Practice Exams Grade II Treatment - Division of Water Quality

PAGE740. Calculate the organic load in Ibs of BOD/day/1000 cu. ft. fora trickling filter 50 ft in diameter and 8 feet deep, a BODdesign loading of 50 Ibs/day/1000 cu. ft., a flow of 250,000gpd, and a primary effluent BOD to filter of 150 mg/L.A. 2 Ibs/day/1000 cu. ft.B. 5 Ibs/day/1000 cu. ft.C. 20 lbs/day/1000 cu. ft.D. 50 Ibs/day/1000 cu. ft.41. Given the following data, calculate the suspende~ soli~srequired to maintain a food to microorganism (F/M) ratio ofO. 3.DATA:. A.B.2100 mg/L.2500 mg/L.C.D.3300 mg/L.4200 mg/L.Daily flow = 1.0 MGD.Average primary effluent BOD = 150 mg/L.Aeration tank capacity = 200,000 gal .42. Given the following data, calculate the mean cell residencetime (MC RT) .DATA:A. 6 days.B. 8 days.C. 10 days.D. 12 days.Influent flow = 3.5 MGD.MLSS = 2850 mg/L.Waste sludge flow = 0.08 MGD.Total secondary system volume = 2.0 MG.Haste activated sludge suspended solids conc ..- 6000mg/L.Final effluent suspended solids = 25 mg/L.43. In an activated sludge plant, it was determined that an SVIof less than 60 was good, between 60 and 80 was fair, andabove 80 indicated bulking would soon follow. A test wasmade and the 30-minute settling volume was 15% and suspended,­solids were 3000 mg/L. Using the scale above, the resultswould be labeled asA. Fair.B. Good.C. Indicative of bulking.D. None of the above. Not enough information was given todetermine.~~. ~nlculate the waste sludge pumping rate if you want to waste2,000 pounds per day with a concentration of return sludgeat 5000 mg/L.A. 29 gpm.B. 33 gpm.C. 35 gpm.D. 37 gpm.