In situ electrochemical manipulation of oxidation-reduction potential in saturated subsurface matrices

ABSTRACT

Application of a low-intensity electric field is known to influence oxidation-reduction (redox) potential in a saturated matrix. In this study, such redox manipulation was attempted in at a site with contaminated aquifer. At the experiment field site, electrodes connected to a direct current (DC) source provided an electric field with an intensity of 1.82 V m⁻¹. Redox potentials at locations 3.0 m and 7.9 m from the cathode decreased by 111 mV and 33 mV within a few hours, respectively, indicating that reducing conditions in the aquifer may be established within the electric field. Overall, it is possible to manipulate in situ redox potential in saturated subsurface matrices by applying low-intensity electric fields.

KEYWORDS:

• Aquifer
• chlorinated solvents
• electroremediation
• redox manipulation
• redox potential

Acknowledgments

The authors thank Mr. Mike Smith, Ms. Alesandra Reed, and Mr. Dung Nguyen (CDM Smith) for their assistance in the field measurements. The authors also thank Dr. James Hardy (ChemCorr) for his assistance with the equipment operation and field measurements, and Mr. Nicholas Santiago (AET) for his help with preparing some of the figures used in this paper.