title: Long-term performance of peat biofilters treating ethyl acetate, toluene, and its mixture in air.
abstract: Three laboratory-scale peat biofilters were operated at 90 s empty bed residence time (EBRT) for over a year. Biodegradation of ethyl acetate, toluene, or a 1:1 mixture were investigated. In first stage, inlet concentration was progressively increased from 0.4 to 4.5 g/m(3). The maximum elimination capacity (EC) found for ethyl acetate was 190 gC/m(3).h, and it was not affected by toluene. The maximum EC found for toluene as a sole contaminant was 150 gC/m(3).h, but the presence of ethyl acetate decreased the toluene maximum EC to 80 gC/m(3).h. From respirometry monitoring, values of 3.19 g CO(2)/gC and 3.06 g CO(2)/gC for pure ethyl acetate and pure toluene, respectively, were found, with overall yield coefficients of 0.13 g dry biomass produced per gram ethyl acetate consumed and 0.28 g dry biomass produced per gram toluene consumed. CO(2) production in the 1:1 mixture was successfully simulated. Dynamics of living and dead cells were monitored in four sections of the biofilters. Concentrations ranged between 2.6 x 10(9) and 3.0 x 10(10) cells per gram-dry peat for total bacteria, and 2.4 x 10(9)-1.9 x 10(10) cells per gram-dry peat for living bacteria. At high loads loss of bacterial density in the inlet zones, and increase in the dead cells percentages up to 60% was observed. In second stage, long-term performance at an inlet concentration of 1.5 g/m(3) was evaluated to show the process feasibility. Good agreement with previous data was obtained in terms of EC and CO(2) production. Restoration of living cells proportion was also observed.
authors.affiliation: Department of Chemical Engineering, University of Valencia. Dr. Moliner, 50, 46100 Burjassot, Spain.
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Alvarez-Hornos
authors.forename: Carmen
authors.initials: C
authors.lastname: Gabaldón
authors.forename: Vicente
authors.initials: V
authors.lastname: Martínez-Soria
authors.forename: Paula
authors.initials: P
authors.lastname: Marzal
authors.forename: Josep-Manuel
authors.initials: JM
authors.lastname: Penya-Roja
authors.forename: Marta
authors.initials: M
authors.lastname: Izquierdo
mesh_terms: D000085:Acetates / Q000032:analysis / Q000378:metabolism*; D000397:Air Pollution / Q000517:prevention & control; D001673:Biodegradation, Environmental; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D015169:Colony Count, Microbial; D005374:Filtration / Q000379:methods; D007220:Industrial Waste; D008855:Microscopy, Electron, Scanning; D012987:Soil; D012988:Soil Microbiology; D014050:Toluene / Q000032:analysis / Q000378:metabolism*
chemical_list: D000085:Acetates; D007220:Industrial Waste; D012987:Soil; D002245:Carbon Dioxide; D014050:Toluene; C007650:ethyl acetate