Patent ID: 6702944
Filing Date: 2004-03-09
Classification: B01D,C02F

Abstract:
A filtration process comprising the steps of:permeating by (a) flowing pressurized water to be filtered into the feed/retentate side of a module having at least one membrane adapted to selectively j reject hardness; (b) collecting a softened permeate from a permeate side of the module; (c) collecting a retentate from the module; and (d) periodically stopping permeation and; (i) injecting a fluid which is acidic or which forms an acid in water into the feed/retentate side of the module; (ii) holding the fluid which is acidic or which forms an acid in water in the feed/retentate side of the module for a selected time; and (iii) flushing the fluid which is acidic or which forms an acid in water from the feed/retentate side of the module as retentate after the expiration of the selected time.