Shear Loss Characteristics of an Aerobic Biofilm

Growth and shear loss characteristics of phenol utilizing biofilm were studied in a concentric cylinder bioreactor. The net accumulation of the biofilm and the substrate utilisation were measured as a function of torque. Uniform biofilms were obtained up to a thickness of around 300 microns, beyond which the surface growth was non-uniform. The substrate utilisation rate, however, reached a constant value beyond film thickness of 50 to 100 microns depending on the operational torque. The maximum phenol removal rate was achieved at a shear stress of 3.5 Nm^-2. The effect of shear stress on net growth rate was found to be described byand a zero net growth was obtained at a shear stress of 18.7 Nm^-2.