In this study, the settled sludge volume was approximately 6.30 mL/25 mL from Figure , which was taken up to 1000 mL (normal size of measuring cylinder for SVI studies), which has become around 252 mL/L. By applying the formula of SVI, the value of SVI obtained was then 34.33 mL/g in 30 min (SVI30). This SVI indicated a sludge with good settling properties according to its variation range. The study exposed very good settling properties of the sludge and the low SVI value ranging between 30 and 60 mL/g TSS was responsible for intensive and quick sedimentation, which has shortened the settle phase to less than 60 min. In conclusion from Figure and the results obtained in this study, the formation of the sludge was highly characterized by high sludge settling velocity, low settling sludge volume and the relatively high settled solid concentration.