Modelling of a biofiltration process of volatile organic compound mixtures in a biofilter

Currently, different methods for air clean-up from chemical pollutants are applied worldwide: adsorption, absorption, and thermal and catalytic oxidation. One of the most promising methods is biological air cleaning. The aim of this study was to test the performance of a developed biofilter with packing material of activated pine bark for biological air cleaning and to mathematically model the biofiltration processes. Comparative analysis of the modelling results for individual pollutants (butyl acetate, butanol and xylene) showed strongest dependence of the efficiency of xylene removal from the air on the amount and ratio of other substances (from 20% to 70%). Thus, the process of removal of pollutants (butanol and butyl acetate) that are easier to biologically decompose was obtained to be influenced to a lesser extent by the amount and ratio (%) of other components. The results also showed that the efficiency of butyl acetate removal mostly depended on the ratio of other substances in the mixture (from 15% to 100%), whereas the efficiency of butyl acetate and xylene removal mostly depended on the amount of other substances in the mixture (from 20% to 100%). With the parameters of the biofilter (height of packing material, incoming air flow velocity) and the pollutants to be removed known, the mathematical expression of the filter efficiency was found, which would allow to make theoretical calculation and selection of the most appropriate parameters of the device as well as to achieve maximum efficiency of air cleaning.