Example problem $2($cont$.)$:

$($a$)$

The activated sludge set$-$up shown above has an influent flow of $10$ MGD $($million gallons per day$)$ and a suspended solids concentration of $50m\frac{g}{L}.$ The waste$-$activated sludge flow rate is $0\mathrm{.}2$ MGD and has a solids concentration of $1\mathrm{.}2\%.$ The effluent $($discharge$)$ has a solids concentration of $20m\frac{g}{L}.$ What is the rate of solids production, called the yield, in units of pounds per day? Assume the system operates continuously at steady state