Idea Transcript
CHAPTER - II SOLID WASTE MANAGEMENT
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SOLID WASTE MANAGEMENT 2.1 Introduction “Solid waste” is the term now used internationally to describe non-liquid waste materials arising from domestic, trade, commercial, industrial, agriculture and mining activities and from the public services. Solid waste comprise countless different materials such as vegetable waste, papers, glass, plastics, wood, yard clippings, food waste, radioactive wastes and hazardous waste. Solid wastes are all the wastes arising from human and animal activities that are normally solids, semi-solids, liquids in containers and those are discarded or useless or unwanted. The term encompasses the heterogeneous accumulation of (Rao, 1991) agricultural, industrial and mineral wastes etc. Solid waste generation is a continually growing problem at global, regional and local levels. There has been a significant increase in municipal solid waste generation in India in the last few decades. The volume of garbage in Indian cities is increasing. Solid wastes create one of the most visible environmental problems in our country. The management of municipal solid waste has become an acute problem due to rapid population growth and economic development in the country (Ramachandra and Shruthi, 2007). In recent, the quantity of municipal solid waste has been increasing rapidly with growing urbanization and modern lifestyle and its composition changing (sadeeq et al., 2011). One of the serious and growing potential problems in larger urban areas is the shortage of land for waste disposal. Landfill siting is an extremely difficult task to accomplish because the site selection process depends on different factors and regulations (Yahaya et al., 2010). Environmental factors are very important because the landfill may affect the surrounding biophysical 10
environment (Sardinia, 2007). Effective Solid waste management can be achieved by controlling the waste generation and taking measures for proper collection, storage, transportation and disposal of solid waste in an environmental and economic manner. Along with these, includes legal, financial, administrative and proper planning for waste handling are the techniques for solid waste management. Integrated solid waste management includes the application of suitable techniques, better management practices and selection of better technologies for waste disposal and management (Tchobanoglous and Kreith, 2002).
2.2 Sources and Classification of Solid Waste Based on the source and type of waste, the classification of municipal solid waste is described below (Manual on Municipal Solid Waste Management, 2000).
2.2.1 Domestic/Residential Waste Domestic waste includes the solid wastes that originate during the household activities such as cleaning, packaging, gardening, cooking and repairs. The waste material consists of old books, empty containers, old furniture and newspaper. 2.2.2 Municipal Waste Municipal waste includes the waste materials arising from the domestic, institutional and commercial activities. The municipal waste comprises of dead animals, dried leaves, crushed vehicles, market waste, street waste and crushed vehicles. 2.2.3 Commercial Waste The waste materials included in the category of commercial waste are classified as garbage, rubbish, organic, inorganic, and hazardous waste and are arisen in departmental stores, offices, hotels, shops, lodges, restaurants, business centers, warehouses, markets, 11
slaughter houses and other commercial establishments. The waste materials comprise of paper, spoiled and discarded goods and packing material. 2.2.4 Institutional Waste The waste materials included in the category of institutional waste are those arising from institutions such as schools, colleges, universities, research institutes, hospitals and other educational centers. It includes waste materials such as garbage and rubbish in which some of the waste materials are harmful to human health and the environment. 2.2.5 Garbage The garbage includes the animal and vegetable waste and the waste is putrescible in nature. It consists of wastes resulting from the sale, handling, storage, cooking and consumption of food. It requires immediate removal of waste handling, storage and disposal. Because the waste produces foul odors and the waste attracts the insects, flies, rats and rodents. 2.2.6 Rubbish Rubbish includes the waste materials which are non-putrescible in nature except ash. It consists of both combustible such as paper, brushes, cardboard and wood, and noncombustible substances such as cans, glass and scrap metals, etc. 2.2.7 Ash Ash result from activities such as the burning of dung, wood, coal and other combustible materials for heating, cooking and other purposes in houses, small industrial establishments and institutions. When the huge amount of ash produced in factories and power plants will come under industrial waste.
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2.2.8 Bulky Waste
Bulky waste comprise of tyres, furniture, refrigerators, cookers, vehicle parts, trees, plastic materials, washing machines, wood etc., arising during the household activities which cannot be stored in the containers of houses.
2.2.9 Street Waste
Street waste includes the wastes that are collected from parks, streets, walkways and vacant places. The street waste comprises of plastic, dried leaves, paper, empty cigarette packs and other empty packets, cardboard and dust. Mostly in developing countries, the littering of public places is a common problem and in the developing countries manual street sweeping has seen whereas in developed countries mechanized street sweeping is practiced.
2.2.10 Dead Animals
The dead animals are divided into large animals and small animals that die naturally or accidentally killed. The large animals are donkeys, cows, sheep and horses which require immediate removal using special equipment for handling. Small animals are rats, cats, dogs and rabbits. This category of animals can be disposed by deep burial in special locations. Otherwise, dead animals attract the flies, insects and causes foul odor and health problems.
2.2.11 Construction and Demolition Waste
These categories of wastes are generated during the activities such as construction, demolition of commercial buildings, houses and other structures. The construction and demolition waste materials such as bricks, plumbing materials, concrete, plastics, stones, 13
heating systems, roofing materials and electrical wires etc., (MoUD, 2000) are mostly nonbiodegradable substances.
2.2.12 Industrial Waste The waste materials resulting from the manufacturing processes and other operations from the industries are included in the industrial waste category. This waste should not be mixed with the municipal solid waste because the waste materials arising from the industries may be hazardous and non-hazardous. They must be disposed off following the standards mentioned under the Hazardous Waste (Management & Handling) Rules, 1989.
2.2.13 Biomedical Waste
The biomedical waste is the waste that is generated during the diagnosis, treatment or immunization of human beings or animals or in research activities pertaining thereto or in the production or testing of biological components (BMW Rules, 1998). The biomedical waste should be disposed by following the Bio Medical Waste (Management & Handling) Rules, 1998. According to the characteristics of waste for their treatment and disposal, biomedical wastes are classified into ten categories. As per the BMW Rules, 1989, the different categories of biomedical waste are described in table 2.1
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Table 2.1 Biomedical Waste Types and Treatment Options Waste Category
Type of Waste Human Anatomical Waste- Human body parts, tissues and
No.1
Treatment and Disposal Method Incineration/deep burial.
organs. Animal Waste - Animal body parts, tissues, organs, Bleeding
Incineration/deep burial.
parts, experimental animals used in research, waste generated No.2
No.3
by veterinary colleges, hospitals and animal houses. Microbiology & Biotechnology Waste - Wastes from
Local autoclaving / microwaving
laboratory cultures, human and animal cell cultures and
/ incineration.
microorganisms. Chemical treatment / autoclaving Waste Sharps - Needles, syringes, scalpels, blades and glass.
No.4
shredding.
Discarded Medicine and Cytotoxic drugs - Contaminated, No.5
No.6
/microwaving and mutilation /
discarded and outdated medicines.
Incineration / destruction and drug
disposal
Solid Waste - Blooded cotton, plasters, bandages, dressings,
Incineration
linens, bedding and other materials contaminated with blood.
microwaving.
Solid Waste - Catheters, tubing, intravenous sets etc., which
securing
landfills.
Disinfection No.7
in
/
autoclaving
by
/
autoclaving/
chemical treatment/ shredding/
are not included under waste sharps. Microwaving and mutilation.
No.8
No.9
No.10
Liquid Waste - Waste generated from the washing and
Chemical
treatment
and
cleaning of laboratories and housekeeping etc.
discharge into drain.
Incineration Ash - Ash from incineration of any biomedical
Disposal in engineered landfill.
waste. Chemical Waste - Chemicals used in disinfections,
Chemical treatment -Discharge
production of biological, insecticides etc.
into drains.
Source: Manual on BMW Rules, 1989.
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2.2.14 Hazardous Waste Hazardous waste means the wastes generated from the industries or institutes cause damage to human health and the environment because of their physical, chemical and biological characteristics. Hazardous waste includes institutional waste, industrial waste and some of the waste materials from residential, commercial activities cause threat to humanity and the environment because of their characteristics. Some containers usually mixed with municipal wastes (IPCC, 2006) such as containers used for paints, solvents and pesticides and become part of the urban waste stream. This type of hazardous waste causes fire at landfill sites. The hazardous waste generating from hospitals and the radioactive wastes requires special handling. The hazardous waste should be disposed separately as per the Hazardous Waste (Management & Handling) Rules, 1989. 2.3.15 Sewage Waste The solid by-products of sewage treatment are classified as sewage wastes. The solid by-products derived from the treatment of organic sludge from both the raw and treated sewage are mostly organic in nature. At the preliminary stage of sewage treatment, the grit is separated which is the inorganic fraction of raw sewage. It must be disposed immediately which may contain pathogens and putrescible organic matter. List of different types and sources of waste is described in Table 2.2
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Table 2.2: Classification of Solid Wastes Types of Solid Waste
Description
Sources
Food waste
Wastes from the cooking and consumption of food, market
Households,
waste, waste from the handling and storage.
commercial such as hotels, stores,
(Garbage)
institutions
and
restaurants, markets, etc. Combustible (primary organic) materials include plastics,
Rubbish
paper, rubber, leaves, yard trimmings, grass, wood, cardboard, boxes, leather and cloth. Noncombustible materials include glass, ceramics, cans, stones, metals and other mineral refuse. Residue from burning used for heating and other purposes in
Ashes and Residues
houses Tyres, furniture, refrigerator, Large auto parts, stoves, trees
Bulky waste
and other large appliances. Street waste
Street sweepings, leaves, catch basin dirt, animal droppings,
Sidewalks, streets, alleys, vacant lots,
dust and dead animals.
etc.
Large animals such as donkeys, cows, horse etc. Small
Dead animals
animals such as dogs, rats, cats etc. Construction
and
demolition waste Industrial
waste
sludge
and
Concrete, stones, plaster, Lumber, wire, roofing and bricks
Construction and demolition sites,
etc.
remodeling and repair
The waste materials resulting from the manufacturing
Factories, treatment plants and power
processes and other operations in the industries such as food
plants etc.
processing wastes. Effluent treatment plant sludge of industries and sewage treatment plant sludge and grit. Hazardous wastes
Radioactive materials, toxic waste and pathological wastes.
Households,
industries,
stores,
hospitals and institutions. Horticulture wastes
Leaves, Tree-trimmings, waste from gardens and parks.
Parks, gardens, trees and public places.
Source: Bhide&Sunderasan, 1987
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2.3 Generation of Solid Waste Wastes differ in the rate of generating, quantity and quality depending upon the area of generation. The quantity and quality depend upon the source like residential areas, industrial areas or commercial areas and also may vary at different times of the year which will have a marked effect on the selection of method for its collection, processing and disposal. Generation of municipal solid waste is related to the demography of the area or city, due to which urban cities generate huge quantities of waste (Arvind et al., 2011). Among the four geographical regions of India, the highest amount of solid waste generated by North India which is 30% of solid waste generated in India i.e., 40,500 tons per day and the least amount of solid waste generated by Eastern India is 17% of all solid waste generated in India i.e.23,500 Tons per day. Among the states in India, Maharashtra,West Bengal, Uttar Pradesh, Tamilnadu and AndhraPradesh generates the highest amount of solid waste i.e., 22,000 TPD, 15,500 TPD, 13,000 TPD, 12,000 TPD and 11,500 TPD respectively. Among the Indian cities the largest amount of solid waste (11,520 TPD) is generated from the metropolitan area, Kolkata. Among union territories, Delhi generates the highest amount of solid waste i.e., 11,500 tons per day.
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Madhya pradesh 3% Rajastan 4%
Maharastra 17%
Others 16%
West Bengal 12%
Gujarat 5%
Uttar Predesh 10%
karnataka 6% Andhra Predesh 9%
Tamil Nadu 9%
Delhi 9%
Source: CPHEEO, 2005
Figure 2.1: Share of States and Union Territories in Urban MSW Generated
2.3.1 Urban Wastes In Andhra Pradesh, 14 cities are generating wastes above 50 tons a day. They are Hyderabad, Vijayawada, Guntur, Rajahmundry, Visakhapatnam, Kurnool, Nellore, Nizamabad, Warangal, Anantapur, Eluru, Kakinada, Khammam and Tirupati. The other cities generate less than 50 tons a day. They are Adoni, Bhimavaram, Chirala, Chittoor, Cuddapah, Gudivada, Guntakal, Hindupur, Karimnagar, Kothagudem and Machilipatnam etc. 2.3.2 Per Capita Waste Generation In India, the per capita waste generation is 0.44 kg/day in 2001 and has increased to 0.5 kg/day in 2011. The amount of waste generation increased by changing of food habits and life styles. Since 2001 means only in one decade, a 50% increase in the solid waste with the increase in per capita waste generation by Indian cities. In India the total municipal solid waste generated is 188, 500 TPD or 68.8 million tons per year and there are 53 cities with 19
more than million population. In these cities, the per capita waste generation is 500 grams/day and together generate the quantity of municipal solid waste is 86,000 tons per day. 2.3.3 MSW – A Growing Challenge Over the next two decades, growing urbanization in India will result in a massive increase of waste. By the year 2021, the urban population is expected to represent 41% of the overall population. A study conducted by the CPCB on the management of MSW in the country estimates that waste generation from the present 48 MT per year is expected to increase to 300 MT per year, by the year 2047 (490 g per capita to 945 g per capita). 2.4. Composition of Municipal Solid Waste in India Waste composition dictates the waste management strategy to be employed in a particular location (Oyelola and Babatunde, 2008). Organics in MSW are putrescible and are food for pests and insects and hence need to be collected and disposed off on a daily basis. Recyclables represent an immediate monetary value to the collectors. Organics need controlled biological treatment to be of any value, however due to the general absence of such facilities, organics do not represent any direct value to informal collectors. The solid waste composition of the Indian cities was shown in the figure 2.2.
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Inerts 25%
Others 4%
Metals 1% Plastic 9%
Paper 8%
Glass 1%
Biodegradabl e 48%
Rags 4%
Source: NEERI, 2005
Fig.2.2: Composition of Municipal Solid Waste in India 2.5 Characteristics of Municipal Solid Waste For better disposal, planning and management of solid waste, the information on the characteristics of wastes is necessary (Gonzalez et al., 2010). The physical and chemical characteristics of municipal solid waste are described as follows: 2.5.1 Physical Properties of Waste The major physical characteristics of MSW include density, moisture content, particle size and distribution, field capacity and Permeability of compacted wastes. 2.5.1.1 Density Density is defined as the mass per unit volume. Knowledge on Density of solid waste is necessary for proper solid waste management practices such as collection, storage, transportation and disposal of solid waste mostly for designing sanitary landfill. In landfills,
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the density may vary depending on the total amount of solid waste and daily dumping of the waste. Density also varies because of the compaction of the wastes, composition and decomposition of wastes. Density of municipal solid wastes in some Indian cities is given in table 2.3. Table 2.3: Density of Municipal Solid Wastes in Some Cities S.No
City
Density(Kg/m3)
1
Bangalore
390
2
Baroda
457
3
Delhi
422
4
Hyderabad
369
5
Jaipur
537
6
Jabalpur
395
7
Raipur
405
Source: Bhide&Sunderasan, 1987
2.5.1.2 Moisture Content Moisture content of solid waste means the weight of the moisture per unit weight of wet material. Moisture content (%) = (Wet weight -Dry weight) x100/Wet weight. A typical range of moisture content is 20-40% and it varies with the season of the year. Moisture increases the weight of the solid wastes and therefore the cost of collection and transport increases. Consequently waste should be insulated from rain or other extraneous water source. Moisture content is a critical determinant in the economic feasibility of waste
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treatment by incineration. During incineration energy must be supplied for evaporation of water and raising the temperature of the vapor. 2.5.1.3 Particle Size and Distribution Recovery of waste materials is a key element in solid waste management. For this purpose, knowledge on the size and distribution of the waste constituents is essential especially in the utilization of mechanical separators and for waste stream process. 2.5.1.4 Field Capacity The total amount of moisture content which can be retained in such amount of solid waste is known as the field capacity of solid waste. There is a significant importance on field capacity for measuring leachate generation in landfills. 2.5.1.5 Permeability of Compacted Wastes Among the physical characteristics of solid waste, permeability of compacted waste is an important character. The movement of liquids, chemicals and gases in a landfill will depend upon the hydraulic conductivity of the waste. The permeability of the wastes in leachate generation and in landfill will depend on other physical characteristics such as the pore size of the solid waste material and surface area. The physical and chemical characteristics of municipal solid waste were presented in Table 2.4 and Table 2.5
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Table 2.4: Physical Characteristics of Municipal Solid Wastes in Indian Cities Population
Number
Range (In
of Cities
Million)
Surveyed
Paper
Rubber, Leather
Glass
Metals
And Synthetics
Total
Inert
Compostable matter
0.1 to 0.5
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2.91
0.78
0.56
0.33
44.57
43.59
0.5 to1.0
15
2.95
0.73
0.35
0.32
40.04
43.59
1.0 to 2.0
9
4.71
0.71
0.46
0.49
38.95
44.73
2.0 to5.0
3
3.18
0.48
0.48
0.59
56.67
49.07
>5.0
4
6.43
0.28
0.94
0.80
30.84
53.90
Source: NEERI (1995)
2.5.2 Chemical Properties of Waste The chemical characteristics of the solid waste are described as follows: 2.5.2.1 Proximate Analysis When the solid waste material is heated to 1050c for one hour, the analysis of loss of moisture content and analysis of weight of residue after combustion (Amin and Yang, 2012) will come under proximate analysis. 2.5.2.2 Fusing Point of Ash During the combustion of the waste materials by fusion, will form a solid resulting the ash. At which temperature the ash resulting from this process is called as fusing point of ash. 2.5.2.3 Elemental Analysis This is also known as ultimate analysis. The values of nitrogen, hydrogen, sulfur, oxygen and carbon of solid wastes can be determined using the elemental analysis. To 24
characterize the composition of the waste, the elemental analysis results utilized. Ex: For biological decomposition process. 2.5.2.4 Essential Nutrients Nitrogen, phosphorous and potassium are the major nutrients used in the fertilizers. Knowledge on essential nutrients is required when the organic matter is converted into fertilizing manure by biological action i.e., for composting. Table 2.5: Chemical Characteristics of Municipal Solid Wastes in Indian Cities Moistur e
Organic matter
Nitrogen Phosphor Potassium Vs. Total ous as as K2O Nitrogen P2O3
C/N Ratio
Calorie Value kca/kg
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25.81
37.09
0.71
0.63
0.83
30.94
43.59
0.5 to1.0
15
19.52
25.14
0.66
0.56
0.69
21.13
43.59
1.0 to 2.0
9
26.89
26.89
0.64
0.82
0.72
23.68
44.73
2.0 to5.0
3
25.6
25.6
0.56
0.69
0.78
22.45
49.07
>5.0
4
39.07
39.07
0.56
0.52
0.52
30.11
53.90
Population
Number
range (In
of Cities
Million)
surveyed
0.1 to 0.5
Source: NEERI (1995)
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2.6 Municipal Solid Waste (MSW) Collection Citizens deposit the wastes by the roadside from where the Conservancy staff transfers it to the community bins using a wheelbarrow or other equipment. The location of the refuse containers should be easily accessible to both the residents and the municipal staff. The collection is one of the key elements in the solid waste stream which consists of removal of waste material and transport to the collection point and final disposal (Bhambulkar, 2011). 2.6.1 Types of Collection Solid waste collection refers to the gathering of solid waste from various sources such as residential, institutional, commercial and public places. The types of collection systems are described as follows: 2.6.1.1 Community Bins The community bins collection system is commonly found in developing countries. This method is cheaper compared to the other methods. In this method, community bins were placed in different locations and the numbers of community bins placed are depending on the total population of that area. The surrounding community members carry and throw the waste in community bins. In this method one of the most important factor is, the bins should be covered properly, collected the waste regularly and kept clean always. Otherwise may cause a public nuisance. Separate bins should be provided for biodegradable and nonbiodegradable waste materials.
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2.6.1.2 Door-to-Door Collection This is the most convenient method for householders. In this method, the waste collector collects the waste from each and every house. The household member should keep the dustbin at the doorstep when the collector arrives and the collector should collect the waste separately. 2.6.1.3 Block Collection In this method, for the collection of waste from the households, the collector set time, day and particular place in the collection vehicle. Households throw that waste in that vehicle consists of containers for collecting the waste. 2.6.1.4 Curbside Collection The home owner is responsible for placing the containers to be emptied at the curb on the collection day and for returning the empty containers to their storage location until the next collection (Tchobanoglous,1993). The table 2.6 shows the advantages and disadvantages of the collection system.
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Table 2.6: Advantages and Disadvantages of the Collection System
System
Description
Advantages
Disadvantages
Economical
Loading the waste into trucks is slow and unhygienic. Waste is scattered around the collection point. Adjacent residents and shopkeepers protest about the odor and appearance.
Households and other Dumping at allocated
generators are required to dump their waste at a specified location or in a
location built enclosure.
Shared container
Block collection
Households and other generators put their waste inside a container which is emptied or removed.
Collector sounds the hornor rings bell and wait at specified locations for residents to bring waste to the collection vehicle.
Low operating costs
If containers are not maintained they quickly corrode or damaged. Adjacent residents complain about the bad odor and appearance.
Low operating cost and less waste on the streets. No permanent container or storage to cause
If all family members are out when the collector comes, waste must be left outside for collection. It may be scattered by wind, animals and waste pickers.
Complaints.
Curbside collection
Door to door collection
Waste is left outside property in a container and Convenient. picked up by passing permanent vehicle or Swept up and storage. collected by the sweeper.
waste may not be collected or some time, causing considerable nuisance.
Waste collector collects the waste from each and Most Convenient for Residents must be available to every house by knocking resident. No waste on handle waste over. Not suitable for apartment buildings because of the the door or rings. streets. amount of Walking required.
Collection laborer Yard collection
Waste that is left out may be scattered by wind, animals, No children or waste pickers. Public If collection service is delayed,
enters property to remove waste.
The most expensive system, because of the walking involved. Very convenient for Cultural beliefs,security Residents. No waste considerations or architectural styles may prevent laborers from in street. entering properties.
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2.6.2 Storage Containers The generated waste is stored within the premises in commercial and industrial areas. Whereas in residential areas, occupants take it out and transfer to community storage bins. Plastic cans with lid are preferred for temporary storage in houses though they are subjected to damage by rats. Appropriate storage containers are required to save the energy and labor and increase the speed of collection and reduce the crew size. It is important that the containers should be functional to the type of materials and the collection vehicles used. Containers should also be durable, easy to handle, economical as well as resistant to corrosion, weather conditions, and metals, glass tips etc. Usually these are made up of thick plastics. When the mechanized collection system is used, the containers are specially designed to fit the truck mounted loading mechanisms.
2.6.3 Transportation to Disposal Sites The material collected in community bins is transferred to transport vehicles for transport to the processing or disposal site. The fleet of transport vehicles should have sufficient capacity for average and peak loads and should be utilized at optimum levels. Regular disposal of refuse is essential to maintain proper sanitation. Transfer refers to the movement of waste or materials from collection points to disposal sites. Transportation of waste from collection point to disposal sites is carried out by using different types of vehicles depending on the distances to be covered by them. Larger vehicles carry the waste from the collection points to the disposal sites. Comparatively small vehicles discharge waste at transfer stations where the wastes are loaded into larger vehicles 29
for transportation to the disposal sites. In metro cities transfer stations are located at different places to support intermediate transfer of waste from the surrounding areas up to the dumping grounds. Transfer stations are centralized facilities where the waste is unloaded from smaller collection vehicles and re-loaded into larger vehicles (including in some instances barges or railroads) for transport to a disposal or processing site. The transportation of garbage from the transfer stations is done generally using trailers and bulk refuse carriers. In large cities, open flatbed trucks, covered trucks and some compactors are in use, whereas in smaller cities tractor-trailers, tricycles and animal carts are common (Sharholy et al., 2008). Collection and transportation of MSW can be schematically shown in Fig 2.3. Door-to-door collection
Community bins
Collection from Community bins (carried out once in 24 hrs) requires manual & multiple handling of waste to dump into transportation vehicles.
Transfer Station (TS)
Disposal sites
Disposal sites
Fig 2.3: Schematic Collection and transportation of MSW 30
2.7 Segregation of Waste The municipal solid waste is mixed with a variety of components such as biodegradable and non-biodegradable substances. If they mixed together, it will be difficult for safe disposal. Segregation of the solid waste is the key element in the solid waste management. A variety of waste materials commonly found in the bins are shown in table 2.7. Table 2.7: Classification for Segregation of Wastes
Biodegradable Wastes
Non-Biodegradable Wastes
Organic Waste
Recyclable Waste
Others (Inorganic /Hazardous Waste)
Leaves/
Rubber
Some medicines
Shampoo bottles
Paints
Used Tea powder Egg Shells
Kitchen waste
Glass
Fluorescent tubes
Fruit peels
Wires
Spray cans
Meat
Metal/ Metal objects
Fertilizers, pesticide Containers
Bones
Plastic
Batteries
Flowers
Rags
Shoe polish
Leather
House dust cleaning Fruit peels
Rexine
Garden Waste
Paper (recyclable)
after
Source: A Supporting Manual for MSW Rules, 2000, CPCB, Delhi
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2.8 Waste Disposal The waste may come for disposal either directly after its transportation or after processing. A disposal could be on land or water logged areas for reclamation. The different functions are interdependent and interrelated which could be better managed by a system approach. Disposal is the final stage in the solid waste management and all the wastes whether they are residential, commercial or from any other sources are collected and transported to a disposal site. It may be a landfill site or an incinerator or some other mode of disposal. Safe disposal of solid waste is important for safeguarding the public health, environment and wildlife as well. Fig.2.4 shows the solid waste disposal methods and the disparity between countries in waste collection and their disposal were shown in table 2.8. An efficient waste management system is the one that provides the ecologically sound disposal option for waste that cannot be reduced, recycled, composted or processed further. A wide range of options is available for the safe disposal. They are listed as follows:
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Source: MOUD, 2010.
Fig.2.4: Municipal Solid Waste Disposal Methods
2.8.1 Open Dumping Open dumping is the most common and oldest method for disposal of solid waste in India, because it is a cheap method (Dhokhikah and Trihadiningrum, 2012) and requires no planning. Some components of refuse are suitable for open dumping. These include street sweepings, ashes and incombustible rubbish. However, serious nuisances and hazards will result if garbage or mixed refuse is disposed of in this manner. They include odours, dust, wind borne paper, flies, fires, rats and mosquitoes that will breed in rain water held in cans. Low lying areas which may be brought up to grade by filling are generally chosen for the dump. 33
2.8.2 Composting Composting is a biological process used for the conversion of bulk organic waste materials into fertilizing manure, known as compost. The composting process is carried out by the action of microorganisms present in the soil and waste materials and animal dung is used for the composting process. Trenches are filled with alternate layers of solid waste and dung and finally it should be covered with soil to prevent flies and insects and loss of moisture. To speed up the bacterial action, the solid waste is shredded to about 5cm in size prior to placement in digesters or bins for decomposition. In the composting process moisture content is the key element and it should be maintained by 30-40%. In 3 to 4 months, manure is ready for use. In a good composting process Carbon:Nitrogen ratio is about 30:1 to 40:1. Several components of mixed municipal solid waste are of no value in the composting process. Only biodegradable materials will be useful in the composting process. Advantages
Compost is an excellent organic additive for agricultural soils.
Its principal value when applied to the soil is acting as a good soil conditioner.
It lightens the soil, promotes aeration and helps to retain moisture by adding humus.
It has some fertilizing value. It contains about 1.5% N, 1% P2O5, 0.8% K20, 30%C and 40% ash.
Compost itself presents no health hazards, as the heat developed during composting kills the pathogens and eggs of parasites.
Completely composted material is not attractive to flies.
It may reduce the volume of total waste for disposal.
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Composting process may become more popular in the future if farmers recognize its benefits and values which are safer than the chemical fertilizer.
It contains several micronutrients needed by plant life.
It increases the permeability of the soil due to its porous nature.
The soil drainage will also improve, thereby reducing the possibility of water logging.
It enriches land fertility.
2.8.3 Vermi Composting Vermicomposting is the process by which worms are used to convert organic materials (usually wastes) into a humus-like material known as vermi compost. Vermicompost is the end product of the breakdown of organic matter by some species of earthworm (Anjaneyulu, 2004). Vermicompost is a natural fertilizer, nutrient- rich contains nitrates, phosphates, potassium and is a good soil conditioner. As a processing system, the vermicomposting of organic waste is very simple. Benefits
It is very rich organic manure.
It does not contain any chemicals harmful to the plants or man.
If done efficiently it is very cost effective.
It is ecofriendly and helps us in converting waste to wealth.
Carefully prepared vermicompost increases the production of certain crops from 3060%.
Provide micro and macro nutrients to the plants. 35
Reduces the use of chemical pesticides.
Improves the quality of crop production.
2.8.4 Ocean Dumping
The disposal of refuse by dumping into sea is possible only in case of coastal cities. While dumping the refuse, care is taken to take the refuse in barges, sufficient distance away, 2 to 3 km from the beach and dumped there. The refuse may be washed ashore under tidal conditions. This method is very costly and is not used in India.
2.8.5 Pyrolysis Pyrolysis is also referred to as destructive distillation or carbonisation. It is the thermal decomposition of organic matter at high temperature (900°C) in an inert (oxygen deficient) atmosphere or vacuum, producing a pyroligenous liquid having high heat value and is a feasible substitute of industrial fuel oil. 2.8.6 Gasification Gasification involves thermal decomposition of organic matter at high temperatures in the presence of limited amounts of air/oxygen, producing mainly a mixture of combustible and non-combustible gas (carbon monoxide, hydrogen and carbon dioxide). This process is similar to Pyrolysis, involving some secondary/different high temperatures (> 1000°C) which improve the heating value of gaseous output and increases the gaseous yield (mainly combustible gases, CO+H2) and lesser quantity of other residues.
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2.8.7 Incineration Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials. Incineration of waste materials converts the waste into ash, fuel gas and heat. The incineration of MSW essentially involves combustion of waste leading to volume reduction and recovery of heat to produce steam that in turn produces power through steam turbines. Basically, it is a furnace for burning waste and converts MSW into ash, gaseous and particulate emissions and heat energy. The efficiency of the technology is linked to the waste characteristics and their properties such as moisture content and calorific values. It requires high temperature of 8000-10000c and sufficient air and mixing of gas steam. The combustion residues include bottom ash, fly ash and non-combusted organic and inorganic materials. Modern incinerators include pollution mitigation equipment such as fuel gas cleaning. There are various types of incinerator plant design: moving grate, fixed grate, rotary-kiln and fluidized bed. The typical incineration plant for MSW is a moving grate incinerator. The advantages and disadvantages of incineration of solid wastes are as follows: Advantages
One of the most attractive features of the incineration process is that it can be used to reduce the original volume of combustibles by 80 to 95 percent (MSW Incineration, Decision Maker’s Guide, 2000).
The output (ash) is considerably more inert (stable) than incinerator input, mainly due to the oxidation of the organic component of the waste stream.
Energy from waste can be recovered.
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The waste is sanitized.
The main advantage of incineration over all other methods is the volume reduction of waste.
Disadvantages
Large initial capital is required.
Qualified technicians are required and they are not always available.
Its operation and maintenance is complex.
Operational costs are beyond the capabilities of the communities.
It is not flexible enough to treat additional quantities.
At times auxiliary fuel is required when the calorific value of the refuse is low and contains high humidity.
Control equipment is needed to avoid air pollution since no incinerator produces emissions completely free of pollution.
2.8.8 Sanitary Landfill Sanitary landfill differs from ordinary dumping in that the material is placed in a trench or other prepared area, adequately compacted and finally covered with soil at the end of the working day. The term modified sanitary landfill has been applied to those operations where compaction and covering are accomplished once or twice a week (Thomas et al., 1968). Such a landfill is a well-controlled and truly sanitary method of disposal of solid wastes upon land. It consists of four basic operations:
The solid wastes are deposited in a controlled manner in a prepared portion of the site.
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The solid wastes are spread and compacted in thin layers.
The solid wastes are covered daily or more frequently, if necessary, with a layer of earth.
The cover material is compacted daily. The final result can be a golf course or play field.
Advantages
The initial capital investment is lower than that required to implement either incineration or composting methods.
Low cost of operation and maintenance.
It is a complete and final method that can receive all types of municipal solid wastes, eliminating the problem of ashes from incineration and materials that do not degrade during composting.
In large sanitary landfills that receive more than 200 tons of refuse per day, methane gas may be recovered and used as an alternative source of energy.
It can be located near an urban area if there is available land. The costs of transportation are then reduced and the landfill can be better supervised.
It reclaims lands that can be used for the construction of parks, recreational areas, or sports fields.
A stationary landfill can begin to operate in a short time.
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Disadvantages
The acquisition of land is the first barrier to construct a sanitary landfill as opposition from the public may be strong due to lack of knowledge of the sanitary landfill technique.
Rapid urbanization has increased land cost. This means that a sanitary landfill has to be located in collection route, raising the cost of transportation.
Construction must constantly be supervised to maintain a high level of quality. In small communities, the cleaning service should make the daily supervision but should have the advice of a knowledgeable professional with experience to oversee the progress of the work from time to time.
The landfill may become an open dump if municipal administrators are reluctant to invest in operation and maintenance.
Contamination of nearby surface and groundwater may occur if proper precautions and not taken.
The most significant settlement occurs in the first two years after the landfill is completed, making the use of the land difficult. Settlement time will depend upon the death of the landfill, type of solid waste, degree of compaction and the amount of rainfall in the area.
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Table 2.8: Disparity between Countries in Waste Collection and their Disposal
Waste collection Low -income countries
40 %
Middle-income countries
60 %
High-income countries
100 %
Proper disposal 5% 30 % 100 %
Source: Cointreau (2008)
2.9 Environmental and Health Impacts of Solid Waste Improper disposal of solid waste contaminates the natural resources like air, water and land and deteriorates the quality of life and human health. Improper solid waste management shows the impact on the planet earth and result in global warming and climate changes. Surface water resources and ground water resources contaminate due to the indiscriminate and improper disposal of solid waste and generation of leachate from the landfills (Rajput et al., 2009). From these landfills, the solid waste generates methane which is a greenhouse gas and has 21 times more global warming potential than the carbon dioxide. Municipal solid waste can attract the insects, flies, rodents and spread diseases such as dengue, malaria and plague.
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Impacts caused by improper solid waste management are listed below:
Rag pickers working at waste disposal site are vulnerable to many diseases like lung infections, skin problems etc.
The burning of the solid waste at the disposal site causes air pollution and consequently spread the diseases and deteriorates health condition of surrounding people.
Methane is one of the greenhouse gases and is the main ingredient of landfill gas, leading to climate change and the methane gas has more potential than the carbon dioxide as a greenhouse gas.
The improper disposal of solid waste can cause foul odor and cause aesthetic nuisance.
The chemical reaction between the pathological, toxic and municipal solid waste components can have serious effects on public health and the environment.
The polluted water from waste disposal sites can contaminate the water resources like lakes and ponds. If these water resources contain chemicals they mix-up with the water bodies and cause health problems.
If the collection vehicles are not covered and designed properly, during the transportation leads to foul odor and can cause damage to the surface of the roads.
Plastic bags are non-biodegradable substances and cause an aesthetic nuisance (Dhayagode et al., 2011).
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Some health care items and dangerous items such as explosive containers, broken glass, hypodermic needles, blades, and blooded cotton may pose risks of injury to people who sort through the waste.
If there are no proper collection systems, waste collection workers may face different types of problems.
While manual handling the waste, the workers have to take protective measures otherwise diseases may attack due to direct contact of pathogens.
If the solid waste is not collected regularly, it may deteriorate the urban environment and cause unhygienic conditions.
From uncollected and decomposing wastes, dust particles and Aerosols can spread (Thirumala et al., 2012) fungi and other disease causing agents.
The open burning and open dumping of municipal solid waste causes air pollution.
During the open burning of the solid wastes some of the products may enter the environment which is hazardous.
Solid waste is the best food for flies and the breeding of flies spread so many diseases.
Uncollected wastes mixing in drains, causing flooding and unsanitary conditions.
If the community bins are not covered, they may attract stray dogs, which has been a major cause of the spread of rabies.
Open waste bins also attract stray and domestic cattle and causes nuisance.
Mosquitoes breed in blocked drains and in rainwater that is retained in discarded cans, tire and other objects. Mosquitoes spread disease, including malaria and dengue.
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Rats find shelter and food in waste dumps. Rats consume and spoil food, spread disease, damage electrical cables and other materials and inflict unpleasant bites.
Garbage dumps contribute to the seepage of toxic chemicals to ground water and such contaminations have been linked up with increases in cancer incidences.
2.10. Waste Management Practices
The better waste management practices are described below and fig. 2.5 shows the most favored and least favored options for waste management.
2.10.1 Waste Prevention Waste prevention is defined as preventing the generation of waste at the source level only and encouraging the methods reuse, recycling and recovery. Solid waste generation is increasing with the change in lifestyles and the high amount of solid waste and improper solid waste management creates a threat to the environment. Best practices are most necessary and essential for better solid waste management. To achieve this, best practice is to be followed 3 Rs principle. 3 Rs principle includes the most preferred options i.e. waste reduction, reuse and recycling for management of solid waste (NSWAI, 2008). For the prevention of solid waste generation, the most effective methods are the waste reduction and reuse.
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Fig.2.5: Waste Management Practices
2.10.2 Reduce Source reduction often also called the waste minimization means less production and less consumption of products or materials. Waste generation may be reduced due to changes in the design, purchase and manufacturing process of products. 2.10.3 Reuse Reuse is closely related to source reduction. Reuse is the next step to the source reduction and reduce is one of the steps of reuse. Reuse means usage of products again and again. By following the method reuse, the amount of waste generation decreases after the consumption and at the same time it reduces the manufacturing of products and finally reduces the amount of solid waste generation at the source level only.
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Many ways to reuse the materials include using rechargeable batteries, refillable pens and donating any unwanted products etc. Reuse is the best method than the recycling. In another way reuse some materials such as metal, glass, energy from the waste materials by the extraction of useful raw materials. These are the Simple and best ways to reuse the products. Domestic reuse is the best example. Where water scarcity is acute, the treated wastewater and reuse it for domestic purposes. Treated sewage can also be conveniently used for boating, fishing, gardening and other recreational purposes. 2.10.4 Recycle
Recycling means the converting of waste materials into useful forms. Recycling is often voiced as the antidote to the solid waste problem. Hence recycling of wastes can only be a supplement to the most effective method of reducing solid waste generation to the maximum possible extent. This has become necessary today due to the following reasons:
Resources of nature are fast depleting due to rising populations and increasing consumption rates. Resource depletion becomes a serious problem unless resources are also generated from waste materials.
Waste products are accumulating in the environment demanding space, health hazards and causing nuisance.
Economic gains motivate recycling to some extent.
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For reducing the quantity of solid waste generation, recycling is another best technique. Recycling means the reusing materials and objects in their original or changed forms rather than discarding them as wastes (Wyld, 2010).
2.10.5 Importance and Benefits of Recycling and Reuse For an integrated solid waste management, “Recycle” and “Reuse” are the key elements. Recycling and reusing materials not only reduces the amount of materials into the solid waste stream also reduces the costs for processing of the collection, transportation and disposal etc. The importance and benefits of recycling and reusing are listed as follows:
By utilizing energy from the waste materials, natural resources should be conserved.
Minimize the impacts on the environment and human health by reducing the amount of waste generated.
The use of recycled materials reduces the pollution and energy consumption.
Affordable market prices for recycled materials.
Helps to establish industries of secondary materials.
Generate income to the society because of the market value of waste materials.
Reduces the amount of waste that has to be imported, by producing secondary raw materials.
Economic development from industrial establishments, levy collection and employment generation.
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2.11 The Stakeholders Involved in the Management of MSWM in INDIA are
The Ministry of Environment and Forests: The Ministry of Environment and Forests is responsible for general aspects related to waste management, and draws up, coordinates the environmental policy and overseas the implementation of the federal legislation regarding waste management.
The Central Pollution Control Board: Coordinate the activities of the State Pollution Control Boards and provide technical assistance and training to the personnel. Disseminate information sponsor research relating to waste management. To perform functions prescribed by the Government.
The State Pollution Control Board: Plans a comprehensive program for the prevention, control or abatement of air pollution and water pollution. To inspect, at all reasonable times, any control equipment or process. Prior to installation of a landfill or incinerator, permission from SPCB must be obtained.
City Corporation: City Corporation issues permits and creates policy for waste management. Provides waste management services or operates disposal, recycling or composting facilities. Often contracts out services to the private sector.
Private Formal Sector: Participates in performing the functions of collection and transportation of the waste and may operate disposal, transfer and recycling facilities.
Private Informal Sector: Participates in collection of the recyclable waste, transfer to the recycling facility and recycling of waste.
Service Users: People who use the service of municipal waste management.
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