For the following waste and river characteristics just upstream from the outfall, find the minimum downstream DO that could be expected. Parameter Wastewater River Flow (m3/s) 0.3 0.9 Ultimate BOD (mg.L) 6.4 7.0 DO (mg/L) 1.0 6.0 DOsat (mg/L) 8.0 8.0 Kd (1/d) 0.2 Kr (1/d) 0.37 Speed (m/s) 0.65