The effect of increasing diameter of sewer on the self cleansing velocity is_____________?
(A) to decrease it
(B) to increase it
(C) fluctuating
(D) nil
The velocity of flow does not depend on_______________?
(A) grade of sewer
(B) length of sewer
(C) hydraulic mean depth of sewer
(D) roughness of sewer
For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be__________________?
(A) X/4
(B) X/2
(C) X
(D) 2X
For normal sludge, the value of sludge index for Indian conditions is________________?
(A) 0 to 50
(B) 50 to 150
(C) 150 to 350
(D) 350 to 500
For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as___________________?
(A) 4.5 to 6.0
(B) 6.5 to 8.0
(C) 8.5 to 10.0
(D) 10.5 to 12.0
Composting and lagooning are the methods of_______________?
(A) sludge digestion
(B) sludge disposal
(C) sedimentation
(D) filtration
In facultative stabilization pond, the sewage is treated by________________?
(A) aerobic bacteria only
(B) algae only
(C) dual action of aerobic bacteria and anaerobic bacteria
(D) sedimentation
The maximum efficiency of BOD removal is achieved in______________?
(A) oxidation pond
(B) oxidation ditch
(C) aerated lagoons
(D) trickling filters
Which of the following unit works in anaerobic conditions ?
(A) sludge digestion tank
(B) sedimentation tank
(C) activated sludge treatment
(D) trickling filters
If the sewage contains grease and fatty oils, these are removed in_________________?
(A) grit chambers
(B) detritus tanks
(C) skimming tanks
(D) sedimentation tanks