27-02-2013, 03:31 PM
SOLID WASTE
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Waste is unwanted or unusable materials.Solid waste means any garbage or refuse; sludge; and other discarded material,including solid, semi-solid resulting from industrial, commercial, mining,and agricultural operations, and from community activities from awastewater treatment plant, water supply treatment plant, or airpollution control facility
According to United Nations Statistics Division(UNSD) it is defined as
"Wastes are materials that are not prime products (that is products produced for the market) for which the generator has no further use in terms of his/her own purposes of production, transformation or consumption, and of which he/she wants to dispose. Wastes may be generated during the extraction of raw materials, the processing of raw materials into intermediate and final products, the consumption of final products, and other human activities. Residuals recycled or reused at the place of generation are excluded."
There are the flowing types of solid waste:
1.Muncipal solid waste
2.Construction waste
3.Industrial waste
4.Medicalwaste
5.hazardouswaste
MUNCIPAL SOLID WASTE
Municipal Solid Waste (MSW) is waste
collected by or on behalf of a local authority.
It comprises mostly household waste and it
may include some commercial and industrial
wastes. Historically, nationally the quantity of
MSW has risen year on year1, presenting a
growing problem for local authorities
particularly as legislation, now limits (by
implication2) the amount of mixed MSW that
can be sent to landfill, comes into effect,
becomes more stringent over time.
CONSTRUCTION WASTE
Construction waste consists of unwanted material produced directly or incidentally by the construction or industries . This includes building materials such as Insulation, nails, electrical wiring, and rebar, as well as waste originating from site preparation such as dredging materials, treestumps, and rubble.
INDUSTRIAL WASTE
Any liquid, gaseous, or solid waste resulting from any process of industry, manufacturing, trade, or business or from the development of any natural resources
The major generators of industrial solid wastes are the thermal power plants producing coal ash, the integrated Iron and Steel mills producing blast furnace slag and steel melting slag, non-ferrous industries like aluminum, zinc and copper producing red mud and tailings, sugar industries generating press mud, pulp and paper industries producing lime and fertilizer and allied industries producing gypsum
DESCRIPTION OF IMPORTANT INDUSTRIAL SOLID WASTE
Coal Ash
In general, a 1,000 MW station using coal of 3,500 kilo calories per kg and ash content in the range of 40-50 per cent would need about 500 hectares for disposal of fly ash for about 30 years’ operation. It is, therefore, necessary that flyash should be utilised wherever possible to minimize environmental degradation.
Integrated Iron & Steel Plant Slag
The Blast Furnace (BF) and Steel Melting Shop (SMS) slags in integrated iron and steel plants are at present dumped in the surrounding areas of the steel plants making hillocks encroaching on the agricultural land. Although, the BF slag has potential for conversion into granulated slag, which is a useful raw material in cement manufacturing, it is yet to be practised in a big way. Even the use of slag as road subgrade or land-filling is also very limited.
Phosphogypsum
Phosphogypsum is the waste generated from the phosphoric acid, ammoniumphospate and hydrofluoric acid plants. This is very useful as a building material. Atpresent very little attention has been paid to its utilisation in making cement,gypsum board, partition panel, ceiling tiles, artificial marble, fiber boards etc.
Red Mud
Red mud as solid waste is generated in non-ferrous metal extraction industries like aluminum and copper. The red mud at present is disposed in tailing ponds for settling, which more often than not finds its course into the rivers,especially during monsoon. However, red mud has recently been successfully
tried and a plant has been set up in the country for making corrugated sheets. Demand for such sheet should be popularised and encouraged for use.
Lime Mud
Lime sludge, also known as lime mud, is generated in pulp & paper mills which is not recovered for reclamation of calcium oxide for use except in the large mills. The lime mud disposal by dumping into low-lying areas or into water courses
directly or as run-off during monsoon is not only creating serious pollution problem but also wasting the valuable non- renewable resources.