landfill site shall be away from habitation clusters, forest areas, water bodies monuments, National Parks, Wetlands and places of important cultural, historical or religious interest.

• A buffer zone of no-development shall be maintained around landfill site and shall be incorporated in the Town Planning Departments land-use plans.

• Landfill site shall be away from airport including airbase. Necessary approval of airport or airbase authorities prior to the setting up of the landfill site shall be obtained in cases where the site is to be located within 20 km of an airport or airbase.

Operation:

Facilities at the Site

• Landfill site shall be fenced or hedged and provided with proper gate to monitor incoming vehicles or other modes of transportation.

• The landfill site shall be well protected to prevent entry of unauthorised persons and stray animals.

• The landfill site shall have wastes inspection facility to monitor wastes brought in for landfill, office facility for record keeping and shelter for keeping equipment and machinery including pollution monitoring equipments.

• Provisions like weigh bridge to measure quantity of waste brought at landfill site, fire protection equipments and other facilities as may be required shall be provided.

• Safety provisions including health inspections of workers at landfill site shall be periodically made.

Pollution prevention

In order to prevent pollution problems from landfill operations, the following provisions shall be made, namely :-

• Diversion of storm water drains to minimize leachate generation and prevent pollution of surface water and also for avoiding flooding and creation of marshy conditions

• Construction of a non-permeable lining system at the base and walls of waste disposal area. For landfill receiving residues of waste processing facilities or mixed waste or waste having contamination of hazardous materials (such as aerosols, bleaches, polishes, batteries, waste oils, paint products and pesticides) minimum liner specifications shall be a composite barrier having 1.5 mm high density polyethylene (HDPE) geomembrane, or equivalent, overlying 90 cm of soil (clay or amended soil) having permeability coefficient not greater than 1 x 10-7 cm/sec. The highest level of water table shall be at least two meter below the base of clay or amended soil barrier layer.

• Prevention of run-off from landfill area entering any stream, river, lake or pond.

Plantation at Landfill Site

• A vegetative cover shall be provided over the completed site in accordance with the and following specifications, namely :-

• (a) Selection of locally adopted non-edible perennial plants that are resistant to drought and extreme temperatures shall be allowed to grow;

• (b) The plants grown be such that their roots do not penetrate more than 30 cms. This condition shall apply till the landfill is stabilised;

• (c) Selected plants shall have ability to thrive on low-nutrient soil with minimum nutrient addition;

• (d) Plantation to be made in sufficient density to minimize soil erosion

Final Landfill Cover

The primary purposes of the final landfill cover are

(1)to minimize the infiltration of water from rainfall and snowfall after the landfill has been completed

(2) to limit the uncontrolled release of landfill gases

(3) to suppress the proliferation of vectors

(4) to limit the potential for fires

(5) to provide a suitable surface for the revegetation of the site

(6) to serve as the central element in the reclamation of the site.

To meet these purposes the landfill cover

must do the following :

● Be able to withstand climatic extremes

● Be able to resist water and wind erosion..

● Resist the effects of differential landfill settlement caused by the release of landfill gas

and the compression of the waste and the foundation soil.

● Resist deformations caused by earthquakes.

● Withstand alterations to cover materials caused by constituents in the landfill gas.

● Resist the disruptions caused by plants, burrowing animals, worms, and insects.

• LANDFILL DESIGN CONSIDERATIONS

Among the important topics that must be considered in the design of landfill (though not necessarily in the order given) are the following:

• 1. Layout of landfill site

• 2. Types of wastes that must be handled

• 3. The need for a convenience transfer station

• 4. Estimation of landfill capacity

• 5. Evaluation of the local geology and hydrogeology of the site

• 6. Selection of leachate management facilities

• 7. Selection of landfill cover

• 8. Selection of landfill gas control facilities

• 9. Surface water management

• 10. Development of landfill operation plan

• 11. Environmental monitoring

• 12. Public participation

Recommendations for Kakinada OR any other town/city

1) Two bin systems should be implemented in the town. 2) People should be charged based on weight or volume of waste they produce. 3) Vehicle used for domestic waste collection should be separated in to 2 components one for organic and another for inorganic.

pic: Tiruchi corporation has 100 carts for collecting segregated waste

4) Use vehicles to collect waste from shopping malls, general stores, and all small scale shops as they have only plastic and paper which are difficult to degrade.

5) Collect organic waste from hotels, hospitals, juice shops, templesas it is completely organic and can be used directly for composting purpose.

6) Food should be completely banned from landfill.no food in any case should be taken to landfill. Only non degradable waste should be sent to landfill.

7) Decentralization system should be followed. Organic waste converter plant in Kakinada should not be shifted to chendurti, as it reduces at least the transportation of organic waste.

8) Privatization: As solid waste management has become more complex, and expectations for government services have changed, political leaders have searched for different ways to provide public services without straining the capabilities of government.

Another organic waste compost plant at the site is not recommended keep using present plant, this will reduce the lead charges and also the cost.

10)Vemicompost has high retail value. Its value is even more than ten times of organic waste compost plant. So vermicomposting plant should be started at present compost plant and land fill site.

11)Segregation should use more than two technologies. If manual separation is done, it will also provide employment.

12)disposal of tyres and other toxics: tyres are among the largest and most problematic sources of waste.the recycling or tyre fires can occur easily burning for months creating substantial pollution in the air and ground .

13)In the East Godavari district the lands are very costly, there is no sign of decreasing the land costs.The available 25 acre land must be used properly. Efficiency of land use must be more. Multi use of land should be preferred.

14)land fill regulations should be followed thoroughly.it must be implemented to the extent possible.i

15)land fill solar energy covers are now starting to be taken more seriously.

16) Municipality workers must be given proper idea about segregation of waste and bring awareness regarding their work small mistakes cannot be accepted as they can lead to risks.

17)Swatch bharat: prime minister Narenda Modi launched his nation wide cleanliness campaign wide the swatch bharat mission or clean India campaign.

18)For effective management Anaerobicdigestorplant, vermicompostplant, organic machine compost plant are suitable. Proportions of waste to sent for various plants should be based on economics and ease in composting. Energy to waste plant is not suitable for Kakinada.

References: 1) Solid and LiquidWaste Management in Rural Areas by unicef. 2) HANDBOOK OF CIVIL ENGINEERING CALCULATIONS, By Tyler G. Hicks. 3) HANDBOOK OF CHEMICAL AND ENVIRONMENTAL ENGINEERING CALCULATIONS by Joseph P. Reynolds, John S. Jeris, Louis Theodore. 4) www.fao.org 5) www.waste-2-energy.eu 6) www.generalcarbon.com 7) www.sciencedirect.com 8) www.environmentalet.hypermart.net 9) http://www.waste-management-world.com 10) http://www.agriclinics.net/vermicomposting 11) http://www.sswm.info 12) http://www.karmayog.com/cleanliness/organicwastedisposal 13) http://www.moef.nic.in 14) http://www.wastedfood.com 15)Manual of On-Farm Vermicomposting and Vermiculture By Glenn Munroe 16) Urban Composting in the Technology and Engineering Classroom BY JENNIFER K. BUELIN-BIESECKER 17) www.natureherbs.com 18) HANDBOOK OF SOLID WASTE MANAGEMENT by George Tchobanoglous. 19) Journals of Indian Association Environmental Management, NEERI, Nagpur. 20) IS10193(part1)-1985, “limits of Air Quality”

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