Waste Water Engineering MCQ Questions & Answers

31

The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known

A) Bio-Chemical Oxygen Demand (B.O.D.) B) Dissolved Oxygen (D.O.) C) Chemical Oxygen Demand (C.O.D.) D) None of these

Discuss

Answer & Solution

Answer: Option B

Solution:

B.O.D. (Bio-Chemical Oxygen Demand) refers to the amount of oxygen required by aerobic bacteria to decompose organic matter present in sewage.

During this process, microorganisms consume oxygen while breaking down organic pollutants biologically.

Hence, it directly measures the oxygen consumed by aerobic biological activity in wastewater.

D.O. (Dissolved Oxygen) represents the oxygen available in water, not the oxygen consumed.

C.O.D. (Chemical Oxygen Demand) measures oxygen required for chemical oxidation of organic matter, not specifically biological decomposition.

Therefore, the correct term describing oxygen used by aerobic bacteria is B.O.D.

32

Removal of oil and grease from sewage, is known

A) Screening B) Skimming C) Filtration D) None of these

Discuss

Answer & Solution

Answer: Option B

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

33

Are available in size Stoneware sewers

A) 10 cm B) 15 cm C) 20 cm D) All the above

Discuss

Answer & Solution

Answer: Option D

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

34

Oxidation process results in the formation of

A) Carbon dioxide B) Nitrates C) Sulphates D) All the above

Discuss

Answer & Solution

Answer: Option D

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

35

The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be

A) 0.9 cm B) 1.2 m C) 1.5 m D) > 1.5 m

Discuss

Answer & Solution

Answer: Option D

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

36

A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is

A) 0.30 m/sec B) 0.35 m/sec C) 0.40 m/sec D) 0.45 m/sec

Discuss

Answer & Solution

Answer: Option D

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

37

In a sludge digestion tank if the moisture content of sludge V₁ litres is reduced from p₁% to p₂% the volume V₂ is

A) $$\left( {\frac{{100 + {{\text{p}}_1}}}{{100 - {{\text{p}}_2}}}} \right){{\text{V}}_1}$$ B) $$\left( {\frac{{100 - {{\text{p}}_1}}}{{100 + {{\text{p}}_2}}}} \right){{\text{V}}_1}$$ C) $$\left( {\frac{{100 - {{\text{p}}_1}}}{{100 - {{\text{p}}_2}}}} \right){{\text{V}}_1}$$ D) $$\left( {\frac{{100 + {{\text{p}}_2}}}{{100 - {{\text{p}}_1}}}} \right){{\text{V}}_1}$$

Discuss

Answer & Solution

Answer: Option C

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38

The minimum diameter of sewer to be adopted is

A) 10 cm B) 12.5 cm C) 15 cm D) 25 cm

Discuss

Answer & Solution

Answer: Option C

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39

In a grit chamber of a sewage treatment plant,

A) Flow velocity 0.15 m to 0.3 m/sec is kept B) Depth of 0.9 m to 1.20 m is kept C) One minute of detention period is kept D) All the above

Discuss

Answer & Solution

Answer: Option D

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

40

In a trickling filter

A) Filtration process is used B) Biological action is used C) Neither A nor B D) Both A and B

Discuss

Answer & Solution

Answer: Option B

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

Waste Water Engineering MCQ Questions & Answers | Civil Engineering