he City of Leeds (England) discharges about 1.4 m3/sec to the Aire River. Without the wastewater discharge, the river flow rate would be 12.7 m3/sec. Given that BOD(river) = 3.0 mg/L and BOD(wastewater) = 30.0 mg/L, what is the concentration of BOD in the river-wastewater mix just below the outfall?