Removal of 2-butoxyethanol gaseous emissions by biotrickling filtration packed with polyurethane foam

•The biotrickling filtration was successfully applied for 2-butoxyethanol removal.•Two inoculation procedures were used: pure culture and activated sludge.•Pseudomonas species appeared in the reactor despite not being detected in inoculum. The removal of 2-butoxyethanol from gaseous emissions was studied using two biotrickling filters (BTF1 and BTF2) packed with polyurethane foam. Two different inoculum sources were used: a pure culture of Pseudomonas sp. BOE200 (BTF1) and activated sludge from a municipal wastewater treatment plant (BTF2). The bioreactors were operated at inlet loads (ILs) of 130 and 195gm−3hour−1 and at an empty bed residence time (EBRT) of 12.5s. Under an IL of ∼130gm−3hour−1, BTF1 presented higher elimination capacities (ECs) than BTF2, with average values of 106±7 and 68±8gm−3hour−1, respectively. However, differences in ECs between BTFs were decreased by reducing the irrigation intervals from 1min every 12min to 1min every 2hours in BTF2. Average values of EC were 111±25 and 90±7gm−3hour−1 for BTF1 and BTF2, respectively, when working at an IL of ∼195gm−3hour−1. Microbial analysis revealed a significant shift in the microbial community of BTF1 inoculated with Pseudomonas sp. BOE200. At the end of the experiment, the species Microbacterium sp., Chryseobacterium sp., Acinetobacter sp., Pseudomonas sp. and Mycobacterium sp. were detected. In BTF2 inoculated with activated sludge, the denaturing gradient gel electrophoresis (DGGE) technique showed a diverse microbial community including species that was able to use 2-butoxyethanol as its carbon source, such as Pseudomonas aeruginosa and Pseudomonas putida as representative species. Although BTF1 inoculated with Pseudomonas sp. BOE200 and higher gas velocity (probably greater gas/liquid mass transfer rate) showed a slight improvement in performance, the use of activated sludge as inoculum seems to be a more feasible option for the industrial application of this technology.