A. Used to remove the grease and oil
B. Those from which sludge is skimmed out
C. Tanks provided with self- cleansing screens
D. Improved version of grit chambers
Related Mcqs:
- 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 - The rate of accumulation of sludge in septic tanks is recommended as____________________?
A. 30 litres/person/year
B. 25 litres/person/year
C. 30 litres/person/month
D. 25 litres/person/month - The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope_________________?
A. 1 in 5
B. 1 in 10
C. 1 in 15
D. 1 in 20 - The normal values of over flow rates for secondary sedimentation tanks, ranges between__________________?
A. 25,000 to 35,000 litres/sqm/day
B. 40,000 to 50,000 litres/sqm/day
C. 50,000 to 60,000 litres/sqm/day
D. 80,000 to 10,000 litres/sqm/day - The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is_____________________?
A. 204 cu.m
B. 208 cu.m
C. 212 cu.m
D. 216 cu.m - The digested sludge from septic tanks, is removed after a maximum period of__________________?
A. 3 years
B. 3.5 years
C. 4 years
D. 5 years - The sewage treatment in septic tanks is due to__________________?
A. Anaerobic decomposition
B. Aerobic decomposition
C. Parasitic decomposition
D. None of these - The flow velocity in detritus tanks is________________?
A. 0.05 m/sec
B. 0.09 m/sec
C. 1.25 m/sec
D. None of these - Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank_________________?
A. Both A and R is true and R is the correct explanation of A
B. Both A and R is true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true - The normal values of over flow rates for sedimentation tanks using coagulant, ranges between__________________?
A. 25,000 to 35,000 litres/sqm/day
B. 40,000 to 50,000 litres/sqm/day
C. 50,000 to 60,000 litres/sqm/day
D. 80,000 to 100,000 litres/sqm/day
