Abstracts

Innovation in the Remediation of
Contaminated Sites 1
Wednesday, October 28, 10:10 – 11:50
Chair: Jason Gerhard
Room: Schubert
132 - Electrokinetically-Enhanced Remediation: An Innovative
Solution to Vexing Challenges for Source Area Remediation
Evan Cox 1 , David Reynolds 2 & James Wang 3
1
Geosyntec Consultant, Waterloo, Ontario, Canada
2
Geosyntec Consultant, Kingston, Ontario, Canada
3
Geosyntec Consultant, Columbia, Maryland, USA
Charlotte Riis & Martin Bymose
NIRAS A/S, Alleroed, Denmark
David Gent
US Army Engineer R&D Center, Vicksburg, Mississippi, USA
Mads Terkelsen
Capital Region, Hilleroed, Denmark
Contaminants in clays and silts are long-term sources of pollutants to groundwater, requiring
costly remediation and monitoring over many decades. Significant advances have been
made in the past few years in the area of electrokinetically (EK) enhanced amendment
delivery to treat contaminant source areas in low permeability (low K) and highly heterogeneous
subsurface materials. EK is an innovative approach that uses electrokinetic mechanisms
to promote migration of amendments through clays/silts through electromigration,
electroosmosis and/or electrophoresis. EK approaches are not dependent on hydraulic conductivity,
and can therefore achieve uniform and rapid distribution of amendments in clays
and silts. Amendments can include electron donors (e.g., lactate), electron acceptors (e.g.,
nitrate), and/or bacteria (e.g., Dehalococcoides, Dehalobacter) for in situ bioremediation
(EK-BIO), or oxidants such as permanganate for in situ chemical oxidation (EK-ISCO).
A recent novel addition to the EK toolbox is EK-thermally activated persulfate (EK-TAP)
which uses the same infrastructure to both deliver persulfate through clays and silts (using
DC current), followed by heating of the soils (using AC current, which is the basis for electrical
resistance heating), to heat the soils to ~40 o C to activate the persulfate and destroy
contaminants in situ.
This presentation will discuss how and where each of these EK remediation technologies
works, and will present results from multiple field applications, including a large full-scale EK-
BIO application at a site in Denmark, a second EK-BIO field application at a United States
Navy site in Florida, and several field applications of EK-TAP, EK-ISCO, and EK-ZVI at
chlorinated solvent sites in the United States and Canada. The results of these field applications
show that EK enhanced amendment delivery can be a cost-effective and sustainable means of
accelerating remediation of source areas in low K and heterogeneous materials.
42 IAH-CNC 2015 WATERLOO CONFERENCE