The dimensions of a rectangular settling tank are L = 24 m, W = 6 m, H = 3 m. If 2 hr, detention time for tank is recommended the rate of flow of sewage per hour is

Concepts:

The detention period means how much time sewage remains inside the tank. It is calculated as:

\(t_d = \frac{V}{Q}\)

Where

V = Volume of tank

Q = rate of flow of sewage

td = detention time

Calculation:

Given:  Detention time, td = 2 hrs.

Dimension of tank:  Length, L = 24 m, Width, W = 6 m and Depth, H = 3 m.

Volume of tank = L × B × H

V = 24 × 6 × 3 = 432 m3

The rate of flow of sewage is calculated as:

\(2 = \frac{432}{Q}\)

Or

Q = 216 m3/hr.