Subsurface Reductive Elimination of Trichloroethylene using Zero-Valent Iron Emplaced by Polymer Solutions
EMSL Project ID
25641
Abstract
Zero-valent iron (ZVI) has been used for in situ remediation of inorganic compounds and chlorinated solvents through engineered permeable reactive barriers and injectable ZVI particles. A key aspect of ZVI application is successful distribution of the particles in the subsurface and contact and reaction with the contaminant of concern. Injection of micron-scale particles is problematic due to the high density of the iron particles which limits the distance particles can be injected from a well when injected with water. Except for the shear-thinning polymer injection methods developed by EMSL researchers, other enhanced emplacement techniques reported major problems, including poor injection uniformity and promotion of microbial reductive dechlorination. ZVI injection in polymer solutions offers a promising mechanism for enhancing the distance and uniformity of ZVI particle injection around an injection well. However, the impact of the polymers on the short and longer-term reactivity of the ZVI has not been tested. As part of a recently funded proposal (Lynch et al. 2006; US Department of Defense-Environmental Security Technology Certification Program), abiotic reactivity of emplaced ZVI in polymer solutions with TCE will be investigated. Since the researchers associated with the EMSL Subsurface Flow and Transport Laboratory have developed extensive knowledge in preparing and handling the necessary polymer solutions for ZVI injections (Oostrom et al., 2005, 2007) and the EMSL has high-quality analytical equipment available for the components shown in Figure 1, the EMSL-SFTL is the appropriate place for these reactivity experiments. To provide design information for injectable ZVI, a series of test will be conducted that quantify the reactivity of ZVI as a function of polymer material type, polymer concentration, initial TCE concentration, and ZVI content.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-25
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Truex MJ, T Macbeth, VR Vermeul, BG Fritz, DP Mendoza, RD Mackley, M Oostrom, TW Wietsma, G Sandberg, T Powell, J powers, E Pitre, MM Michalsen, S Ballock-Dixon, and L Zhong. 2010. "Demonstration of Combined Zero-Valent Iron and Electrical Resistance Heating for In Situ TCE Remediation." PNNL-SA-76701, Pacific Northwest National Laboratory, Richland, WA. [Unpublished]
Truex MJ, VR Vermeul, DP Mendoza, BG Fritz, RD Mackley, M Oostrom, TW Wietsma, and T Macbeth. 2011. "Injection of Zero Valent Iron into an Unconfined Aquifer Using Shear-Thinning Fluids." Ground Water Monitoring and Remediation 31(1):50-58.