Flotation is an alternative to a settling tank. During flotation the sludge will float on top of the water surface, while in a settler the sludge will settle.
When carrying out a flotation, supersaturated water is injected together with the influent. The sludge particles will bind to these air bubbles and will thus form a kind of foam which rises to the top of the water surface. The sludge may then simply be removed using a scraper.
This supersaturated water is produced by mixing purified waste water with compressed air.
A flotation is commonly used in biological treatment plants. Usually, it can handle a higher flow rate than a sedimentation unit.
Account must be taken of the chemical resistance of the material in the flotation tank.
PCA can help you with this technology, both in design and construction of the installation.