Recycling of the Exhausted Cation Exchange Resin for Stabilized Landfill Leachate Treatment

Ion exchange is a reversible process. Thus, once the media becomes exhausted, it can be regenerated and the resin is returned to its original ionic form for reuse. Regeneration involves pollutants desorption from the media using processes that drive the pollutants from the media without destroying it. In previous studies, cation exchange resin was used for mature municipal landfill leachate treatment, particularly for ammoniacal-nitrogen (NH3-N) removal. The effectiveness of the media in NH3-N removal was promising. However, the most important disadvantage of cation resins was their high cost. Furthermore, storage or dumping of the exhausted media will significantly increase the related cost. Thus, the exhausted media regeneration is economically essential. In the present study, the experiments resolved the effects of several solvents (i.e. sulfuric acid (H2SO4), sodium chloride (NaCl) and distilled water) on the recovery efficiency of cationic resin, optimum concentration of the regenerant, optimum regeneration contact time, regenerant regeneration capacity and the maximum losses of resin after regeneration. The results indicated that cation exchange resin can be reused for several times with good recovery efficiency. After 5 times reuse, the cation exchanger regenerated via 0.5N H2SO4 at 15min contact time achieved about 83.4% recovery efficiency for NH3-N from landfill leachate.