The SSVI (Stirred Specific Volume Index) is used to determine the settling properties of an activated sludge. It is a simple test that is easy and quick to perform, and yet provides considerable information about the sludge settlement characteristics.
The SSVI can be used both in routine plant operation and it can be used for the design of a final sedimentation tank.
A complete operating manual is supplied with the SSVI equipment that details how the SSVI test is performed and how the results are interpreted.
The equipment consists of the following items :
- Slow speed stirrer and timer unit
- A Perspex tube with a 50cm graduated scale and stirring paddle
- Power supply (separate unit Type 311)
The timer defaults to the standard 30 minutes test time, but it can be set for any time between 1 and 99 minutes.
At the end of the test the timer emits an audible signal.