91. The velocity of flow does not depend on_______________?
A. grade of sewer
B. length of sewer
C. hydraulic mean depth of sewer
D. roughness of sewer
✅ The correct answer is option B.
Environmental Engineering MCQs
92. Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about_______________?
A. 10 to 25
B. 50
C. 75
D. 100
✅ The correct answer is option C.
93. Which of the following chemical compounds can be used for dechlorination of water ?
A. carbon dioxide
B. bleaching powder
C. sulphur dioxide
D. chloramines
✅ The correct answer is option C.
94. Which of the following sewers is preferred for combined system of sewage ?
A. circular sewer
B. egg shaped sewer
C. rectangular sewer
D. none of the above
✅ The correct answer is option B.
95. For a given discharge, the efficiency of sedimentation tank can be increased by______________?
A. increasing the depth of tank
B. decreasing the depth of tank
C. increasing the surface area of tank
D. decreasing the surface area of tank
✅ The correct answer is option C.
96. When there is no recirculation of sewage, then recirculation factor is_______________?
A. 0
B. 1
C. infinity
D. none of the above
✅ The correct answer is option B.
97. The rate of Alteration of pressure filters is_________________?
A. less than that of slow sand filters
B. in between the filtration rate of slow sand filters and rapid sand filters
C. greater than that of rapid sand filters
D. equal to that of slow sand filters
✅ The correct answer is option C.
98. The effect of increasing diameter of sewer on the self cleansing velocity is_____________?
A. to decrease it
B. to increase it
C. fluctuating
D. nil
✅ The correct answer is option B.
99. The process in which the chlorination is done beyond the break point is known as_________________?
A. prechlorination
B. post chlorination
C. super chlorination
D. break point chlorination
✅ The correct answer is option C.
100. The maximum permissible limit for flouride in drinking water is______________?
A. 0.1 mg/litre
B. 1.5 mg/litre
C. 5 mg/litre
D. 10 mg/litre
✅ The correct answer is option B.