Environmental Engineering MCQ Questions & Answers

21

The detention period for oxidation ponds is usually kept as

A) 48 hours B) 24 hours C) 10 to 15 days D) 3 months

Discuss

Answer & Solution

Answer: Option C

Solution:

In environmental engineering, the detention period for oxidation ponds is typically kept as 10 to 15 days (Option C).

Oxidation ponds, also known as stabilization ponds, are wastewater treatment systems that use natural processes such as sunlight, algae growth, and bacterial action to treat wastewater. The detention period refers to the average time that wastewater remains in the pond before being discharged.

A detention period of 10 to 15 days allows sufficient time for the biological and chemical processes in the oxidation pond to effectively treat the wastewater, reducing its pollutant levels and improving its quality before discharge.

Therefore, the correct option is Option C: 10 to 15 days.

22

If the sewage contains grease and fatty oils, these are removed in

A) Grit chambers B) Detritus tanks C) Skimming tanks D) Sedimentation tanks

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

23

The design discharge for the separate sewer system shall be taken as

A) Equal to dry weather flow (DWF) B) 2 × DWF C) 3 × DWF D) 6 × DWF

Discuss

Answer & Solution

Answer: Option D

No explanation is given for this question. Let's Discuss on Board

24

The design discharge for the combined sewer system shall be taken as

A) Equal to rainfall B) Rainfall + DWF C) Rainfall + 2 DWF D) Rainfall + 6 DWF

Discuss

Answer & Solution

Answer: Option C

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25

The major disadvantage of lime soda process of water softening is that

A) It is unsuitable for turbid and acidic water B) Huge amount of precipitate is formed which creates a disposal problem C) The effluent cannot be reduced to zero hardness D) It is unsuitable for softening the water of excessive hardness

Discuss

Answer & Solution

Answer: Option B

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26

Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R: The sand used in slow sand filters is finer than that in rapid sand filters
Select your answer based on the coding system given below:

A) Both A and R is true and R is the correct explanation of A B) Both A and R is true but R is not the correct explanation of A C) A is true but R is false D) A is false but R is true

Discuss

Answer & Solution

Answer: Option A

No explanation is given for this question. Let's Discuss on Board

27

Which of the following sewers is preferred for combined system of sewage?

A) Circular sewer B) Egg shaped sewer C) Rectangular sewer D) None of the above

Discuss

Answer & Solution

Answer: Option B

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28

The settling velocity of a particle in a sedimentation tank increases if

A) Particle size is decreased B) The surface area of tank is increased C) The depth of tank is decreased D) None of the above

Discuss

Answer & Solution

Answer: Option D

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29

Air binding phenomena in rapid sand filters occur due to

A) Excessive negative head B) Mud ball formation C) Higher turbidity in the effluent D) Low temperature

Discuss

Answer & Solution

Answer: Option A

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30

The chemical most commonly used to increase speed of sedimentation of sewage is

A) Sulphuric acid B) Copper sulphate C) Lime D) Sodium permanganate

Discuss

Answer & Solution

Answer: Option C

No explanation is given for this question. Let's Discuss on Board

Environmental Engineering MCQ Questions & Answers | Civil Engineering