Installation for water treatment by flotation and corresponding water treatment method

Abstract

A system and process for treating water wherein water to be treated is directed to an inlet zone and from the inlet zone to a mixing zone. A flotation zone receives water from the mixing zone. A clarified water collection area is disposed adjacent the flotation zone for receiving clarified water from the flotation zone. There is provided one or more spray nozzles disposed in the mixing zone for injecting pressurized water into the mixing zone and generating air bubbles in the mixing zone such that the air bubbles are mixed with the water to be treated. A perforated plate separates the inlet zone and the mixing zone and includes an array of openings through which water to be treated passes as the water to be treated moves from the inlet zone to the mixing zone. The openings in the perforated plate give rise to a homogeneous mixture of the water to be treated and the air bubbles that result from the pressurized water being injected into the mixing zone by the one or more spray nozzles. Suspended matter and particulate in the water agglomerates around or with the air bubbles and the air bubbles carry the suspended matter and particulate to the surface of the water to be treated. Once the water and air bubbles reach the flotation zone, the air bubbles with the associated suspended matter and particulate can be removed from the surface of the water by a flotation process.