A. With beds of rocks and gravels
B. Lined with stones
C. Both A. and B.
D. Neither A. nor B.
A. 2 days
B. 7 days
C. 12 days
D. 14 days
A. 30 to 40%
B. 40 to 60%
C. 60 to 80%
D. 80 to 90%
A. 10 days
B. 20 days
C. 30 days
D. 60 days
A. 10 cm
B. 15 cm
C. 20 cm
D. All the above
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon dioxide
A. Nitrates
B. Nitrites
C. Free ammonia
D. None of these
A. 100 mg/l
B. 200 mg/l
C. 300 mg/l
D. 400 mg/l
A. Velocity at dry weather flow
B. Velocity of water at flushing
C. Velocity at which no accumulation remains in the drains
D. Velocity of water in a pressure filter
A. d = 0.2 B
B. d = 0.5 B
C. B = 0.2 d
D. B = 0.5 d