The polluted water is one which_______________?

Question: Lagoons used for purification of polluted water
[A].

are large shallow artificial lakes also known as clarification lakes, maturation ponds or oxidation ponds.

[B].

use micro-organisms/bacteria in presence of dissolved oxygen.

[C].

gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended solid < 1 mg/litre and BOD = 3.8 mg/litre.

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.

Question: Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan
[A].

with greater number of blades.

[B].

of increased diameter.

[C].

both (a) & (b).

[D].

neither (a) nor (b).

Answer: Option C

Explanation:

No answer description available for this question.

Question: In water treatment plant, zeolite process is used to remove the __________ of water.
[A].

acidity

[B].

alkalinity

[C].

hardness

[D].

iron & zinc

Answer: Option C

Explanation:

No answer description available for this question.