A. Filtration process is used
B. Biological action is used
C. Neither A. nor B.
D. Both A. and B.
Related Mcqs:
- In trickling filter, B.O.D. is reduced to___________________?
A. 30 to 40%
B. 40 to 60%
C. 60 to 80%
D. 80 to 90% - Pick up the correct statement from the following ?
A. Maximum daily flow = 2 times the average daily flow
B. Maximum daily flow = average daily flow
C. Sewers are designed for minimum permissible velocity at minimum flow
D. All the above - The detention period for plain sedimentation water tanks, is usually____________________?
A. 4 to 8 hours
B. 8 to 16 hours
C. 16 to 24 hours
D. 24 to 36 hours - Chlorination of water is done for the removal of____________________?
A. Bacterias
B. Suspended solids
C. Sediments
D. Hardness - Facultative bacteria survive in_____________________?
A. The presence of oxygen
B. The absence of oxygen
C. Both cases A. and B.
D. Neither A. nor B. - The presence of free ammonia in sewage, is detected by___________________?
A. Boiling
B. Adding potassium permanganate
C. Adding sulphuric acid
D. Phenol-di-sulphuric acid - In septic tanks, decomposition of organic bacteria, is done by_____________________?
A. Anaerobic bacteria
B. Aerobic bacteria
C. Both types of bacterias
D. None of these - If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of__________________?
A. Degradation
B. Active decomposition
C. Recovery
D. Cleaner water - pH value of sludge during alkaline regression stage, is__________________?
A. More than 7
B. Less than 7
C. Less than 6
D. More than 6 - In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is____________________?
A. Q/(B × D)
B. Q/(L × D)
C. Q/L
D. Q/(B × L)
