Ways of reduction of quantity and degree of pollution of sewage
The task of ecological technology is development and introduction of such methods of processing of raw material and products which allow to stop completely or sharply to reduce dump of harmful substances with sewage. New technological processes should be created on the basis of complex use of initial raw material and materials.
1. Reactionary sewage – the unique ecologically proved decision is obtaining of products on other reactions proceeding without formation of water (though it not always technically or economically probably).
2. The water, contained in raw material and initial products, - it is necessary preliminary removal of water from raw material and initial products.
3. Washing water – 1) the sharp improvement of quality of initial raw material and the products, excluding the necessity of their washing; 2) application for washing non-water solvents; 3) introduction of modern circuits and the perfect equipment; 4) wide application of regeneration methods (adsorption, ion changing, reverse osmosis, etc.) and destructive methods (ozonization, chlorination, biological oxidation, etc.) for the components polluting raw material and products.
4. Mother liqueur – the carrying out of technological processes in non-water environment, application of "dry" methods of manufacturing of products, repeated using of mother liqueur.
5. Water extracts and absorption liquids - replacement of water by non-water solutions, regeneration of extragent and absorbent, their repeated using.
6. Cooling waters - application of air cooling.
7. Other kinds of sewage – the reuse of these waters with intermediate clearing, replacement of water by non-water solvents at washing of equipment and container, application of more perfect vacuum pumps and other equipment, etc.
Necessary degree of sewage clearing. It should be such that quality of water in reservoirs after flowing in them of sewage was not lower than quality of water according to requirements «Rules of protection of superficial waters from pollution by sewage». For this purpose the data on quantity and structure of sewage and the data of researches of a reservoir are required.
Definition of conditions of descent of sewage in reservoirs is made on parameters: organoleptic properties, maximum concentration limit, the dissolved oxygen, рН, the content of the toxic and harmful substances, the suspended substances, etc.
Methods of sewage destruction (a burial place, pumping in chinks, pumping in sea depths, thermal destruction). Firm waste products of industrial enterprises and ways of their processing.
Until recently many industrial wastes were exposed to liquidation. Such approach to the decision of problem of waste products is obsolete. Only those waste products are exposed to liquidation which practically cannot be used or advanced on target products by modern methods. The majority of waste products are exposed to physical and chemical processing with the purpose of extraction from them useful components. As a result of it new firm residues or sludges are formed. Further processing of these waste products is inexpedient. Thus, in technology of processing of waste products a final stage of process can be liquidation of a highly toxic part of waste products or a final deposit, extraction from which of useful components is practically impossible.
In our country and abroad are practically used the following methods of liquidation of waste products: dumps and sludge storages, sanitary earthen covering, a burial place or pumping in deep underground chinks, burning and pyrolysis.
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