You are a consultant engineer, who is tasked with designing a wastewater

treatment plant for a small community. It is decided to use a completely

mixed, conventionally aerated sludge system to treat the wastewater. In $2050$

$($the design year chosen for the project$),$ it is estimated that there will be $5000$

houses in the area, with an average occupancy of $3\mathrm{.}2$ people per house. In

addition, it is estimated that the volume of effluent that a local company

produces will increase to $43,200$ m$3$ d$-1$ and will have a BOD concentration of

$5$ mg L$-1.$ This effluent will also need to be treated by the wastewater

treatment plant.