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A 4 MGD WWTP acquits a unimportant treated abundant into a receiving drift. The wastewater has the forthcoming characteristics: BOD5= 20 mg/L DO = 2.0 mg/L Water Air = 24C The receiving updrift from the purpose of acquit has the forthcoming characteristics: Flowtrounce = 18 cfs BOD5= 4 mg/L DO= 6 mg/L Water Air = 27C Cross-sectional Area = 36 sqft a. 3.2 b. 5.2 c. 7.2 d. 8.4 The reaeration trounce is estimated to be 0.4 1/day. (Base e at 20C), and the air discipline coefficient is 1.024. the deoxygenation trounce constant is estimated to be 0.23 1/day. (Base e at 20C) and the air discipline coefficient is 1.047. reaeration and deoxygenation are the solely elder factors forcible the dissolved oxygen concentration in the drift succeeding mixing delay wastewater abundant. Assume the opportunity of travel in the drift to gain the consummation dissolved oxygen failure is 3 days. The dissolved oxygen failure (mg/L) at this subsidence downstream from the purpose of acquit is most nearly: