The gas−liquid mass transfer coefficient is a key parameter to the design and operation of biotrickling filters that governs the transport rate of contaminants and oxygen from the gas phase to the liquid phase, where pollutant biodegradation occurs. Mass transfer coefficients are typically estimated via experimental procedures to produce empirical correlations, which are only valid for the bioreactor configuration and range of operational conditions under investigation. In this work, a new method for the estimation of the gas−liquid mass transfer coefficient in biotrickling filters is presented. This novel methodology couples a realistic description of the packing media (polyurethane foam without a biofilm) obtained using microtomography with computational fluid dynamics. The two-dimensional analysis reported in this study allowed capturing the mechanisms of the complex processes involved in the creeping porous air and water flow in the presence of capillary effects in biotrickling filters. Model predictions matched the experimental mass transfer coefficients (±30%) under a wide range of operational conditions.
Bibliographical noteFunding Information:
The present work has been sponsored by the CONICYT—Chile (National Commission for Scientific and Technological Research) project Fondecyt 1190521. The financial support from the Regional Government of Castilla y León is also gratefully acknowledged (UIC71 and CLU-2017-09). J.D. thankfully acknowledges funding from projects Fondecyt 1180685, CONICYT Basal FB0008, and from Fondo de Ayuda a la Investigacion (FAI), Universidad de los Andes, INV-IN-2017-05.
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