Mathematical modeling of the biofiltration of ethyl acetate and toluene and their mixture

A dynamic model for ethyl acetate and toluene removal by biofiltration is presented. Haldane-type kinetic expressions that include the oxygen limitation. the inhibition effect due to high concentration of substrate, and the cross-inhibition between substrates have been considered. A decrease in the biomass density with the bed height was proposed to represent the performance of peat biofllters over a broad range of operating conditions. Experimental yield coefficients have been derived from the experimental CO(2) production data. The unknown kinetic parameters of the model along with the coefficient for axial biomass density distribution were calibrated using experimental data from two peat biofilters treating ethyl acetate and toluene as single pollutants. The biofilters were operated during 2 years, operating in the empty bed residence time range between 22 and 90s and in the inlet load range between 20 and 200 gm(-3) h(-1). Good agreement between the gaseous concentration profiles and the predicted profiles was found in almost all cases. The model was adequately validated by simulation of the removal of a 1:1 (w/w) ethyl acetate/toluene mixture in a peat biofilter operating under similar operating conditions than in the single pollutant biofiltration. The model proposed herein can be used for design purposes. (C) 2008 Elsevier B.V. All rights reserved.