Biofiltration of toluene in the absence and the presence of ethyl acetate under continuous and intermittent loading |
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Authors: | F Javier Álvarez‐Hornos Carmen Gabaldón Vicente Martínez‐Soria Paula Marzal Josep‐Manuel Penya‐roja |
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Affiliation: | Department of Chemical Engineering, University of Valencia. Dr. Moliner, 50, 46100 Burjassot, Spain |
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Abstract: | BACKGROUND: Two peat biofilters were used for the removal of toluene from air for one year. One biofilter was fed with pure toluene and the other received 1:1 (by weight) ethyl acetate:toluene mixture. RESULTS: The biofilters were operated under continuous loading: the toluene inlet load (IL) at which 80% removal occurred was 116 g m?3 h?1 at 57 s gas residence time. Maximum elimination capacity of 360 g m?3 h?1 was obtained at an IL of 745 g m?3 h?1. The elimination of toluene was inhibited by the presence of ethyl acetate. Intermittent loading, with pollutants supplied for 16 h/day, 5 days/week, did not significantly affect the removal efficiency (RE). Biomass was fully activated in 2 h after night closures, but 6 h were required to recover RE after weekend closures. Live cell density remained relatively constant over the operational period, while the dead cell fraction increased. Finally, a 15 day starvation period was applied and operation then re‐started. Performance was restored with similar re‐acclimatization period to that after weekend closures, and a reduction in dead cell fraction was observed. CONCLUSION: This study demonstrates the capacity of the system to handle intermittent loading conditions that are common in industrial practices, including long‐term starvation. Copyright © 2008 Society of Chemical Industry |
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Keywords: | biofiltration toluene carbon dioxide production living and dead cells transient loads starvation |
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