Question

Domestic sewage of large cities:

• A. Has very high amounts of suspended solids and dissolved salts
• B. Does not require aeration when treated in sewage treatment plants
• C. High BOD as it contains both aerobic and anaerobic bacteria
• D. Is processed by aerobic and then anaerobic in secondary treatment in sewage treatment plant.

Answer 1

The correct option is D

Is processed by aerobic and then anaerobic in secondary treatment in sewage treatment plant.

Secondary treatment of sewage and other wastewater is the stage of wastewater treatment designed to substantially degrade the biological content of the sewage. This usually uses biological processes.