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The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called_______________? A. A heap B. Plateau C. WindrowD. None of these
The gas which may cause explosion in sewers, is_________________? A. CarbondioxideB. Methane C. Ammonia D. Carbon monoxide
The discharge per unit plan area of a sedimentation tank, is generally called________________? A. Over flow rate B. Surface loading C. Over flow velocityD. All the above
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 minutesD. 2 hours
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 outC. The men entering the manhole should be advised…
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/secD. 0.75 m/sec
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/dayC. 50,000 to 60,000 litres/sqm/day D. 80,000 to 100,000 litres/sqm/day
At the junction of sewers___________________? A. Top of smaller sewer is kept lower B. Top of larger sewer is kept lower C. Tops of both the sewers are at the same levelD. None of these
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 flowsD. All of the above
The sewer that unloads the sewage at the point of treatment is called_________________? A. Main sewerB. Outfall sewer C. Branch sewer D. House sewer