Ion exchange of ammonium in zeolites:: A literature review

The objective of this review was to acquire knowledge concerning the ammonium ion exchange technique within the field of wastewater treatment. General concepts as well as details concerning the loading and the regeneration phases were included. Both chemical and biological regeneration processes were reviewed. Concerning ion exchangers, the study focused on different kinds of zeolites. The possibilities of employing the ion exchange technique for the recovery of nitrogen was also discussed. The study was carried out as a literature review. Conclusions from this study are that full-scale wastewater treatment plants that employ the ammonium ion exchange technique are scarce and few applications have been developed to recover ammonia nitrogen, for example, for agricultural purposes. Zeolites are somewhat heterogeneous because of natural variations of the minerals. Factors that influence the ammonium adsorption during the loading phase are well known. Biological regeneration has primarily been developed to decrease the brine consumption at regeneration or to improve the conventional nitrification-denitrification process. If the ion exchange technique is to be used to recover ammonium, both chemical and biological regeneration might be employed.