This method results in space savings and in cost savings (the investment in a classic clarifier). The microscopic air bubbles (20 to 50 micron) of the supersaturated water attach to the sludge flakes like balloons and lift them to the surface of the flotation-unit. This floating sludge is thickened by means of a sludge-thickening grid. The partly dewatered sludge is then skimmed into the sludge compartment. In case of a difficult forming of sludge floc, poly-electrolyte can be added. In this way, even with very light sludge, we get a very clear effluent.
The dry solid content of the sludge can be adjusted by a simple level controller and the motion speed of the skimmer. The water, supersaturated with dissolved air, is produced in a pressure vessel. The water used in this vessel is recycled from the processed wastewater from the effluent compartment.