Patent ID: 7563375
Filing Date: 2009-07-21
Classification: B01D,Y02A

Abstract:
1. A method of cleaning a fouled Reverse Osmosis (RO) membrane in a module for RO separation, said membrane having a feed side and an opposite permeate side and extending between a front end and a rear end of said module, said module having a front-end feed port and a rear-end brine port in communication with said feed side of the membrane, and at least one permeate port in communication with said permeate side of the membrane, a normal RO separation process in the same module including feeding raw saline solution, which comprises solvent, dissolved salts and a potential foulant, with osmotic pressure PO 1 , to said front-end feed port at gauge pressure PF 1 >PO 1 , collecting weak saline solution called permeate from said permeate port at gauge pressure PP 2 , and removing residual brine from said rear-end brine port at gauge pressure PB 3 >PO 1 , the foulant accumulating at the feed side of the RO membrane, said cleaning method comprising a) feeding dilute saline solution to the permeate side of the RO membrane under gauge pressure PD b) feeding concentrated saline solution to the feed side of the RO membrane under gauge pressure PC c) withdrawing the concentrated saline solution together with the separated foulant and the penetrated solvent from the feed side of the RO membrane, wherein said gauge pressure PC