U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Electrokinetics: Electric Current Technologies


Electrokinetics relies upon application of a low-intensity direct current through the soil between ceramic electrodes that are divided into a cathode array and an anode array. This mobilizes charged species, causing ions and water to move toward the electrodes. Metal ions, ammonium ions, and positively charged organic compounds move toward the cathode. Anions such as chloride, cyanide, fluoride, nitrate, and negatively charged organic compounds move toward the anode. Removal of contaminants at the electrode may be accomplished by several means, among which are: electroplating at the electrode; precipitation or co-precipitation at the electrode; pumping of water near the electrode; or complexing with ion exchange resins.

Adobe PDF LogoTechnology Overview Report: Electrokinetics

This report prepared by the Ground Water Remediation Technologies Analysis Center (GWRTAC) provides an introduction to the general principles of the electrokinetic technology, its criteria for application, performance, advantages and limitations to use, selected commercial applications, and references.

4.5 Electrokinetic Separation (In Situ Soil Remediation Technology)
In Remediation Technologies Screening Matrix and Reference Guide, Version 4.0. Federal Remediation Technologies Roundtable.

The Center for Public Environmental Oversight (CPEO), Washington, DC.

Adobe PDF LogoElectrokinetic Remediation and Its Combined Technologies for Removal of Organic Pollutants from Contaminated Soils
Huang, D., Q. Xu, J. Cheng, X. Lu, and H. Zhang.
International Journal of Electrochemical Science, Vol 7, 4528-4544, 2012

This paper reviews six types of electrokinetic (EK) remediation applications to soil contaminated with organic compounds: the direct EK technique, EK combined with Fenton's reagent, EK combined with surfactants or co-solvents, EK combined with bioremediation, EK combined with ultrasonic remediation, and the technology known as Lasagna. Basic principles, characteristics, application areas, research developments, and prospects are described for these six techniques. The technology combinations, contaminant types, soil types, and reported removal efficiencies are compiled into a table with references.

Electrokinetic Remediation of Organochlorines in Soil: Enhancement Techniques and Integration with Other Remediation Technologies
Gomes, H.I., C. Dias-Ferreira, and A.B. Ribeiro.
Chemosphere 87:1077-1090(2012)

This review summarizes strategies that have been tested to improve electrokinetic remediation effectiveness for organochlorines in soil, including techniques to solubilize contaminants (surfactants, cyclodextrins), control soil pH, and couple electrokinetics with other remediation techniques (zero-valent iron, phytoremediation, permeable reactive barriers, oxidation/reduction, ultrasonication, biodegradation). Removal efficiencies reported in real contaminated soils are much lower than the ones obtained with spiked kaolinite, indicating the influence of factors such as contaminant weathering and adsorption to soil particles.

Environmental Electrokinetics for a Sustainable Subsurface
Lima, A.T., A. Hofmann, D. Reynolds, C.J. Ptacek, P. Van Cappellen, L.M. Ottosen, S. Pamukcu, et al.
Chemosphere 181:122-133(2017)

Electrokinetics (EK), a soil remediation technique recognized mainly for in situ treatment of low-permeability soils, has been combined with more conventional techniques and can significantly enhance the performance of several remediation technologies, including in situ chemical oxidation, in situ chemical reduction, enhanced in situ bioremediation, and phytoremediation. This paper highlights new EK applications that might play a role in sustainable treatment of contaminated sites.

Opportunities for Groundwater Microbial Electro-Remediation
Pous, N., M.D. Balaguer, J. Colprim, and S. Puig.
Microbial Biotechnology [Publication online 6 Oct 2017 ahead of print]

Microbial electro-remediation by means of microbial electrochemical technologies (MET) can be applied to groundwater treatment in situ or ex situ, as well as to monitoring chemical state or microbiological activity. In this technological approach, electroactive bacteria are able to use a solid electrode as an electron donor alternative to organic matter/hydrogen or as an electron acceptor alternative to oxygen/nitrate. Depending on contaminant and groundwater characteristics, a MET system can be operated as a microbial fuel cell (MFC) or as a microbial electrolysis cell (MEC). The MFC is an autonomous device from which energy can be extracted, while the MEC is a device that accepts energy to support or enhance a bioelectrochemical process. This paper reviews the application of microbial electro-remediation to organics, chlorinated hydrocarbons, inorganics, and nutrients (e.g., nitrate) in groundwater.

Adobe PDF LogoElectrokinetic-Enhanced In Situ Remediation Fact Sheet
Naval Facilities Engineering Command, 4pp, 2023

This fact sheet discusses how EK delivery methods work and explores two EK case studies for bioremediation and ISCO. Lessons learned and key considerations for applying and implementing EK technologies are also summarized. An EK-enhanced delivery method can achieve a more uniform distribution of amendments into the target treatment zone at low-permeability sites compared to hydraulic-based methods. EK can be used to implement in situ bioremediation, in situ chemical oxidation (ISCO), and in situ chemical reduction.