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

Best Western Winrock Inn
Albuquerque, New Mexico
October 25, 2004

On Monday, October 25, 2004, the following members of the Remediation Technologies Development Forum’s (RTDF’s) Permeable Reactive Barriers (PRB) Action Team Steering Committee met:

Bob Puls, U.S. Environmental Protection Agency (EPA)
John Vidumsky, DuPont
Bob Gillham, University of Waterloo
Tom Krug, GeoSyntec
Chuck Reeter, U.S. Naval Facilities Engineering Service Center

Tom Sale of Colorado State University and Christine Hartnett of ERG were also present.

INTRODUCTION

Bob Puls and John Vidumsky thanked the participants for attending and said that two topics would be discussed: (1) providing assistance to a group in Chile and (2) identifying opportunities for the RTDF to participate in field work activities.

PROVIDING SUPPORT TO FUNDACIÓN CHILE

Puls said that Fundación Chile plans to initiate several remedial projects in the near future, some of which might involve PRBs. Puls said that Juan Ramon Candida—one of Fundación Chile’s representatives—has expressed interest in having the PRB Steering Committee review some of the proposed projects.

The RTDF PRB Action Team recently expanded its mission to encompass the idea of using iron as a treatment strategy for contaminated source zones. This decision has prompted Steering Committee members to look for opportunities to conduct some field work. The goal is to identify an existing source-zone-treatment project and identify ways that the RTDF can add value to the project. Attendees talked briefly about the type of support the RTDF can offer. Puls did not know whether EPA would be able to supply money for field work, but he did say that the Agency would be able to provide in-kind services, such as labor and analytical laboratory services. Chuck Reeter said that the Navy is in the same position: while the Navy can commit to providing in-kind services, it is unclear how much money will be available for environmental projects in the coming year. Attendees talked about the issues they want to explore in the field. They expressed the following ideas:

• Identifying cheaper and better monitoring methods. Attendees agreed that reliable and affordable monitoring techniques are needed for measuring the impact treatment strategies have on source zones.
  
  
• Measuring flux reductions. Attendees talked about measuring the impact that treatment has on contaminant flux. They agreed that it would be useful to measure flux reduction in source zones as well as downgradient areas.
  
  
• Comparing the performance of different source treatment technologies. Several iron-related technologies have been proposed as treatment strategies for source zones. These include nanoscale iron, emulsified zero-valent iron (EZVI), and iron-clay mixing. Bob Gillham said that it might be interesting to perform side-by-side comparisons of these technologies.

Attendees tried to identify sites that would be good candidates for field study. They identified four sites, all of which have started (or plan to start) source zone treatment activities:

• Measuring flux reductions. Attendees talked about measuring the impact that treatment has on contaminant flux. They agreed that it would be useful to measure flux reduction in source zones as well as downgradient areas.
  
  
• DuPont’s Martinsville site. Vidumsky and Sale provided information about this site, which has a well-defined source zone and is contaminated with carbon tetrachloride. An iron-clay mixture was emplaced in the source zone about 2 years ago, Sale said; ground water and soil samples have been collected to examine how effective treatment has been. Although extensive monitoring has already been performed, there are some interesting questions that still merit exploration at this site: Is the iron still reactive? What happened to the methylene chloride? Did the sampling methods introduce some bias?
  
  
• DuPont’s Florence site. Sale provided information about this site, which has a 40-foot by 40-foot by 40-foot source zone. Contaminants detected at this site include carbon tetrachloride, 1,1,2,2-trichloroethane, xylene, and chloroform. Although evidence suggests that the contaminant plume is naturally attenuating, DuPont plans to launch a source zone remediation effort during the second or third quarter of 2005. (Efforts will be made to keep the project under the $200,000 mark.) More characterization needs to be performed, however, before proceeding with remediation.
  
  
• Navy’s Camp Lejeune site. Sale and Reeter provided information about this site, at which a drycleaner is the suspected source of contamination. Sale said that dense nonaqueous-phase liquid (DNAPL) has been detected but that contaminant concentrations in the soil are fairly low. About 4 years ago, surfactant cosolvent flushing was performed in an effort to address the site. In about 4 to 6 weeks, another remedial strategy—clay-iron deep mixing—will be deployed. Sale said that CH2MHILL, the contractor hired to address the site, welcomes the idea of getting the RTDF involved. Before deciding whether to accept this offer, Sale said, Steering Committee members should be aware of the fact that the site has a complicated source zone and it is generating some gas.
  
  
• Navy’s Indian Head site. Tom Krug said that the Strategic Environmental Research and Development Program/Environmental Security Technology Certification Program (SERDP/ESTCP) is funding an effort to evaluate EZVI’s efficacy. At this point, the research team is performing laboratory studies to determine whether EZVI-induced degradation processes are biotic or abiotic. Assuming that the laboratory phase goes well, funds will be provided to deploy EZVI in the field in summer 2005. Indian Head, a site with contaminants in the DNAPL range, has been identified as a candidate for field application. Krug said that the remediation team would like to establish two subplots within Indian Head’s source zone and perform a side-by-side comparison of two installation methods. More characterization needs to be performed to determine the full extent of the source zone. If it proves to be small, the demonstration project might encompass most of it.

ACTION ITEMS

• Several Steering Committee members said that they planned to attend the SERDP/ESTCP meeting that is scheduled to take place in Washington D.C., November 30 through December 2, 2004. They agreed to reconvene at that meeting and continue talking about opportunities for the RTDF to get involved with field work. Krug said that he plans to visit the Indian Head site on November 30, 2004; if anyone is interested in joining him, they should contact Krug and Reeter as soon as possible to make plans.
  
  
• Puls said that he would like more information on all four of the sites that were mentioned during the meeting. Krug agreed to distribute the proposal that was put together for the SERDP/ESTCP project. Sale agreed to write brief summaries for the three sites (i.e., the Martinsville site, the Florence site, and Camp Lejeune) that he had discussed during the meeting. (He will complete these summaries before the abovementioned SERDP/ESTCP meeting takes place.)