Patent ID: 9707517
Date: 2017-07-18
CPC Classifications: B01D,C02F,Y02A

Claim:
1. An electrodialysis device comprising a) a vessel b) a cathode and an anode in said vessel in operative association with a source of direct current; c) a first feed path; d) a second feed path; e) a feed inlet providing an aqueous feed stream flow from an upstream direction to a downstream direction through both said first feed path and said second flow path, said feedstream comprising anionic scale imparting species (ASIS) present in a first (ASIS) concentration, cationic scale imparting species (CSIS) present in a first (CSIS) concentration, anionic non scale imparting species (ANSIS) and cationic non scale imparting species (CNSIS); f) a first membrane group separating said first feed path and said second feed path, said first membrane group comprising at least two elements i) and ii); wherein: i) is an anion selective membrane permitting transfer of (ASIS) from said first feed path to said second feed path, ii) is a cation selective membrane permitting transfer of (CSIS) from said second feed path to said first feed path; g) a second membrane in fluid communication with said second feed path, said second membrane permitting passage of (ANSIS) therethrough and out of said second feed path; h) a third membrane in fluid communication with said first feed path, said third membrane permitting passage of (CNSIS) therethrough and out of said first feed path; i) a first feed path outlet downstream from said first feed path adapted to carry a first effluent therein having a reduced (ASIS) concentration compared with said first (ASIS) concentration; j) a second feed path outlet downstream from said second feed path adapted to carry a second effluent therein having a reduced (CSIS) concentration compared to said first (CSIS) concentration.