waste water engineering MCQs – Page 2

Practise focused waste water engineering questions with marked answers for exam preparation and subject revision.

waste water engineering Mcqs
21. The Chezys constant C in the formula V = C_________________?
comments icon0

A. Shape of the sewer

B. Roughness of sewer surface

C. Size of the sewer

D. All the above
22. Pick up the correct statement from the following ?
comments icon0

A. Rate of digestion of sludge is more at higher temperature

B. Thermophilic organisms digest the sludge if the temperature ranges from 40 to 60C

C. Mesophilic organisms digest the sludge if the temperature is between 25 and 40C

D. All the above
23. Traps_________________?
comments icon0

A. Dissolve the foul gases

B. Create symphonic action to increase the quick disposal of sewerage

C. Are used to trap the rats entering sewers

D. Are water seals which prevent the entry of foul gases
24. 1000 kg of sewage contains________________?
comments icon0

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
25. For efficient working of a sewer, it must be ensured that _____________?
comments icon0

A. Minimum velocity of 0.45 m/sec, is maintained at its minimum flow

B. A maximum velocity of 0.90 m/sec, is maintained at its maximum flow

C. Both A. and B.

D. Neither A. nor B.

26. Assertion A.: The determination of pH value of sewerage is important. Reason (R): The efficiency of certain treatment methods depends upon the availability of pH value________________?
comments icon0
A. Both A and R are true and R is the correct explanation of A

B. Both A and R are true but R is not a correct explanation of A

C. A is true but R is false

D. A is false but R is true

27. Aerobic bacterias___________________?
comments icon0

A. Consume organic matter as their food

B. Oxidise organic matter in sewage

C. All the above

D. Flourish in the presence of free oxygen

28. For the open drain (N = 0.025) shown in the below figure, the discharge is________________?
comments icon0
A. 28.88 cumecs

B. 29.88 cumecs

C. 26.88 cumecs

D. 27.88 cumecs

29. Pick up the correct statement from the following ?
comments icon0
A. All the above

B. The sewer pipes of sizes greater than 0.4 m diameter are designed as running 2/3rd or 3/4th full at maximum discharge

C. The minimum design velocity of sewer pipes is taken as 0.8 m/sec

D. The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge

30. The sludge does not contain waste water from_________________?
comments icon0

A. Wash basins

B. Bath rooms

C. Toilets

D. Kitchen sinks

31. The porosity of sediments in sewer pipes, is usually taken as___________________?
comments icon0

A. 0.01

B. 0.011

C. 0.013

D. 0.012

32. For detecting the nitrates in sewage, the colour may be developed by adding________________?
comments icon0

A. None of these

B. Potassium permanganate

C. Phenol-di -sulphuric acid and potassium hydroxide

D. Sulphuric acid and napthamine

33. For house drainage minimum gradient is__________________?
comments icon0
A. 1 in 60

B. 1 in 80

C. 1 in 10

D. 1 in 400

34. 15 cumecs, the depth d and width are related by For drains up to___________________?
comments icon0

A. B = 0.5 d

B. d = 0.2 B

C. B = 0.2 d

D. d = 0.5 B
35. The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is_____________________?
comments icon0
A. 0.05556 cumec

B. 0.05554 cumec

C. 0.0556 cumec

D. 0.05552 cumec

36. In trickling filter, B.O.D. is reduced to___________________?
comments icon0

A. 40 to 60%

B. 30 to 40%

C. 60 to 80%

D. 80 to 90%

37. The coagulant widely used for sewage treatment, is_________________?
comments icon0

A. Ferric sulphate

B. Ferric chloride

C. Chlorinated copperas

D. Alum

38. The rate of accumulation of sludge in septic tanks is recommended as____________________?
comments icon0

A. 25 litres/person/year

B. 30 litres/person/month

C. 30 litres/person/year

D. 25 litres/person/month

39. The maximum diameter of sewers adopted in the designs is_______________?
comments icon0

A. 4.0 m

B. 2.0 m

C. 1.0 m

D. 3.0 m
40. 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___________________?
comments icon0
A. 160 cm

B. 140 cm

C. 100 cm

D. 120 cm