Paper mill sludge (PMS) was utilized to prepare granular activated carbon (GAC) fillers for fluidized-bed bioreactor (FBBR) through stream activation. The properties of the PMS were tested and the optimum conditions for the production process were determined. Then, the GAC fillers were used in the FBBR to investigate the capacity for wastewater treatment. The results showed that the optimal conditions were: carbonization temperature of 450 degrees C, carbonization time of 50 min, activation temperature of 800 degrees C and activation time of 60 min. The specific surface area of the GAC fillers was 130 m2/g and the grain density was 1.34 x 10(3) kg/m3. The wastewater treatment results showed that after40 days ofrunning, under the conditions of influent COD of 800 mg/L and HRT of2 h, the COD removal efficiency was about 90%, which demonstrated that PMS-based GAC fillers were feasible for FBBR.