Electrochemically regenerated water deionization

A method of abating scale formation in an electrodeionization apparatus comprising at least one deionization cell interposed between a cathode chamber and an anode chamber, said method comprising:

• a) introducing ion containing feed water into said deionization cell and removing ions from said water therein;
• b) forming a concentrate stream comprising ions removed from said feed water by said deionization cell;
• c) treating at least a portion of said concentrate stream remotely of said deionization cell and cathode chamber to precipitate and remove scale forming ions from said concentrate stream remotely of said cell and cathode chamber;
• and,
• d) forming an acidified concentrate remotely of said deionization cell and said cathode chamber;
• and,
• e) introducing at least a portion of said acidified concentrate to said electrodeionization apparatus and contacting it with scale prone surfaces therein.

A water treatment apparatus comprising:

• a) an electrodeionization unit comprising;
• i) a cation exchange chamber containing a cation exchange media;
• ii) an anion exchange chamber containing an anion exchange media;
• iii) a bipolar interface separating said cation exchange chamber and said anion exchange chamber;
• iv) a cathode chamber located on a side of said cation exchange chamber opposite said bipolar interface, and containing at least one electrode operative at least as a cathode;
• v) an anode chamber located on a side of said anion exchange chamber opposite said bipolar interface, and containing at least one electrode operative at least as an anode;
• vi) a concentrate chamber interposed between said anode chamber and said anion exchange chamber;
• and,
• vii) a concentrate stream flow path coupled to said cathode chamber and said concentrate chamber;
• and,
• b) a concentrate conditioning unit coupled to said concentrate stream flow path for receiving a concentrate stream produced by said electrodeionization unit comprising;
• i) a scale precipitation chamber in fluid communication with at least a portion of said concentrate stream and containing at least one electrode operative at least as a cathode;
• ii) an acidification chamber adjacent said scale precipitation chamber and separated therefrom by a cation exchange membrane, said acidification chamber having an inlet coupled to a concentrate stream source and an outlet coupled to an acidified concentrate stream flow path;
• and,
• iii) an anode chamber adjacent said acidification chamber opposite said scale precipitation chamber and containing at least one electrode operative at least as an anode;
• whereby, upon activation of said electrodes, scale forming ions present in a concentrate stream passing through said scale precipitation chamber are precipitated therein.

A water treatment apparatus comprising:

• a) an electrodeionization unit comprising:
• i) at least one ion exchange chamber containing an ion exchange media;
• ii) a cathode chamber located on one side of said at least one ion exchange chamber and containing at least one electrode operative at least as a cathode;
• iii) an anode chamber located on a side of said at least one ion exchange chamber opposite said cathode chamber and containing at least one electrode operative at least as an anode;
• iv) at least one concentrate chamber adapted to receive ions removed from a feed water source in said ion exchange chamber;
• and,
• v) a concentrate stream flow path coupled to said electrodeionization unit for receiving a concentrate stream produced therein;
• and,
• b) a concentrate conditioning unit coupled to said concentrate stream flow path for receiving a concentrate stream produced by said electrodeionization unit comprising;
• i) a scale precipitation chamber in fluid communication with at least a portion of said concentrate stream and containing at least one electrode operative at least as a cathode;
• ii) an acidification chamber adjacent said scale precipitation chamber and separated therefrom by a cation exchange membrane, said acidification chamber having an inlet coupled to a concentrate stream source and an outlet coupled to an acidified concentrate stream flow path;
• and,
• iii) an anode chamber adjacent said acidification chamber opposite said scale precipitation chamber and containing at least one electrode operative at least as an anode;
• whereby, upon activation of said electrodes, scale forming ions present in a concentrate stream passing through said scale precipitation chamber are precipitated therein.