In a sedimentation tank, the detention period for water ranges from __________ hours.
A. 2 to 4
B. 8 to 12
C. 16 to 20
D. 24 to 32
Answer: Option A
A. 2 to 4
B. 8 to 12
C. 16 to 20
D. 24 to 32
Answer: Option A
Fluorosis is caused due to the presence of excessive amount of __________ in drinking water.
A. Mercury
B. Lead
C. Fluoride
D. Arsenic
Smog is not formed due to the presence of __________ in the atmosphere.
A. SO2
B. NOx
C. CO2
D. Any of these
Dose of chlorine for disinfection of water is about __________ mg/litre of water.
A. 0.01
B. 0.1
C. 0.3
D. 1
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