Patent ID: 8119005

Claim:
A method for partial desalination of a concentrated salt solution to obtain a diluted salt solution, comprising the steps of: (a) providing at least one desalination unit, including: a central chamber compartment having opposedly disposed first and second sides, and a bottom extending between said first and second sides, a first chamber compartment located at said first side of said central chamber compartment, a second chamber compartment located at said second side of said central chamber compartment, and a system of membranes including a first membrane installed between said central and first chamber compartments, and a second membrane installed between said central and second chamber compartments, wherein said first membrane is permeable substantially to water and salt, and wherein said second membrane is permeable substantially exclusively to water; (b) placing a charged substance in said central chamber compartment; (c) filling said central, first and second chamber compartments with a concentrated salt solution (SS) to be desalinated, wherein a salt solution containing said charged substance is formed in said central chamber compartment; (d) opening said first membrane between said first and central chamber compartments, thereby creating fluid exchange between said chamber concentrated SS in said first compartment and said salt solution containing said charged substance in said central chamber compartment; (e) closing said first membrane between said first and central chamber compartments upon reaching ionic and pressure equilibrium between said concentrated SS and said salt solution containing said charged substance; (f) opening said second membrane between said second and central chamber compartments, thereby permitting water absorption into said central chamber compartment from said concentrated SS in said second chamber compartment, thereby diluting said salt solution containing said charged substance in said central chamber compartment, and thereby obtaining a diluted SS therein; (g) closing said second membrane; and (h) discharging said diluted SS from said central chamber compartment through said bottom thereof.