Q$4/4$:

An aerobic complete$-$mix reactor $($no recycle$)$ with a volume of $1000L$ receives a $500\frac{L}{d}$

wastewater flow and has an effluent soluble COD concentration of $10m\frac{g}{L}.$ For one of the

wastewaters with the characteristics given below $($select as you will$),$ determine

$($a$)$ the $$ value $($hydraulic retention time$)$ for the reactor in days,

$($b$)$ the oxygen used per day in $(\frac{g}{d}),$

$($c$)$ the effluent volatile suspended solids concentration $($assume biomass oxygen equivalent of

$1\mathrm{.}42g\frac{O^2}{g}$ VSS$),$ and

$($d$)$ the observed yield in $g$ VSS$/$g bsCOD removed.