Q. What is Sedimentation tank ?

This is a process in which the water is passed through bases or tanks in which the velocity of water is so reduced or water is given a period of rest that permits the heavy Suspended particles settle at the bottom by action of gravity and force in the Sedimentation tank . This is necessary because water contains suspended matter which might choke the filters.

There are two types of Sedimentation.

1. Plain Sedimentation

2. Sedimentation with coagulants or Chemical Sedimentation.

Detention Period - 6-to8 hrs for Plain Sedimentation & 1.5 To 3 hrs for Chemical Sedimentation.

Depth of flow - 3 to 6 meters.

Velocity of flow - 30 cm / min.

Length of tank = 3 to 4 time of width of tank.

Bottom slope - 1: 100

In case of circular tank dia less than 60m.

Type of Sedimentation Tank -

1. Horizontal flow Sedimentation Tank

2. Up ward flow Sedimentation Tank

3. Circular Sedimentation Tank