Design the dimensions of the septic tank for a small colony of 150 persons provided with an assumed water supply from the municipal head works at a rate of 120 litres per person per day. Assume any data you may need?

Step 1:-Number of users for the septic tank=150 persons

Step 2:-Tank Capacity

Consider the whole quantity of water to be as a sewage

∴Flow of sewage per day=150*120=1800 litre

The detention period varies from 12 to 72 hours

Detention period in common practice is used to be 24 hours. …