Patent ID: 9339765
Filing Date: 2016-05-17
CPC Classification: B01D,C02F,Y02A

Claim Text:
1. A method of reducing scale imparting ion content of a desalination unit (DSU) feed stream comprising: a) passing a direct current through a pair of electrodes in an electrolysis device (ED) so as to energize said pair of electrodes as a cathode and an anode respectively; b) feeding an aqueous stream to said ED, said aqueous stream having an anionic scale imparting species (ASIS), an anionic non-scale imparting species (ANSIS), a cationic scale imparting species (CSIS), and a cationic non scale imparting species (CNSIS) therein, said ASIS being present in a first ASIS concentration and said CSIS being present in a first CSIS concentration; c) contacting said aqueous stream in said ED along a first feed path and along a second feed path separated by a first membrane group, said second feed path also being in fluid communication with a second membrane, and said first feed path also being in fluid communication with a third membrane group, said first membrane group permitting transfer of ASIS from the first feed path to the second feed path and permitting transfer of CSIS from the second feed path to the first feed path, said second membrane permitting passage of ANSIS therethrough and out of said second feed path, said third membrane permitting passage of CNSIS therethrough and out of said first feed path, whereby after passage of said aqueous stream through said first feed path a first effluent is provided and after passage of said aqueous stream through said second feed path a second effluent is provided, wherein said first effluent has a reduced ASIS concentration compared to said first ASIS concentration and said second effluent has a reduced CSIS concentration compared to said first CSIS concentration; and d) feeding either or both of said first and second effluents to said DSU as said DSU feed stream, with the proviso that when both said first and second effluents are fed to said DSU, they are fed separately and are not mixed.