a) Town Cybertown has been directed to upgrade its primary WWTP to a secondary plant than can meet an effluent standard of 30 mg/L BODs and 30mg/L suspended solid (SS) and selected a completely mixed activated sludge system. Assuming that BODs of the SS may be estimated to 54% of the SS concentration. Determine: i. Concentration of BOD in effluent (3) ii. Mean cell residence time iii. Hydraulic detention time iv. Aeration basin volume Table 1: Characteristic of WWTP Characteristics Flow BODS Ks 0.150 m/s 84 mg/L 100 mg/L BODS 2.5 d 1 0.05d1 0.50 mg VSS/mg BODs removed Hm ka Y