Q. Secondary sewage treatment is mainly a
A) Biological process
B) Physical process
C) Mechanical process
D) Chemical process
Explanation
[Solution from source] Secondary treatment of sewage is a biological process: the primary effluent is aerated so that aerobic microbes form flocs and consume the organic matter, reducing the BOD. Primary treatment, by contrast, is a physical removal of debris by filtration and sedimentation. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.