Challenges in electrochemical remediation of chlorinated solvents in natural groundwater aquifer settings

[Display omitted] •Identification of knowledge gaps in applied in situ electrochemical remediation.•High complexity using natural geology and field-extracted contaminated groundwater.•Corrosion of the cast iron anode prompted significant precipitation of iron oxides.•A simple geochemical model captu...

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Bibliographic Details
Published in:Journal of hazardous materials 2019-04, Vol.368, p.680-688
Main Authors: Hyldegaard, Bente H., Jakobsen, Rasmus, Weeth, Eline B., Overheu, Niels D., Gent, David B., Ottosen, Lisbeth M.
Format: Article
Language:English
Subjects:
Electrochemical
Geology
Groundwater
Modelling
Ranking
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Summary:[Display omitted] •Identification of knowledge gaps in applied in situ electrochemical remediation.•High complexity using natural geology and field-extracted contaminated groundwater.•Corrosion of the cast iron anode prompted significant precipitation of iron oxides.•A simple geochemical model captured the overall observed system response.•Rankings of parameter influence on the execution of electrochemical remediation. Establishment of electrochemical zones for remediation of dissolved chlorinated solvents in natural settings was studied. An undivided 1D-experimental column set-up was designed for the assessment of the influence of site-extracted contaminated groundwater flowing through a sandy aquifer material, on the execution of laboratory testing. A three-electrode system composed of palladium coated pure iron cathodes and a cast iron anode was operated at 12 mA under varying flow rates. The natural settings added complexity through a diverse groundwater chemistry and resistance in the sand. In addition, significant precipitation of iron released through anode corrosion was observed. Nevertheless, the complex system was successfully modelled with a simple geochemical model using PHREEQC. A ranking of the significances of system parameters on the laboratory execution of electrochemical remediation in natural settings was proposed: Geological properties > anode corrosion > site-extracted contaminated groundwater > the carbonate system > sulphate > hydrology > less significant unidentified parameters. This study provides insight in actual challenges that need to be overcome for in situ electrochemical remediation.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2018.12.064