Study of biofilm and fluidization of bioparticles in a three-phase liquid-fluidized-bed reactor

A three-phase, liquid-fluidized-bed biofilm reactor was operated over wide ranges of liquid velocity, air velocity, medium concentration, and substrate surface loading. The biofilm characteristics (total colonization, polysaccharide content, density, and thickness) and the specific detachment coefficient (b(s)) were determined by a combination of experimental measurements and a hydrodynamic model. The results demonstrated that dense and thin biofilms were induced by the physical condition of high particle-to-particle contacts and high liquid turbulence. The biofilm's polysaccharide content was increased by increased air turbulence and a low substrate availability. The specific detachment coefficient, b(s), was strongly correlated to the concentration of the medium (negatively) and the polysaccharide content (positively). Overall, the b(s) can be controlled significantly by the gas and liquid velocities; increasing either velocity tends to increase b(s).