- A. TOD > BOD > COD
- B. TOD > COD > BOD
- C. BOD > COD > TOD
- D. COD > BOD > TOD
Environmental Engineering
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The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by
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For normal sludge, the value of sludge index for Indian conditions is
- A. 0 to 50
- B. 50 to 150
- C. 150 to 350
- D. 350 to 500
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Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R: The sand used in slow sand filters is finer than that in rapid sand filters
Select your answer based on the coding system given below:- A. Both A and R is true and R is the correct explanation of A
- B. Both A and R is true but R is not the correct explanation of A
- C. A is true but R is false
- D. A is false but R is true
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The per capital consumption of a locality is affected by
(i) Climatic conditions
(ii) Quality of water
(iii) Distribution pressure- A. Only (i)
- B. Both (i) and (ii)
- C. Both (i) and (iii)
- D. All (i), (ii) and (iii)
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Select the correct statement.
- A. 5 day BOD is the ultimate BOD
- B. 5 day BOD is greater than 4 day BOD keeping other conditions same
- C. 5 day BOD is less than 4 day BOD keeping other conditions same
- D. BOD does not depend on time
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The effect of increasing diameter of sewer on the self cleansing velocity is
- A. To decrease it
- B. To increase it
- C. Fluctuating
- D. Nil
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In chlorination, with the rise in temperature of water, death rate of bacteria
- A. Increases
- B. Decreases
- C. Remains unaffected
- D. None of the above
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Sewage treatment units are normally designed for
- A. 5 – 10 years
- B. 15 – 20 years
- C. 30 – 40 years
- D. 40 – 50 years
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The time of concentration is defined as
- A. The time taken by rainfall water to run from most distant point of water shed to the inlet of sewer
- B. The time required for flow of water in sewer to the point under consideration
- C. Sum of (A) and (B)
- D. Difference of (A) and (B)
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When there is no recirculation of sewage, then recirculation factor is
- A. 0
- B. 1
- C. Infinity
- D. None of the above