Objective:
Source zone treatment is likely to be a required component of corrective action plans at most dense non-aqueous phase liquid (DNAPL) spill sites, including sites where complete removal is unlikely. Assessing the performance of DNAPL source zone treatment requires characterization of the DNAPL and DNAPL residuals before and after treatment. The objective of this project is to assess the performance of thermal treatment technologies applied to DNAPL source zones. Emphasis will be placed on quantifying performance by conventional and relevant risk-based measurements. A DNAPL source zone treatment performance paradigm will be established that practitioners, regulators, and site owners can use both to predict the performance of DNAPL source zone treatment in various hydrogeologic settings and to monitor the performance of DNAPL source zone treatment at sites where thermal treatment technologies are applied. Technology Description: According to hydrogeology, the project will categorize Department of Defense (DoD) and non-DoD sites where thermal treatment for DNAPL has been implemented and collect performance data from those sites. The data gathered will be critically reviewed, and idealized conceptual models that describe DNAPL source zone treatment performance, with respect to site-specific features commonly encountered in the environment, will be developed. Additional performance data then will be collected at selected sites that have undergone treatment to assess the effectiveness of thermal treatment technologies for improving the long-term quality of groundwater down-gradient of the site. Based on the conceptual models developed, the data collected, and the field investigations, fate and transport models will be applied to further evaluate the performance of thermal treatment technologies under different hydrogeologic settings and to identify additional performance metrics that may be useful for monitoring thermal treatment applications. Expected Benefits: Cost benefits to DoD will be realized through an increased understanding of the efficacy of thermal treatment of DNAPL source zones, improved awareness and understanding of the historical successes and failures of DNAPL source zone treatment at DoD sites, and advanced techniques for measuring the performance of DNAPL source zone treatment and its long-term impacts on contaminant migration in groundwater. Understanding how various hydrogeologies may impact DNAPL recovery, residual mass and distribution, and corresponding contaminant migration to groundwater, can help to ensure that future implementation of thermal DNAPL source zone treatment technologies adequately meets long-term risk reduction. The knowledge, for example, that partial DNAPL source zone removal may adequately reduce contaminant flux into groundwater could result in substantial savings to DoD. Conversely, the results of this work will help the DoD to avoid conditions where DNAPL source zone treatment could mobilize DNAPL or sites where adequate DNAPL removal is impracticable. (Anticipated Project Completion - 2007) Principal Investigator: Dr. Paul Johnson
Arizona State University Civil & Environmental Engineering Center G-Wing, Office ECG 140 P.O Box 875306 Tempe, AZ 85287-5306 Telephone: (480) 965-3895 Fax: (480) 965-0557 E-mail: paul.c.johnson@asu.edu DoD Liaison: Ms. Kira Lynch U.S. Army Corps of Engineers Seattle District 4735 East Marginal Way, South Seattle, WA 98134 Telephone: (206) 764-6918 Fax: (206) 764-3706 E-mail: kira.p.lynch@usace.army.mil | 
