A packed‐column bioreactor for phenol degradation: Model and experimental verification

Abstract

AbstractPseudomonas putida (ATCC 17484) has been grown in a pure culture, slime layer inside a continuous packed‐column bioreactor. The bioreactor has been characterized in terms of liquid holdup, dispersion, air stripping, fixed biomass concentration, and degradation rate capabilities. The experimental data has been used to develop a predictive model using mechanistic equations for the operation of packed columns and the biokinetics of pure culture phenol degradation.The liquid holdup, dispersion and liquid‐to‐air mass transfer coefficients were found to be correlated by power law equations commonly used for packed column absorption and stripping equipment. The microorganisms developed a uniform slime layer over the 3‐mm diameter glass spheres, measured to be 200 μm thick. Phenol inlet concentrations of 500 ppm were degraded 100% and at rates up to 1.2 × 10−3 kg m−3 s−1. These results compare favorably with the best biodegradation results reported elsewhere in the literature for other bioreactor designs. The packed‐column bioreactor has the advantages of no moving parts and the need for minimum aeration (air fluxes less than 0.001 ms−1), thereby reducing volatile stripping losses.A computer model of the bioreactor was found to predict accurately the experimental trend in biodegradation capacities and rates with liquid flux. It is shown to be a useful model for studying design parameter changes or for determining scale‐up characteristics due to its simplicity and mechanistic basis.