Zeolite A synthesized from coal fly ash of a thermal power plant was applied to treat ammonium in wastewater in a continuous column model. The study showed that zeolite A in the form of granules treated well NH4+ in wastewater using a continuous column treatment model with a treatment efficiency of higher than 90%. Design parameters were determined such as speed ≤ 20 m/h, material layer height ≥ 600 mm, and the inlet ammonium concentration can be up to 50 mg NH4+-N/L. The breakthrough point appeared after a 5.75 h operation with C0 = 50 mg/L, H = 600 mm, V = 5 m/h. This model can completely be applied in practice to treat ammonium, replacing the column treatment method using other types of adsorbents such as coal fly ash, and activated carbon from corncob.