KC Carroll is Principal Investigator for a SERDP Project:

Facilitated Transport Enabled In Situ Chemical Oxidation of 1,4-Dioxane-Contaminated Groundwater

Funded By: Strategic Environmental Research and Development Program or SERDP (DoD) Project ER-2302

http://www.serdp.org/Program-Areas/Environmental-Restoration/Contaminated-Groundwater/Emerging-Issues/ER-2302

Objective

1,4-dioxane occurrence in large groundwater contamination plumes represents a significant liability because of potential adverse health risks and remediation costs. Properties of 1,4-dioxane, including infinite water solubility, negligible adsorption, and low volatilization, have resulted in extensive groundwater contaminant plumes. The objectives of this project are to: (1) develop the ability to cost-effectively remediate 1,4-dioxane using facilitated-transport enabled in situ oxidation; (2) investigate the ability of delivery agents to enhance the effectiveness of commonly used advanced oxidation process (AOP) reagents, such as O3 combined with H2O2, through complexation; (3) investigate the ability of delivery agents to increase the specificity of oxidant reactivity for 1,4-dioxane and to enhance the stability and longevity of the oxidant; (4) investigate the effectiveness of facilitated transport of oxidants complexed with delivery agents within sediments collected from a Department of Defense (DoD) site; and (5) investigate the biodegradation of delivery agents as a method for creating timed-release of oxidants from complexation. This oxidant-facilitated transport technology has the potential to increase treatment effectiveness and decrease costs for both source zones and low-concentration plumes.

Technical Approach

This project will develop in situ chemical oxidation as a viable technology for 1,4-dioxane groundwater plume remediation by enhancing the solubility, stability, and transportability of strong oxidants (e.g., O3), which will facilitate the in situ treatment of groundwater plumes. This will be achieved through the co-injection of oxidants with chemical agents that facilitate the transport of the oxidant. Several delivery enhancement alternatives will be considered. Oxidants will complex or partition into the delivery agent molecule, which in return, will increase the amount of oxidant that can be delivered to the plume. Also, decreases in reactivity during facilitated transport may increase specificity of oxidation for compounds of concern including 1,4-dioxane and co-contaminant chlorinated solvents that also partition into the delivery agent. A parallel technology is planned to delay the release of oxidant such that it will enhance reagent delivery at the plume scale. This delay of oxidant release from delivery agent complexation could be designed to occur through microbiological or abiotic decomposition of the delivery agent, which could significantly prolong the effectiveness of the technology.

Benefits

This project will develop a novel, cost-effective, in situ treatment alternative for 1,4-dioxane-contaminated source zones and groundwater plumes, and it will advance the understanding of processes controlling the complexation of oxidants and the impact of complexation, or other transport-related processes, on oxidation reactions. Co-injecting oxidants with a complexing agent will be used to facilitate the transport of oxidants into groundwater plumes to increase the longevity and transportability of oxidants, enhance the treatable volume of 1,4-dioxane groundwater plume, and decrease the cost and time required to remediate such contaminated sites. This method for in situ advanced oxidation of 1,4-dioxane has the potential to significantly decrease remediation costs and support the effective management of DoD sites contaminated with 1,4-dioxane.



Project Approach

This project is developing advanced oxidation processes for in situ chemical oxidation of groundwater contaminants including 1,4-dioxane.



Project Team

KC Carroll from NMSU

Mark L. Brusseau from University of Arizona

Thomas Boving from University of Rhode Island

Raymond Ball from EnChem Engineering, Inc.




Published Results: Peroxone Activated Persulfate Treatment of 1,4-Dioxane in the Presence of Chlorinated Solvent Co-Contaminants

By Dylan Eberle, Raymond Ball, and Thomas Boving (2015) Chemosphere. http://dx.doi.org/10.1016/j.chemosphere.2015.08.063

Eberle (2015) Figure: The degradation rates (k1) for 1,1,1-TCA, 1,4-dioxane, and TCE are plotted against the molar oxidant:contaminant ratio. The data indicate that the rate of oxidation for each contaminant is predictable within the range tested.



Eberle (2015) Figure: Oxidation of 1,4-dioxane by PAP. Four oxidant:contaminant ratios were investigated. The 10:1 reaction was shown to continue for at least 312 h (supporting information). The reaction for the most concentrated oxidant formulations, 510:1 and 1030:1, was so rapid that a second 24 h experiment, with a denser sampling interval, was conducted to capture degradation in those systems.



Published Results: In-situ activation of persulfate by iron filings and degradation of 1,4-dioxane

By Hua Zhong, Mark L. Brusseau, Yake Wang, Ni Yan, Lauren Quig, and Gwynn R. Johnson (2015) Water Research 83: 104-111

Zhong (2015) Figure: Degradation of dioxane in the presence of iron filings in batch reactor system. Controls of persulfate with iron filings, sulfate with iron filings, and dioxane with iron filings are also included.



Zhong (2015) Figure: Electron paramagnetic resonance (EPR) spectra illustrating detection of radical formation for different reaction combinations at the start of reaction (~2 min).



Additional Efforts

Training and Tech Transfer

https://twitter.com/kcc_carroll

https://www.linkedin.com/pub/kenneth-c-carroll/55/8aa/615

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Link to list of publications.