Purification of waste water predominantly containing light materials such as fats and oils

摘要

Waste water treated by pre-sedimentation, enters an aeration system or flotation plant (7). Impurities remaining at this stage are removed by tiny air- or gas bubbles, carrying them to the liquid surface. They are returned to the sedimentation plant, for disposal with light materials already separated. An Independent claim is included for the plant performing the operations with gravity pre-sedimentation tank (1) containing an aeration system, or followed by a flotation plant (7). The flotation plant outlet line (12) recycles floats to the pre-sedimentation tank. Preferred Features: Splitting- and flocculating agents are dosed in the flotation plant. These separate emulsified oil and fat components, and agglomerate macroflocs capable of flotation. At the aeration or flotation stage, oxygen is dissolved under pressure to saturation. If appropriate any nutrients necessary to promote biological activity are inoculated. An oxidation unit (11) is used to breaks down any bio-toxic molecules, connected ahead of the bioreactor (10). The aeration- or floating system precedes a receiver tank (8).