WASTE: A PILING PROBLEM FOR THE ENVIRONMENT AND SOCIETY: AN OVERVIEW OF WASTE MANAGEMENT THROUGH WASTE REDUCTION, REUSE, RECYCLING AND CLEANER PRODUCTION TECHNOLOGIES

Rajiv K. Sinha

1.0 Introduction : Waste a Consequence of Human Life

Waste is an inevitable byproduct of all human developmental (industries and agriculture; transport and communication) and cultural (feeding, housing and clothing; education & recreation) activities, and is directly proportional to the consumption of resources. The root of waste problem is the ëculture of consumerismí and is directly proportional to the affluency of the human societies. To this has added the ëculture of disposablesí. Large number of goods in the society are being manufactured for only ëone time useí, and to be discarded as waste after use. Modern urban culture of using ëenormous amount of waterí (for washing, cleaning and bathing); consuming ëcanned and bottled foodsí, ëfrozen foodsí, ëtake-away foodsí; using ëdisposableí home equipments (spoons, cups, plates, tumblers and safety razors), medical instruments (syringes, sharps and needles), office equipments (writing pens and utilities); exchange of ëgreeting cardsí on all occasions, and using plastic bags in all grocery shopping, has escalated the waste problems.

Packaging of materials has become part of our modern urban culture eventually resulting as waste. Everything needs fine packaging today, from cornflakes to computers, from gifts to garments, from flowers to foods. Life today cannot be imagined without plastic bags, glass bottles, paper boxes, tins and cans. Plastics being most versatile, convenient and light weight, are good packaging material ultimately ending as hazardous waste.

Waste Generation in the Cities

Cities have become major ëcenters of consumption and waste generationí all over the world. In fact a city ëconsumesí as well as ëproduceí. This is called ëurban metabolismí. City use some 75 % of world resources and release a similar proportion of wastes. According to UN Population Fund Report (1990), a city with one million population consumes 2000 tones of food and 9,500 tones of fuel, generating 2000 tones of solid wastes (garbage and excreta) and 950 tones of air pollutants;

consumes 6,25,00 tones of pure water and secrete 5,00,000 tones of sewage. UNEP (1996) worked out the urban metabolism of London city. Greater London with a population of 7 million consumed 2,400,000 tones of food; 1,200,000 tones of timber; 2,200,000 tones of paper; 2,100,000 tones of plastics; 360,000 tones of glass; 1,940,000 tones of cement; 6,000,000 tones of bricks, blocks, sand and tarmac; 1,200,000 tones of metals every year and produced 11,400,000 tones of industrial and demolition wastes; 3,900,000 tones of household, civic and commercial wastes and 7,500,000 tones of wet, digested sewage sludge. Everyday London dispose off some 6,600 tones of household wastes.

2. Sources of Urban Wastes Generated in Our Society

The main sources of wastes in the cities are the garbage from the households, hotels and restaurants; the refuses from offices and business establishments, hospitals and medical clinics; the rejects from the various leather, rubber, foam, plastic, textile, metallic and automobile industries; the left-over and the discarded products from the vegetable and fruit markets and the slaughter houses. The broad sources can be divided as follows-

(1). Domestic wastes from the households and the personal human excreta;

(2). Commercial wastes from the consumer stores, warehouses, offices and institutions;

(3). Industrial wastes from the manufacturing & processing industries;

(4). Biomedical wastes from hospitals and public health institutions.

3. Types of Urban Wastes Generated in Our Society

The Municipal Solid Wastes (MSW)

The residential, commercial and institutional solid wastes consisting of the organic (combustible) and inorganic (noncombustible) wastes are the main constituent of the MSW. The organic fraction consist of materials like food waste, all types of papers and plastics, cardboard, textile, leather, rubber, wood and garden waste. The inorganic fraction consist of items like glass, crockery, tins, cans, aluminum, ferrous metals and dirt.

Processed food waste constitute the largest part of MSW these days. Under the strict ëquality controlí and ëuse by dateí regulation large number of food products are thrown away in the dustbin if the ëdate of useí has expired. Grocery stores and medicine shops have to follow the regulation strictly to escape penalties. Most drugs and prescription medicines have to be used by a particular date.

The Industrial Solid Wastes (ISW) or Developmental Wastes

ISW can be called as the ëdevelopmental wastesí as industrialization is an important human developmental activity for human welfare and economic prosperity. Both the ëprimary industriesí (mineral mining and agriculture industry producing the raw material) as well as the ësecondary industriesí (consumer industries processing the raw materials for producing consumer goods) produce huge amount of wastes.

Due to strict ëquality controlí measures and to meet the required ëstandardí there are large numbers of rejections of items in the consumer industries, especially the food processing industries which do not meet the specification. Everyday, several kilograms of baked breads in the bakeries are thrown in the dustbin for minor fault in production. And, consumer industries today, produce more ëdisposableí goods instead of ëdurablesí and ërepairablesí and that is a major cause of solid waste escalation.

4. The Changing Nature and Increasing Complexities of the Waste in the Modern Technological Society

Waste generated by the traditional societies were little and ësimpleí, mostly containing natural and organic matters, while those generated by the modern technological societies are large and ëcomplexí .Industrial products were composed of relatively limited number of materials from the natural resources, many of them biological in origin and hence biodegradable. Now with technological advancement a new category of ësynthetic materialí have come into existence. Increasing complexities have occurred in the composition of solid waste ever since the technological revolution of the 20^th century. The technological development which mainly influenced the character of the MSW was the ëindustrial revolutioní and the agro-chemicals driven ëgreen revolutioní of the 1940s. Waste components that have an important influence on the composition of the MSW are food waste, paper and plastic wastes, the white goods and the hospital wastes. The processing of some new materials discovered by technology such as ësemiconductorsí, ëoptical fibersí, new class of ëceramicsí, and ëcompositesí requires the use of large amount of toxic chemicals which creates health problems for the industrial workers and the public who use the products and also for the environment when they are discarded as ëhazardous wastesí. Another cause of concern is that most of these new materials cannot be easily decomposed in nature and hence their safe disposal is creating extraordinary technical, health, environmental, economic, political and social problems.

Increasing Hazardous Wastes

Wastes either solid, liquid, sludge or gaseous containing toxic chemicals, radioactive substances and infectious materials which poses potential risk to human health and environment are categorized as ëhazardous wastesí. There is virtually no sector of modern human cultural and developmental activities which do not make use of some ëchemicalsí which eventually ends up as hazardous waste. According to United Nations Environment Program (UNEP) about 10 million ëchemicalsí have been ësynthesizedí in laboratories since the beginning of the 20^th century and between 1000-2000 new ones appears every year worldwide, and consequently about 338 million tones of hazardous wastes are produced annually. Toxicity, radioactivity, flammability, chemical reactivity, corrosivity, non-biodegradability, carcinogenicity, mutagenicity, infectiousness, oxidizing and leachating are some of the characterstics of hazardous wastes.

Proliferating Plastic Wastes

Percentage of plastics in MSW has also increased tremendously during the last 50 years. The use of plastic has increased from almost non-measurable quantities in the 1940s to between 7 - 8 %, by weight, in 1992. It is anticipated that the use of plastics will continue to increase, but at a slower rate than during the past 25 years. The plastic materials found in the MSW are of seven (7) categories. The polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and other multi-layered plastic materials.

Mounting White Goods and Bulky Items

There are ëbulky itemsí such as furniture, lamps, bookcase, filing cabinets, etc.; ëconsumer electronicsí wastes like worn-out, broken, and no longer wanted items like stereos, radios, computer and television sets; ëwhite goodsí such as worn-out and broken household, commercial and industrial appliances like stoves, refrigerators, dishwashers, cloth washers and driers. The rejected auto-parts like tires, batteries and accessories are also constituents of MSW. About 230 to 240 million rubber tires are disposed off annually in landfills or in tire stockpiles.

Hospital Wastes

While a large percentage (85 %) of hospital waste is general refuse of MSW, 10 % is ëinfectiousí and 5 % is non-infectious but potentially toxic and radioactive. Dressing and swabs contaminated with blood and body fluids; syringes, needles and sharps; surgically removed placenta, tissues, tumors, organs or limbs are potentially infected wastes from hospitals. Hospital wastes are of special category and require special care.

5. Hazardous Waste and Products in Urban Homes

Modern urban society is exposed to several types of hazardous products everyday either in home or in workplace. National Institute of Occupational Safety and Health in the US has reported 884 ëneurotoxicí chemical compounds in the products of the perfumes and cosmetics used by the women in her daily life. Some solid wastes with hazardous materials are always generated in our homes in the form of cleaners, detergents and shampoos, auto parts, pesticides and disinfectants and the expired medicines. Many relatively innocuous items, such as plastics, glossy magazines, and flashlight batteries used in homes, contain metallic elements. Metals of particular concern from public health point are cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb). After combustion with MSW metals are either emitted as particulate matter or vaporized into air. Mercury pose a particular problem because it volatilizes at a relatively low temperature, 675 ° F. Virtually all of the mercury in MSW is due to the disposal of household dry cell batteries (mercury, alkaline, and carbon-zinc types). A smaller amount of mercury may come from the disposal of broken home thermometers.

Heavy metal cadmium is present in all food processing equipment, kitchenware enamels, pottery glazes and plastics and relatively high levels in the sea foods. The highly toxic PCBs are added to paints, copying and printing paper inks, adhesive and plastics to improve their flexibility. Fish food contain generally higher levels of PCBís. High levels of PCBís were reported from the breakfast cereals in Sweden and Mexico as a result of contamination by ëpackaging materialsí. Canned and bottled foods contains chemicals as ëpreservativesí. The University of Arizona, U.S., found that about 100 hazardous items are discarded per household each year. Australian study made in Melbourne in 1990-92 also found 89,576 kg of hazardous wastes from households.

Household Hazardous Products in Urban Homes

Product s Hazardous Characterstics

1. Household Cleaners

(a). Abrasive scouring powders Corrosive

(b). Ammonia and ammonia based cleaners Corrosive

(c). Aerosols Flammable

(d). Drain openers Corrosive

(e). Glass cleaners Irritant

(f). Wood and metal cleaners and polishes Flammable

(g). Chlorine bleach Corrosive

(h). Toilet bowl cleaner Corrosive

(i). Upholstery and carpet cleaner Flammable and / or Corrosive

(j). Washing machine detergents Corrosive

2. Personal / Healthcare Care Products

(a). Hair-waving lotion Poison

(b). Medicated shampoos Poison

(c). Nail polish remover Poison / Flammable

(d). Shoe and silver polish Flammable

(e). Outdated medicines Poison

(f). Alcoholic products Flammable

3. Home Maintenance and Improvement Products

(a). Paint, thinners and removers Flammable

(b). Insecticides & disinfectants Poison

(c). Adhesives Flammable

(d). Pool acids and chlorine Corrosive

(e). Furniture Polish Flammable

4. Automotive Products

(a). Antifreeze Poison

(b). Car batteries Corrosive

(c). Used waste oil Flammable

(d). Brake and transmission fluid Flammable

(e). Used and rejected tires Flammable

(f). Oil and fuel additives Flammable

(g). Grease and rust solvents Flammable

(h). Radiator coolant (Ethylene glycol) Poison

5. Lawn and Garden Products:

(a). Chemical Fertilizers Poison

(b). Herbicides and Pesticides Poison

6. Home Electrical Appliances

(a). Used dry cell batteries (with Hg and Cd) Corrosive

(b). Used Electric Bulbs & Tube Lights Corrosive

 

 

Ill-Effects of Hazardous Wastes on Human Health

Hazardous wastes and substances pose grave risks to human health at all times- during generation, storage as well as during disposal and it is a risk not only to the present generation but also the future generations as it affects the ëhereditary materialsí. What is the matter of serious concern is that the household hazardous wastes (HHW) are disposed by the residents along with the municipal solid wastes (MSW) with grave consequences for the municipal refuse collectors. A refuse worker in San Diego,California, lost his sight when hazardous waste from a residence spilled on his face. It is also posing a serious problem for the landfills. If the MSW contains hazardous wastes (HHW) more volatile organic compounds (VOCs) are produced in the landfills. VOCs are toxic and pose grave risk to public health and environment.

Household hazardous wastes collectively amount to a significant quantity. The combined health effects of exposure to two or more chemicals that produce similar effects are often much greater than the ëadditive effectsí of separate exposure to each of the chemicals.The deleterious effects of chemicals like arsenic, lead, cadmium, mercury, vinyl chloride, all pesticides and herbicides are well documented. They are hazardous to health in even minute amount. US scientists predict that up to 20,000 Americans may die of cancer, each year, due to the low levels of ëresidual pesticidesí in the chemically grown food.

6. Waste Generated in the Developed and Developing Nations of World

The United Nations Environment Program (1992) carried out a study of per capita waste generation in the low, middle and the high-income countries and found it to be 0.5, 1.5 and 3.5 kg. per day per person respectively. The solid wastes generated in the rich affluent societies of the developed nations are exceptionally large in quantity and varied in quality (components). Of these, a considerable part is hazardous waste. In the US, each sunset sees a new mountain of nearly 410,000 tones of garbage. The countries of the European Community (EC) throws away an estimated 2 billion tones of solid waste each year. The World Watch Institute (WWI), Washington, reported that 14 out of 16 members of OECD countries showed increase ingeneration of MSW per person between 1980 ñ 85. Only Japan and West Germany produced less waste, but after unification MSW in Germany skyrocketed. Americans and Canadians are great waste makers. They generate roughly twice as much garbage per person as West Europeans or Japanese do. In his /her lifetime an average American wear and discard 250 shirts and 115 pairs of shoes; use and discard 27,50 newspapers, 3900 weekly magazines and 225 pounds of phone directories; consume 12,000 paper grocery bags, use 28,627 aluminum cans weighing 1022 pounds, use 69,250 pounds of steel and 47,000 pounds of cement. (United Nation Environment Program Report, 1992).

The Scandinavian nations generate much less waste than the Europeans. In poor underdeveloped and developing countries of Asia, Asia-Pacific and Africa, waste is a luxury, only produced by the wealthy minority which of course is increasing with the growing consumerism. Waste reuse and recycling is a way of life, and many poor societies survive here by scouring the garbage of the rich for valuable scraps.

The developed countries follow meticulous planning for waste storage, collection, transfer and recycling or disposal in landfills. Waste separation and recycling is a common practice. There is sad lack of such environmental consciousness, both among the people and the government in the developing countries. High population and low income (revenue) is also a prohibitory factor in good waste management planning in these countries. Wastes are mostly dumped in the open, often on the roadsides and collected in open vehicles. Landfills are mostly an ordinary ëwaste dump sitesí in the outskirts of the city.

Average Per Capita Solid Waste Generated by Some Developed (Rich) &

Developing (Poor) Nations (Per day in Kg)

Country Waste Generation Country Waste Generation

USA 1.80 ñ 2.60 Italy 0.69 ñ 1.75

Japan 1.38 - 2.10 Pakistan 0.25 ñ 0.60

France 1.10 ñ 1.90 Indonesia 0.33 ñ 0.55

Singapore 0.87 ñ 1.37 India 0.15 ñ 0.51

Germany 0.75 ñ 1.85 Nigeria 0.16 - 0.46

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Source: World Watch Institute, Washington (1990 Values)

Urban Waste Generated in Some Developed Countries (In tones)

Country Annual Generation Country Annual Generation

USA 20,00,00,000 Sweden 25,00,000

Canada 1,26,00,000 Switzerland 21,46,000

Australia 1,00,00,000 Denmark 20,46,000

Spain 89,28,000 Norway 17,00,000

Netherlands 54,00,000 New Zealand 15,28,000

Belgium 30,82,000 Finland 12,00,000

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Source: Blueprint for Green Planet ; Dorling Kindersley, London (1987)

Waste Components of the Developed and Developing Nations

There is marked difference in the waste components of the rich developed societies of Europe, America and Australia, and the developing poor societies of Asia, Africa and Latin America. The developed societies throw away more paper, plastic, metal and glass wastes and less food wastes because they consume more papers, plastics, metals and glasses, and processed and packed foods. They also throw away more ëwhite goods and electronics itemsí. This is because the cost of repair is very high and new ëimproved modelsí keep on invading the market. People prefer buying new models instead of going for costly repair of the old ones.

In the developing countries, people resort to ërepair of goodsí several times before discard. They also sell the papers, plastics, metals and glasses in the market for money, instead of throwing them away into the MSW. People indirectly participate in recycling of these materials, although not for ecological reasons, but for economic reasons. Some paper, plastic and metal scraps from the MSW are picked up by ëragpickersí. It is a source of their livelihood. In the developing societies greater amount of food wastes are thrown into the MSW, but it do not reach the dump sites. Stray animals (cows, pigs and dogs) often feed on the municipal waste bins.

Typical Solid Waste Components in the MSW of Developing Societies

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Waste Components (at source) ( % age) Characterstics

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1. Vegetable, fruit and animal matters 27.0 B, C & R

2. Dry & green grasses and leaves 5.6 B, C & R

3. Paper and paper products 10.9 B, C & R

4. Plastic materials (PET, HDPE, LDPE, PS, PVC, PP) 5.4 NB, C & R*

5. Leather, foam (synth.) and human hair 3.7 B-NB, C & R

6. Cotton, jute and burlap 6.1 B, C & R

7. Rubbers (synth.) including cycle and auto tires 2.9 NB, C & R**

8. Metals (magnetic & non-magnetic) 2.0 NB, NC & R

9. Concrete, pebbles, earth-stones, sands and dusts 25.0 NB, NC & R

10. Ash and coal 9.0 B, C & R

11. Wooden materials 0.4 B, C & R

12. Glasses and ceramics 2.0 NB, NC & R

Source: Waste Management (R.K. Sinha & A.K. Sinha) 2000 100.0

(B = Biodegradable; NB =Non-biodegradable;

C= Combustible; NC= Non-combustible; R= Recyclable; R* = Recycling is hazardous; R** = Recycled as energy source; NR= Non-recyclable)

Typical Solid Waste Components in the MSW of Developed Societies ( in % age)

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Organic Inorganic

1. Food Waste 9.0 10. Glass 8.0

2. Paper 34.0 11. Tin cans 6.0

3. Cardboard 6.0 12. Aluminum 0.5

4. Plastics 7.0 13. Other Metal 3.0

5. Textiles 2.0 14. Dirt, Ash etc. 3.0

6. Rubber 0.5

7. Leather 0.5 -----------------------------------------------

8. Yard waste 8.5 Total = 100.00

9. Wood 2.0

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Source: Integrated Solid Waste Management; McGraw-Hill (1993)

7. Waste Situation in Australia

A big environmental challenge which Australia is facing today like any other developed nation is the tremendous waste generation, consumerate with its high rate of consumption. In total, Australia generates 4.5 billion tones of waste every year of which 2 billion tones are solid waste (dominated by mining wastes), another 2 billion tones are liquid waste (dominated by sewage) and nearly half billion tones of gaseous wastes contributing to the greenhouse problem. These were 1995/96 figures. Average per capita waste generation in Australia is 681 kg per year (CSIRO Report,1996 ) much higher than any other nation in world except the U.S. Unfortunately a huge component of this waste is ëpaper wasteí and the non-biodegradable ëplastic wasteí which is growing alarmingly in every city. Plastics and papers are being used indiscriminately in every home, the shopping centers, the fast food outlets and the advertising (junk mail) and packaging industries. Garden wastes and food scraps make up 50 % of the curbside collections. Most Australian cities have meticulous planning for waste collection, transfer, recycling and or disposal.

Since most Australian cities are located on the coast they discharge most of their effluent into the oceans. According to one estimate, each year, about 10,000 tones of phosphorus and 100,000 tones of nitrogen are discharged to the near ocean environment in Australia (CSIRO Report, 1996). This can have serious environmental consequences for the marine ecosystem and health impacts for the human ecosystem as the two are connected through the food chain. Attempts are being made to treat the city wastewater and storm water through the ëConstructed Wetland Technologyí.

Waste Generation in the Urbanised and Less Urbanised Australia

The Industry Commission of Australia (1990) estimated that in 1989 the average amount of household waste collected was lower in State capital cities (336 kg / head / year) than in rest of Australia (427 kg / head / year) which included smaller settlements and the non-urbanised areas. This was contrary to the general expectation that people in cities and urban areas create more per capita of solid waste. The inference drawn is that larger cities of Australia have more ëefficient metabolismí of waste than the smaller settlements. Residents in larger cities are also more conscious and aware towards ësource reductioní ëreuseí and ërecyclingí of household wastes. CSIRO study found that in Melbourne 69 % of MSW is already being reused, reprocessed or reduced (broken down) for use in building and non-building activities like roads and pavements construction. Sydney residents reduced their weekly solid wastes from 21.6 kg in 1993 to 18.6 kg in 1995; and increased their weekly amount of ërecyclablesí from 2.8 kg to 3.8 kg . In 1994 large cities of Australia recycled 50 % of their newspapers which was up from 44 % in the 1990.

Hazardous Wastes Generated in Australia

It is estimated that nearly 100,000 tons of hazardous wastes are stockpiled throughout Australia awaiting safe disposal. A typical household in Australia generates between 1.5 to 2.0 kg of hazardous wastes per year (CSIRO Report ). What is concerning is that there exist no management plan in majority of Australian cities to collect, transport and dispose these hazardous wastes separately. They are mixed with general municipal wastes by the residents and disposed in the municipal bins. Of grave concern is the discharge of old stocks of banned hazardous chemicals like organochlorines (DDT) and arsenate pesticides in the municipal wastes.

The ëFriends of the Earth-Brisbaneí reports that Australia produces around 14,000 tonnes of uranium ëtailingsí each day which contains up to 80 % of the original radioactivity of the extracted ore. A massive radioactive waste dump site is being planned in the Billa Kallinga region of South Australia and another in Western Australia. Australia has followed the UNEP sponsored international rules for hazardous waste storage, transport and disposal, and has made good use of bioremediation technologies for dealing with its mining wastes.

Liquid Hazardous Wastes Generated in Five Australian Cities

Cities Tons / Year Rate (Kg / person)

1. Sydney 62,000 18

2. Melbourne 90,000 30

3. Adelaide 40,000 40

4. Perth 26,000 24

5. Brisbane 17,000 14

Source: State of the Environment, Australia, 1996 (CSIRO Publication)

8. Classification of Solid Wastes

(A). Physical Classification

This is based on their appearance and general nature

(2).Rubbish (Used paper and plastic products and sweeps from premises)

(3).Ashes (Burnt residues of solid wastes)

(4).Bulky Wastes (Home and office furniture and appliances, white goods)

(5).Street Refuses (Litter, dirt and debris from roads collected by municipal councils)

(10).Farm and Cattle Wastes (Crop residues, spoiled fallen fruits and vegetables, cattle dung)

(11).Sewage Treatment Residues (Sludge)

(12).Special Wastes (Containing hazardous chemical, biological and radioactive materials)

(B). Ecological Classification

All human wastes are either biodegradable (degraded / diluted by nature) or non-biodegradable.

(i). The Biodegradable Wastes

Wastes which can be naturally biodegraded (decomposed) in nature either left unattended or dumped in proper places. It may take time from few days to several months and years to degrade those wastes, but it does happen ultimately. Some organic materials in the waste decomposes rapidly ( 3 months to 5 years), while others slowly (up to 50 years or more). The biodegradability depends to a large extent on the lignin content of the waste. Lesser the lignin content, rapid will be the biodegradation rate of that organic material. Nature has those ëdecomposer microorganismsí (mainly bacteria and fungi) in soil, air and water which perform the task. Life on earth would have been impossible without them. The biodegradable waste include all plant, animal and human products, the kitchen waste in every home and restaurants, wastes from the agriculture farm, food processing industries, slaughter houses, fish and vegetable markets, and paper and cotton wastes. All these wastes mainly contain organic matters.

(ii). The Non-biodegradable Wastes

Human ingenuity has created some ënew and synthetic materialsí in the wake of technological revolution. They contain both organic and inorganic chemicals and resins and creates more ëcomplexí type of waste after being discarded. Nature do not possess any organism and mechanism to degrade them. They are ënon-biodegradableí wastes and because they cannot be decomposed, they can remain in the ecosystem for years and decades polluting the environment. Common examples are all forms of plastics, x-ray films, celluloid films, cells and batteries, several chemicals and all synthetics.

(iii). The Hazardous Wastes

It has already been discussed above.

(C). Economic Classification

Solid wastes has been economically classified on the basis of their recycling potential to recover valuable secondary raw materials from them.

(i). The Recyclable Wastes

Several categories of MSW and also ISW can be potentially recycled to get new valuable products. These include all metals, papers, plastics, glasses, garden wastes, construction and demolition wastes, wood, waste oil, tires, lead-acid batteries and household batteries. All ëbiodegradable wastesí are potentially recyclable into compost.

(ii).Non-Recyclable Wastes

Some categories of MSW and ISW cannot be recycled. Recycling can create severe health and environmental problems. These include several biomedical, chemical and radioactive hazardous wastes.

9. Resolving the Waste Problem : Role of Consumer Industries, Government and Society in Waste Management

Waste management involve all administrative, economic, ecological, technological and legal planning and require the input of knowledge of diverse disciplines of material science, political science, economics, geography, sociology, demography, urban planning, public and environmental health, communication, conservation, and civil and mechanical engineering. We are facing the escalating cost of dealing with current and future generation of mounting wastes, specially the hazardous wastes, and also the health cost to the people suffering from it.

Waste is no longer considered as a discarded product to be disposed off from the human ecosystem. Waste is in fact, a ëmisplaced resourceí to be brought back into the human ecosystem. The word ëreí has become a critical factor for human existence on earth. We have to ëre-thinkí about our ëconsumerist behaviorí and about the way we ëuseí(or misuse) and ëdiscardí the environmental resources in our daily life. We have to learn to ëre-duceí waste generation in daily life, to ëre-pairí, ëre-useí, ëre-cycleí and ëre-coverí all those resources including the waste articles back into the human ecosystem as far as practicable. ëRe-thinkingí in the human brain can only translate into actions of ëreducingí, ërepairingí, ëreusingí and ërecyclingí of wastes and has to be part of modern human culture. We have to mend our ways, change our behavior and attitude of life, re-order our priorities, simplify our life-style, and then only the gigantic problem of mounting solid waste, which literally threatens to bury the mankind alive, can be overcome. Only a ëconserving and recyclingí society would be the ësustainable human societiesí of the future and the ëthrowaway wasteful societiesí would perish.

Society has to begin the process of recycling at the source ñ the home, office, or factory- so that fewer materials will become part of the disposable solid wastes of a community. Efforts must be made to reduce the quantity of materials used in both packaging and obsolescent goods. Waste reduction may also occur at the household, commercial, or industrial facility through ëselective and judicious buying and consumingí patterns and the reuse of products and materials. Source reduction is an option that will conserve resources and also has economic viability. Recycling economy is a

closed loop in which consumers, manufacturers and waste collectors and haulers, all have a critical sustaining role to play. Many waste articles in the society are ëpotentially recyclableí, but they may not actually be recycled unless there is a practical way to do so and there is a demand / market for the ërecycled goodsí. The waste haulers would be encouraged to collect the recyclable wastes if there is a demand by the recycling industries, and the recycling industries will buy these wastes (as secondary raw materials for processing) only if it is less expensive (economically cheaper) than the primary (virgin) raw material. The consumers will buy recycled items only if it is as good as the product made from virgin materials and still less expensive. None of them are bothered about the high ëenvironmental costí of the procurement of the primary raw materials from earth or the products made from them. When recycled materials have a high ësocial and economic valueí despite the cost of collecting and processing, they find a ready market. Much of the gold, silver and other precious metals that were ever mined and extracted from their primary ores centuries ago is still circulating (recycling) in our economy (human ecosystem). Materials with low social and economic value relative to the cost of collecting and processing do not find a ready market.

Industries producing consumer goods have to play more responsible role in waste management program because they have potential to generate waste twice in the life-cycle of the goods produced. First at the ëproduction levelí when they process the virgin raw materials and generate ëindustrial wastesí. Second at the ëconsumption levelí when the goods produced by them are used and discarded by the society as ëmunicipal solid wasteí (MSW). Industries should have the ethical responsibility to produce not only ëdurableí but also ërepairableí goods and articles, and adopt the ëcleaner methods of productioní. Also, the cost of repair has to be significantly lower than the cost of the new article to encourage consumers for insisting on repair rather than replacement.

Industrialists also owe moral obligation to provide necessary information to its prospective buyers on the matter of using, handling, conservation, disposal and recycling potentialities of its products. In designing new products, the industry must assess its potential and even suspected adverse impact on its consumers health and the environment.

Government, industries, science and society all have to join hands in fighting the menace of piling waste. Government must encourage and promote the recycling industries using waste as raw materials by way of reduced taxation, reduced cost of water and electricity supply etc. Given current technology, not all the municipal or industrial wastes can be readily recycled. Nor do all the waste materials have qualities that currently make them a valuable commodity in the recycling marketplace. The government and industries have to embark on the policy of production of ëdurable and repairable goodsí for long and multiple uses, and stop the production of ëdisposableí items of one time use by the society. Any government policy, any waste reducing and recycling technology cannot help unless the society is conscious. A ëconsumer educationí program is needed to educate the society about the hidden ëenvironmental valueí (the energy and water it has saved, the pollution and deforestation it has prevented) of the recycled goods. All recycled goods should have ërecycled tagí telling about the origin and life history of the goods (from which waste it was produced) and how it has saved the environment. It would develop a sense of ëcivic prideí among the consumers that he / she is helping the environment.

10. Waste Storage, Separation, Collection and Transfer to Treatment and Disposal Facilities

Sanitary storage of solid wastes in covered containers, and the source segregation of the ërecyclablesí from the general waste stream by the residents in homes and institutions; weekly / fortnightly collection of these wastes by the municipal authorities or their appointed agents, and transfer of the recyclables to the Material Recovery Facilities (for re-separation and recycling of metals, glasses, plastics, papers, and cardboards) and the general commingled waste (from the kitchen and yard), either to the composting sites (for compost formation) or to the combustion facilities (for energy generation), and the residuals to the landfills for final disposal, has revolutionized the waste management program with environmental sanitation, in several developed countries. Most developing countries have, however, failed to meet these objectives in waste management. Traditional system of waste storage in open containers, waste collection in open vehicles and disposal in ordinary ëwaste dump-sitesí still continues.

However, collection of unseparated (commingled) and separated solid waste in an urban area is increasingly becoming more difficult and complex because the generation of ëresidential and commercial-industrialí solid waste take place in every home, every apartment building, and every commercial and industrial facility as well as in the streets, parks, and even vacant areas. The mushroom-like development of suburbs in the megacities of world has further complicated the collection task in most developed countries. As the pattern of waste generation become more diffuse, and the total quantity of waste increases, the logistics of collection become more complex. They have become more critical because of the high costs of fuel and labor. Of the total amount of money spent for collection, transportation and disposal of solid wastes in 1992, approximately 50 to 70 % was spent on the collection phase. This must have increased substantially now with the increase in labor and fuel cost.

Unfortunately, there is no system of collection, separation and storage of ëhousehold hazardous wastesí ( discarded dry cells and alkaline batteries, fused bulbs, auto parts, containers of pesticides and cleaning chemicals etc.) in most of the developed countries. Some cities of U.S. has probably started separate collection of HHW after some episodes of accidents. The HHW are mostly disposed by the residents along with the general MSW in the same bin, which contain kitchen or yard wastes. This is the practice in most Australian cities too.

Waste Collection System : Responsibilities of Residents and Government

The residents or tenants are responsible for placing the ëcommingled solid wasteí and the separated ërecyclable wastesí in storage containers and reach them to the curbs on the previous evening of the designated day fixed for collection by the municipal councils. Wastes have to be properly tied in paper or plastic bags and not let loose in the containers. Waste is usually picked up from the containers placed on the curbs, very early in the morning. This is to avoid the traffic congestion on the streets while the huge ëwaste vehiclesí is moving. The council ërefuse collectors crewí picks up the waste containers and empty the bagged / packed wastes into the waste vehicle, which mechanically draws the waste in and also go on compacting it continuously with in-built mechanism. Both manual and mechanical means are used to collect wastes from the commercial facilities.

The principal types of collection vehicles used for the collection of separated wastes are -(1) Standard collection vehicles; and (2).Specialized collection vehicles, including closed-body recycling trucks, recycling trailers, modified flat bed trucks, open-bin recycling trucks, and compartmentalized trailers. Brisbane City Council has recently introduced a new vehicle to collect both recyclable as well as the commingled wastes together in different compartments.

Mechanized Curbside Waste Collection

Over the past 15 years or more, there has been significant increase in the use of ëmechanical collections systemsí of waste from the curbsides of residential and commercial areas in the developed countries. Residents and establishments have been provided with special containers for onsite storage of wastes which is an integral part of the collection system. The containers are designed specifically to work with the ëcontainer-unloading mechanismí attached to the waste collection vehicle. The large containers are unloaded mechanically in the collection vehicles and also compacted. The containers vary in size from 75, 90 to 120 galons, and are fitted with wheels, so that it can be easily tilted back and moved to the curbside by residents.

Waste Treatment at Materials Recovery Facilities (MRFs)

Even though recyclable waste materials have been separated at source by residents, additional separation and processing is required at the MRFs to improve the individual quality (specifications) of the recyclable waste components, so that they can be reused and recycled effectively. This is done both manually and mechanically. MRF function as a centralized facility for the re-segregation, cleaning, packaging, compacting and transport (including shipping to overseas waste exchange centers) of large volumes of recyclable materials recovered from the MSW. The types of source-separated waste materials that are re-separated at the MRFs are ñ

(1). Paper and cardboard from mixed paper and cardboard;

(2). Aluminum cans, tin cans, plastics and glass from a mixture of these materials;

(3). Aluminum from commingled aluminum and tin cans;

(4). Plastics by class (PET, HDPE, LDPE, PP, PS, PVC etc.) from commingled plastics;

(5). Glass by color (clear, amber and green)

Waste need to be reduced in size and volume to facilitate smooth transfer to the disposal sites or the MRFs or for transport to other states or shipment to overseas for waste exchange and recycling. Most of the waste collecting vehicles are fitted with waste compaction mechanism. Large waste containers kept in commercial areas or in high-rise apartments are also fitted with waste compacters. At MRFs, all recyclable wastes are not only re-separated, but also mechanically reduced in size to facilitate storage and further transport to different recycling industries. This is achieved through several ways- shredding, grinding, crushing, milling and compacting. The objective of size reduction is to obtain a final product that is reasonably ëuniformí and considerably ëreduced in volumeí as compared to the original haphazard form. Glass containers and other glass products are usually crushed to reduce storage and shipping cost. Crushed glasses can also be easily separated mechanically through screening or optically by color. Aluminum and tin cans are also crushed to reduce their volume and increase their density. Crushed aluminum cans can be blown into large transport trailers for shipping. Balers and compacters are also used to reduce the volume of paper, cardboard, plastics, aluminum and tin cans. Wood grinders are used to shred large pieces of wood (large branches, broken pallets etc.) into chips, which can be used as fuel, and finer material, which can be composted.

11. The 3 Rís Rule for Waste Management ( Waste Reduction, Reuse and Recycling) through Waste Education

(a). Waste Reduction by Reducing Material Use at Source

This is the best option in the waste management hierarchy. Science & technology, the industry and the society all have to play critical role towards waste reduction. Technological advancement has undergone a process of ëdematerializationí for reducing the consumption of resources (metals, plastics, glasses etc.) in manufacturing products, with consequent reduction in waste generation. Many packaging items (cans and bottles), consumer ëelectronic goodsí and even the ëautomobilesí have become lighter, slikker and smaller. Since 1977, the popular 2-liter PET plastic soft drinks bottles have been reduced from 68 grams each to 51 grams, a 25 % reduction in material used per bottle. One hundred 12 fluid ounce aluminum cans which weighed 4.5 pounds in 1972, only weighed 3.51 pounds in 1992, a 22 % reduction in material use. Steel beverage cans have also been downsized and are now 40 % lighter than they were in 1970. This means that people can still enjoy a good quality of life while consuming smaller amounts of resources from the environment. Lesser resource use would also mean ëlesser energy consumptioní and ëlesser waste generationí, thus benefiting the environment in every way.

(b). Educating People for Reducing Waste at Source

If people judiciously use the 5 Pís (paper, plastic, power, petrol & potable water) in daily life, it would dramatically reduce all the three wastes- the solid, liquid and the gaseous from the environment. Public have to be educated to embrace the following environmentally friendly practices in daily life-

(2). Buy ëdurable goodsí and ëavoid disposableí ones as far as practicable;

(3). Chose products with lose and less packaging, and that too by papers and not plastics.

(4). Avoid presenting and accepting gifts in ëambitiously packed and rappedí papers or plastics;

(8). Insist on both side printing and photocopying unless absolutely necessary.

(c). Reusing Reusable Waste Materials to Reduce Waste

There are several articles like bottles and jars made of glasses and tough plastic materials, large tins, metallic cans and cansisters which can remain in our economy and ecosystem for very long time (if not discarded as waste) just by simple cleaning and washing. They might have been originally made for some other use, but now can be reused for different purpose- especially for storing and packaging. It is rather a ëresource reuseí.

(d). Educating People to Reuse the Reusable Waste Materials in Homes

People should embrace the following environmentally friendly practices -

(1). While shopping look for products packed in ëreusableí and ërefillableí containers;

(2). Use reusable ëcotton bagsí for all grocery shopping;

(4). Use ërechargeableí batteries in all instruments and appliances;

(8). Motorists should insist on the use of ëretreated tiresí if they are still appropriate.

(e). Recycling of Commercial and Industrial Wastes into ëSecondary Raw Materialsí : Extracting Gold from the Garbage

Recycling involve a complex industrial processing requiring the use of some energy, water and chemicals to effectively and efficiently reconvert the waste materials into ësecondary raw materialsí to manufacture new products or at least recover ëenergyí from them in the form of heat. Several of the items of commercial wastes viz. paper, leather, rubber, cotton rags, metals and glasses, wood and plastics can be recycled in different industries to get valuable products. The grocery and kitchen wastes, agriculture, dairy and slaughter house wastes can be recycled to get ëfuel and fertilizerí (compost).It is like getting ëgold from the garbageí and ësilver from the sewageí. Science has provided a tool in the hands of mankind to renew all those ënon-renewable resourcesí on earth which otherwise cannot be ërenewedí by natureís mechanism. This would also save tremendous energy, preserve forest, prevent soil erosion and pollution and reduce global warming.

Recycling of Metal Scraps

Metals like iron and aluminum can be effectively recycled for ever. The ferrous scraps include autos, household appliances, equipment, bridges, cans and other iron & steel products. The largest amount of recycled steel has traditionally come from large items like road unworthy cars and appliances. The shipyards, railyards and the automobile junkyards offer vast amount of waste metallic products to be recycled. They can alone meet more than 50 % of the worldís metal requirements. Nearly half of the iron and steel which has already entered into the human ecosystem is now being used through recycling. Iron scraps costs little more than iron ore but can be converted into steel with much lower economic and environmental cost. Using coke for iron ore reduction produce copious particulate matters including carcinogenic benzopyrene. Recycling of iron reduces this emission by 11 kg/metric tons of steel produced and also cuts iron ore waste and coal mining wastes by 1100 kg/metric tons recycled.

Non-ferrous scrap metals include aluminum, copper, lead, tin, and precious metals. They are recovered from common household items (outdoor furniture, kitchen cookware and appliances, aluminum cans, ladders, tools, hardware); from construction and demolition projects (copper wire, pipe and plumbing supplies, light fixtures, aluminum siding, gutters and downspouts, doors, windows); and from large consumer, commercial and industrial products (appliances, automobiles, boats, trucks, aircraft, machinery). The amount of aluminum which has already entered into the human ecosystem is sufficient to cater the needs of the society through recycling and there is no need to process it from the virgin ores. Recycling aluminum uses only 5 % of the energy needed to produce new aluminum from its ore ëbauxiteí. Recycling aluminum reduces air pollution including the toxic ëfluorideí by 95 %.

Copper can be recycled from the boilers of hot water systems, old car radiators and copper pipes. Electric cabling and wiring contains copper and aluminum which can be recycled. Lead can be recycled from old car batteries and old lead pipes. Lead is recycled in high rate because it is highly toxic and processing from its ore is highly damaging to both man and environment.

Recycling of Paper and Cardboard Wastes:

About 30 % of the paper products which we use today are made from recycled papers and cardboards. Three common grades of paper recycled are corrugated cardboard, high grade office paper and old newsprint. Waste papers and card boards make excellent pulp for making different grades of paper to be used for stationary, magazine and newspapers, game boards, ticket stubbs, cereal and cake mix boxes, grocery bags, tissue papers, paper towels, egg boxes, cards and packaging materials. Office papers are recycled to manufacture computer papers, writing and printing papers.

Recycling half of the papers used in the world today would meet almost 75 % of the demand for the new paper and would liberate 8 mha of forest from clear-felling. Waste paper recycling also saves tremendous energy and water and prevent the use of chemicals. 64 % less energy and 58 % less water is needed to make papers from recycled fibers than to make from virgin pulp obtained from the plants. However, infinite recycling of paper is not possible because the fibers become shorter and shorter and the quality of papers declines.

Recycling of Glasses:

Glasses are 100 % recyclable and can be effectively recycled for ever. The recyclable glasses in MSW are container glass (for food and beverage), flat glass (e.g. window panes), and pressed amber or green glass. Glasses to be recycled is often separated by color into categories of clear, green and amber. Manufacturer adds about 40 tons of cullet (broken glasses) to every 100 tons of raw materials (silica sand) to produce glass. The cullets melt at low temperature than the primary raw materials and hence require 25-30 % less energy on addition and also extends the life of melting furnaces.

Recycling of Plastic Wastes:

Recycling of plastic wastes is not really a good option and is rather a hazard for the human health and the environment. It gives out ëtoxicí fumes of ëdioxinsí during melting. Two types of plastics most commonly recycled in world are Polyethylene Terephthalate (PET) and High Density Polyethylene (HDPE). PET is recycled to make soft drink bottles, deli and bakery trays, carpets, fibrefill and geotextiles. HDPE is recycled to manufacture plastic milk and detergent bottles, recycling bins, agricultural water pipes, bags and motor oil bottles. LDPE (Low Density Polyethylene) is recycled to make new plastic bags and films. PVC (Poly Vinyl Chloride) is recycled to manufacture drainage pipes, non-food bottles and fencing posts. Recycled polypropylene (PP) is used in auto-parts, carpets and geo-textiles. Recycled polysterine (PS) is used to manufacture wide range of office accessories, vedieo-cassettes and cases.

Different plastics cannot always be recycled together and also the resulting plastic is hard and brittle. To overcome this problem a ëcompatibilserí molecule that sticks together the different plastic molecules have been developed. Such commingled plastic with much gloss and sturdiness as the originals can be used to make ëcar bumpersí and fence posts.

Environmental Benefits of Recycling of Some Waste Materials to Recover Resources of Mass

Consumption by the Society

Waste Energy Pollution Reduction in Water Forest

Recyled Savings Control Solid Waste Savings Protection

1. Iron & Steel Scraps 60-70 % 30 % 95 % 40 % 100 %

2. Aluminum Cans 90-95 % 95 % 100 % 46 % 100 %

3. Papers Wastes 60-65 % 95 % 100 % 58 % 100 %

4. Glass Wastes 30-32 % 20 % 60 % 50 % -

Source : State of the World, 1984 (Report of WWI, Washington)

(f). Recycling of MSW to get ( 2 Fís) Fuel and Fertilizer

Retrieving Energy from Waste

The organic municipal solid wastes enriched with ëbiomassí and materials with high calorific value (combustible) can be recycled to yield either gaseous fuel ëmethaneí (biogas) or liquid fuel ëethanolí by fermentation. The wastes can be directly incinerated and the heat liberated is used for steam generation and electricity production. Combustion by incineration of solid waste achieves the dual objectives of ëvolume reductioní and energy generation, so that less and less amount of waste (in the form of combusted ashes) finally goes to the landfills. Efficient incinerators reduce the volume of waste deposited to landfills by 90 % and weight by 75 %. The new idea is to use the wastes a source of fuel in ëcement kilnsí in cement industries to replace the costly fossil fuels. The emission problems accompanying incineration is also minimized to a great extent. But only wastes with high calorific value is useful for energy recovery. However, waste with high organic components should preferably be used to produce fertilizers and not fuel. A mean calorific value for municipal waste is 8.5 MJ / kg. Allowing for the moisture content (typically 20-30 % by weight) good quality MSW has an average calorific value of 10.5 MJ / kg. The calorific value of coal briquettes is about 22 MJ / kg and hence MSW has half of its energy as compared to coal.

Biogas: The biogas technology by the use of anaerobic ëmetanobacteriaí utilizes the organic wastes rich in cellulosic materials with high carbon and nitrogen (C/N) ratio. It produces both fuel and fertilizer. Each ton of organic waste by dry weight yields about 36 cum of biogas and 350 kg of biomanure. Methane is a clean burning substance and on combustion yields 550 BTU of heat per cft of its volume. Even the sewage sludge rich in organic matter and high C/N ratio is efficiently recycled to yield methane.

Coal Briquetts: A technology to recycle the agricultural wastes into a non-polluting fuel has been developed. The dried biomass is crushed and pre-heated to a temperature of 100-120 ° C and then compacted.

Fuel Pellets : A technology has been developed for converting garbage into non-polluting fuel pellets. The garbage is first shredded and blown dry in rotary kiln. It is then blended with combustible wastes like saw dust and is then pelletized. The pellets have calorific value around 4,000 kcal /kg and there is no harmful emission upon combustion.

Converting Waste into Compost

All municipal solid wastes have considerable organic matter rich in NKP and a combination of micro and macro elements and can be conveniently recycled into compost production. Also, there is always greater economic as well as ecological wisdom in converting as much ëwaste into compostí (waste-to-compost), so that less and less waste finally go to the landfills. Composting technology has now been significantly improved with our modern scientific knowledge in ëmicrobiologyí and ëbiotechnologyí to ëbiodegradeí all kinds of organic wastes including the ëmunicipal solid wastes (MSW)ícontaining sufficient organic components under a completely controlled environmental conditions. MSW contain 70-80 % by weight of organic materials. Yard waste which is part of the MSW may contain even higher percentage of organic matter and certain industrial wastes such as those from the ëfood processingí, ëagriculturalí and ëpaper-pulp industriesí are mostly organic in composition. Controlling the biological, physical and the chemical factors can significantly enhance the composting process without the emission of foul odor and without the loss of essential nutrients from the compost.

12. Landfill Disposal of Raw Solid Wastes and the Residual Wastes after Biological and Thermal Treatments

Finally some raw solid waste or the residual portion of it, after reusing and recycling, have to be disposed off safely, and the landfills provides the ëultimate graveyardí for all such wastes and their residues. Landfills are the physical engineering facilities used for the disposal of solid waste or the residual solid wastes (treated biologically / chemically / thermally) in the surface soils of the earth. Landfills have become the most common method of waste disposal under the ëintegrated solid waste managementí plan. Modern landfills are made much more ëenvironmentally secured and sanitaryí.

Modern landfills are constructed in sections. It starts with excavation and preparation of landfill bottom and subsurface sides. Excavations and bottom preparations are also carried out progressively over time (as the wastes continue to be deposited) rather than at once. Excavated materials (often the native soil containing microorganisms ) are stockpiled nearby for later use as ëlandfill coverí. The landfill bottom is shaped as such to provide drainage of leachate, and a low-permeability liner is installed extending up to the side walls. Liners usually consist of layers of ëcompacted clayí and / or ëgeomembraneí material designed to prevent migration of landfill leachate and landfill gas. Leachate collection and extraction facilities are placed within or on top of the liner. Horizontal gas recovery trenches are installed at the bottom of the landfill. The excavated trenches are filled with gravel, and perforated plastic pipes are installed in them. The landfill gas is extracted through the pipes.

Waste placement and filling operations is carried out on daily basis and is completed each day. Waste deposited each day is spread out in 18 to 24 inches layers and compacted. Each day of waste deposited and compacted is covered with 6-12 inches of native soil from the stockpile or by alternative material such as compost. After the filling is complete over a period of time, the landfills are covered with ëfinal coverí which is applied to the entire landfill surface. The final cover usually consist of multiple layers of soil and / or geomembrane materials designed to enhance surface drainage, intercept percolating water, and support surface vegetation. Landfills are finally closed after its capacity is full, but environmental and social impact assessment (ESIA) has to continue for long time, which may range from 30 to 50 years.

Leachate discharge and emission of landfill gases (methane, carbon dioxide, carbon monoxide, hydrogen, trace volatile organic compounds (VOCs)) are two important health and environmental concerns for the landfill disposal of MSW. Trace gases may carry ëcarcinogenicí and ëteratogenicí compounds into the environment. While methane and carbon dioxide are ëgreenhouse gasesí, methane can cause explosion when present in air in concentrations between 5 and 15 %. Attempts are being made to generate electricity from the landfill gases in several countries.

The cost involved in landfill construction is not only up-front, but also in its monitoring and maintenance, for controlling landfill gases and the leachate collection etc. The up-front development costs for new landfills vary from US $ 10 m to $ 20 m before the first load of waste is placed in the landfill.

13. Preventing Waste is Preventing the Problem : Embarking on Cleaner Production Technology for Reducing the Waste Quantity With Toxicity

Waste management by various treatment methods- physical, chemical, biological and thermal, manage all kinds of wastes including the hazardous wastes, albeit at a high economic and environmental cost and yet with the risk to human health and the environment continues in several cases. There is greater economic and ecological wisdom in waste management by preventing their generation at very source so that the techno-economic problem for their treatment and safe disposal do not arise. This will also save precious resources from going to waste, save the tremendous amount of time and money to be spent on safe storage, transport and disposal, save water and energy, and above all, save the environment and human health. Whereas waste treatment consume energy and resources and pollute the environment, waste prevention through cleaner production conserves energy and resources and protect the environment.

Industries, generating hazardous waste have become highly sensitive to the potential social (health), legal, economic and ecological liabilities associated with generation of hazardous wastes. The liabilities are not only limited up to the cost of storage, transport, and safe disposal but also for cleaning up the contaminated sites and for the adverse health effects on people accidently exposed to the waste. Therefore, the less waste generated means, the less waste to store, transport, treat and dispose, and reduced liabilities for any spills, accidents and environmental disasters. Further, less toxic wastes are generally easier to handle and less costly to dispose off. Finally, it may be less costly to reduce hazardous wastes at source than to pay for the remedial measures.

Pollution Prevention Pays (Cleaner Production Pays Money Back)

ëPollution prevention pays and increases profitsí and ëPrevention is the best remedyí. The proverb is as good for environmental health, as it is for human health. Preventing waste is like preventing a ësocial diseaseí to occur. While waste reduction mainly reduces the ëvolumeí or ëquantityí of waste generated, waste prevention by cleaner production reduces both quantity as well as the ëhazardous qualityí of waste. Because the objectives of waste reduction is not only reduction in ëvolumeí but also the ëtoxicityí of the waste.

There is greater economic and ecological wisdom in developing environmental technologies which can ëpreventí the use of hazardous substances and materials in the industrial processing, so that there is no generation of hazardous wastes (as a by-product) in the first place. Reducing or eliminating use of hazardous materials in the production process will decrease not only hazardous waste generation but also the quantity of hazardous materials in air emissions and wastewater effluents. This will in turn reduce the capital investment in treatment systems needed for pollution control. Use of chemicals sometimes becomes inevitable in industrial processing to get a valued product. There is need to search and develop ëalternativesí and ësubstitutesí for such chemicals / materials that are ëlesser evilí or none at all. If the ëbiodegradable plastic materialí becomes an economic reality it would dramatically reduce the hazardous plastic wastes.

Cleaner Production Methods in Industries

Cleaner production is the final answer in any waste management program. UNEP has pioneered the promotion of cleaner production philosophy. It has-

1. Launched an ëInternational Declaration on Cleaner Productioní, which now has over 159 signatories;
2. Established with the United Nation Industrial Development Organization, 15 National Cleaner Production Centers in developing and Eastern European countries;
3. Set up an ëInternational Cleaner Production Information Clearing Houseí;

There can be several approaches to cleaner production, pollution prevention and waste reduction in industries-

1. Improving process technology and equipment that alter the primary source of waste generation. By changes in the process itself, it may be possible to reduce the amount and toxicity of the wastes generated.
2. Improving plant operations, such as housekeeping, materials handlings and equipment maintenance, monitoring and waste tracking; automating process equipment and integrating mass balance calculations into process design.
3. Substituting raw materials that introduce fewer hazardous or smaller quantities of such substances into the production process.

    

4. Redesigning or reformulating the end products.
5. Recycling a potential industrial waste or portion of it ëon the siteí where it is generated. Sometimes while resorting to cleaner production some byproducts are inevitably produced which is recycled.

A reduction in volume of hazardous wastes will lessen the environmental impact, lower the operating cost of industries, decrease the complexity of waste transport and disposal, and reduce potential liability. Several services industries in world have also ëchanged production processí and switched over to ëcleaner productioní with both economic as well as ecological gains. Few case studies are cited here.(UNEP Report).

Case Studies of Cleaner Industrial Production

(1). In 1987 the Polaroid Corporation of US producing instant photographs launched a US $ 10 million Toxic Waste Reduction Program. It was fined US $31,000 by EPA for hazardous waste generation and violation of laws. It completely eliminated the use of category II Cr (VI) compounds which were carcinogens and highly toxic, replacing them by recyclable dyes with higher molar absorptivity and hence requiring less dye per picture. This reduced hazardous waste generation by 80 % and the remaining waste generated are more readily treated, requiring lower disposal cost. This substitution is saving Polaroid about US $ 1 million a year.

(2).The FSM Sosnowiec Company of Poland manufacturing car headlight reflectors emitted dangerous ëcyanideí and heavy metals like chromium, nickel, copper etc. in the effluents. A ënew plating systemí was introduced which reduced the emission of cyanide by 80 %, chromic acid by 60 %, copper by 95 % and nickel by 98 %. The wastewater is now reused. The company invested US $ 36,000 and is saving US $ 193,000 per year.

(3). The Northtrop Corporation of California, US, earlier used a toxic ëbiocideí to eradicate the algal weeds that accumulated in the cooling towers. Now it uses ëozoneí which kills the algae in microseconds by oxidation and in the process gets absorbed in the water and never escapes to the atmosphere. The company invested US $ 450,000 and is now saving US $ 300,000 per year.

(4). Century Textiles of India earlier used ësodium sulphideí for dyeing which besides foul odor produced highly toxic ësulphidesí (30 ppm) in the effluents which was much above the safety limits and was fined by the Pollution Control Board. The company substituted the chemical sodium sulphide with a cheap non-toxic vegetable by-product ëhydrolí from the maize starch industry and eliminated the emission of sulphides. The company has gained in producing better quality cloth and by saving on the expenditure involved in pollution control. Hydrol produces less corrosion than sodium sulfide meaning lower maintenance cost.

(5). The PT Semen Cibinong cement company of Indonesia introduced a sophisticated monitoring and control system at an investment of US $ 375,000 to ensure an ëoptimum temperatureí in the operation of the kilns. At lower temperature the quality of the cement is destroyed resulting into lots of wastes, and at higher temperature more fuel is consumed with greater emission of SO2 and NOx. By maintaining right temperature the production of below standard cement (rejects) was reduced by 40 % and emissions of SO2 and NOx were significantly cut down.

(6). Producers of gift-wrapping papers in US, simply switched from solvent to water based inks. This saved the company US $ 35,000 per year on hazardous waste management costs. Furthermore, it saved the company from having to install an air-pollution control system, costing several million dollars, to control volatile organic carbon emissions.

(7). A printed-circuit-board manufacturer in the US now uses electrolytic recovery to reclaim metals from the drag-out from the copper and tin-lead plating baths. They recover about 9 kg of copper metal and 4.5 kg of tin-lead metal each week and allow the treated wastewater to be safely discharged to the sewer system. The company now saves over US $ 33,200 per year in treatment and disposal costs.

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