waste water engineering MCQs – Page 3

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

waste water engineering Mcqs
41. Before discharging the foul sewage into rivers, it is generally treated by_____________________?
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A. All the above

B. Screening

C. Sedimentation

D. Oxidation

42. For sewers, inverted siphon is provided for___________________?
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A. One pipe

B. Three pipes

C. Two pipes

D. Four pipes

43. If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, is___________________?
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A. 1 in 100

B. 1 in 60

C. None of these

D. 1 in 120
44. The flow velocity in detritus tanks is________________?
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A. 0.05 m/sec

B. 0.09 m/sec

C. None of these

D. 1.25 m/sec

45. The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is___________________?
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A. 2.0

B. 1.5

C. 4

D. 3

46. For evaporation and measurement of settable solids, the apparatus used, is________________?
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A. A test tube

B. A breaker

C. A jar

D. An Imhoff cone
47. The sewer pipes__________________?
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A. All the above

B. Are designed for generating self-cleansing velocities at different discharge

C. Carry sewage as gravity conduits

D. Should resist the wear and tear caused due to abrasion

48. The most effective arrangement for diverting excess storm water into a natural drainage, is____________________?
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A. None of these

B. Overflow weir

C. Leaping weir

D. Siphon spill way
49. Removal of oil and grease from sewage, is known____________________?
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A. Screening

B. None of these

C. Filtration

D. Skimming
50. Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further deposition leading to complete blocking of the sewer?
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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

51. In very first stage of decomposition of the organic matter in sewage________________?
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A. Nitrites are formed

B. Nitrates are formed

C. Ammonia is formed

D. Carbondioxide is formed

52. Pathogens (or pathogenic bacterias) in water may cause___________________?
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A. Dysentery

B. Typhoid

C. Cholera

D. All the above
53. A nuisance is experienced in diluting water if dilution factor is less than_________________?
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A. 60

B. 40

C. 20

D. 100

54. Disposal to sewage in large cities, is done in__________________?
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A. Purification

B. Dilution

C. Irrigation

D. Oxidation

55. The spacing of bars of perforations of fine screens used for the treatment of sewage, is_______________?
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A. 2 to 3 mm

B. 3 to 5 mm

C. 8 to 10 mm

D. 5 to 8 mm

56. The ratio of minimum hourly flow to the average flow of sewage is_________________?
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A. 2-Jan

B. 4-Jan

C. 4-Mar

D. 1/3
57. In a sludge tank, the gas mainly produced, is_________________?
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A. Oxygen

B. Nitrogen

C. Hydrogen

D. Carbon dioxide
58. The non-clog pump which permits solid matter to pass out with the liquid sewage, is________________?
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A. Centrifugal pump

B. None of these

C. Reciprocating pump

D. Pneumatic ejector

59. The algae dies out in the zone of_____________________?
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A. Degradation

B. Cleaner water

C. Active decomposition

D. Recovery

60. A manhole is generally provided at each__________________?
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A. Change of gradient

B. Junction

C. All the above

D. Bend