Q$1.$ A batch settling test has been performed on an industrial wastewater having an initial suspended solid of

$597m\frac{g}{\text{I}}$ to develop criteria for the design of a primary clarifier. The test column was $5in.$ in diameter and $8ft$ high,

and sampling ports were located $2,4,6,$ and $8ft$ from the water surface in the column. The suspended solids

remaining after various sampling times are given in table below. The wastewater flow is $2\mathrm{.}5$MGD$.$ Determine:

a$.$ The design overflow rate and detention time if $65\%$ of the suspended solids are to be removed. Use scale$-$

up factors of $0\mathrm{.}65$ for the overflow and $1\mathrm{.}75$ for the detention time.

b$.$ The diameter if a circular clarifier is used

c$.$ The design diameter of the clarifier if equipment is available in $5-$ft increments

d$.$ The depth of the tank

Depth, ft Time, min

$1020304560$

$2394352243182148$

$4460406337295216$

$6512429376318306$

$810181142120813151405$