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:
- Screening
- Aeration
- Sedimentation
- Coagulation
- Flocculation
- Filtration
- 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