A wastewater treatment plant discharges 10 MGD effluent containing 200 mg/L ultimate BOD into a stream flowing at 90 MGD with ultimate BOD of 5 mg/L. The deoxygenation constant, kd, is 0.12 /day. (a) What is the ultimate BOD(BODu) remaining in the stream at a distance of 10,000m downstream if the stream flows at a constant speed of 0.10m/s ? (b) What should be the treatment plant effluent BODu(Cw) in mg/L if the ultimate B0Du at 10,000m downstream cannot exceed 5 mg/L