Waste Water Engineering

101. If the flame of a miner's safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains

1. Hydrogen sulphide
2. Carbon dioxide
3. Methane
4. Oxygen

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102. If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains

1. Hydrogen sulphide
2. Carbon dioxide
3. Methane
4. Oxygen

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103. If the grit in grit chambers is 4.5 million litres per day, its cleaning is done

1. Manually
2. Mechanically
3. Hydraulically
4. Electrically

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104. If the length of overland flow from the critical point to the mouth of drain is 13.58 km and difference in level between the critical point and drain mouth is 10 m, the inlet time is

1. 2 hours
2. 4 hours
3. 6 hours
4. 8 hours

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105. 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

1. 2 hours
2. 3 hours
3. 4 hours
4. 5 hours

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106. 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

1. 100 cm
2. 90 cm
3. 80 cm
4. 50 cm

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107. If the pH value of sewage is 7

1. It is acidic
2. It is alkaline
3. It is neutral
4. None of these

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108. If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is

1. 1045 mm
2. 1065 mm
3. 1075 mm
4. 1095 mm

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109. Imhoff cone is used to determine

1. Settleable solids
2. Suspended solids
3. Dissolved solids
4. None of these

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110. Imhoff cone is used to measure

1. Total organic solids
2. Total solids
3. Total in organic solids
4. Settleable solids

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