Identify the correct statement about secondary sewage treatment.
(A)In secondary treatment, useful aerobic microbes grow rapidly and form flocs. Flocs are masses of bacteria associated with fungal filaments to form mesh-like structures.
(B)The growing microbes consume organic matter and thus reduce the biochemical oxygen demand. When BOD of sewage has reduced, the effluent is passed into settling tank.
(C)In settling tank, the bacterial flocs settle and the sediment is called activated sludge
(D)All the above statements are correctCorrect
Answer: (D)
Solution
Statements (a), (b) and (c) each correctly describe secondary treatment (floc formation, BOD reduction,
See the full step-by-step solution
Create a free account to read the complete working, and practise questions like this in a timed test.