title: Effect of the polarity reversal frequency in the electrokinetic-biological remediation of oxyfluorfen polluted soil.
abstract: This work studies the feasibility of the periodic polarity reversal strategy (PRS) in a combined electrokinetic-biological process for the remediation of clayey soil polluted with a herbicide. Five two-weeks duration electrobioremediation batch experiments were performed in a bench scale set-up using spiked clay soil polluted with oxyfluorfen (20 mg kg-1) under potentiostatic conditions applying an electric field between the electrodes of 1.0 V cm-1(20.0 V) and using PRS with five frequencies (f) ranging from 0 to 6 d-1. Additionally, two complementary reference tests were done: single bioremediation and single electrokinetic. The microbial consortium used was obtained from an oil refinery wastewater treatment plant and acclimated to oxyfluorfen degradation. Main soil conditions (temperature, pH, moisture and conductivity) were correctly controlled using PRS. On the contrary, the electroosmotic flow clearly decreased as f increased. The uniform soil microbial distribution at the end of the experiments indicated that the microbial activity remained in every parts of the soil after two weeks when applying PRS. Despite the adapted microbial culture was capable of degrade 100% of oxyfluorfen in water, the remediation efficiency in soil in a reference test, without the application of electric current, was negligible. However, under the low voltage gradients and polarity reversal, removal efficiencies between 5% and 15% were obtained, and it suggested that oxyfluorfen had difficulties to interact with the microbial culture or nutrients and that PRS promoted transport of species, which caused a positive influence on remediation. An optimal f value was observed between 2 and 3 d-1.
authors.affiliation: Chemical Engineering Department, Research Institute for Chemical and Environmental Technology (ITQUIMA), University of Castilla- La Mancha, 13071, Ciudad Real, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Barba
authors.affiliation: Chemical Engineering Department, Research Institute for Chemical and Environmental Technology (ITQUIMA), University of Castilla- La Mancha, 13071, Ciudad Real, Spain. Electronic address: jose.villasenor@uclm.es.
authors.forename: José
authors.initials: J
authors.lastname: Villaseñor
authors.affiliation: Chemical Engineering Department, Faculty of Chemical Sciences and Technology, University of Castilla- La Mancha, 13071, Ciudad Real, Spain.
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Rodrigo
authors.affiliation: Chemical Engineering Department, Faculty of Chemical Sciences and Technology, University of Castilla- La Mancha, 13071, Ciudad Real, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Cañizares
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001673:Biodegradation, Environmental; D000077215:Clay; D004560:Electricity; D052918:Environmental Restoration and Remediation / Q000379:methods*; D055768:Halogenated Diphenyl Ethers / Q000378:metabolism*; D006540:Herbicides / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D000538:Aluminum Silicates; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D012989:Soil Pollutants; C016027:oxyfluorofen; D000077215:Clay
keywords: Bioremediation; Electrokinetics; Oxyfluorfen; Polarity reversal; Polluted soil