SVI (ml/g) = SV30 (ml/L)
General SVI Guidelines
- < 80 - fast settling sludge, if supernatant is turbid low SVI indicates "old" sludge
- 100 - 200 - the range most activated sludge systems operate. Remember your secondary clarifier determines the upper limit for SVI.
- >250 - indicates severe bulking caused by filaments, non-filamentous bulking, or being extremely early on the growth curve.
Remember - the above ranges are just guidelines. Always refer to how well your secondary clarifier functions to get your system's true range for best SVI.