Question

Study the following statements regarding tertiary treatment of sewage and choose the correct option.

i. It produces methane gas.

ii. The effluents formed from these plants undergo chlorination.

iii. BOD is significantly increased at this step.

iv. It includes screening and passage of effluent through grit chamber.

विकल्प

• Statements i and ii are correct.

• Statement ii and iii are correct.

• Statements i and iv are incorrect.

• Statements iii and iv are correct.

Answer 1

Statements i and ii are correct.

Explanation:

At the secondary treatment stage, BOD is dramatically reduced.

The effluent is screened and sent through a grit chamber as part of the preliminary treatment.