1. In the secondary treatment unit of a WWTP, the activated sludge aeration has the following dimensions: 7.0m wide by 30.0m long by 4.3m effective liquid depth. The plant operating parameters are as follows: Flow=0.07m3/s Soluble BOD5 after primary settling =130mg/L MLVSS=1,500mg/L MLSS =1.40 (MLVSS) Settled sludge volume after 30min=230.0mL/L Determine the following: (a) BOD loading (kg/(m3d), (b) F/M ratio, (c) SVI, (d) aeration period (HRT) 2. Using the following assumptions, determine (a) the solids retention time, (b) the cell wastage flow rate, and (c) the return sludge flow rate for the WWTP in Problem 1. Assume: Allowable BOD in effluent =15.0mg/L Suspended solids in effluent =15.0mg/L(30% of SS account for BOD ) Yield coefficient (Y)=0.50mgVSS/mgBOD5 removed Decay rate of microorganisms (kd)=0.060d1