Question

What is the main objective of secondary treatment of sewage plants?

(a) To remove the suspended particles

(b) To remove the contaminants

(c) To remove the BOD

(d) To remove the organic material

I had been asked this question by my college director while I was bunking the class.

The question is from Effects and Control Measures of Marine Pollution topic in section Environmental Pollution of Energy Management

Answer 1

Correct answer is (c) To remove the BOD

For explanation: The main objective of secondary treatment of sewage plants is to remove most of the BOD. BOD decided the contamination of water pollutants. Secondary treatment of sewage treatment can remove at least 85% of the BOD.