Partially Separate Sewer System
In this system, two sets of sewers are laid. A portion of stormwater is allowed to enter in the sewers carrying sewage and the remaining stormwater flows through a separate set of the sewer. Thus, the load on the treatment plant is controlled and kept within the capacity of the treatment plant.
Advantages of Partially Separate Sewer System
Following are the advantages of a partially separate system:
1) It combines the advantages of both the combined system and separate system.
2) The entry of stormwater prevents the silting of the sewer.
3) The sewers are of reasonable size.
4) The problem of disposing stormwater from houses is simplified.
Disadvantages of Partially Separate System
Following are the disadvantages of a partially separate system:
1) The velocity of flow is low in dry weather.
2) There is a possibility of overflow.
3) The entry of stormwater in the sewer may increase the load on the pumping and treatment unit.
4) If the diversion of stormwater is not done at a proper time, then it may create unnecessary troubles.