Evaluation of adsorption and desorption characteristics and economic viability of ammonium recovery using natural zeolite clinoptilolite from treated municipal wastewater

ABSTRACT A flow diagram of the wastewater treatment process incorporating the ammonium recovery system proposed in this study. Effluent treated by the conventional activated sludge process is first treated by a drum filter and then passes through a column packed with clinoptilolite. The ammonium ions adsorbed in the column are used to produce ammonium sulfate via a hollow fiber membrane contactor. Promoting a circular economy and mitigating global warming have become urgent priorities in the wastewater treatment sector. A system utilizing natural zeolite clinoptilolite (NZC) to recover ammonium from municipal wastewater and produce ammonium sulfate via a hollow fiber membrane contactor presents a promising alternative to conventional chemical fertilizers. To support the development of this system, the adsorption and desorption characteristics of NZC were investigated, and its potential for greenhouse gas reduction and economic viability were assessed. The results revealed that NZC exhibits high robustness, maintaining stable adsorption performance even after repeated use. Under a scenario in which NZC is reused more than 34 times without degradation, a potential for reducing greenhouse gas emissions was demonstrated. However, operational costs were found to exceed current levels, primarily due to the high procurement cost of NZC and increased capital expenditures. These factors represent critical challenges that must be addressed for future large-scale implementation.