29. Temporary hardness of water may be removed by adding
A.calcium hydroxide
B.calcium carbonate
C.calcium chloride
D.sodium bicarbonate

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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

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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

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32. The purest form of naturally occurring water is
A.rain water
B.river water
C.pond water
D.well water

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33. Calgon is used for removal of
A.sodium carbonate
B.permanent hardness of water
C.potassium carbonate
D.none of these

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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

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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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