1. The quantity of water flowing per hour per unit horizontal area is called ______.

[A] Displacement time
[B] Detention time
[C] Overflow rate
[D] Flowing through period

Answer: Option C

2. Which of the following sequences is most suitable for treating raw surface water to make it suitable for drinking?

[A] Screening -> Disinfection -> Sedimentation -> Filtration
[B] Screening -> Sedimentation -> Filtration -> Disinfection
[C] Screening -> Filtration -> Sedimentation -> Disinfection
[D] Screening -> Sedimentation -> Disinfection -> Filtration

Answer: Option B

Explanation: The correct sequence is:

  1. Screening
  2. Aeration
  3. Sedimentation
  4. Coagulation
  5. Flocculation
  6. Filtration
  7. Disinfection


3. _____ is the application of chlorine before filtration.

[A] Super chlorination
[B] Double chlorination
[C] Pre chlorination
[D] Plain chlorination

Answer: Option C

4. The coliform organism in 100 ml of drinking water should not be more than _____.

[A] 250
[B] 300
[C] 1000
[D] 1

Answer: Option D


5. In which treatment unit is ‘Schmutzdecke’ formed?

[A] Rapid sand filter
[B] Slow sand filter
[C] Coagulation tank
[D] Sedimentation tank

Answer: Option B


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