Design a set of activated sludge aeration tanks. The flow rateto treat is 5.6 MGD and the BOD concentration is 150 mg/L. Thedesign solids concentration (X) at steady-state is 2,000 mg/l. Thedesign MCRT is 7 days. The kinetic coefficients are as follows:K = 2 g BODg cells?d,Ks = 25 BOD/L, Kd= 0.06 day-1, Y = 0.5 gBODg cells?d. The influent ammonia concentration is40 mg/l and nitrification is needed. It takes 1400ft3of air per pound of BOD. Userectangular tanks with a depth of 12 ft, a length to width ratio of6 to 1, and a maximum length of 110 ft. Determine thefollowing:
a) The hydraulic retention time (hr)
b) The steady-state effluent BOD concentration (mg/L)
c) The number of tanks and their lengths (ft) and widths(ft)
d) The air requirement(ft3/min)
