TITLE: Phenol Degradation in a Three-Phase Fluidized-Bed Bioreactor.

AUTHOR: A. D. Richards;   A. M. Fricke;   J. E. Scott.

INST.  AUTHOR: Massachusetts Inst. of Tech., Oak Ridge, TN. School of Chemical Engineering Practice.

SPONSOR: Department of Energy, Washington, DC.


PUB.  TYPE: Technical Report

PUB.  COUNTRY: United States

SOURCE: Department of Energy [DE],  Jun 83,  61p.


The operation of a three-phase fluidized-bed bioreactor for removing phenol from wastewater was studied. The reactor system consisted of a bacterial population (predominantly pseudomonads) attached to inert coal particles, which was fluidized by a stream of simulated wastewater containing approximately 0.1 g/L phenol. Oxygen was bubbled through the reactor to support the aerobic bacteria. The kinetics of phenol degradation by the attached organisms was investigated in batch shake-flask experiments. The rate of phenol degradation showed a first-order dependence on phenol concentration at high-oxygen concentrations (P/sub O sub 2 / = 1 atm) and a zero-order dependence on phenol at low-oxygen concentrations (P/sub O sub 2 / less than or equal to 0.2 atm). The kinetic data were well-described by a competitive inhibition model. The reactor was modeled as well-mixed with gas-liquid interfacial mass-transfer limitations. The model predicted an optimal value for the mass-transfer coefficient, above which oxygen inhibition reduces performance and below which mass-transfer limitations occur. Comparison of reactor operating data with model predictions showed that the liquid phase of the reactor was well-mixed and that the reaction rate was limited by the mass transfer of oxygen from the gaseous to the liquid phase. The mass-transfer component should be increased for more efficient reactor operation. (ERA citation 08:033058)