A Model for the Biofiltration of Butyl Acetate and Xylene Mixtures by a Trickle-Bed Air Biofilter

摘要

A mathematical model that incorporates the rates of the mass transfer process and the biofilm reaction is presented to predict the performance of a trickle-bed air biofilter (TBAB) for treating butyl acetate and xylene mixtures. A thorough understanding of the factors that influence these rates is necessary before the practical application of a TBAB for treating many kinds of pure and mixed volatile organic compounds (VOC) in the air stream. The model presented consists of a set of mass balance equations for butyl acetate, xylene and oxygen in the bulk gas phase and within the biofilm. The butyl acetate and xylene concentration profiles of the gas phase predicted by the model were in good agreement with the measured data documented in a previous study. The most relevant parameters were evaluated in a sensitivity analysis to determine their respective effects on the model performance. Four parameters were identified to strongly influence the model performance, the surface area of the biofilm per volume unit of the packing material (A_s), the empty-bed residence time (EBRT), the maximum specific growth rate of the microorganism (mu_m), and the microbial yield coefficient (Y). The practical application of the model to derive the performance equationis also presented and discussed. This equation makes it possible to simultaneously obtain a relatively high VOC removal efficiency and to minimize the capital cost.