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Environmental Engineering Multiple Choice Questions on “Oxygen Demand”.
1. _____ is the amount of oxygen required to oxidize only organic matter in sewage.
a) Turbidity
b) BOD
c) COD
d) DO
Answer: b
Clarification: BOD is the amount of oxygen required to oxidize only organic matter in sewage. It is always less than COD as COD oxidizes both organic and inorganic matter.
2. The full form of BOD is __________
a) Biodegradable oxygen demand
b) Biological oxygen demand
c) Biochemical oxygen demand
d) Bandwidth on demand
Answer: c
Clarification: The full form of BOD is biochemical oxygen demand. It is measured in ppm or mg/L.
3. The biochemical oxygen demand is computed by __________
a) Dissolved oxygen / Dilution factor
b) Dissolved oxygen + Dilution factor
c) Dissolved oxygen – Dilution factor
d) Dissolved oxygen * Dilution factor
Answer: d
Clarification: BOD = Dissolved oxygen * Dilution factor.
Where Dilution factor = Volume of diluted sewage sample / Volume of undiluted sewage sample.
4. The value of deoxygenation constant is independent of the temperature.
a) True
b) False
Answer: b
Clarification: The value of deoxygenation constant is directly proportional to the temperature. It increases with increase in temperature.