A. 10 to 25
B. 50
C. 75
D. 100
Related Mcqs:
- 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 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 ratio of 5 day BOD to ultimate BOD is about_______________?
A. 1/3
B. 2/3
C. 3/4
D. 1.0 - The velocity of flow of water in a sedimentation tank is about__________________?
A. 5 to 10 cm/sec.
B. 15 to 30 cm/sec.
C. 15 to 30 cm/minute
D. 15 to 30 cm/hour - The length of rectangular sedimentation tank should not be more than_______________?
A. B
B. 2B
C. 4B
D. 8Bwhere B is the width of the tank
- The settling velocity of a particle in a sedimentation tank increases if______________?
A. particle size is decreased
B. the surface area of tank is increased
C. the depth of tank is decreased
D. none of the above - The chemical most commonly used to increase speed of sedimentation of sewage is_______________?
A. sulphuric acid
B. copper sulphate
C. lime
D. sodium permanganate - For a given discharge, the efficiency of sedimentation tank can be increased by______________?
A. increasing the depth of tank
B. decreasing the depth of tank
C. increasing the surface area of tank
D. decreasing the surface area of tank - The settling velocity of a particle in a sedimentation tank depends on__________________?
A. depth of tank
B. surface area of tank
C. both depth and surface area of tank
D. none of the above - The settling velocity of a particle in a sedimentation tank increases if_________________?
A. particle size is decreased
B. the surface area of tank is increased
C. the depth of tank is decreased
D. none of the above
