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a small community wishes to construct an activated sludge wastewater treatment plant to treat their wastewater. the wastewater from the community has an average flow rate of 0.0022 m^3/s (190 m^3/day) and an influent substrate concentration of 250 mg/L as COD and all of them are essentially soluble. for sizing the syst em, the mean cell residence time is selected to be 5 days. the reactoer kinetic constants are u max= 2.4 d^-1 (1/day), Ks=75 mg/L as COD, Y=0.4 VSS/g COD and Kd=0.096 d^-1(1/day)
the design engineer propsed a fully mixed tank with a volume of 25 m^3. you have asked to evaluate this design and the follow parameters have to be calculated.
1. what is the hydraulic residence time of this reactor?
2. what is the COD removal efficiency of this system?
3. what is the biomass concentration in aeration tank?
4. what is the F/M ratio?
5. what is the sludge production rate?