External mass transfer analysis for simultaneous removal of carbohydrate and protein by immobilized activated sludge culture in a packed bed batch bioreactor

Abstract

External mass transfer effects were analyzed for removal of carbohydrate and protein by immobilized activated sludge culture in a packed bed bioreactor. The bioreactor was made from 52cm glass tubing with 5.0cm inner diameter (with a total volume of 1020cm3). The microbial culture was immobilized on microporus polyurethane cut into cubic pieces of approximately 1.5cm in length. The effect of flow rate on mass transfer and removal of carbohydrate and protein were analyzed theoretically and compared with experimental data. The rate constants were estimated using external film diffusion models at different flow rates (900, 1200, 1800cm3h−1). Based on the experimental data, correlations between the Colburn factor (JD) and Reynolds number (Re) as JD=5.7×Re−0.90 and JD=5.7×Re−0.18 were found to be adequate to predict the removal of carbohydrate and protein, respectively.