Top 250+ Solved Water and Wastewater Engineering MCQ Questions Answer

From 226 to 240 of 273

Q. The most commonly used chemical for de-chlorination of water, is

a. Sodium thiosulphate

b. Sodium bisulphate

c. Sodium sulphite

d. Sulphur-dioxide

  • c. Sodium sulphite

Q. To remove very fine suspended particles from water, the method adopted is

a. Screening

b. Sedimentation

c. Boiling

d. Filtration

  • d. Filtration

Q. Sunlight

a. Helps growth of bacterias

b. Impedes growth of algae

c. Increases dissolved oxygen content

d. Reduces turbidity

  • b. Impedes growth of algae

Q. The detention period for plain sedimentation water tanks, is usually

a. 4 to 8 hours

b. 8 to 16 hours

c. 16 to 24 hours

d. 24 to 36 hours

  • d. 24 to 36 hours

Q. Air valves are generally provided in pressure pipes of water supply

a. At pipe junctions (B) (C) (D)

b. At summits

c. At low points

d. Near service pipes

  • b. At summits

Q. The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of

a. 5 kg/cm2

b. 6 kg/cm2

c. 7 kg/cm2

d. 10 kg/cm2

  • c. 7 kg/cm2

Q. Flow through period, in sedimentation tanks, is

a. Equal to detention period

b. More than detention period

c. Less than detention period

d. Detention period divided by displacement efficiency

  • c. Less than detention period

Q. The maximum hourly consumption, is generally taken as

a. 110 %

b. 120 %

c. 140 %

d. 150 %

  • d. 150 %

Q. Hardness of water can be removed by boiling if it is due to

a. Calcium bicarbonates

b. Calcium sulphates

c. Calcium chloride

d. Calcium nitrates

  • a. Calcium bicarbonates

Q. Hardness of water is caused by

a. Presence of soap lather

b. Presence of chlorides and sulphates of sodium and potassium

c. Presence of bicarbonates, sulphates or chlorides of calcium and magnesium

d. Turbidity

  • c. Presence of bicarbonates, sulphates or chlorides of calcium and magnesium

Q. The average domestic consumption under normal conditions in an Indian city per day perperson, is

a. 105 litres

b. 115 litres

c. 125 litres

d. 135 litres

  • d. 135 litres

Q. A pressure conduit carrying water beneath a stream or a canal, is known as

a. Sag (B) (C) (D)

b. Depressed pipe

c. Inverted syphon

d. All the above

  • d. All the above

Q. Permanent hardness of water can be removed by

a. Adding alum

b. Adding lime

c. Adding chlorine

d. Zeolite process

  • d. Zeolite process
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