A lagoon with volume 1200 m3 has been receiving a steady flow of a conservative waste at a rate of 100 m3/day for a long enough time to assume that steady-state conditions apply. The waste entering the lagoon has a concentration of 10 mg/L. Assuming completely mixed conditions:
(a) What would be the concentration of pollutant leaving the lagoon?
(b) If the input waste concentration suddenly increased to 100 mg/L, what would the concentration in the effluent be 7 days later?
(c) Same questions for a non conservative pollutant with rate constant k= 0.2/day