Ammonia removal from compost leachate using zeolite. III. Regeneration of zeolite columns

The effects of hydraulic reteneration time (HRT), and the strength of the r egenerating solution on the ammonia adsorption capacity and the zeolite reg eneration were studied using bench-scale packed zeolite columns. A 0.6 M Na Cl solution fed at a HRT of 1 h was preferred for the regeneration process, and more than 95% of adsorbed ammonium ions were recovered after using 7-8 bed volumes (BV) of the regenerating solution. The adsorption-regeneration time ratio was approximately 5:1. High concentration of potassium ions in the composting leachate competed with NH4+ ions for the exchange sites, res ulting in a reduction in the efficiencies of ammonia removal and zeolite co lumn regeneration. However, Zeolite still proved to have a great potential as a medium for ammonia removal in treating composting leachate.