Method for regenerating anion exchange resins in bicarbonate form

Process for regenerating to a bicarbonate form, a charged ion exchange resin which is present in aqueous suspension and used for the removal of strong acid ions from water, and which after regeneration is separated from an effluent formed during the regeneration and reused, the regeneration being conducted by contacting the charged resin with an aqueous treating medium which forms an aqueous suspension with the resin, comprising:

• (a) providing in the aqueous suspension a quantity of calcium carbonate in excess of that which is necessary to maintain solid calcium carbonate in the resin suspension during the entire period of the regeneration, with the pH of the resin suspension during the regeneration being at about 5 to about 7;
• and
• (b) simultaneously introducing into the aqueous suspension carbon dioxide, with the partial pressure of the carbon dioxide above the resin suspension being maintained at between about 5.times.10.sup.-3 MPa and about 1.0 MPa, during the period of the regeneration, wherein the concentration of bicarbonate ion in the resin suspension is kept constant during the entire period of the regeneration.