Engineering Questions with Answers - Multiple Choice Questions

Environmental Engineering MCQ – Oxidation and Stabilization Ponds

1 - Question

Which of the following is an anaerobic process for treating sewage?
a) Oxidation pond
b) Imhoff tank
c) Oxidation ditch
d) Rotating Biological Contactors

View Answer

Answer: b
Explanation: Oxidation pond, Oxidation ditch and Rotating Biological Contactors are an aerobic process of treating sewage whereas Imhoff tank is an anaerobic process of treating sewage.




2 - Question

The minimum design depth of oxidation pond is ___________
a) 0.3m
b) 0.5m
c) 1m
d) 1.5m

View Answer

Answer: c
Explanation: The minimum design depth of oxidation pond is 1m while its maximum design depth is 1.5m.




3 - Question

Oxidation pond is ineffective in removing pathogenic bacteria.
a) True
b) False

View Answer

Answer: b
Explanation: Oxidation pond is highly efficient in removing pathogenic bacteria with an efficiency of 99.9%.




4 - Question

The detention period of oxidation pond is ___________
a) 12-36 hours
b) 4 hours
c) 10-20 days
d) 30-60 seconds

View Answer

Answer: c
Explanation: Oxidation ponds have a long detention period between 10 to 20 days.




5 - Question

The maximum BOD removal efficiency of an oxidation pond is ___________
a) 90%
b) 68%
c) 70%
d) 80%

View Answer

Answer: a
Explanation: The BOD removal efficiency of an oxidation pond lies between 80% and 90%, so the maximum BOD removal efficiency is 90%.




6 - Question

What is the minimum depth of water to be kept in the oxidation pond?
a) 0.3m
b) 0.5m
c) 1m
d) 1.5m

View Answer

Answer: c
Explanation: The minimum depth of water to be kept in the oxidation pond is 0.3m and the depth of sludge deposited in the pond is 0.02m per year.




7 - Question

Which chemical is added to the oxidation pond to avoid bad odor?
a) Calcium chloride
b) Sodium nitrate
c) Potassium chloride
d) Silver nitrate

View Answer

Answer: b
Explanation: Sodium nitrate is added to the oxidation pond to avoid bad odor. It acts as an oxidizing agent and also as the food of the plant.

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