QUESTION
Objective Question
The aeration process adopted in an activated sludge plant, which ensures optimal utilization of
air, is known as
Answer
( Option D)
Activated aeration
Solution
Tapered aeration is an aeration arrangement in an activated sludge process in which the rate
of air supply is varied along the length of the aeration tank.
Oxygen demand is highest near the inlet because the incoming sewage contains a high concentration of organic matter.
As sewage flows through the tank, organic matter is progressively consumed.
Therefore, oxygen demand decreases towards the outlet.
Accordingly, the air supply is gradually reduced along the length of the tank.
