Factors affecting the quantity of sanitary sewage
The quantity of sanitary sewage or D.W F is mainly affected by the following factors:
1) Rate of water supply
The quantity of sanitary sewage varies with the rate of water supply. The rate of water supply is not constant, but it fluctuates. These fluctuations may be seasonal, daily and hourly The rate of sewage is assumed as equal to the rate of water supply.
The quantity of sanitary sewage directly depends on the population. As the population increases the quantity of sanitary sewage also increases and vice versa.
3) Type of area served
The quantity of sanitary sewage also depends on the type of area such as residential, industrial or commercial.
4) Infiltration and exfiltration
The percolation of subsoil water in the sewer through the defective joints or cracks of sewer is called infiltration.
The leakage of sewage from the sewer into the ground surrounding the sewer is called ex-filtration. Infiltration increases the quantity of sewage. On the other hand ex-filtration decreases the quantity of sewage.