title: Effect of methanol on the biofiltration of n-hexane.
abstract: This study investigated the removal of recalcitrant compounds in the presence of a hydrophilic compound. n-Hexane is used as a model compound to represent hydrophobic compounds. Methanol has been introduced in mixture with n-hexane in order to increase the bioavailability of n-hexane in trickle-bed-air-biofilters (TBABs). The mixing ratios investigated were: 70% methanol:30% n-hexane, and 80% methanol:20% n-hexane by volume. n-Hexane loading rates (LRs) ranged from 0.9 to 13.2 g m(-3) h(-1). Methanol LRs varied from 4.6 to 64.5 g m(-3) h(-1) and from 2.3 to 45.2 g m(-3) h(-1) depending upon the mixing ratio used. Biofilter performance, effect of mixing ratios of methanol to n-hexane, removal profile along biofilter depth, COD/nitrogen consumption and CO(2) production were studied under continuous loading operation conditions. Results have shown that the degradation of n-hexane is significantly enhanced by the presence of methanol for n-hexane LRs less than 13.2 g m(-3) h(-1). For n-hexane LR greater than 13.2 g m(-3) h(-1), even though methanol had impacted n-hexane biodegradation, its removal efficiency was higher than our previous study for biodegradation of n-hexane alone, in presence of surfactant, or in presence of benzene. On the other hand, the degradation of methanol was not impacted by the presence of n-hexane.
authors.affiliation: School of Energy, Environmental, Biological and Medical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH 45221-0012, USA. zehraoan@mail.uc.edu
authors.forename: Abderrahman
authors.initials: A
authors.lastname: Zehraoui
authors.forename: Ashraf Aly
authors.initials: AA
authors.lastname: Hassan
authors.forename: George A
authors.initials: GA
authors.lastname: Sorial
mesh_terms: D001673:Biodegradation, Environmental; D002849:Chromatography, Gas; D005374:Filtration / Q000379:methods*; D006586:Hexanes / Q000302:isolation & purification*; D000432:Methanol / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D055549:Volatile Organic Compounds / Q000302:isolation & purification
chemical_list: D006586:Hexanes; D055549:Volatile Organic Compounds; C026385:n-hexane; D009584:Nitrogen; D000432:Methanol