UPSC Civil Service Exam Questions - Engineering

Q1:

Activated sludge is the

A resultant sludge removable from the aeration unit

B sludge settled in the humus tank

C sludge in the secondary tank post-aeration rich in microbial mass

D sludge.in the secondary tank post aeration, rich in nutrients.

ANS:C - sludge in the secondary tank post-aeration rich in microbial mass

Activated sludge is a thick soft substance used for removing pollutants from waste water by a biological reaction that involves oxygen. The activated sludge is then separated from the treated wastewater and disposed of or returned to the process as needed.