Chemical Engineering - Environmental Engineering

41. 

The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria.

A. anaerobic
B. saphrophytic
C. aerobic
D. parasitic

Answer: Option C

Explanation:

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42. 

Presence of dissolved impurities of __________ is responsible for the red brownish color of water.

A. carbonates
B. bi-carbonates
C. iron & manganese
D. arsenic

Answer: Option C

Explanation:

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43. 

TLV of aldrin in public water supply system is about __________ μg/litre.

A. 0.5
B. 17
C. 357
D. 1097

Answer: Option B

Explanation:

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44. 

A gas is termed as non-toxic, if its maximum permissible concentration (TLV) ranges from __________ ppm.

A. 1000 to 2000
B. 3000 to 6000
C. 6000 to 9000
D. 10000 to 100000

Answer: Option D

Explanation:

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45. 

Removal of __________ is accomplished by aeration of water.

A. dissolved gases
B. suspended solids
C. dissolved solids
D. none of these

Answer: Option A

Explanation:

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