TY - JOUR
T1 - 1,4-Dioxane Soil Remediation Using Enhanced Soil Vapor Extraction
T2 - I. Field Demonstration
AU - Hinchee, Robert E.
AU - Dahlen, Paul R.
AU - Johnson, Paul C.
AU - Burris, David R.
N1 - Funding Information:
The work presented in this manuscript was funded by the Environmental Security Technology Certification Program (ESTCP) and is gratefully acknowledged. The field site search was facilitated by Hunter Anderson, Ph.D. of the Air Force Civil Engineering Center. Assistance of the McClellan facility Groundwater and SVE Program Manager, Kenneth Smarkel, Ph.D., P.E. in facilitating this project is appreciated. Dave Becker of the US Army Corps of Engineers provided technical support including key guidance at several points in the project. Successful field implementation of this project was largely accomplished by AECOM with Kimiye Touchi, P.E. as project manager and Paul Graff, P.E. as oversight lead.
Publisher Copyright:
© 2018, National Ground Water Association
PY - 2018/3/1
Y1 - 2018/3/1
N2 - 1,4-Dioxane is totally miscible in water, sequestering in vadose pore water that can serve as a source of long-term groundwater contamination. Although some 1,4-dioxane is removed by conventional soil vapor extraction (SVE), remediation is typically inefficient. SVE efficiency is hindered by low Henry’s Law constants at ambient temperature and redistribution to vadose pore water if SVE wells pull 1,4-dioxane vapors across previously clean soil. It was hypothesized that heated air injection and more focused SVE extraction (“Enhanced SVE” or XSVE) could increase the efficiency of 1,4-dioxane vadose treatment, and this new process was tested at former McClellan Air Force Base, CA. The XSVE system had four peripheral heated air injection wells surrounding a 6.1 m × 6.1 m × 9.1 m deep treatment zone with a central vapor extraction well. After 14 months of operation, soil temperatures reached as high as ~90 °C near the injection wells and the treatment zone was flushed with ~20,000 pore volumes of injected air. Post-treatment sampling results showed reductions of ~94% in 1,4-dioxane and ~45% in soil moisture. Given the simplicity of the remediation system components and the promising demonstration test results, XSVE has the potential to be a cost-effective remediation option for vadose zone soil containing 1,4-dioxane.
AB - 1,4-Dioxane is totally miscible in water, sequestering in vadose pore water that can serve as a source of long-term groundwater contamination. Although some 1,4-dioxane is removed by conventional soil vapor extraction (SVE), remediation is typically inefficient. SVE efficiency is hindered by low Henry’s Law constants at ambient temperature and redistribution to vadose pore water if SVE wells pull 1,4-dioxane vapors across previously clean soil. It was hypothesized that heated air injection and more focused SVE extraction (“Enhanced SVE” or XSVE) could increase the efficiency of 1,4-dioxane vadose treatment, and this new process was tested at former McClellan Air Force Base, CA. The XSVE system had four peripheral heated air injection wells surrounding a 6.1 m × 6.1 m × 9.1 m deep treatment zone with a central vapor extraction well. After 14 months of operation, soil temperatures reached as high as ~90 °C near the injection wells and the treatment zone was flushed with ~20,000 pore volumes of injected air. Post-treatment sampling results showed reductions of ~94% in 1,4-dioxane and ~45% in soil moisture. Given the simplicity of the remediation system components and the promising demonstration test results, XSVE has the potential to be a cost-effective remediation option for vadose zone soil containing 1,4-dioxane.
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U2 - 10.1111/gwmr.12264
DO - 10.1111/gwmr.12264
M3 - Article
AN - SCOPUS:85040606687
SN - 1069-3629
VL - 38
SP - 40
EP - 48
JO - GroundWater Monitoring and Remediation
JF - GroundWater Monitoring and Remediation
IS - 2
ER -