Water treatment procedure using plant with biological reactor and filter membrane employs oxygen-lean gas to clean membrane

摘要

The procedure, comprising stages in which the water is passed through a biological reactor (1) designed to receive a biomass and through at least one filter membrane (3) immersed in the reactor or in a second reactor linked to the first, introducing air or oxygen for aerobic or anoxic phases, recuperating the clarified effluent and cleaning the membrane with an injected oxygen-lean gas. Where two reactors are used at least one of them is closed, and the oxygen-lean gas can be obtained from the top of a closed reactor or a supplementary gas comprising nitrogen, carbon dioxide and oxygen-lean air can be employed. The procedure can also use air fractionated to produce an oxygen-lean fraction used for cleaning the membrane and an oxygen-rich fraction for the reactor.