Question

A municipal corporation is required to treat $1000$ $m^3/day$ of water. It is found that an overflow rate of 20 m/day will produce a satisfactory removal of the discrete suspended particles at a depth of $3m$. The diameter (in meters, rounded to the nearest integer) of a circular settling tank designed for the removal of these particles would be.

• A. 8

Answer 1

The correct option is A 8
$Q=1000\frac{m^3}{day}$

$\text{Overflow Rate}=20m/day$

$H=3m$

Surface Area of circular Tank

$=\frac{1000}{20}$

$=50m^2$

Assuming diameter to be ‘d’

Hence, $\frac{\pi }{4}\times d^2=50$

$d=\sqrt{\frac{50\times 4}{\pi }}$

$=7.978$

$\approx 8m$