Question

The stage in which the biological processes is used to purify water in a wastewater treatment plants is called :

• A. secondary sewage treatment
• B. wastewater reduction
• C. biochemical reduction
• D. primary sewage treatment

Answer 1

The correct option is A secondary sewage treatment

Secondary treatment is a waste water management technique which uses physical phase separation and a biological process.

Physical phase separation removes suspended solids. Biological process is employed to remove organic matter.

Example: Bacteria and protozoa consume biodegradable soluble organic contaminants