$6-9.$ Using Table $6-4,$ select an in$-$line blender to mix alum with a design flow rate of $485($m$^(3))/($h$).$ The design water temperature is $10$C $.$ Verify that the detention time and velocity gradient meet the design criteria for adsorption$/$destabilization$.$ Assume that the water power is $80\%$ of the motor power, that the mixing time must be between $0\mathrm{.}3$ and $0\mathrm{.}8$s $,$ and that there will be a stand$-$by mixer for redundancy. Because this problem will require some iteration, a spreadsheet solution is highly recommended.