Unformatted text preview: first-order decay model for biochemical oxygen demand (BOD) and the model we derived in class for oxygen transfer from the atmosphere. Ignore any effect of aquatic life on the dissolved oxygen balance. DATA: Lake: Volume: V = 2 x 10 7 m 3 Average depth: d = 10 m Temperature: T = 20 o C River (incoming): Flow rate: Q r = 0.5 m 3 s-1 Dissolved oxygen: DO r = 9.0 mg L-1 Oxygen transfer from the atmosphere to the lake: Transfer coefficient: K = 5 x 10-5 cm s-1 Saturation concentration, dissolved oxygen: DO sat = 9.1 mg L-1 Waste: Flow rate: Q w = 0.075 m 3 s-1 BOD content: BOD w = 150 mg L-1 BOD decay rate: k = 0.2 d-1 Dissolved oxygen: DO w = 8 mg L-1 READING: Chapter 9, pp. 332-374 Interfacial mass transfer example posted on website...
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- Spring '10
- Chemical oxygen demand, Qw Lake