Patent ID: 9090491
Filing Date: 2015-07-28
Classification: B01D,C02F,Y02A

Abstract:
1. A method of removing boron from saline water, comprising the steps of: providing a saline water pretreatment stage having a nano-filtration (NF) membrane assembly; feeding a first amount of seawater having a given boron concentration to the NF membrane assembly at a predetermined pressure and flow rate; increasing the pH of the fed seawater from natural seawater pH to a pH value ranging between 8.5 and 10 in order to alkalize the NF membrane assembly; passing the saline water through the NF membrane assembly to produce NF permeate having a boron concentration less than about 0.4 mg/l; feeding the NF permeate for further processing at a predetermined recovery ratio, the NF permeate having a pH ranging from 8.5 to 10; providing a second treatment stage having a reverse osmosis (RO) membrane assembly; feeding the NF permeate to the RO membrane assembly at a predetermined pressure and flow rate; passing the NF permeate through the RO membrane assembly to produce desalinated water having a boron concentration less than about 0.2 mg/l; feeding a second amount of seawater to another RO membrane assembly at a predetermined pressure and flow rate to produce RO permeate having a boron concentration of about 1 mg/L; blending the desalinated water having a boron concentration less than about 0.2 mg/L with the RO permeate having a boron concentration of about 1 mg/L to produce desalinated water having a boron concentration less than about 0.4 mg/L.