Sedimentation with Circular Clarifier
The aerated mixture, rich in flocs, is forwarded to the clarifier. The clarifier is a tank which is opportunely designed to create the right conditions of quietness, to allow settlement of the sludge flocs.

On the bottom of the tank there are mechanical organs (scraping blades) which forward the settled sludge towards a collecting sump when the decanted superficial water, comes out of the clarifier without biological sludge, ready to be discharged into the surroundings in full respect of the standard limits of the local law. Alternatively, the water can be forwarded to a recovery system (filtration) and re- used in the process.
