A river above a town has a flow of 200 L/s and a BOD5 of 1 m
A river above a town has a flow of 200 L/s and a BOD5 of 1 mg/L. The river is the receiving water for 25 L/s of treated sewage (BOD5= 25 mg/L) from the town and 25 L/s of untreated effluent (BOD5=175