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Prevention
and Control of Water Pollution
Water pollution are contributed due to industrial
effluents and sewage. The time has came to avert major
disaster. Effluent treatment systems have to be
incorporated in industry. Industries, where it is
already in existence, need to operate their plants
regularly without looking for savings.
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New
techniques that need no water is highly
beneficial. Some of the wet processes is replaced
by the dry processes. For example, metal pickling
once carried out by acids is replaced by sand
blasting in which no liquid effluent is generated.
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To
minimize the volume of effluents, the waste water
that is less polluted may be used in rinsing. For
instance, in the mercerizing of yarn, the final
rinse water containing little alkali is used for
the first and second rinsing of yarn containing
excess alkali.
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Concentrated
wastes, low in volume, are mingled with diluted
waste for treatment or disposal. It can be
segregated from other streams of diluted wastes,
for reduction in pollution load and the diluted
wastes after minor treatment is utilised for
irrigation. This method is used for treating
tannery effluents.
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Small
industries cannot afford treatment plants as they
frequently discharge their effluents, near
agricultural lands and on roads. It can be avoided
by setting up a common effluent treatment plant
where industries are located.
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Waste
can be converted into wealth. For instance, in our
country distilleries can set up bio-gas plants
which are fed by their effluents resulting in
reduction in fuel costs and decrease in effluent’s
strength.
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The
sludge obtained is a problem. The sludge from pulp
and paper industry may be used for manufacturing
boards used in packing or in preparation of
artificial wooden panels while those from the
electroplating industry may form water–proofing
compounds.
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Recovery
of chemicals and metals is practiced in most
industries. The reclaimed waste water can be
reused for industrial processes such as boiler,
feeding, cooling, which will help cut down the
fresh water needs. And paper mills, sugar
industries and distilleries that let out more
effluents can be used for irrigation or as
fertilizers after proper treatment, without
affecting ground water.
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