THE EFFECT OF AIR SUPERFICIAL VELOCITY ON BIOFILM ACCUMULATION IN A 3-PHASE FLUIDIZED-BED REACTOR

The aim of this investigation was to evaluate the effect of air superf icial velocity (U-G) on biofilm growth in an aerobic three-phase fluid ized-bed reactor. Spherical shape polymer particles (2.7 mm diameter a nd density of 1180 kg . m(-3)) were used as support material. The reac tor influent was a synthetic wastewater, mainly composed of glucose, g lycerine and meat extract (COD of about 180 mg . l(-1)) and reactor op eration was carried out at an organic load of about 8 kg COD . m(-3). d(-1). The results indicate that biofilm accumulation decreases when g as superficial velocity increases in the range of 0-20 m . h(-1). Howe ver, COD removal efficiencies were practically independent of U-G, whe reas biofilm characteristics were significantly affected by air superf icial velocity.