The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is____________________?

The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is____________________?

A. 30 minutes
B. 1 hour
C. 1 hour and 30 minutes
D. 2 hours

Pick up the incorrect statement from the following for allowing workers to enter sewers_______________?

Pick up the incorrect statement from the following for allowing workers to enter sewers_______________?

A. The particular manhole and one manhole on upstream and one manhole on downstream should remain open for 30 minutes
B. Proper tests for the presence of poisonous gases must be carried out
C. The men entering the manhole should be advised to smoke in the sewer
D. Warning signals should be erected

To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is_________________?

To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is_________________?

A. 0.50 m/sec
B. 0.60 m/sec
C. 0.70 m/sec
D. 0.75 m/sec

Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for__________________?

Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for__________________?

A. Unexpected large scale infiltration of stream water
B. Unexpected increase in the population
C. Under estimates of maximum and average flows
D. All of the above