Garden City is finalizing the design of an activated sludge WWTP and has the following design information available. Design Flowrate = 4 MGD; Plant Water Temperature = 22°C. A) Design the Activated Sludge Tank for the WWTP. Using the design information below, determine: (a) the substrate, S, concentration in mg/L in the activated sludge tank, (b) the detention time of the tank in hours, and (c) the volume of the tank in m3 . Again, Q = 4 MGD.
B) Design the Activated Sludge Tank for the WWTP (continued). Using the design information given in the previous problem, calculate the: (a) cell wasting (Qw) and (b) cell recycling (Qr) rates in MGD for the tank. (c) What is the value of the F:M ratio in mg BOD5/mg MLVSS-day? Is this value acceptable? Use the equations below to calculate cell wasting and recycling rates: Qr/Q = X/(Xr-X) and Qw = (VX)/(θCXr)
Activated Sludge Tank Design Information:
MCRT (c) Ks | 10 days 100 mg/L 0.5 0.05/day 2.5/day Xo, Xe Negligible | 3,500 mg/L MLVSS 10,000 mg/L MLVSS Influent BOD5 | 220 mg/L Y Xr kd Um