Patent ID: 8980100
Filing Date: 2015-03-17
Classification: B01D,C02F,Y02A,Y02W

Abstract:
1. A method for desalination by reverse osmosis and reverse osmosis membrane cleaning, comprising: providing a feed stream of water to be desalinated; filtering the feed stream through an ultrafiltration membrane, thereby removing turbidity including bacteria and viruses from said feed stream; filtering the feed stream through positively charged media, thereby removing biofoulants, bacteria and viruses from said feed stream, wherein the step of filtering the feed stream through an ultrafiltration membrane is conducted prior to the step of filtering the feed stream through the positively-charged media; and removing salt from the feed stream by reverse osmosis, wherein the reverse osmosis is conducted at an operating flux, wherein the operating flux results in an energy consumption, and wherein conducting the reverse osmosis at a flux lower than the operating flux does not reduce the energy consumption by more than 10%; and cleaning at least one reverse osmosis membrane used in removing salt from the feed stream by reverse osmosis, comprising, for a reverse osmosis membrane having a feed side and a permeate side: maintaining a concentration differential by adding reverse osmosis concentrate to the feed side of the reverse osmosis membrane, thereby allowing the reverse osmosis concentrate to remain in the feed side and causing a flow of a permeate water from the permeate side to the feed side due to the concentration differential.