Treatment of liquid effluent at the plant before d
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Treatment of liquid effluent at the plant before discharge into any public water system:-
The effluent from all the sections of the plant is collected in a central collection tank. The supernatant liquid is screened and pumped into shallow lagoon of 30-60 cm deep. Air/oxygen is blown into the lagoon with aerator or oxygen pipes. The BOD is mainly removed by this method. The effluent is then chlorinated and also treated with 1-2% potassium permanganate in rubberlined or concrete tanks. The reaction time varies from 0.5 to several hours. After, the oxidizing treatment lime is added to precipitate most of the harmful impurities still remaining. The effluent is then again put into a set of another lagoon when the water is sun dried. The sludge is dug up and discharged in a barred land. The sludge is sometimes burnt or incinerated with a tall chimney and then dumped in a barren uninhabited place.
