title: Airborne toluene removal for minimizing occupational health exposure by means of a trickle-bed biofilter.
abstract: The paper presents the experimental results on a biotrickling pilot plant, with a water scrubber as pre-treatment, finalized to the treatment of an airborne toluene stream in a working place. The air stream was characterized by a very high variability of the inlet concentrations of toluene (range: 4.35-68.20 mg Nm(-3)) with an average concentrations of 16.41 mg Nm(-3). The pilot plant has proved its effectiveness in toluene removal, along a 90-day experimentation period, in steady-state conditions. The scrubbing pre-treatment has achieved an average removal efficiency of 69.9 %, but in particular it has proven its suitability in the rough removal of the toluene peak concentrations, allowing a great stability to the following biological process. The biotrickling stage has achieved an additional average removal efficiency of 75.6 %, confirming the good biodegradability of toluene. The biofilm observation by a scanning confocal laser microscope has evidenced a biofilm thickness of 650 μm fully penetrated by toluene degrading bacteria. Among the micro-population Pseudomonas putida resulted the dominant specie. This bacterium can therefore be considered the responsible for most of the toluene degradation. The whole experimented process has determined an average 92.7 % for toluene removal efficiency. This result meets the most stringent limits and recommendations for occupational safety, given by authoritative organizations in the USA and EU; it also meets the odorous threshold concentration of 11.1 mg Nm(-3).
authors.affiliation: School of Industrial Engineering, University LIUC-Cattaneo, Corso Matteotti 22, I-21053, Castellanza, Varese, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Raboni
authors.affiliation: Department of Biotechnologies and Life Sciences, University of Insubria, Via Dunant 3, I-21100, Varese, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Torretta
authors.affiliation: Department of Civil and Environmental Engineering, University of Roma "La Sapienza", Via Eudossiana 18, I-00184, Rome, Italy. paolo.viotti@uniroma1.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Viotti
mesh_terms: D000393:Air Pollutants / Q000302:isolation & purification* / Q000378:metabolism; D001673:Biodegradation, Environmental; D018441:Biofilms; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D016273:Occupational Exposure / Q000517:prevention & control*; D016272:Occupational Health; D016958:Pseudomonas putida / Q000378:metabolism*; D014050:Toluene / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D014050:Toluene
keywords: Air pollution; Air treatment; Biotrickling; Occupational exposure; Toluene; VOCs