Grain hardness is measured by the __________ hardness testing method.

Question: Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in
[A].

coagulation and flocculation of colloids.

[B].

oxidation of carbonaceous matter to CO2.

[C].

nitrification or oxidation of ammonia derived from breakdown of nitrogeneous organic matter to the nitrite and eventually to the nitrate.

[D].

all (a), (b) and (c).

Answer: Option D

Explanation:

No answer description available for this question.