Investigation of External Mass Transfer during Biodegradation of Congo Red Dye in a Recirculating Packed Bed Bioreactor

摘要

A quantitative investigation of the effect of external mass transfer on the overall rate of biodeg-radation of Congo Red dye in a recirculating packed bed bioreactor(RPBB)was performed.The isolated Bacillus subtilis MN372379 species was immobilized on the packing material made of low-density polyeth-ylene(LDPE)foam cubes in the RPBB.The overall dye removal rates were measured at varied recirculat-ing flow conditions and an empirical correlation for the external mass transfer coefficient was determined.The observed rate of removal of Congo Red dye in the RPBB was found to be increasing with the recir-culation rate.An empirical correlation to predict the non-dimensional Colburn factor was obtained as J_D=1.34 Re~(-0.3).The dimensionless correlation for mass transfer coefficient would enable the design and scale-up of an RPBB with minimal impact of exter-nal mass transfer resistance on the overall rate of dye bio-degradation.