The paper describes the results of an investigation conducted for the purpose of exploring the possibility of using a natural zeolite, occurring in central-northern Sardinia, for removing the ammonium ions contained in effluents discharged from wastewater treatment plants. Laboratory tests have been carried out on samples of wastewater effluents from a treatment facility in different sized columns containing appropriately ground zeolitic material, either untreated or in the Na-exchanged form. The results demonstrate the efficacy of the zeolite tested, especially in its Na-exchanged form, in removing the ammonium cation and the possibility of employing this mineral in municipal and industrial wastewater treatment processes.