Waste(redirected from waste management system)
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solid waste, discarded materials other than fluids. In the United States in 1996, nearly 210 million tons—about 4.3 lb. (2 kg) per person daily (up from 2.7 lb./1.2 kg in 1960)—were collected and disposed of by municipalities. In that year, municipal garbage included 12.4 million tons of glass and about 80 million tons of paper and paperboard (by far the largest constituent); in addition enormous tonnages of food residues, yard trimmings, textiles, plastics, and sludge formed in sewage treatment were produced. Although the amount of the increase has been slowed somewhat by recycling and composting programs and improvements in packaging, the amount of solid waste continues to increase annually. Moreover, the most common disposal methods pollute land, water, or air to some degree (see pollution). Management of solid waste therefore presents an increasingly acute problem.
Recycling of solid wastes is an option that many municipalities have explored in recent years. It not only facilitates disposal but conserves energy, cuts pollution, and preserves natural resources. To make cans from recovered aluminum, for example, requires 10% of the energy needed to make them from virgin ore. At the same time ore is saved, and the pollution resulting from mining and processing are avoided. Making steel bars from scrap requires 74% less energy and 50% less water, while reducing air-polluting emissions by 85% and mining wastes by 95%.
Similarly, sludge from treated sewage can be used for fertilizer, but it has been less costly to dump it at sea or on open land (see sewerage). Dumped sludge has killed marine life and threatened beaches along the Eastern seaboard; elsewhere in the United States it is a growing nuisance. Between 1975 and 1985 the amount of sludge dumped in U.S. coastal waters increased by 60%; the effects of dumping and illegal dumping are still felt despite the fact that it has been illegal since the beginning of 1992. Recycling and composting take care of approximately 2.7% of municipal solid waste.
(in industry), any material that is left over from the production process. Wastes include materials with a wide range of compositions and physicochemical properties. Examples are such by-products as ore fines, cuttings, and turnings; inert substances that are separated from minerals and fuels during enrichment; and ashes and slags that are formed during the combustion of fuels. The amount of waste depends on the production technology used, the quality of the starting materials, the dimensions of the material, and the way in which the production processes are coordinated.
Progress in engineering has sharply reduced quantities of waste; furthermore, a significant portion of industrial waste is
|Table 1. Toxic chemical warfare agents used by capitalist countries|
|Structure||Physiological classification||Chemical behavior|
|1The structure of a representative compound is shown|
|Tabun ................||Nerve agent||Unstable|
|Phosphorylthiocholines1 ....||Nerve agent||Stable|
|Hydrogen cyanide...........||HCN||General poison||Unstable|
|Cyanogen chloride............||ClCN||Genera l poison||Unstable|
|Mustard gas...............||S(CH2CH2Cl)2||Choking agent, vesicant||Stable|
|Trichlorotriethylamine .........||N(CH2CH2Cl)3||Choking agent, vesicant||Stable|
|Lewisite.........||Cl2AsCH=CHCl||Choking agent, vesicant||Stable|
|Chloroacetophenone.......||Lacrimator, irritant||Fuming, unstable|
|o-Chlorobenzalmalononitrile.||Lacrimator, sternutator, irritant||Fuming, unstable|
|Chloropicrin.............||Cl3CNO2||Choking agent, lacrimator, irritant||Unstable|
|Adamsite...............||Sternutator, irritant||Fuming, unstable|
|Lysergic acid diethylamide ...||Psychotomimetic||Unstable|
|Quinuclidine ester of diphenyl-oxyacetic acid.................||Pscychotomimetic||Unstable|
used as a raw material for producing by-products. A decrease in the quantities of waste and the reuse of waste significantly reduces the consumption of raw materials and supplies. Production costs are lowered, while production efficiency is raised. In the USSR and elsewhere new technologies are being devised, while the existing production processes are being improved in order to maximize the reduction in the quantities of waste and, where possible, to completely eliminate waste.
Closed-loop recycling is one new development. The quantities of waste in the form of waste water and industrial air pollution have been sharply reduced, particularly in the chemical, metallurgical, and petroleum-refining and processing industries as well as in the coal, pulp, and paper industries. Another method of waste reduction is the creation of industrial complexes in which one plant utilizes the waste products of another plant as raw materials. Such measures are means of conserving natural resources as well as of improving the quality of the atmosphere, hydrosphere, and soil. In the USSR the reduction or utilization of waste are part of the plan for the supply of raw materials and for the development of industrial production. Incentives in the form of bonuses for workers serve to encourage the practice of collecting, storing, and shipping wastes in many branches of industry.
A. I. IMSHENETSKII
by-products created in the processing of textile fibers. In Soviet industry, waste is classified as visible or invisible. Visible waste includes selvage waste—processed fiber that has emerged as waste from the spinning of semifinished articles and is returned for reprocessing; reworkable waste—soiled fiber, noils, and waste from opening machines that can be used in spinning after it is loosened and cleaned; wadded material, used to make wadding; and unusable waste. Invisible waste results from the removal of moisture from the raw material and the dispersion of fiber particles. Waste is undesirable because it reduces production output and increases the prime cost of production.