The aim of this research was to develop a zeolite carrier for wastewater treatment in a small-size sewage treatment facility. To evaluate the ion-exchange characteristic of zeolite medium, the isotherm equation of both Langmuir and Freundlich model were examined. It was found that the maximum absorption amount (qm) and adsorption strength (1/n) were about 2.94 mg NH4+-N/g and 0.3854, respectively. In order to validate the adsorption performance by applying the zeolite carrier to the in-situ field, nitrogen removal efficiency was evaluated by a retrofitted process in the small sewage treatment where carbon-nitrogen ratio was especially low in influent. By the application of this proposed method, the effluent TN concentration was in the range of 6.5-20 mg/L (average of 12.9 mg/L) which may satisfy sufficient discharge standard limit. The zeolite medium had ion-exchange capacity of 30-40% of influent NH4+-N concentration, and TN removal efficiency improved about 40% compared to the existing process. Therefore, the renovation of the carrier utilization shows the possibility of pre-treatment of NH4+-N in influent and thus improves the TN removal efficiency of wastewater treatment.