Assuming the pollutant is well mixed in the lake, find pollutant in the lake.The two-pond system shown in Figure P12 is fed by a stream with flow rate 1.0 MGD

(mil-lions gallons per day) and BOD (a non conservative pollutant) concentration 20.0 mg/L.The rate of decay of BOD is 0.30/day. The volume of the first pond is 5.0 million gallons,12,and the second is 3.0 million.Assuming complete mixing within each pond, find the BOD concentration leaving each pond.