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A wastewater stream has a 5-day BOD at 20 °C equal to 170 mg/L and initial...

A wastewater stream has a 5-day BOD at 20 °C equal to 170 mg/L and initial BOD equal to 330 mg/L. Find the 15-day BOD at 15 °C. (Assume temperature coefficient θ = 1.053)

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Answer #1

5 day BOD at 20o C is given as

where

L5 = 5 day BOD = 170 mg/l

Lu = initial BOD = 330 mg/l

k = rate constant

t = time = 5 days

Therefore

k = 0.145

Rate constant at 15 oC is given by

= 0.112

15 day BOD at 15oC is given by

= 268.5 mg/L

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