Question

Secondary treatment of sewage water:
A.Removes solid particles and debris
B.Removes dissolved and suspended biological matter
C.Involves conventional sedimentation and filtration
D.Reduces the bio-chemical oxygen demand of water
E.Increases the bio-chemical oxygen demand of water
Choose the correct answer from the options given below:

• A. A,B and D only
• B. B and E only
• C. B and D only
• D. A,C and E only

Hint:

Secondary treatment focuses on reducing BOD and cleaning biological matter, which is essential for safe water disposal.

Answer 1

The Correct Option is A

Secondary treatment of sewage water primarily removes dissolved and suspended biological matter through processes like biological treatment, which helps reduce the biochemical oxygen demand (BOD) of the water. It does not increase BOD, which would be counterproductive to water quality.