A. 1 to 2 minutes
B. 30 to 45 minutes
C. 2 to 6 hours
D. 2 to 6 days
Related Mcqs:
- Generally the detention period for grit chambers is kept as_______________?
A. 1 minute
B. 5 minutes
C. 2-4 hours
D. 12 hours - The detention period for oxidation ponds is usually kept as______________?
A. 4-8 hours
B. 24 hours
C. 10 to 15 days
D. 3 months - The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally_______________?
A. less and more
B. less and less
C. more and less
D. more and more - The amount of coagulant needed for coagulation of water increases with_______________?
1) increase in turbidity of water
2) decrease in turbidity of water
3) increase in temperature of water
4) decrease in temperature of water
The correct answer is?A. (1) and (2)
B. (1)and (4)
C. (2) and (3)
D. (2) and (4) - The working conditions in imhoff tanks are_______________?
A. aerobic only
B. anaerobic only
C. aerobic in lower compartment and anaerobic in upper compartment
D. anaerobic in lower compartment and aerobic in upper compartment - The overflow rate for plain sedimentation tanks is about__________________?
A. 500 to 750 litres/hour/ m2
B. 1000 to 1250 litres/hour/ m2
C. 1250 to 1500 litres/hour/m2
D. 1500 to 2000 litres/hour/m2 - The time of concentration is defined as_______________?
A. the time taken by rainfall water to run from most distant point of water shed to the inlet of sewer
B. the time required for flow of water in sewer to the point under consideration
C. sum of (A) and (B)
D. difference of (A) and (B) - The means of access for inspection and cleaning of sewer line is known as_______________?
A. inlet
B. manhole
C. drop manhole
D. catch basin - The hourly variation factor is usually taken as______________?
A. 1.5
B. 1.8
C. 2.0
D. 2.7 - Laying of sewers is usually done with the help of________________?
A. a theodolite
B. a compass
C. sight rails and boning rods
D. a plane table
