Secondary sewage treatment is mainly a

(a) mechanical process

(b) chemical process

(c) biological process

(d) physical process

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1 Answers

Correct option (c) biological process

Explanation

In secondary or biological treatment of municipal waste, the organic matter is decomposed with the help of microbes. Decomposition of organic matter occurs by one of the three methods-water hyacinth ponds, trickling filter method and activated sludge method. After decomposition the treated water is sterilised through chlorination and recycled.

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