Awell-mixed lagoon with volume 1,500 m has been received a steady flow of a conservative waste at a rate of 120 m3/day for a long enough time to assume that steady- state conditions apply. the waste entering the lagoon has a concentration of 12 mg/l. i. what is the concentration of pollutant in the effluent leaving the lagoon? ii. if the input waste concentration suddenly increases to 120mg/l, what would the concentration in the effluent be 7 days later?