SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
PERMEABLE REACTIVE BARRIERS ACTION TEAM
STEERING COMMITTEE MEETING

Sheraton Oceanfront Hotel
Virginia Beach, Virginia
4:00 p.m.-6:00 p.m.
September 17, 1997

On September 17, 1997, members of the Permeable Reactive Barriers (PRB) Action Team Steering Committee of the Remediation Technologies Development Forum (RTDF) met in Virginia Beach, Virginia. The following members were present:

Bob Puls (Co-chair)
Tom Early
Bob Gillham
Gary Jacobs
Rich Landis
Robert Orth
Dale Schultz
Tim Sivavec
Rich Steimle
Steve White

Also present was Colin Devonshire of Eastern Research Group, Inc.

INTRODUCTION

Bob Puls informed the group that Steering Committee member Liyuan Luang recently left Oak Ridge National Laboratory and thus would no longer serve on the committee. Puls said that her position will be filled by another representative of the Department of Energy (DOE); probably either Tom Early or Gary Jacobs. The Action Team also needs to recruit a new co-chair to take the place of Dale Schultz, who recently stepped down.

LONG-TERM PERFORMANCE RESEARCH STRATEGY

Puls said that since its inception, the PRB Action Team has made the long-term performance of PRBs its primary focus. Within the last 6 months, members of the Steering Committee wrote a paper to define some long-term performance issues and then incorporated the ideas into several recent proposals submitted to agencies including DOE, the U.S. Environmental Protection Agency's (EPA's) Technology Innovation Office, and the Department of Defense (DOD). None of these proposals was successful, and Puls noted that over the last 18 months numerous other PRB proposals submitted by parties associated with the Action Team were also unsuccesssful. Although each proposal has had a unique slant, they have shared some common threads, and several of them have touched on the issue of long-term performance. Puls asked the group if assessing long-term performance was still the Action Team's first priority. He said he would like the RTDF to help coordinate disparate PRB research efforts to meet the specific needs of each funding source (e.g., DOE, EPA, DOD, industry, etc.) in order to gain research funding.

The group agreed that long-term performance remains the most important research area for the advancement of PRB technology. Several members pointed out, however, that it is difficult to determine long-term performance until a group of PRB systems can be operated and studied for several years. Puls said that some members of the Steering Committee envisioned collecting core samples over time from three to five sites. Analysis would focus on correlating the local geochemistry of each site with observed effects on the cores from each PRB and on assessing microbial effects on PRB performance. Tim Sivavec said this research also should identify aqueous geochemical analyses that can be used to measure activity of the reactive walls. Sivavec pointed out that the budgets for upcoming PRB installations may not be able to accommodate more monitoring wells, but this additional instrumentation is needed to provide a picture of geochemical changes throughout the reactive walls. Sivavec said monitoring wells that simply measure input and output ground water cannot show the geochemical or microbial changes occurring as ground water passes through the PRB. The group agreed that a common problem in these projects is finding enough funding to equip the PRB with instruments to measure performance, when the minimum instrumentation requirements for compliance monitoring are much less costly. Rich Steimle said that recent proposals have failed to explain the importance of measuring long-term performance, namely, that many PRBs are being proposed for remediation without sufficient proof of their long-term efficacy. The group discussed efforts to use accelerated testing to simulate long-term performance of PRBs. Members pointed out that these methods still differ from actual field conditions. Puls said that studying three sites that are well-instrumented for a variety of performance parameters would greatly improve the Action Team's confidence in its understanding of PRB technology.

Research Funding

The Steering Committee agreed that since long-term performance is still its top priority, the most important question is how to raise funds for the required research. Tom Early said it was his understanding that while some agencies (e.g., DOE, EPA, DOD) may be interested in an interagency PRB research project, they rejected the recent PRB proposals because the timing of the projects was unsuitable. Early said that these agencies may be interested in revisiting a coordinated set of proposals in fiscal year 1999. Others concurred that the proposals would be more successful if coordinated to leverage funds from several agencies at once. Early and others noted, however, that each agency will likely have its own specific research needs that any joint research effort will have to address. Thus, incorporating more funding sources will increase the scope and cost of the overall project.

Members said that a subgroup is needed to identify potential funding sources, which could then be targeted by a single proposal in a "shotgun approach." This subgroup must identify the research and technical needs of each funding source and address them in the proposal. Steve White said that DOD may want to fund research only for DOD sites. Sivavec said that the proposal should focus on existing PRB sites rather than proposed or planned sites. Sivavec also said that the proposal should sell the fact that a major goal of this research would be to develop a PRB design and construction protocol that will reduce the amount of monitoring required on future PRBs.

The group proposed a number of possible sites to be addressed by this research:

• Lowry, Colorado. Coring at this site is unusually complicated.

• Elizabeth City, North Carolina. The thickness of this reactive barrier (only 2 feet) may be a problem, although members noted that most of the breakdown reactions seem to occur in the first foot of the reaction zone.

• Somersworth, New Hampshire

• Moffet Field, California

• Dover Air Force Base, Delaware. This site has very dilute ground water.

• Denver Federal Center, Colorado

Also mentioned were sites at Oak Ridge National Laboratory, Rocky Flats, and Kansas City.

The group discussed the following possible funding sources:

• EPA

• Waste Committee
• National Risk Management Research Laboratory
• SITE Program

• DOE

• DOD

• Strategic Environmental Research and Development Program
• Environmental Security Technology Certification Program
• Construction Engineering Research Laboratory
• Base-level sources

Puls said the subgroup should pull together a coordinated and coherent proposal for an interagency research project that incorporates both the Action Team's desired scope and the research and technical requirements of all the potential funding sources. He asked the following members to inquire at their respective agencies and to identify their specific requirements for funding PRB research:

• Tom Early and Gary Jacobs: DOE

• Bob Puls and Tim Sivavec: EPA and General Electric

• Steve White, Ed Marchand, and Dennis O'Sullivan: DOD

Puls asked these members to prepare this information by the end of October and suggested that the subgroup meet in November to integrate their findings into a comprehensive proposal to be completed by the end of the calendar year. The Steering Committee will have to submit this proposal in February 1998.

Members acknowledged that not all of the sources may agree to provide funding. Puls said he thought the Steering Committee could ensure success by feeling out each agency to determine its specific needs. Early said it was his understanding that DOE is prepared to dedicate funding to this research.

Research Approach

Bob Gillham pointed out that even if such a proposal were successful, comparing data from multiple sites will necessitate standardized research protocols (e.g., sampling, laboratory analyses). Puls said that it was unclear how such an interagency project might actually execute this PRB research. Puls suggested dividing the project among principal investigators from each agency, who would oversee and coordinate the various research areas (e.g., geochemical characterization, microbial activity). Some members were hesitant about this approach, and all agreed that, while there are several ways to divide the project among the funding sources, the project's structure will ultimately depend on the specific agencies involved. Puls and Early said that rather than develop multiple interagency agreements, it might be easier to focus the funds from each agency on a discrete segment of the overall project. Members discussed the possibility of using one contractor, one field crew, and one analytical laboratory to perform the work for all the involved sites. Sivavec said the research should use existing analytical protocols as much as possible to reduce costs.

ADDITIONAL STEERING COMMITTEE GOALS

The group discussed its need to expand the Action Team's scope to other reactive media and contaminant classes besides zero-valent iron and chlorinated solvents, respectively. Early said that DOE is interested in PRBs for treatment of radionuclides. Puls said the United States Geological Survey (USGS) is studying multiple-treatment (e.g., zero-valent iron, phosphate precipitation) PRB remediation of uranium at Fry Canyon, Utah. Dale Schultz asked the group if there is interest in using biological PRBs to oxidize hydrocarbons. Members were aware of a few areas of interest in the topic, including one DOD site, and an ongoing investigation of oxygen-releasing compounds at the University of Waterloo.

NEXT ACTION TEAM MEETING

Puls proposed that the Action Team devote its next full meeting to alternative media (e.g., biological media, zeolites) and contaminant classes (e.g., acid mining waste, radionuclides, hydrocarbons). The group agreed that such a meeting should focus, as much as possible, on field applications of these methods rather than laboratory investigations. Puls said the Steering Committee should spend the next few months searching for suitable parties to speak at this meeting.

Puls asked how often the Action Team should hold its general meetings. While in the past the meetings have been every 3 or 4 months, members suggested holding them every 6 months in the future because PRB projects did not seem to progress quickly enough to warrant meeting more frequently.

Sivavec told the group that Battelle Pacific Northwest National Laboratory will hold a large conference in the spring that will include several sessions on PRBs, and the Action Team should avoid overlapping its meeting topics with those of the Battelle conference. Puls asked if the meeting should have a different format to distinguish it from typical conferences. White suggested scheduling discussion panels for each related group of presentations. Members agreed that the meetings should continue to feature field trips to relevant PRB sites. Puls said the next field trip should be to an alternative media/contaminant site such as Fry Canyon, Utah, and asked the group to look for other suitable locations. Members suggested additional meeting topics, including destructive media, monitoring systems, and PRB construction methods, and also discussed having a poster session for presentations by PRB-related suppliers and contractors. Puls suggested the Action Team hold its next full meeting in March and said the Steering Committee could discuss the exact date and location in a future conference call.

ACTION ITEMS

• By the end of October, the proposal subgroup will define the research requirements of the potential funding agencies.

• Some members of the subgroup will meet before Thanksgiving to combine these requirements into a comprehensive proposal, to be completed by the end of the calendar year.

• The Steering Committee will search for a location and speakers for the next Action Team meeting, tentatively scheduled for March 1998, which will focus on alternative media and contaminant classes.