title: Transient Performance of Biofilters Treating Mixtures of Hydrophilic and Hydrophobic Volatile Organic Compounds.
abstract: The biological degradation of hydrophilic and hydrophobic volatile organic compounds (VOCs), discharged in pulp and paper and wood products air emissions, was examined under transient operating conditions. Two identical bench-scale biofilters were operated in parallel in order to study the influence of step loads on the removal of a-pinene, a hydrophobic VOC, and methanol, a hydrophilic VOC. The biofilter media consisted of a mixture of wood chips and spent mushroom compost that was further mixed with either perlite or small-size wood chips. The biofilters provided complete methanol removals during the start-up period due to the absorption process followed by biodegradation. For a-pinene, however, there was an acclimation period of 1 week to 10 days before the biofilters achieved 100% a -pinene removal efficiency. Step changes in the methanol loading rate did not affect the performance of the biofilters with respect to methanol. However, these fluctuations significantly influenced a-pinene biodegradation provided enough time (i.e., several days) was allowed. The removal rate of a-pinene gradually decreased along the column after each step increase in methanol inlet concentration. It appears that the presence of high concentrations of metha-nol, a hydrophilic and easily biodegradable compound, adversely impacted the growth of the a-pinene degrading microbial community, thereby decreasing a-pinene removal capacity of the biofilters over time. Unlike a-pinene, the methanol biodegradation rate was not affected by the presence or absence of a-pinene and with a-pinene fluctuations in the inlet airstream.
authors.affiliation: a Department of Chemical Engineering and Applied Chemistry , University of Toronto , Toronto , Ontario , Canada.
authors.forename: Madjid
authors.initials: M
authors.lastname: Mohseni
authors.affiliation: a Department of Chemical Engineering and Applied Chemistry , University of Toronto , Toronto , Ontario , Canada.
authors.forename: D Grant
authors.initials: DG
authors.lastname: Allen