Problem \#4. Your boss has asked you to design an anaerobic digester and biogas collector tank. Use kinetic parameters from the table below and the information below to determine the required volume for the digester, the flow rate of methane, and volume of an external tank pressurized to 500kPa needed to hold 33% of the daily biogas production. - Peak sludge flowrate =800m3/d of mixed primary and waste activated sludge - Sludge thickened to 4.0% - Temperature of digester =35C - Influent bCOD=3,200g/m3 - Design effluent bCOD=500g/m3 - Design safety factor =3 - There will be no recycle - Gas evolves from the digester at atmospheric pressure (101.3kPa) - Biogas composition: 55%CH4,45%CO2 Summary of design parameters for completely mixed suspended growth Adapted from Metcalf \& Eddy, 2003