$(15)$

Primary effluent is to be treated by two parallel trains using the complete mix activated sludge process. Assume average flow conditions, and the following for the activated sludge process:

Plant effluent BODL$=8m\frac{g}{L}$

Total plant peak flow $=5MGD,$ Total plant average flow $=2MGD$

Primary effluent $BO{D}_L=138m\frac{g}{L}$

Biomass yield $=0\mathrm{.}55kg$ biomass $\frac{?}{kg}$ BOD

Endogenous decay rate $(b)=0\mathrm{.}04$ day$-1$

Solids Retention Time $(c)=8$ days

MLVSS concentration in the aeration tank $=3000m\frac{g}{L}$

Waste and recycle solids concentration $=12,000m\frac{g}{L}$

a$)$ Calculate the aeration tank volume in cubic meters.

b$)$ Determine the mass and volumetric flow rates $(k\frac{g}{?}$ day and cubic meters per day$)$ of wasted sludge.

e$)$ Determine the food to microorganism ratio $($F$/$M$)$ for the aeration tank in $kg$ BOD per day per kg MLVSS$.$