1993 Volume 19 Issue 6 Pages 1179-1183
In dialysis wastewater treatment by a fluidized-bed bioreactor using polyurethane cubes as support particles, substrate consumption and microbial growth processes were investigated, focussing on the earlier stage of the process. Retained microbes were found to initiate growth inside the particles after sticking from water phase and to form biofilms after experiencing decay and falling-off. The mass increases very quickly and reaches a steady value in an unexpectedly short time. Following the growth of retained microbes, the mass of suspended microbes also reaches a steady value relatively quickly, recovering from a minimum caused by entrapment by the support particles. These prosesses were shown to be explained well by mass balance equations with the Monod kinetic equation by introducing new terms for sticking and falling-off processes. Rate coefficients are determined for various influent conditions.
