| Title | Bioelectrochemical treatment of groundwater containing BTEX in a continuous-flow system: Substrate interactions, microbial community analysis, and impact of sulfate as a co-contaminant |
| Abstract | Microbial electrochemical technologies (MET) are increasingly being considered for in situ remediation of contaminated groundwater. However, their application potential for the simultaneous treatment of complex mixtures of organic and inorganic contaminants, has been only marginally explored. Here we have analyzed the performance of the 'bioelectric well', a previously developed bioelectrochemical reactor configuration, in the treatment of benzene, toluene, ethyl-benzene and xylenes (BTEX) mixtures. Although to different extents, all BTEX were found to be degraded in the bioelectrochemical system, operated using a continuous-flow of groundwater at a hydraulic retention time of 8.8 h, with the graphite anode potentiostatically controlled at +0.200 V vs. the standard hydrogen electrode. In the case of toluene and ethyl-benzene, biodegradation was further confirmed by the GC-MS identification of fumarate-addition metabolites, previously shown to be involved in the activation of these contaminants under anaerobic conditions. Degradation rates were higher for toluene (31.3 ± 1.5 mg/L d) and lower for benzene (6.1 ± 0.3 mg/L d), ethyl-benzene (3.3 ± 0.1 mg/L d), and xylenes (4.5 ± 0.2 mg/L d). BTEX degradation was linked to electric current generation, with coulombic efficiencies falling in the range 53-69%, although methanogenesis also contributed to contaminant degradation. Remarkably, the system also allowed removal of sulfate simultaneously with toluene. Sulfate removal was likely driven by the hydrogen abiotically generated at the cathode. Taken as a whole, these findings highlight the remarkable potential of this innovative reactor configuration for application in a variety of contamination scenarios. |
| Source | New biotechnology (Print) 53, pp. 41–48 |
| Keywords | BTEXGeobacterMicrobial electrochemical technologiesSulfate |
| Journal | New biotechnology (Print) |
| Editor | Elsevier Life Science, Amsterdam, Paesi Bassi |
| Year | 2019 |
| Type | Articolo in rivista |
| DOI | 10.1016/j.nbt.2019.06.004 |
| Authors | Palma, Enza; Espinoza Tofalos, Anna; Daghio, Matteo; Franzetti, Andrea; Tsiota, Panagiota; Cruz Viggi, Carolina; Papini, Marco Petrangeli; Aulenta, Federico |
| Text | 407387 2019 10.1016/j.nbt.2019.06.004 Scopus 2 s2.0 85068146126 BTEX Geobacter Microbial electrochemical technologies Sulfate Bioelectrochemical treatment of groundwater containing BTEX in a continuous flow system Substrate interactions, microbial community analysis, and impact of sulfate as a co contaminant Palma, Enza; Espinoza Tofalos, Anna; Daghio, Matteo; Franzetti, Andrea; Tsiota, Panagiota; Cruz Viggi, Carolina; Papini, Marco Petrangeli; Aulenta, Federico Istituto di Ricerca sulle Acque, Italy; Universita degli Studi di Roma La Sapienza; Technical University of Crete; University of Milano Bicocca Microbial electrochemical technologies MET are increasingly being considered for in situ remediation of contaminated groundwater. However, their application potential for the simultaneous treatment of complex mixtures of organic and inorganic contaminants, has been only marginally explored. Here we have analyzed the performance of the bioelectric well , a previously developed bioelectrochemical reactor configuration, in the treatment of benzene, toluene, ethyl benzene and xylenes BTEX mixtures. Although to different extents, all BTEX were found to be degraded in the bioelectrochemical system, operated using a continuous flow of groundwater at a hydraulic retention time of 8.8 h, with the graphite anode potentiostatically controlled at 0.200 V vs. the standard hydrogen electrode. In the case of toluene and ethyl benzene, biodegradation was further confirmed by the GC MS identification of fumarate addition metabolites, previously shown to be involved in the activation of these contaminants under anaerobic conditions. Degradation rates were higher for toluene 31.3 ± 1.5 mg/L d and lower for benzene 6.1 ± 0.3 mg/L d , ethyl benzene 3.3 ± 0.1 mg/L d , and xylenes 4.5 ± 0.2 mg/L d . BTEX degradation was linked to electric current generation, with coulombic efficiencies falling in the range 53 69%, although methanogenesis also contributed to contaminant degradation. Remarkably, the system also allowed removal of sulfate simultaneously with toluene. Sulfate removal was likely driven by the hydrogen abiotically generated at the cathode. Taken as a whole, these findings highlight the remarkable potential of this innovative reactor configuration for application in a variety of contamination scenarios. 53 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85068146126 origin=inward Articolo in rivista Elsevier Life Science 1871 6784 New biotechnology Print New biotechnology Print New biotechnology. Print PALMA ENZA federico.aulenta AULENTA FEDERICO carolina.cruzviggi CRUZ VIGGI CAROLINA |
