Present clean and clear solutions to the following problems. Do not forget to highlight the final answer.

Wastewater from an industrial plant was tested in a pilot activated sludge plant, and the kinetic constants were calculated as:

Maximum growth rate constant $=5$ day$1,$

Yield $=0\mathrm{.}4,$

Half saturation constant $=200$ mg$/$L

The influent BOD is $1500$ mg$/$L$,$ and a flow rate of $20,000$ m$3/$day is expected. The aerators to be used will limit the suspended solids in the aeration tank to $4000$ mg$/$L$.$ The available aeration volume is $5000$ m$3.$ What efficiency of BOD removal can be expected?

Properties of water at $10\backslash$deg C:

Density: $999\mathrm{.}84$ kg$/$m$3$

Viscosity: $1\mathrm{.}310$ x $10-3$ kg$/$m$-$s