Patent ID: 7273555

Claim:
A process for continuous countercurrent ion exchange comprising: a. piping a contaminated feed stream into a closed loop cation exchange contactor, the contactor comprising an ion exchange resin bed, the contactor further comprising three or more reaction segments, the segments comprising at least an adsorption segment, a regeneration segment and a pulse segment, each segment separated from the other segments by one or more valves; b. moving a resin regeneration stream through the resin bed within the loop contactor in one direction, adding acid to the resin bed in the regeneration segment, regenerating the hydrogen ion content of the resin by contacting the resin with the acid; c. recycling a portion of the resin regenerative stream comprising excess unused acid back into the contactor to concentrate the resulting end product spent brine and use the excess acid as a resin bed regenerant, the step of recycling comprising mixing regeneration acid with acid dilution water and combining the resulting mixture with the spent brine; d. simultaneously moving the feed stream through the contactor in same direction as the regeneration stream, piping the contaminated feed stream through the adsorption segment, treating the feed stream by flowing the stream through the resin bed and piping the treated feed stream out of the contactor; e. stopping the flowing of the feed stream and the regeneration stream and advancing the regenerated resin bed by activating the pulse segment; f. resuming the flow of the feed stream and regeneration stream after the resin has stopped advancing.