29. Temporary hardness of water may be removed by adding
A.calcium hydroxide
B.calcium carbonate
C.calcium chloride
D.sodium bicarbonate
30. The maximum desirable limit (BIS of mercury in the drinking water is
A.0.05 mg/l
B.0.9 mg/l
C.0.1 mg/l
D.0.001 mg/l
31. From the following sanitizers which one comes under category of surface active agents?
A.Tetra phosphate
B.Teepol
C.Meta phosphate
D.None of these
32. The purest form of naturally occurring water is
A.rain water
B.river water
C.pond water
D.well water
33. Calgon is used for removal of
A.sodium carbonate
B.permanent hardness of water
C.potassium carbonate
D.none of these
34. The water being used in dairy industry should contain not more than
A.5 proteolytic and/or lipolytic organisms per ml
B.10 proteolytic and/or lipolytic organisms per ml
C.15 proteolytic and/or lipolytic organisms per ml
D.20 proteolytic and/or lipolytic organisms/ml
35. The activated sludge process consists of returning a portion of the clarifier
A.effluent water entering the reactor
B.influent water coming out of the reactor
C.influent water entering the reactor
D.effluent water coming out of the reactor
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