Pilot-scale tests were carried out for nitrogen removal from ammonium plant effl uent using gel carriers on which anaerobic ammonium oxidation (anammox) sludge was immobilized. The nitrogen removal system was equipped with an anammox vessel of 5 m 3 volume and the pretreatment processes were carried out for continuous feeding tests. The nitrogen removal in the anammox vessel could be started up within approximately 2 months of acclimation using ammonia synthetic plant effl uent (ammonia

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... er) at 30°C. After that, stable nitrogen removal in the anammox vessel was confi rmed at 16.1°C even though the infl uent was changed to another kind of wastewater based on urea. Moreover, nitrogen removal in the anammox vessel reached the designated denitrifi cation rate within 3 days at 30°C after infl uent wastewater was returned to the original ammonia wastewater. Finally, the anammox vessel was operated using the ammonia wastewater at a low water temperature. The nitrogen conversion rate was stably observed 1.9 kg-N·m 3 ·d -1 at 17.1°C. These results strongly suggest that this nitrogen removal system using anammox gel carrier can be applied to nitrogen removal from industrial effl uent under low water temperature.