Updated: Question in GATE 2012 Civil Engineering Paper with Solution
June 22, 2012
An activated sludge system (sketched below) is operating at equilibrium with the following information. Wastewater related data: flow rate = 500 / hour, influent BOD = 150 mg/L, effluent BOD = 10 mg/L. Aeration tank related data: hydraulic retention time = 8 hours, mean-cell-residence time = 240 hours, volume = 4000 , mixed liquor suspended solids = 2000 mg/L.
The food-to-biomass (F/M) ratio (in kg BOD per kg biomass per day) for the aeration tank is