Design an activated sludge system to treat 1000 m3 /d of wastewater to meet effluent BOD5 and TSS concentration of 20 mg/L each. Assume that the effluent pBOD5 to VSS ratio is 75%, and that the volatile fraction of the MLSS is 70%. Determine the following: (a) Minimum SRT (b) effluent soluble BOD5 (c) biomass specific utilization rate (d) design SRT (e) HRT in the aeration tank if the maximum MLSS concentration that the secondary clarifier can sustain is 3000 mgSS/L (f) sludge production rate in kgSS/d and kgVSS/d (g) if the RAS is 1% suspended solids, determine the waste sludge flow rate (h) the recirculation ratio (i) the oxygen demand in kg/d