Formatted Title
Technology Development from Concept to Field Implementation of EK Enhanced Amendment Delivery for In Situ Remediation in Low-Permeability Materials
Background/Objectives
A common challenge to achieving remediation goals at sites with complex geology is contaminant mass stored in low-permeability (low-k) materials acting as long-term sources. The main limitation of enhanced in situ remediation using conventional hydraulic-based techniques is the inability to effectively deliver the required amendments to the target area and/or formation. Electrokinetic (EK) enhanced amendment delivery for in situ remediation represents a fundamentally different and improved approach to overcoming the challenge of remediating contaminant sources in low-k materials. Over the past 10 plus years, there has been significant technological advancement of EK enhanced in situ remediation demonstrated in several field-scale applications of the technology for in situ bioremediation (EK-BIO) and in situ chemical oxidation (EK-ISCO). The U.S. Environmental Protection Agency (USEPA) Office of Research and Development (ORD) recently commissioned a project, led by Geosyntec, to prepare an Engineering Issue Paper (EIP) on EK Enhanced In Situ Remediation aimed to disseminate the technology development and project experiences. This presentation will introduce this EIP and discuss the fundamentals and the case studies presented in the EIP.
Approach/Activities
To prepare this EIP, over 90 individual literatures, including mainly peer-reviewed technical journal articles and various project reports, were reviewed and summarized. Fundamental EK mechanisms for amendment transport in the subsurface, including electromigration (ion migration), electroosmosis, and electrophoresis are clearly explained. Each EK mechanism was discussed in details and research results were presented to articulate how these mechanisms are applied to create the intended processes in the field. Following the discussions of technology fundamentals, the report takes the audience through a stepwise process of evaluating, developing, and ultimately implementing the EK technology. The stepwise process generally follows the CERCLA FS and RD framework that addresses remedial technology screening, remedial alternative evaluations, bench-scale treatability study, pilot test, and full-scale remedy design and implementation. These discussions are further supported with select case studies that include specific project data and results.
Results/Lessons Learned
USEPA’s EIPs are a series of technology transfer documents that summarize the state of current practice information on selected waste treatment and site remediation technologies. The EIP to be presented here, to be published by USEPA in 2024, summarizes the current knowledge of EK enhanced in situ remediation technologies that can specifically address contaminants in low-k aquifer materials where conventional hydraulic delivery technologies often face challenges. This EIP presents, in addition to technology fundamentals, specifics of four selected case studies that cover bench-scale treatability study of EK-BIO, pilot-scale EK-ISCO and EK-BIO demonstrations and full-scale EK-BIO remedy implementation and completion. These real-world experiences addressed contaminant sources in challenging geology, including glacial till, silty clay, and saprolite. As a technology transfer document, this EIP includes tremendous amount of peer-reviewed technical information for the practitioners to develop an in-depth understanding of this technology. There are also discussions of best practices related to screening the EK enhanced in situ remediation technology for applicability at a given site. With the discussions of information following the FS and RD framework, plus the case studies providing sufficient project details, this EIP will allow the practitioners to connect the state of practice of this technology to their given sites or projects that can benefit from this technology.