The percentage of chlorine in fresh bleaching powder is about________________?

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.

Question: Maximum allowable concentration of CO2 in air for safe working is __________ ppm (parts per million).
[A].

50

[B].

1000

[C].

2000

[D].

5000

Answer: Option D

Explanation:

No answer description available for this question.

Question: A shallow pond in which the sewage is retained and biologically treated is called
[A].

oxidation

[B].

Imhoff tank

[C].

lagoon

[D].

skimming tank

Answer: Option A

Explanation:

No answer description available for this question.

Question: Ionisation potential employed in the industrial electrostatic precipitator is of the order of
[A].

30 to 70 kV DC

[B].

30 to 70 kV AC

[C].

230 V AC

[D].

230 V DC

Answer: Option A

Explanation:

No answer description available for this question.