The theoretical densimetric Froude number values with favourable effect on the clarifier performance

- A physical model of a circular, centre-feed settling tank was set.
- Investigation of flow patterns at different operative conditions was carried out.
- Three-layer flow phenomenon in clarifier is related to densimetric Froude number.
- Formation of the upper current improves the quality of the effluent.
- Low densimetric Froude number indicates formation of a three-layer flow.