A soil vapor extraction pilot study in a deep arid vadose zone. Part 1: field study summary
- Apogen Technologies, Los Alamos, NM (United States)
- Los Alamos National Laboratory, NM (United States)
Non-radioactive liquid chemical waste was disposed at Material Disposal Area (MDA) L within Technical Area 54 (TA-54) at the Los Alamos National Laboratory (LANL) from the early 1960's until 1985. Three surface impoundments, one pit, and 34 vertical shafts comprise the MDA L disposal facilities. None of the disposal areas were lined. Under LANL's Environmental Program, extensive sampling and analysis have been conducted to characterize the vadose zone beneath MDA L and to determine the nature and extent of contaminant releases from the former disposal units. The major contaminant release at the site is a subsurface organic solvent vapor-phase plume consisting primarily of several chlorinated volatile organic compounds (CVOCs) including 1,1,1-trichloroethane (TCA), trichloroethene (TCE), Freon, tetrachloroethene (PCE). TCA was found in the greatest concentration, constituting the majority of the plume mass, and it also exhibits the greatest lateral and vertical extent in the organic vapor plume. A numerical model to characterize the subsurface plume has been developed based on the site conceptual model and refined using data from ongoing compliance monitoring. The primary goal of the pilot test was to provide information necessary to determine the effectiveness of SVE as a treatment method for the VOC vapor plume. To achieve this objective, commercially available SVE equipment meeting functional requirements established by previous vapor extraction testing and extensive vadose zone characterization activities was leased, temporarily installed, and operated at each of two test extraction wells in sequence. Granular activated carbon was used to treat the SVE emissions. Subsurface vapor monitoring captured the reduction in soil vapor concentrations and subsurface pressure changes. Active extraction was conducted from extraction wells constructed near the source term over a two-month period, resulting in the removal of more than 800 lbs of VOCs. Rebound monitoring was conducted to provide information on the nature of the source. Rebound monitoring indicated a fairly rapid source response, with preliminary data showing concentrations in monitoring boreholes closest to the source reaching steady state at concentrations lower than pre-test levels. Data from this study will be used to refine the MDAL L numerical model in order to assess the long term effectiveness of SVE as a remedy for the subsurface vapor-phase plume at MDA L in support of the corrective measure evaluation for MDA L. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21317016
- Report Number(s):
- INIS-US-09-WM-07311; TRN: US10V0216060613
- Resource Relation:
- Conference: WM'07: Waste Management Symposium 2007 - Global Accomplishments in Environmental and Radioactive Waste Management: Education and Opportunity for the Next Generation of Waste Management Professionals, Tucson, AZ (United States), 25 Feb - 1 Mar 2007; Other Information: Country of input: France; 16 refs
- Country of Publication:
- United States
- Language:
- English
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