Environmental Engineering

Question: Noise pollution level in a chemical plant is expressed in
[A].

roentgen

[B].

decibel

[C].

hertz

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Coal mines drainage waste water (acidic in nature) results from the earth’s water percolating through the voids created in coal bed during mining. This polluted water which either drains out naturally to water courses or are removed before starting the mining is
[A].

neutralised by alkali treatment.

[B].

left as such without any treatment.

[C].

diluted with fresh water to reduce its acidity.

[D].

none of these.

Answer: Option A

Explanation:

No answer description available for this question.

Question: Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal
[A].

by chemical coagulation.

[B].

in sedimentation tanks equipped with mechanical scrapper.

[C].

in vacuum filter.

[D].

in clarifiers.

Answer: Option B

Explanation:

No answer description available for this question.

Question: The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated.
[A].

decreases.

[B].

increases.

[C].

remains constant.

[D].

may increase or decrease ; depends on the chemical characteristics of polluted water.

Answer: Option A

Explanation:

No answer description available for this question.

Question: Which of the following radioactive wastes emits all α, β & γ rays and hence is the most hazardous of all radioactive emitters?
[A].

I-131

[B].

Sr-90

[C].

Au-198

[D].

Ra-226

Answer: Option D

Explanation:

No answer description available for this question.

Question: Dose of chlorine for disinfection of water is about __________ mg/litre of water.
[A].

0.01

[B].

0.1

[C].

0.3

[D].

1

Answer: Option D

Explanation:

No answer description available for this question.

Question: Iron & manganese present as pollutant in water can not be removed by
[A].

ion exchange process.

[B].

oxidation followed by settling & filtration.

[C].

lime soda process or manganese zeolite process.

[D].

chlorination.

Answer: Option D

Explanation:

No answer description available for this question.

Question: Iron & manganese present in the polluted water is removed by
[A].

simple filtration.

[B].

oxidation followed by settling & filtration.

[C].

chemical coagulation.

[D].

chlorination only.

Answer: Option B

Explanation:

No answer description available for this question.

Question: Aerobic biological oxidation ponds used for the purification of polluted water
[A].

destroys/removes pathogen from the sewage.

[B].

is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents.

[C].

destroys/removes pathogen much more effectively if the sewage is chlorinated.

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.

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.