The effect of air superficial velocity on biofilm accumulation in a three-phase fluidized-bed reactor

The aim of this investigation was to evaluate the effect of air superficial velocity (UG) on biofilm growth in an aerobic three-phase fluidized-bed reactor. Spherical shape polymer particles (2.7 mm diameter and density of 1180 kg•m−3) were used as support material. The reactor influent was a synthetic wastewater, mainly composed of glucose, glycerine and meat extract (COD of about 180 mg•l−1) and reactor operation was carried out at an organic load of about 8 kg COD•m−3•d−1. The results indicate that biofilm accumulation decreases when gas superficial velocity increases in the range of 0–20 m•h−1. However, COD removal efficiencies were practically independent of UG, whereas biofilm characteristics were significantly affected by air superficial velocity.