NITRATE REMOVAL USING ION-EXCHANGE RESIN - EFFICIENCY OF POTASSIUM-CHLORIDE REGENERATION

Increasing nitrate concentration in public water supplies required the use of specific treatments. In most cases, denitratation by ion excha nge resin is prefered to biological processes. The main disadvantage o f this process is the production of highly saline regeneration eluates ([Na+]=13-15 g.l-1, [Cl-]=13-15 g.l-1, [NO3-]=10-15 g.l-1, [SO42-]=4- 8 g.l-1) which are generally discharged in rivers or in wastewater net works. Resin regeneration by potassium chloride instead of sodium chlo ride could allow the use of this eluates in agriculture. Experiments h ave been carried out on two strong base anion exchange resins (IMAC HP 555 and IMAC HP 441 from ROHM & HAAS) exhausted with water rich in ni trate or in nitrate and sulphate. Results show that KCl regeneration l eads to higher nitrate capacities than NaCl regeneration. Efficacity s eems to be the same for sulphate removal.