Show me the steps to solveProblem # $3$

A water treatment plant has a flow of $30,000$ m$3/$d$.$ The detention times in the rapid$-$mix and

flocculation tanks are $40$ s and $30$ min, respectively. The water temperature is $20$ C$.$ Assume that

the optimal velocity gradient for rapid mixing is $800$ s$-1$ and for slow mixing is $40$ s $-1.$ Determine:

$(1)$ Volume of rapid$-$mix tank

$(2)$ Power requirement for rapid mixing

$(3)$ Size of flocculation tank

$(4)$ Power requirement for slow mixing