Question

Sewage water is purified by

• A. Microorganisms
• B. Light
• C. Fishes
• D. Aquatic plants

Answer 1

The correct option is A Microorganisms

Sewage is composed of organic matter and domestic waste. The pollutants are removed by the sewage treatment process to mitigate it's adverse impact on the environment when it is released. The sewage pass through primary, secondary and tertiary treatment. The microorganisms by aerobic and anaerobic metabolism degrade the organic matter in secondary and tertiary treatment respectively making it disinfected.

Hence, the correct answer is 'Microorganisms'.