Problem 10. A lagoon is to be designed to accommodate an input flow of 0.10 m3/s of non-conservative pollutant with a concentration 30.0 mg/L and a reaction rate of 0.20 day-1. The effluent from the lagoon must have a pollutant concentration of less than 10.0 mg/L. Assuming complete mixing, and that there is an outlet for 0.10 m3/s, how large must the lagoon be? (assume steady state).

Fig: 1