Question

B)Water is a precious resource and no existence of life without it. It has been predicted that there will be a water scarcity in the future due to water pollution. a. Can you share your views how the water is getting polluted nowadays? (Any four ways) (2) b. Write any two measures to stop the water pollution at your level?

A). As an Engineer, you are requested to implement a small wastewater treatment plant for our college campus. Explain the different steps or stages involved in the wastewater treatment process.

Answer 1

The various ways in which water is getting polluted are as follows :-

* Excessive use of pesticides, insecticides and chemical fertilizers polluting the underground water by leaching and surface water by mixing through surface runoff in surface waters.

* Direct disposal of untreated industrial effluents containing harmful chemicals into surface water.

* Disposal of domestic wastes containing organic matters, soaps and detergents into surface water.

* Due to acid rains falling in surface water bodies which is also the result of air pollution. etc

In order to reduce water level the following measures can be adopted :-

* Mitimize the use of insecticides, pesticides and chemical fertilizers in agricultural practices.

* Treatment of sewage wastes from industries and households prior to disposal in water bodies.

The various stage in waste water treat ment process are :-

Screening :- in this process waste water is passed through a coarse screen where large particles present gets filtered.

Detritus / Grit chamber :- in this process fine suspended particles gets settled and removed as sludge.

Skimming tank :- here oil and grease particles if present are removed.

Primary Clarifier :- in this process suspended organic matter are removed and little dissolved organic matter are also removed.

Biological treatment :- Here dissolved organic matter are removed by the action of micro organisms in aerobic process in presence of oxygen and by anaerobic micro organisms in absence of oxygen.

Disinfection :- finally the water is subjected to disinfection by adding chlorine or UV Ray's or ozone etc.

Disposal :- now waste water is free from impurities and micro organisms and is safe to be disposed in water bodies.

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