Abstract: Present invention relates to a method and apparatus for purification of water, said method comprises the steps of feeding the water into a reactor (4) through one or more inlet tubes (1) or inlet zones and feed water an substrate through carrier elements for bio film (5) which have a large protected surface (>200 m2/m3 carrier elements) and large pore volume (>60%), and that the carrier elements are fluidized for the removal of waste sludge, wherein the ratio of charge of the elements (5) by normal duty corresponds to an amount corresponding to 90%-100%, more preferred 92%-100%, and most preferred 92%-99% of the vet volume of the reactor (4), said carrier elements (5) is kept substantially at rest or hindered movement between the times surplus sludge is removed, and that the carrier elements being fluidised for removal of surplus sludge, said carrier elements (5) having a specific gravity in the area of 0.8-1.4, more preferred 0.90-1.1 and most preferred 0.93-0.

Abstract: Present invention relates to a method and apparatus for purification of water, said method comprises the steps of feeding the water into a reactor (4) through one or more inlet tubes (1) or inlet zones and feed water an substrate through carrier elements for bio film (5) which have a large protected surface (>200 m2/m3 carrier elements) and large pore volume (>60%), and that the carrier elements are fluidised for the removal of waste sludge, wherein the ratio of charge of the elements (5) by normal duty corresponds to an amount corresponding to 90%-100%, more preferred 92%-100%, and most preferred 92%-99% of the vet volume of the reactor (4), said carrier elements (5) is kept substantially at rest or hindered movement between the times surplus sludge is removed, and that the carrier elements being fluidised for removal of surplus sludge, said carrier elements (5) having a specific gravity in the area of 0.8-1.4, more preferred 0.90-1.1 and most preferred 0.93-0.