A stream survey revealed that the reaeration constant is 0.05 d¯' and the deoxygenation constant is 0.030 d. If the initial deficit is 5.00 mg/L and the ultimate BOD after mixing is 12.0 mg/L, how long will it take to reach the critical point in the DO sag? а. 16.43 d b. 25.46 d c. 17.05 dd. 9.2 d. 9.27 d

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