Removal of toluene vapour from air stream using a biofilter packed with polyurethane foam

Abstract

Biodegradation of toluene vapour was investigated for 168 days in a polyurethane packed biofilter inoculated with a mixed microbial population. Biofilter consisted of five square cross-section modular units each of size 0.16 m × 0.16 m × 0.20 m and filled with the polyurethane foam cubes up to a height of 0.15 m. Inlet concentration of toluene was varied from 0.04 to 2.5 g m-3 and the volumetric flow rate of toluene loaded air from 0.06 to 0.90 m3 h-1. Depending upon initial loading rates, removal efficiency ranging from 68.2 to 99.9% and elimination capacity ranging from 10.85 to 90.48 g h-1 m-3 were observed during steady state operations. More than 90% removal efficiency was observed up to an inlet loading rate of 76.3 g h-1 m-3. High carbon recovery (>90%) indicated effective biodegradation in the bed. Low variation of pH (7.2-8.8) and pressure drop (45.8-76.3 Pa) was observed. The stability of the biomass was evident from the fast response of the biofilter to shutdown and restartup. © 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.