In Situ Treatment and Management Strategies for 1,4-Dioxane-Contaminated Groundwater
ER-2307
Objective
The overall objective of this project is to develop integrated, site-specific management approaches for 1,4-dioxane-contaminated sites through applied research on novel in situ treatment technologies, modifications to existing technologies, and a better understanding of plume transport and attenuation characteristics. By identifying ways in which innovative and conventional technologies can work together to treat 1,4-dioxane and chlorinated volatile organic compound (CVOC) contamination, the goal will be to develop approaches that are appropriate and customizable for particular site conditions.
Technical Approach
Currently, there is limited technical information on the typical scale and conditions within 1,4-dioxane sites, as well as the efficacy of various natural and engineered attenuation processes for 1,4-dioxane. Because the characteristics of 1,4-dioxane differ from those of typical chlorinated co-contaminants and can lead to significantly different plume dimensions, it is critical to evaluate the treatment options within the context of the expected geochemical conditions of the 1,4-dioxane and CVOC plumes. The research thrusts for this project are designed to address these knowledge gaps through the following hypotheses-driven tasks: (1) Use data mining of existing 1,4-dioxane site records to establish plume magnitudes and dimensions and to evaluate the basic conceptual model of 1,4-plume dynamics relative to co-located CVOC plumes. Efforts will test the hypothesis that the chemical properties of 1,4-dioxane result in plumes that are generally classifiable as large and dilute and that this will dictate the appropriate remedy selection; (2) Determine reaction pathways, rates, and efficacy of catalyst-based oxidation and reduction of 1,4-dioxane, and develop potential in situ approaches for this process in the presence of CVOC co-contaminants. Efforts will test the hypothesis that catalysis is a robust approach for treating problematic compounds like 1,4-dioxane; (3) Evaluate biodegradation potential of 1,4-dioxane under a range of natural and engineered geochemical conditions, including in tandem with other methods (both conventional and innovative) for treating 1,4-dioxane and CVOC co-contaminants. Efforts will test the hypothesis that chlorinated solvents and strategies for their removal can either inhibit or enhance apparent 1,4-dioxane removal; and (4) Conduct a pilot test of gas-based oxidant barriers as a low-energy enhancement to 1,4-dioxane treatment for source treatment and/or plume control. Efforts will test the hypothesis that chemical oxidation of 1,4-dioxane will be promoted via the delivery of ozone, and longer-term aerobic biodegradation of 1,4-dioxane will be stimulated through decomposition of ozone to oxygen.
Benefits
The results of this project will aid DoD by developing low-cost remedial solutions for long-term management of environmental liabilities at contaminated sites where an emerging contaminant, 1,4-dioxane, has been identified as a potential problem. This includes sites where no or limited remediation has been implemented, such that selection of an appropriate and cost-effective remedy is necessary to ensure that emerging contaminants are being treated. Further, it includes sites where remediation is ongoing or may have already been completed to address one or more primary constituents (e.g., CVOCs), but where the impacts or effectiveness of these efforts on emerging contaminants (e.g., 1,4-dioxane) are unknown or have not been investigated. Finally, it includes sites where intensive remediation efforts have already been completed and have resulted in very low residual levels of primary contaminants as well as emerging contaminants. Continued management of this residual contamination is often required, and it is important to know if typical strategies for these “low-risk sites” are also applicable for management of emerging contaminants. Importantly, the presence of emerging contaminants such as 1,4-dioxane at these sites increases the uncertainty in the closure cost and time frame estimates. An opportunity exists to identify in situ remediation processes that will adequately treat 1,4-dioxane in the presence of chlorinated solvent co-contaminants. (Anticipated Project Completion - 2015)
Points of Contact
Principal Investigator
Dr. David Adamson
GSI Environmental, Inc.
Phone: 713-522-6300
Fax: 713-522-8010
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.