2. The wastewater treatment plant for a small city can handle an average influent flowrate of 3,000 m/d. The activated sludge process with recycle has the following parameters. Operating parameters Influent bCOD = 1800 mg/L MLSS = 2500 mg/L SRT = 12 d Coefficients Yk = 3.0 g VSS/g VSS/d Ks = 60 mg BCOD/L Y = 0.40 g VSS/g bCOD kd = 0.08 g VSS/g VSS/d fd = 0.15 g VSS/g VSS COD/BOD = 1.6 g/g = Calculate the following: (25 points) (a) The aeration tank volume (in m) (b) The hydraulic retention time (in h) (c) The oxygen required in the aeration tank (in kg/d) (d) The required sludge disposal rate (in kg TSS/d) (e) The BOD concentration in the aeration tank (in mg/L)