Patent ID: 7070695

Claim:
A method of treating water comprising the steps of: (a) filtering a feed water by flowing feedwater from a feed side of a membrane to a permeate side of the membrane to produce permeate on the permeate side of the membrane; (b) collecting a portion of the permeate in communication with a resilient energy storage means and deforming the resilient storage means from an initial state by applying feed water under pressure to the feed side of the membrane, the collected permeate having a pressure equal to or less than the pressure of the applied feed water; and (c) periodically reducing the pressure on the feed side of the membrane below the pressure of the collected permeate by connecting the feed side to a drain, to flow at least a portion of the collected permeate from the permeate side of the membrane to the feed side of the membrane, the flow of collected permeate being assisted by the resilient energy storage means returning at least partially towards the initial state, wherein feed water is applied to the feed side of the membrane during step (c).