METHOD OF SEWAGE WATER PURIFICATION BY PRESSURE FLOTATION

FIELD: water purification. ^ SUBSTANCE: sewage water purification by pressure flotation in the paper-and-pulp industry. Water saturation with gas under pressure in a saturator; pressure release to the atmospheric pressure; suspended contaminants floation by the gas bubbles forming while the pressure release; and separation of the contaminants from the water. Part of the purified liquid flow is saturated with gas in the saturator. Then, the water saturated with gas gets throttled while being simultaneously mixed with the rest of the treated water in the ejector, thus forming evenly foamed water at the output. Circulation water of the paper-and-pulp manufacture, which contains fibers and fillers, can be purified too, while part of the purified water flow is saturated with atmospheric air in the saturator at the pressure of 3 to 5 atmospheres. While purification sewage water from sulphate or alkaline processes, containing fibers or alkaline lignin, part of the treated water flow is saturated with air containing 3 to 25% of carbon dioxide in the saturator. The treatment is performed at water temperatures of 7°C to 60°C. ^ EFFECT: possibility of purification of various sewage water types; intensifying the treatment process at large; simplification of the whole purified water volume gas saturation process. ^ 3 cl, 3 ex