A perfectly mixed aeration pond with no recycle serves as the biological reactor for a small community. The pond receives 30m^3/d of influent with a BOD5 of 350mg/L that must be reduced to 20mg/L before discharge. It has been found that the kinetic constants for the system are Ks = 100mg/L BOD5, Kd = .1 d^-1, Um = 1.6 d^-1, and Y is .6 mg VSS/mg BOD5.
a) What must the hydraulic detention time be in the aeration pond?
b) What mass of microbes will be produced in the pond each day?