Civil Engineering - Waste Water Engineering MCQs Part 7

1. In areas where light rains are uniformly distributed throughout the year, the type of sewerage system to be adopted is

A.
separate system
B.
combined system
C.
partially combined system
D.
none of these.

 Answer Option B

2. For detecting the nitrates in sewage, the colour may be developed by adding

A.
Pottassium permanganate
B.
Sulphuric acid and napthamine
C.
Phenol-di-sulphuric acid and pottassium hydroxide
D.
None of these.

 Answer Option C

3. The value of Chezy's constant is used in

A.
Chezy's formula
B.
Bazin's formula
C.
Kutter's formula
D.
Manning's formula.

 Answer Option B

4. The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning's formula, is given by

A.
Bazin
B.
Crimp and Bruge
C.
William-Hazen
D.
Kutter.

 Answer Option B

5. For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of

A.
100 cm
B.
120 cm
C.
140 cm
D.
160 cm
E.
180 cm.

 Answer Option D

6. The formula used for determining flow velocities in sewers, is known as

A. Chezy's formula
B. Bazin's formula
C. Kutter's formula
D. Manning's formula.

 Answer Option D

7. The sewage treatment units in which anaerobic decomposition of organic matter is used, are called

A. imhoff tanks
B. trickling filters
C. sludge sedimentation tanks
D. none of these.

 Answer Option B

8. 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.

 Answer Option D

9. The most efficient cross section of sewers in a separate sewerage system is

A. parabolic
B. circular
C. rectangular
D. new egged.

 Answer Option B

10. If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is

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

 Answer Option D

11. Pick up the incorrect statement from the following for allowing workers to enter sewers

A. The particular manhole and one manhole on up stream and one manhole on down stream should remain open for 30 minutes
B. Proper tests for the presence of poisonous gases must be carried out
C. The men entering the manhole should be advised to smoke in the sewer
D. Warning signals should be erected
E. None of these.

 Answer Option C

12. The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock's law, is

A.
B.
C.
D.

 Answer Option B

13. 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.

 Answer Option D

14. The rate of accumulation of sludge per person per year, is

A. 10 litres
B. 15 litres
C. 20 litres
D. 25 litres
E. 30 litres.

 Answer Option C

15. The disintegrating pump in which solid matter is broken up before passing out, is

A. centrifugal pump
B. reciprocating pump
C. pneumatic ejector
D. none of these.

 Answer Option A

16. The quantity of liquid waste which flows in sewers during the period of rainfall, is known

A. sanitary sewage
B. industrial waste
C. storm sewage
D. none of these.

 Answer Option C

17. The most efficient cross-section of sewers in a combined sewerage system is

A. parabolic
B. circular
C. rectangular
D. new egged.

 Answer Option B

18. Pick up the incorrect size of stone ware sewers

A. 52.5 cm
B. 67.5 cm
C. 82.5 cm
D. 90 cm
E. none of these.

 Answer Option E

19. The grit and silt of the grit chambers, may not be used for

A. raising low lying areas by dumping
B. concreting
C. both (a) and (b)
D. neither (a) nor (b).

 Answer Option B

20. In a sludge tank, the gas mainly produced, is

A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon dioxide
E. Methane.

 Answer Option E

21. The intensity of rain is expressed in

A. cm/minute
B. cm/hour
C. cm/day
D. none of these.

 Answer Option B

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. 0.450 kg in suspension
E. both (a) and (c) of above.

 Answer Option E

23. The normal values of over flow rates for sedimentation tanks using coagulent, ranges between

A. 25, 000 to 35, 000 litres/sqm/day
B. 40, 000 to 50, 000 litres/sqm/day
C. 50, 000 to 60, 000 litres/sqm/day
D. 80, 000 to 100, 000 litres/sqm/day
E. none of these.

 Answer Option C

6. The formula used for determining flow velocities in sewers, is known as

A. Chezy's formula
B. Bazin's formula
C. Kutter's formula
D. Manning's formula.

 Answer Option D

7. The sewage treatment units in which anaerobic decomposition of organic matter is used, are called

A. imhoff tanks
B. trickling filters
C. sludge sedimentation tanks
D. none of these.

 Answer Option B

8. 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.

 Answer Option D

9. The most efficient cross section of sewers in a separate sewerage system is

A. parabolic
B. circular
C. rectangular
D. new egged.

 Answer Option B

10. If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is

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

 Answer Option D

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