A complete-mix activated sludge process (CMAS) is to be designed to treat 10,000 m3/ day of domestic wastewater having a BOD 5 of 250mg/L. The National Pollution Discharge Elimination System (NPDES) permit requires that the effluent BOD 5 and TSS concentrations should be 20mg/L or less on an annual average basis. The following biokinetic coefficients obtained at 20C will be used in designing the process: Y=0.6 mgVSS/mgBOD5,k=5d1,Ks=60mg/LBOD5, and kd=0.06d1. Assume that the MLVSS concentration in the aeration basin is maintained at 3,000mg/L and the VSS: TSS ratio is 0.80 . The temperature of the wastewater during the winter months is expected to remain at 18C for extended periods. During the summer, the wastewater temperature may reach 25C for several weeks. Hint: Take the temperature correction coefficients () of 1.07,1.00, and 1.04 will be used to correct k,Ks, and kd, respectively. Determine the following: a) Volume of the aeration basin in m3. b) Mean cell residence time necessary to meet the NPDES permit during the summer months