Unformatted text preview: 4. The following are characteristics of an effluent from a lagoon at a confined animal feedlot operation (CAFO) and a stream into which the effluent is to be discharged. Parameter CAFO effluent Stream (prior to CAFO discharge) Flow (m 3 /s) 0.33 5.67 BOD L (mg/L) 450 1.1 DO (mg/L) 0.0 8.3 k d (d-1 at 20 o C) N/A 0.22 k r (d-1 at 20 o C) N/A 0.78 velocity (m/s) N/A 0.55 T ( o C) 41 23 (a) If the CAFO lagoon effluent is discharged to the stream, what is the minimum DO that will be observed downstream? At what distance downstream does this minimum DO occur? (b) How much BOD 5 must be removed from the CAFO lagoon effluent, if any, if the DO in the river (after CAFO discharge) is never to go below 5 mg/L? If necessary, assume k for the lagoon effluent is 0.30 d-1 (at 20 o C)....
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This note was uploaded on 06/03/2011 for the course 53 50 taught by Professor Parkin during the Spring '11 term at University of Iowa.
- Spring '11