wastes

Types of wastes :

1. Municipal Solid Waste

Municipal solid waste (MSW) is generated from households, offices, hotels, shops, schools and other institutions. The major components are food waste, paper, plastic, rags, metal and glass, although demolition and construction debris is often included in collected waste, as are small quantities of hazardous waste, such as electric light bulbs, batteries, automotive parts and discarded medicines and chemicals.
Generation rates for MSW vary from city to city and from season to season and have a strong correlation with levels of economic development and activity. High-income countries (such as Australia, Japan, Hong Kong, China, Republic of Korea, and Singapore) produce between 1.1 and 5.0 kg/capita/ day; middle-income countries (such as Indonesia, Malaysia and Thailand) generate between 0.52 and 1.0 kg/capita/day, whilst low-income countries (such as Bangladesh, India, Viet Nam and Myanmar) have generation rates of between 0.45 and 0.89 kg/capita/ day.

SOURCE

TYPICAL WASTE GENERATORS

TYPES OF SOLID WASTES

1. Residential

Single and multifamily dwellings

Food wastes, paper, cardboard, plastics, textiles, leather, yard wastes, wood .

2. Industrial

Light and heavy manufacturing, fabrication, construction sites,

Housekeeping wastes, packaging, food wastes, construction and demolition materials

3. Commercial

Stores, hotels, restaurants, markets, office buildings .

Paper, cardboard, plastics, wood, food wastes, glass, metals, special wastes .

4. Institutional

Schools, hospitals, prisons, government centres .

Same as commercial

5. Municipal Services

Street cleaning, landscaping, parks, beaches, other recreational areas

Street sweepings, landscape and tree trimmings, general wastes from parks, beaches, and other recreational area

2. Industrial Solid Waste

Industrial solid waste in the Asian and Pacific Region, as elsewhere, encompasses a wide range of materials of varying environmental toxicity. Typically this range would include paper, packaging materials, waste from food processing, oils, solvents, resins, paints and sludges, glass, ceramics, stones, metals, plastics, rubber, leather, wood, cloth, straw, abrasives, etc. As with municipal solid waste, the absence of a regularly up-dated and systematic database on industrial solid waste ensures that the exact rates of generation are largely unknown. Industrial solid waste generation varies, not only between countries at different stages of development but also between developing countries . In People’s Republic of China, for example, the generation ratio of municipal to industrial solid waste is one to three. In Bangladesh, Sri Lanka and Pakistan, however, this ratio is much less. In high-income, developed countries, such as Australia and Japan, the ratio is one to eight. However, based on an average ratio for the region, the industrial solid waste generation in the region is equivalent to 1 900 million tonnes per annum. This amount is expected to increase substantially and at the current growth rates, it is estimated that it will double in less than 20 years. As the existing industrial solid waste collection, processing and disposal systems of many countries are grossly inadequate, such incremental growth will pose very serious challenges.

3. Agricultural Waste and Residues

Expanding agricultural production has naturally resulted in increased quantities of livestock waste, agricultural crop residues and agro-industrial by-products. Among the countries in the Asian and Pacific Region, People’s Republic of China produces the largest quantities of agriculture waste and crop residues followed by India. In People’s Republic of China, some 587 million tonnes of residues are generated annually from the production of rice, corn and wheat alone. In Myanmar, crop waste and residues amount to some 4 million tones per year (of which more than half constitutes rice husk), whilst annual animal waste production is about 28 million tonnes with more than 80 per cent of this coming from cattle husbandry.

4. Hazardous Waste

With rapid development in agriculture, industry, commerce, hospital and health-care facilities, the Asian and Pacific Region is consuming significant quantities of toxic chemicals and producing a large amount of hazardous waste. Currently, there are about 110 000 types of toxic chemicals commercially available. Each year, another 1000 new chemicals are added to the market for industrial and other uses. The availability of robust data on the generation of hazardous waste for the Asian and Pacific Region is limited by the reliability of information on the quantities and types of hazardous waste produced at the country level. This is due to a variety of reasons, including the lack of qualified personnel to undertake the necessary assessment, the reluctance of industries to provide process information (including waste arising data) and a poor appreciation of the extent to which generated waste is hazardous. Where data is available, significant difficulties are encountered in seeking to draw international comparisons due to differences in classification and definition of hazardous waste from country to country within in the region. Most hazardous waste is the by-product of a broad spectrum of industrial, agricultural and manufacturing processes, nuclear establishments, hospitals and health-care facilities. Primarily, high-volume generators of industrial hazardous waste are the chemical, petrochemical, petroleum, metals, wood treatment, pulp and paper, leather, textiles and energy production plants (coal-fired and nuclear power plants and petroleum production plants). Small- and medium-sized industries that generate hazardous waste include auto and equipment repair shops, electroplating and metal finishing shops, textile factories, hospital and health-care centres, dry cleaners and pesticide users. The principal types of hazardous waste generated in the Asian and Pacific Region, include waste solvents, chlorine bearing waste and pesticideorganophosphate - herbicide-urea-fungicide bearing waste. In particular, solvents are extensively used in the region and, as a consequence, large quantities of waste solvents are produced.

Various waste management practices : 1. Municipal Solid Waste

(a) Collection and Transfer
In many cities of the region, municipal solid waste (MSW) is gathered in a variety of containers ranging from old kerosene cans and rattan baskets to used grocery bags and plastic drums or bins. In some cities, neighbourhood-dumping areas have been designated (formally or informally) on roadsides from which bagged and loose waste is collected. Waste collection (and, where appropriate, waste transfer) frequently constitutes the major solid waste management cost for the region’s cities. A wide variety of collection systems are used including doorto- door collection and indirect collection, by which containers, skips or communal bins are placed near markets, in residential areas and other appropriate locations. In the high-income industrialized countries of Australia, Japan, New Zealand, Republic of Korea and Singapore, collection and transfer services are capital-intensive and highly mechanized employing standardized collection vehicles, compactors and containers and providing collection rates in the range of 90 per cent and collection services to most urban and even rural areas. Source separation and subsequent collection of recyclables is governed by regulation and is facilitated by the provision of colour-coded bins or bags or by the establishment of area recycling centres. Whilst a significant number of these cities continue to retain parts of the collection process within their direct municipal control, many others have contracted private sector waste collection firms and have made private sector trade and industrial establishments responsible for the collection and disposal of their own solid waste. Financial constraints and the lack of technical expertise severely limit the effectiveness of solid waste management in the cities and towns of the poorer developing nations. Shortages of storage bins, collection vehicles, non-existent and/or inadequate transfer stations, traffic congestion and a lack of public compliance are factors affecting collection efficiency, resulting in low waste collection rates. In some cities, heaps of refuse are routinely left uncollected and there are illegal deposits on open land, drains and canals. The lack of coordination and overlapping of responsibilities among various government agencies and different levels of local government also contribute to the problem.

(b) Material Recovery, Reuse and Recycling
In many countries of the region, including Japan, Republic of Korea and Singapore, the rate of recovery of recyclable materials from MSW has improved significantly in recent years. Within the region, overall resource recovery has grown from less than 10 per cent of all MSW in 1988 to 30 per cent in 1998, with much of the increase attributable to greater rates of recovery of paper and paperboard, plastics, glass and metals. In terms of the total tonnage of materials recovered, paper and paperboard represent the largest category (almost 60 per cent of the total) and this often masks the importance of recovery rates for other materials. For example, recovered aluminium represents only about 3 per cent of the total tonnage of recovered materials, yet in terms of its economic value, recovered aluminium far exceeds the paper product category.

(c) Disposal Methods for MSW (i) Open Dumping
Open dumping is the most widespread method of solid waste disposal in the region and typically involves the uncontrolled disposal of waste without measures to control leachate, dust, odour, landfill gas or vermin. In some cities, open burning of waste is practised at dumpsites. In many coastal cities, waste is dumped along the shoreline and into the sea, such as Joyapura in Indonesian or dumped in coastal and inland wetlands and ravines as is being practised in Mumbai, Calcutta, Colombo, Dhaka and Manila. The scarcity of available land has led to the dumping of waste to very high levels; waste thickness is often over 12 metres and may be over 20 metres, which was the case of the Quezon City dumpsite in the Philippines. An additional hazard on uncontrolled dumpsites arises from the build-up of landfill gas (predominantly methane), which has led to outbreaks of fire and to adverse health effects on workers and adjacent residents . adopted as a solution with old cars and refrigerators being dumped into the lagoons of French Polynesia and municipal waste being bundled into wire gabions for use in sea wall construction in the Marshall Islands. In the latter case, the gabions allowed leachate and loose waste items to pass directly into the ocean water.
(ii) Landfilling
In the Asian and Pacific Region, the disposal of solid waste at a semi-engineered or full sanitary landfill has been adopted by cities from both low and high-income countries as the most attractive of disposal options. Bandung, Singapore, Hong Kong, China, Seoul, Chennai and Tokyo do have well designed and reasonably operated sanitary landfills, whilst other cities in Australia, People’s Republic of China, Japan, Republic of Korea, Malaysia and Thailand have adopted controlled tipping or sanitary land filling for solid waste disposal. Kuala Lumpur employs disused tin mines for MSW landfills around the city.
(iii) Composting
Whilst small-scale composting of organic waste is widespread in the region, attempts to introduce large-scale composting as a means of reducing the quantities of municipal solid waste requiring disposal, or with the intention of creating a revenue stream from the sale of compost, have been met with limited success. Most of the composting plants in the region are neither functioning at full capacity nor do they produce compost of marketable value. The high operating and maintenance costs results in compost costs that are higher than commercially available fertilisers, whilst the lack of material segregation produces compost contaminated with plastic, glass and toxic residues. Under such circumstances, little of the compost produced is suitable for agriculture application.
(iv) Incineration
For much of the Asian and Pacific Region, the incineration of MSW remains an expensive and technically inappropriate waste disposal solution. The development of waste incineration facilities has been constrained by the high capital, operating and maintenance costs and by increasingly stringent air pollution control regulations . In addition, the combustible fraction of much of the MSW generated in the low and middle-income countries of the region is relatively low, with high organic and moisture contents. For example, the Indonesian city of Surabaya imported an incinerator that is currently operating at two-thirds of its design capacity as the waste needs to be dried on-site for five days before it is suitable for combustion. Even without the cost of air pollution control mechanisms, it is estimated that the cost of waste incineration in this instance is roughly 10 times greater than the cost of open dumping/land filling in other Indonesian cities.

2. Industrial Solid Waste

The methods employed in the disposal of industrial solid waste are broadly the same as those used to dispose of MSW and comprise open dumping, land filling (both semi-engineered and sanitary landfilling) and incineration. In many countries, including Bangladesh, People’s Republic of China, India, Indonesia, Malaysia, Philippines and Thailand, non-hazardous industrial solid waste is accepted at either open dumps or landfills along with municipal solid waste (although where facilities are available potentially hazardous industrial solid waste is disposed of either in secure landfills or is incinerated). In those developing countries with few waste management facilities, industrial waste is often dumped on private land or is buried in dump pits within or adjacent to the site of the industrial facility from which it has emanated.

3. Agricultural Waste and Residues

In most traditional, sedentary agricultural systems, farmers use the land application of raw or composted agricultural wastes as a means of recycling of valuable nutrients and organics back into the soil and this remains the most widespread means of disposal. Similarly, fish farming communities in Bangladesh, People’s Republic of China, India, Indonesia, Malaysia, Philippines, Thailand and Vietnam commonly integrate fish rearing with agricultural activities such as livestock husbandry, vegetable and paddy cultivation and fruit farming . Many countries with agricultural-based economies use agricultural wastes to produce biogas through anaerobic digestion. The biogas (approximately 60 per cent methane) is primarily used directly for cooking, heating and lighting, whilst the slurry from the anaerobic digesters is used as liquid fertiliser, a feed supplement for cattle and pigs and as a medium for soaking seeds prior to germination . Purpose-built sanitary landfills have been developed to receive hazardous waste in Australia, Japan, Malaysia, New Zealand and Republic of Korea, whilst hazardous waste incinerators have been developed in Australia, Japan, Hong Kong, China, Malaysia, Republic of Korea, Singapore and Thailand . Other countries such as Bangladesh, People’s Republic of China, India, Mongolia, the Philippines, Pakistan, Sri Lanka and many Island States in the South Pacific subregion usually co-dispose hazardous waste along with MSW in open dumps or seek to store particularly toxic wastes in sealed containers . In some countries, including Australia, Japan, Hong Kong, China, Republic of Korea and Singapore, progress has been made on methods for detoxification of hazardous waste and subsequent immobilization by fabrication into bricks and other usable materials. In Thailand, a major programme of hazardous waste management is underway along the Eastern Seaboard where petrochemical, chemical and non-ferrous industries produce some 250000 to 300000 tonnes of commercially viable hazardous industrial waste each year. A hazardous waste treatment plant, managed by the Industrial Estate Authority of Thailand, has been established at the Map Ta Phut Industrial Estate, a focal point of the country’s petrochemical and chemical industries.

4. Biomedical Waste

The number of hospitals and health care institutions in the Asian and Pacific Region has been increasing to meet the medical and health care requirements of the growing population. Although city planners have long taken into consideration the provision of medical and health care institutions and services, until recent years, they, and even municipal waste management authorities, have paid very little attention to the wastes generated from these facilities, which are potentially hazardous to human health and the environment. In recent years, however, serious concern has arisen regarding the potential for spreading pathogens, as well as causing environmental contamination due to the improper handling and management of clinical and biomedical waste. Whilst regulatory programmes and guidelines to control waste from such institutions have been introduced in most developed countries, including Australia, Japan, New Zealand, and Singapore, in developing countries, such as Bangladesh, People’s Republic of China, India, Indonesia, Pakistan and the Philippines, such programmes have yet to be fully developed .

5. Radioactive Waste

Information regarding disposal practices for radioactive waste is not extensive and few systematic country surveys have been conducted. In Japan, low level radioactive waste generated from 46 operating nuclear power plants is packed into 2000 litre drums and temporarily stored in on-site storehouses. Special enclosed containers are used to package eight drums together and these are then sea and land transported to the Rokkasho-mura Burial Centre in Aomori Prefecture for permanent storage (Tanaka 1993). In Indonesia, low level radioactive waste generated from four nuclear research centres is conditioned into cement matrices in blocks and the embedded wasteblocks are transported to the RWMC (Radioactive Waste Management Centre) at Serpong for permanent burial (Suyanto and Yatim 1993). Other countries of the region such as India, Pakistan and Republic of Korea uses permanent land burial methods for the disposal of radioactive waste (Greenpeace 1998).

6. Transboundary Movement of Hazardous Waste

The Asian and the Pacific Region is under considerable pressure as a favoured dumping ground for hazardous waste, particularly as domestic pressure has been exerted on industries operating in the industrial nations to dispose of their hazardous waste in a controlled, and hence expensive, manner. Between 1994 and 1997, the industrialized nations sent a total of 3.5 million tonnes of hazardous waste to countries in the Asian and Pacific Region. The first documented case of such imports to People’s Republic of China occurred in September 1994 and by the first quarter of 1995, Chinese customs identified 22 separate incidents involving some 3,000 tonnes of foreign hazardous waste. From 1995 to
1996 Chinese customs uncovered almost one case per week of mislabelled hazardous waste, mostly from United States, Republic of Korea, and Japan in particular (Greenpeace 1997). In June 1998, 640 tonnes of Californian waste was found dumped in a Beijing suburb; the waste included toxic sludge, used syringes and decomposing animal bodies (Greenpeace 1997). Over the same period, India has also seen an increase in the dumping of hazardous waste from industrialized nations (Anjello and Ranawana 1996, Agarwal 1998). Thousands of tonnes of toxic waste are being illegally shipped to India for recycling or dumping, despite a New Delhi court order banning imports of toxic materials. In 1995, Australia exported more than 1 450 tonnes of hazardous waste, including scrap lead batteries, zinc and copper ash, to India, whilst some 569 tonnes of lead battery waste were brought in through the main seaport of Mumbai between October 1996 and January 1997 (Greenpeace 1998).