Environmental Engineering

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: Biological oxidation ponds remove organic matters present in the polluted water by
[A].

using the activities of bacteria and other micro organisms.

[B].

aerobic oxidation.

[C].

both (a) & (b).

[D].

neither (a) nor (b).

Answer: Option C

Explanation:

No answer description available for this question.

Question: Oil and grease present in an emulsified state in waste water discharged from industries can be removed by
[A].

biological oxidation.

[B].

skimming off.

[C].

settling out using chemical reagents.

[D].

chlorination.

Answer: Option C

Explanation:

No answer description available for this question.

Question: Deaeration of high pressure boiler feed water is done to reduce
[A].

foaming from boilers.

[B].

its dissolved oxygen content.

[C].

its silica content.

[D].

caustic embrittlement.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Irradiation of water by ultraviolet light of suitable wavelength is commonly used for disinfection of water in
[A].

food industry.

[B].

municipal sewage treatment.

[C].

petroleum refinery.

[D].

iron & steel plant.

Answer: Option A

Explanation:

No answer description available for this question.

Question: Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of
[A].

ozone and iodine.

[B].

chlorine or its compounds.

[C].

ultraviolet light for irradiation of water.

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.

Question: COD of raw municipal sewage may be in the range of about __________ mg/litre.
[A].

1-2

[B].

5-10

[C].

90-120

[D].

1500-2500

Answer: Option C

Explanation:

No answer description available for this question.

Question: BOD of raw municipal sewage may be in the range of about __________ mg/litre.
[A].

1-2

[B].

5-10

[C].

150-300

[D].

2000-3000

Answer: Option C

Explanation:

No answer description available for this question.

Question: Corrosion in boilers can be prevented by
[A].

deaeration of feed water.

[B].

enhancing pH of feed water by adding alkali.

[C].

feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen and prevents corrosion.

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.

Question: Foaming and priming in boiler operation can be reduced by reduction in __________ in feed water.
[A].

turbidity

[B].

color (Hazen)

[C].

total solids

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.