HW 11 - 4 The following are characteristics of an effluent...

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53:050 Natural Environmental Systems Homework Assignment No. 11 – Spring 2011 Due Friday April 15 by 8:30 am 1. (a) Problem 9-23 in Davis and Masten. Since the answer is given you need to make sure you show all work used to arrive at your answer. (b) Problem 9-24 in Davis and Masten. (c) Are the differences between your answers for (a) and (b) expected? Why or why not? 2. Problem 9-27 in Davis and Masten. Since the answer is given you need to make sure you show all work used to arrive at your answer. 3. Problem 9-30 in Davis and Masten. Please use the data in the following “corrected” table. Parameter Wastewater Umvelinqangi River Flow (m 3 /s) 0.1507 1.08 BOD 5 (mg/L @ 20 o C) 30 not measured BOD L (mg/L) not measured 11.4 k @ 20 o C (d -1 ) 0.4375 N/A DO (mg/L) 1.00 7.95 velocity (m/s) N/A 0.390 depth (m) N/A 2.8 temperature ( o C) 16 16 bed-activity coefficient N/A 0.200
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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.

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