Nitrification process performance was evaluated using a three-phase fluidized-bed bioreactor. A synthetic effluent was used for this experiment containing 180-230 mg/L of chemical oxygen demand (COD), 25-30 mg/L. of N-NH4+, 12 to 13 mg/L of total phosphorous, and micronutrients. The bioreactor used for denitrification behaved as completely mixed. The results indicate that the nitrification process was efficient, reaching efficiencies of about 98%. The best results related to the efficiency of the denitrification process were obtained when the processes were supplemented with the carbon source. The results indicated an efficiency of 86-98% COD removal.