51. The rate of filtration in slow sand filters in million litres per day per hectare is about_____________?
A. 50 to 60
B. 100 to 150
C. 500 to 600
D. 1400 to 1500
✅ The correct answer is option A.
Environmental Engineering MCQs
52. The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is_______________?
A. check valve
B. sluice valve
C. safety valve
D. scour valve
✅ The correct answer is option B.
53. The depression of water table in a well due to pumping will be maximum_______________?
A. at a distance R from the well
B. close to the well
C. at a distance R/2 from the well
D. none of the above
✅ The correct answer is option B.
54. As compared to geometrical increase method of forecasting population, arithmetical increase method gives________________?
A. lesser value
B. higher value
C. same value
D. accurate value
✅ The correct answer is option A.
55. Composting and lagooning are the methods of_______________?
A. sludge digestion
B. sludge disposal
C. sedimentation
D. filtration
✅ The correct answer is option B.
56. The major disadvantage of lime soda process of water softening is that_________________?
A. it is unsuitable for turbid and acidic water
B. huge amount of precipitate is formed which creates a disposal problem
C. the effluent cannot be reduced to zero hardness
D. it is unsuitable for softening the water of excessive hardness
✅ The correct answer is option B.
57. Generally the detention period for grit chambers is kept as_______________?
A. 1 minute
B. 5 minutes
C. 2-4 hours
D. 12 hours
✅ The correct answer is option A.
58. The type of sewer which is suitable for both combined and separate system is_____________?
A. circular sewer
B. egg shaped sewer
C. horse-shoe type sewer
D. semi-elliptical sewer
✅ The correct answer is option B.
59. The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is______________?
A. 1
B. 100
C. infinite
D. zero
✅ The correct answer is option B.
60. The most commonly used sewer under culverts is_______________?
A. circular brick sewer
B. circular cast iron sewer
C. semi-elliptical sewer
D. horse-shoe type sewer
✅ The correct answer is option A.