waste water engineering MCQs – Page 5

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

waste water engineering Mcqs
81. The self-cleansing velocity of water flowing through pipe lines, is___________________ ?
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A. 0.5 metre/sec

B. 1 metre/sec

C. 2 metres/sec

D. 0.25 metre/sec

82. In normal conditions, the period for sludge digestion, is_______________?
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A. 10 days

B. 20 days

C. 60 days

D. 30 days
83. A manhole is classified as shallow if its depth is between_________________?
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A. 0.4 to 0.5 m

B. 0.7 to 0.9 m

C. 0.9 to 1.20 m

D. 0.5 to 0.7 m

84. In 1000 kg of sewage, the total solids approximate___________________?
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A. 5 kg to 7.5 kg

B. 0.5 to 1.0 kg

C. 1 kg to 2.0 kg

D. 7.5 kg to 10 kg

85. In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is____________________?
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A. [(100 P1)/(100 + P2)] V1

B. [(100 + P1)/(100 P2)] V1

C. [(100 P1)/(100 P2)] V1

D. [(100 + P2)/(100 P1)] V1

86. Rate of flow of sewage is generally assumed__________________?
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A. Less than the rate of water supply

B. At 150 litres per capita

C. Equal to the rate of water supply

D. More than the rate of water supply

87. Sewer manholes are generally provided at________________?
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A. The change of direction

B. The junctions of sewers

C. All of these

D. The change of gradient

88. The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is____________________?
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A. 75 m

B. 30 m

C. 45 m

D. 20 m

89. Clogging of sewers, is caused due to_______________?
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A. Low discharge

B. Greasy and oily matters

C. All the above

D. Silting

90. The laying of sewers is done with____________________?
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A. Magnetic compass

B. Clinometer

C. Level

D. Theodolite

91. The ratio of design discharge to the surface area of a sedimentation tank is called____________________?
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A. Overflow velocity

B. Overflow rate

C. Surface loading

D. All of these
92. If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is________________?
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A. 4 hours

B. 3 hours

C. 2 hours

D. 5 hours

93. Inter-distance between ventilation columns in a sewer line is kept__________________?
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A. 50 m to 100 m

B. 100 m to 150 m

C. 25 to 50 m

D. 150 m to 300 m
94. The normal values of over flow rates for secondary sedimentation tanks, ranges between__________________?
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A. 40,000 to 50,000 litres/sqm/day

B. 25,000 to 35,000 litres/sqm/day

C. 80,000 to 10,000 litres/sqm/day

D. 50,000 to 60,000 litres/sqm/day

95. Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?
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A. Carbonaceous demand

B. First stage demand

C. Initial demand

D. All of these
96. If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is_________________?
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A. 100 cm

B. 80 cm

C. 50 cm

D. 90 cm

97. The normal value of over flow rates for plain primary sedimentation tanks, ranges between________________?
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A. 25,000 to 35,000 litres/sqm/day

B. 80,000 to 100,000 litres/sqm/day

C. 50,000 to 60,000 litres/sqm/day

D. 40,000 to 50,000 litres/sqm/day
98. For trunk and out-fall, the type of sewers generally used, is_____________________?
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A. Horse shoe shaped

B. Circular shaped

C. Standard egg shaped

D. Parabolic shaped

99. The standard B.O.D. of water is taken for_________________?
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A. 2 days

B. 5 days

C. 1 day

D. 3 days

100. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is_____________________?
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A. 20

B. 5

C. 10

D. 15