Waste Water Engineering MCQ Questions & Answers

21

3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is

A) 100 mg/l B) 200 mg/l C) 300 mg/l D) 400 mg/l

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Answer & Solution

Answer: Option C

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22

1000 kg of sewage contains

A) 0.112 kg in suspension B) 0.112 kg in solution C) 0.225 kg in solution D) Both A and C of above

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Answer & Solution

Answer: Option D

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23

Water content of sewage is about

A) 90 % B) 95 % C) 99 % D) 99.9 %

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Answer & Solution

Answer: Option D

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24

A circular sewer section is preferred to because

A) It is cheaper in construction B) It provides maximum area for a given perimeter C) It provides maximum hydraulic mean depth D) All the above

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Answer & Solution

Answer: Option D

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25

The ratio of minimum hourly flow to the average flow of sewage is

A) $$\frac{1}{4}$$ B) $$\frac{1}{3}$$ C) $$\frac{1}{2}$$ D) $$\frac{3}{4}$$

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Answer & Solution

Answer: Option B

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26

In a fully mechanised composting plant, involves

A) Mechanized receipt B) Mechanized segregation C) Mechanized pulverising of refuse D) All of these

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Answer & Solution

Answer: Option D

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27

For drainage pipes in buildings the test applied before putting them to use, is

A) Water test B) Smoke test C) Straightness test D) All the above

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Answer & Solution

Answer: Option B

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28

During purification process of sewage the gas given off, is

A) Carbon dioxide B) Hydrogen C) Ammonia D) All the above

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Answer & Solution

Answer: Option D

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29

Antisyphonage pipe is fitted

A) At the end of septic tanks B) On manholes C) With a W.'trap D) At the beginning of sewer line

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Answer & Solution

Answer: Option C

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30

The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is

A) $$\frac{{{{\text{d}}^2}\left( {0.011{\text{d}} + 0.785{\text{H}}} \right)}}{{\text{Q}}}$$ B) $$\frac{{{\text{d}}\left( {0.022{\text{d}} + 0.085{\text{H}}} \right)}}{{\text{Q}}}$$ C) $$\frac{{{\text{d}}\left( {0.785{\text{d}} + 0.011{\text{H}}} \right)}}{{\text{Q}}}$$ D) $$\frac{{{\text{d}}\left( {0.285{\text{d}} + 0.011{\text{H}}} \right)}}{{\text{Q}}}$$

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Answer & Solution

Answer: Option A

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Waste Water Engineering MCQ Questions & Answers | Civil Engineering