. A wastewater treatment plant discharges 1.0 m3/s of effluent having an ultimate BOD of 40.0 mg/L into a stream flowing at 10.0 m3/s. Just upstream of the discharge point, the stream has an ultimate BOD of 3.0 mg/L. The deoxygenation constant is estimated at 0.22/d. (a) Assuming complete and instantaneous mixing, find the ultimate BOD of the mixture of waste and stream just downstream of the outfall. (b) Assuming a constant cross-sectional area for the stream equal to 55.0 m2, what ultimate BOD would you expect to find at a point 10,000. m downstream of the outfall