IB sludge index measurement
To correctly size a settling tank, you need to know the Hazen speed of the liquid to be treated. The Hazen velocity or ascension velocity is determined by measuring the sludge index.
This is very easy to do. You’ll need:
- a 1 liter Imhoff cone (glass ideally, but a plastic test tube type equivalent is sufficient)
- at least one liter of liquid to be treated (optional, but common for large plants)
- optional: the coagulants and flocculants that will be used (at the planned dosages),
- A watch or timer
- TSS measuring equipment
Protocol for adjusted volume:
- Mix the liquid to be analyzed correctly
- Pour 1 L into the test tube
- Start the timer, wait 30 minutes
- Read the result: volume reached by the sludge (for example 440 ml/L).
This is the value that is decisive for the calculation of the Hazen speed.