SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM SEDIMENT REMEDIATION ACTION TEAM MEETING
Radisson Plaza Lord Baltimore
Baltimore, Maryland
February 18-19, 2004

WELCOME AND INTRODUCTIONS
Dennis Timberlake, National Risk Management Research Laboratory (NRMRL)—U.S. EPA
Nancy Grosso, Dupont Corporate Remediation

Dennis Timberlake and Nancy Grosso, co-chairs of the Remediation Technologies Development Forum’s (RTDF’s) Sediments Remediation Action Team, welcomed meeting attendees (see Attachment A (PDF, 8 pp., 37 KB)) and reviewed the conference agenda. Grosso indicated that the purpose of the meeting was to update members about ongoing RTDF projects and discuss the state of development for in situ treatment technologies in sediment remediation. She added that the focus of the meeting would be on chemical and biological approaches, and sequestration/immobilization approaches. Grosso mentioned that the group will post a thorough meeting summary with accompanying presentations to the RTDF Web site (www.rtdf.org).

GENERAL SESSION
Project Updates

EPA’s Contaminated Sediment Remediation Guidance for Hazardous Waste Sites
Leah Evison, U.S. EPA—Office of Superfund Remediation and Technology Innovation (OSRTI)

Evison reported that EPA’s OSRTI is developing a technical guidance document for sediment remediation at hazardous waste sites. She said that the document should be ready for a final review in May/June 2004. The final version will differ significantly from an earlier draft, Evison said, noting that OSRTI made extensive revisions to the latter after collecting comments from industry, state, and environmental groups at workshops held during 2003. Evison advised the group of the following changes:

• Chapter 1: Introduction—Increased emphasis has been placed on assessing and addressing floodplain soils, upland sources, and background levels. In addition, a more detailed focus on understanding ongoing versus historical sources of contamination has been added.
• Chapter 2: Remedial Investigation—A new section assessing trend stability using sediment trend analysis has been added, and the Conceptual Site Model has been adapted to include information on bioavailability.
• Chapter 3: Feasibility Study—New sections on state cost share and the long term effectiveness and permanence of remediation have been added.
• Chapter 4: Monitored Natural Recovery (MNR)—Evison indicated that there are many potential natural recovery processes including sorption, burial, diffusion, advection, and dispersion (listed in the general order of preference). Each is an acceptable method of remediation, although their effectiveness will depend on general site conditions. Information on revised lines of evidence supporting MNR, including historical trends and predictive tools, were also added.
• Chapter 5: In Situ Capping—OSRTI added information on enhancing the chemical isolation capacity and/or decreasing the thickness of caps. In addition, the document was changed to emphasize performance monitoring and the importance of using extra care during the design phase.
• Chapter 6: Dredging and Excavation—OSRTI revised the text to place greater emphasis on predicting and minimizing resuspension, contaminant transport, and the underestimation of residuals. Instead of offering a full endorsement of specialized equipment, the document was revised to recognize the advantages of using traditional equipment.
• Chapter 7: Remedy Selection—Evison emphasized the distinction between principal threat and low-level waste. If a waste threat is low-level, then MNR and in situ remedies should be considered. As the risk level rises, project managers should consider the level of uncertainty associated with the effectiveness of each remedy. When uncertainty is high, the remedy selection should be more closely scrutinized.
• Chapter 8: Monitoring—The review team clarified the importance of good baseline data, monitoring plans, and the lines-of-evidence approach to decision criteria.

Evison closed by noting that the document should be more general and avoid a prescriptive tone.

EPA’s Contaminated Sediment Technical Advisory Group (CSTAG)
Steve Ells, U.S. EPA—OSTRI

Ells provided an outline of CSTAG’s goals and an update of the seven CSTAG project sites (see Attachment B (PDF, 22 pp., 205 KB)). The goals include (1) helping project managers manage and investigate sites, (2) establishing a network to share information and encourage consistency in the management of sediment remediation sites, and (3) providing a mechanism for monitoring and evaluating various remedies at large, complex sites.

Ells said that CSTAG performs site visits, noting that each site visit includes (1) a half day briefing by the project managers, (2) a half day visit to the site (by car, foot, or boat), and (3) a half day meeting allowing stakeholders (state representatives, trustees, and community groups) to share opinions and provide feedback on how EPA is meeting the needs of the site and the community. Based on visits to six contaminated sites, Ells provided examples of recommendations made by the CSTAG team based on the 11 EPA principles for managing sediment remediation sites (site locations are noted in parentheses).

• Control sources early—Portland Harbor (Portland, OR).
• Involve the community early and often—Kalamazoo River (Kalamazoo, MI).
• Coordinate with states, local governments, tribes, and natural resource trustees—Palos Verdes Shelf (Los Angeles, CA).
• Develop and refine a conceptual site model that considers sediment stability—Kalamazoo River.
• Use an iterative approach in a risk-based framework—Houstatonic/Rest of River (Pittsfield, MA).
• Carefully evaluate the assumptions and uncertainties associated with site characterization data and site models—Lower Duwamish Waterway (Seattle, WA).
• Select site-specific, project-specific, and sediment-specific risk management approaches that will achieve risk-based goals—Lower Duwamish Waterway.
• Ensure that sediment cleanup levels are clearly tied to risk management goals—Houstatonic/Rest of River.
• Maximize the effectiveness of institutional controls and recognize their limitations—Kalamazoo River.
• Design remedies to minimize short-term risks while achieving long-term protection—Palos Verdes Shelf.
• Monitor during and after sediment remediation to assess and document remedy effectiveness—Ashland/Northern States Power Lakefront (Ashland, WI).

Ells added that CSTAG intends to make follow-up visits to sites in Kalamazoo, Michigan, Ashland, Wisconsin, and Pittsfield, Massachusetts during Fall 2004. In addition to these activities, OSRTI has plans to (1) open a Superfund Sediment Resource Center, (2) develop four new fact sheets, and (3) set up panel discussions at the National Sediment Conference in St. Louis, Missouri, which is scheduled to take place October 26-28, 2004.

Sediment Management Work Group (SMWG)
Nancy Grosso, Dupont Corporate Remediation

Grosso indicated that the SMWG was formed in May 1998 to advance risk-based, scientifically sound approaches for evaluation of sediment management decisions. To accomplish this goal, the group collects, develops, analyzes, and shares data on the effectiveness of sediment management technologies and approaches. Grosso summarized the group’s past initiatives and highlighted current pursuits, which include:

• Gaining acceptance of the SMWG Risk-Based Framework.
• Continuing the dialogue on EPA’s draft Contaminated Sediment Remediation Guidance.
• Supporting efforts to develop a methodology for evaluating MNR.
• Developing a methodology for evaluating sediment stability and dialogue on its regulatory acceptance.
• Supporting regulatory acceptance of MNR and capping.
• Continuing the active dialogue regarding a risk-based program for sediment management.
• Developing a Comparative Net Risk Reduction Methodology.
• Advocating expansion of CSTAG’s role to include early review of evaluation and remedy selection decisions consistent with Headquarters’ scientific policy.
• Maintaining dialogue with the International Joint Commission on adopting the SMWG Framework for Great Lakes Sediment Sites.

Grosso also announced that SMWG plans to deliver a presentation at the National Sediments Conference, which is scheduled to take place in St. Louis, Missouri, October 26-28, 2004 (see Attachment C (PDF, 14 pp., 167 KB) for Grosso’s presentation).

Interstate Technology Regulatory Council’s (ITRC) Contaminated Sediments Team
Brad Helland, Washington Department of Ecology

Helland introduced himself as a member of the ITRC, a state-led coalition dedicated to achieving regulatory acceptance of innovative environmental technologies. He explained that the ITRC’s Contaminated Sediments Team is working on a technical regulatory document that addresses the problems associated with contaminated sediments. The document will include definitions, conceptual site models, risk assessments, source controls, and remediation strategies. Regulatory challenges and stakeholder concerns will also be an integral part of the document. Helland concluded by submitting a formal request for case studies and/or lessons learned focusing on innovative remediation technologies (see Attachment D (PDF, 16 pp., 99 KB) for Helland’s presentation).

Group members commented that the ITRC is a good vehicle for transmitting technical information to state regulatory staff, and that the ITRC’s work is necessary to help break down regulatory barriers that exist at the state and federal levels.

ACTION TEAM GENERAL BUSINESS ITEMS

Monitored Natural Recovery (MNR) Subgroup’s Framework and Associated Papers/Presentations
John Davis, The Dow Chemical Company

Davis said that the focus and goal of the MNR Subgroup is to develop a framework for the technical evaluation of MNR in contaminated sediments (see Attachment E (PDF, 11 pp., 550 KB)). In addition, he informed the audience of the Subgroup’s effort to develop case histories that assess the effectiveness of MNR. Davis said that Subgroup members have succeeded in developing a framework that embraces a weight-of-evidence approach to assessing effectiveness, noting that the MNR framework includes five essential lines of evidence:

• Historical record of source controlCIncluding internal and external sources.
• Characterization of fate and transport processesCInvolving both sediment and chemical processes.
• Historical records of contaminants in sedimentsCUsing past sampling events and sediment cores.
• Trend analysis of relevant biological endpointsCIndicating if biological recovery is occurring.
• Development of predictive toolsCDetermining whether observed risk reduction is expected to continue into the future.

Davis said that Subgroup members recently presented this framework at the International Conference on Remediation of Contaminated Sediments in Venice, Italy. Davis indicated that five manuscripts were produced at this conference and will soon be made available to the public. Davis added that the MNR group is working with RTDF and OSRTI to get input on each of the manuscripts and will post papers to the RTDF web site once input is provided.

Ground Water—Surface Water Interaction Subgroup’s Document
Nancy Grosso, Dupont Corporate Remediation

Grosso indicated that a RTDF Sediment Remediation Action Team Subgroup is in the process of producing a document that summarizes the proceedings of a Ground WaterCSurface Water (GW/SW) Workshop that was held in October 2002 (see Attachment F (PDF, 8 pp., 1,145 KB)). The document summarizes technical issues from the workshop and presents discussion topics and associated conclusions in an organized manner. Grosso noted three areas of consensus that were reached at the workshop:

• The need to develop a sound conceptual model to evaluate GW/SW interaction.
• The importance of framing the scale of investigation around the questions posed.
• Several conditions, including physical and biochemical processes, affect the fate and transport of contaminants from GW to SW.
• Grosso noted that the summary document is in final draft form and will soon be posted to the RTDF Web site. Some of the technical issues that require further discussion include:
• How to approach evaluation at a site where no impact is apparent and only GW quality data are available.
• How to approach evaluation when multiple inputs are likely.
• How to assess in large tidal and estuarine settings where watershed-scale problems are likely.

Miscellaneous Business Items (PDF, 4 pp., 37 KB)
Nancy Grosso (Dupont Corporate Remediation) and Dennis Timberlake (EPA)

Timberlake and Grosso indicated that the actions taken by the Sediments Remediation Action Team are dictated by those who attend the meetings and technical workshops. While activities such as technical workshops are useful, the group is striving towards collaborative research efforts in the field and laboratory to develop or improve remediation technologies for contaminated sediments. The co-chairs opened the floor to the audience, asking for ideas on how the Action Team can better spend its energies. Audience members suggested exploring the following topics:

• GW/SW measurement technologies and associated case studies.
• Using tracers with a comparison to temperature.
• Studying non-aqueous phase liquid (NAPL) movement in GW/SW.
• Evaluating the cost-effectiveness of using in situ probes to determine metal speciation.
• Integrating metal chemistry into fate and transport.
• Expanding knowledge of physical/geologic characteristics of sediments. (Plume analysis is available but sediment data is lacking.)
• Conducting technology bench-marking. Determine what characteristics of soil interfaces lack remediation technologies, study these areas, and develop technologies that address weaknesses.
• Interaction of surface water circulation and pore water in loosely consolidated sediments.
• Field study of the chemical oxidation of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs).
• Use of geotextiles as a bio-intrusion barrier to benthic organisms.
• Delivery mechanisms of in situ treatment technologies—Moving from the laboratory to the field.

WORKSHOP—IN SITU TREATMENT TECHNOLOGIES FOR CONTAMINATED SEDIMENTS

Workshop Agenda, Process, and Goals
Kelly Madalinski, OSRTI, U.S. EPA

Madalinski reviewed the workshop agenda and indicated that the goals of the workshop are to (1) highlight research and development work, (2) capture the state-of-development among in situ treatment technologies, (3) learn and share experiences about the application of technologies, and (4) discuss potential collaborative efforts (see Attachment G (PDF, 10 pp., 46 KB)). He noted that the workshop will consist of short presentations and general discussions on in situ technologies, including biological/chemical approaches and immobilization/sequestration approaches.

Panel 1: Chemical and Biological Approaches

In Situ Enhancement of Anaerobic Microbial Dechlorination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) in Marine and Estuarine Sediments
Max Haggblom, Rutgers University

Haggblom explained that his work at Rutgers University focuses on developing strategies for in situ enhancement of microbial activity including (1) redox manipulation, (2) electron donor addition, and (3) the addition of “haloprimers” (see Attachment H (PDF, 27 pp., 1,393 KB)). His team works locally in areas that contain high concentrations of dioxins (such as the Passaic River and New York/New Jersey (NY/NJ) Harbor). Haggblom indicated that he spends a lot of his time studying sediments in search of dehalogenating bacteria. The goals of his team are to (1) identify organisms responsible for dechlorination, and (2) identify environmental conditions that enhance and accelerate dechlorination of PCDD/Fs by native microbial populations.

Haggblom indicated that at increasing depths within a marine system, an array of different anaerobic microbial processes are observed. His studies suggest that the presence of sulfates in the sediment almost completely shuts down microbial processes. Haggblom’s goal is to speed up dechlorination processes by developing and adding enrichment cultures to the sediment. Thus far, his team has created a pure culture model that inhibits undesirable microbial activity and stimulates desired dechlorination activities. Haggblom concluded that:

• The capacity for anaerobic PCDD/F dechlorination appears to be widely distributed in estuarine/marine environments.
• The activities and interactions of diverse microbial populations will affect the fate of organohalides.
• Dehalococcoides ethenogenes strain 195 can dechlorinate PCDD/Fs and other halogenated aromatic compounds.
• The activity of dehalogenating bacteria can be stimulated with select “haloprimers” to enhance bioremediation of contaminated sediments.

Hydrogen Enhancement of Sediment Microbial Activity and Contaminant Degradation
Peter Adriaens, University of Michigan
John Wolfe, Limno-Tech, Inc.

Adriaens informed the group that his report is the culmination of 12 years of research, development, and implementation (see Attachment I (PDF, 21 pp., 293 KB)). He thanked Haggblom for establishing a solid framework on dioxins and noted that he would cover less dioxin microbiology and would instead emphasize the application of remedial strategies. Adriaens added that he would cover the scientific principles and technology development of sediment remediation strategies while his partner, John Wolfe, would focus on technology implementation.

Adriaens and Wolfe set out to determine whether the microbiology within the sediment is limited by the hydrogen pool. They intended to find whether the hydrogen pool can be enhanced by adding a low-concentration dissolved hydrogen substrate designed to enhance the total respiratory competence of the sediment. They found that the addition of hydrogen not only increases the metabolic competence of the sediment, but it actually enhances the dechlorination of historically contaminated dioxins and PCBs. Adriaens noted that hydrogen gas is relatively cheap and diffuses rapidly into the sediment. Thus, he concluded that injecting hydrogen into sediments is a feasible in situ remedial strategy. Adriaens noted, however, that before this strategy can be instituted effectively, a number of scientific challenges need to be addressed. For example, Adriaens said, his team needs to (1) gain a better understanding of how hydrogen diffuses in the sediment; (2) develop a correlation between hydrogen enhancement, ecological response and dechlorination activity; and (3) study a number of temporal effects including the impact of bioavailability on long-term activity.

Wolfe presented the results of experiments conducted by Limno-Tech, Inc. and the University of Michigan on how to implement the aforementioned remedial strategy into the field. The team began with bench-scale studies of hydrogen amendment using cell elutions, slurries, and a sediment column. Successful enhancement of reductive microbial activity was demonstrated in each case, and promising results for contaminant degradation were also obtained. These studies are continuing, with plans to move to a more complex field pilot. A number of unresolved issues remain:

• What is the ideal form of hydrogen to introduce?
• To what depth do you inject the hydrogen?
• How do you minimize resuspension?
• What is the optimal spacing of injection points?

Wolfe said that this is just the first report in a 5-year study, noting that the team intends to resolve these issues in the near future.

In Situ Dechlorination of PCBs in Sediments using Zero-Valent Iron (ZVI)
Kevin Gardner, University of New Hampshire

Gardner discussed the effectiveness of introducing ZVI to dechlorinate PCBs in contaminated sediments (see Attachment J (PDF, 28 pp., 625 KB)). His team used various sizes of ZVI on contaminated sediments from sites such as to New Bedford, Massachusetts. They worked with fine-grain sediments containing high concentrations of organic carbon and found that while nanoscale ZVI achieves the desired remedial effect faster than microscale iron, each has the same long-term effectiveness. Gardner noted that nanoscale ZVI is more expensive and dangerous to use than microscale ZVI; therefore, microscale iron is a more feasible option.

Gardner found that dechlorination occurs extremely fast in the beginning stages and levels off as the contaminant degrades. He noted, however, that the iron may dissipate before the desired remedial effect is achieved. In addition, to avoid suspension of iron in the water column, Gardner’s team determined that the iron should either be mixed directly into the sediment or a reactive cap should be used. While the team does not know exactly how much a ZVI-based treatment approach would cost, Gardner estimates that materials will cost approximately $50 per cubic yard.

Panel 2: Chemical and Biological Approaches (continued)

Electrochemical GeoOxidation (ECGO) In Situ Sediment Treatment Technology
J. Kenneth Wittle, Electro-Petroleum, Inc.

Wittle indicated that the patented ECGO process for the mineralization of organic materials in sediments has been used extensively in Europe, with 50 sites and over 2 million cubic yards treated (see Attachment K (PDF, 60 pp., 2,902 KB)). He explained that electrodes are placed at various injection points, creating an electrical current that adds electrons to the sediment and stimulates chemical reactions. Electro-Petroleum, Inc. is currently testing the ECGO technology on projects in New Jersey, Georgia, and Minnesota.

Wittle’s presentation focused on the Erie Pier demonstration project in Duluth, Minnesota, a project designed to provide realistic information on the cost, ease of implementation, and effectiveness of the ECGO process. His team constructed two test cells and initiated extensive monitoring of temperature, pH, and biological change within each environment. Wittle’s team found that (1) PAH concentrations were not significantly reduced, (2) PCB concentrations were reduced, (3) pH did not change, and (4) plant and animal life were not adversely affected. He concluded that because plant growth (humic acids) actually bind PAHs in the system, the ECGO technology must undergo more extensive testing before wide-scale implementation is feasible in sediments similar to those found at the Erie demonstration site. Wittle noted that such testing is currently underway at facilities in Coleraine, Minnesota.

Electrochemical GeoOxidation (ECGO) of PAH Contaminated Sediment Update on Erie Pier ECGO Demonstration
Tommy Myers, U.S. Army Corps of Engineers, Engineer Research and Development Center

Myers provided an update on the aforementioned Erie Pier ECGO demonstration project, concentrating on statistical analysis of the monitoring data (see Attachment L (PDF, 22 pp., 446 KB)). Using the same equipment and data as Wittle, Myers found that the ECGO process did not significantly affect the PAH or PCB concentrations. While the data show that PCB concentrations decreased, Myers concluded that this was not in response to the ECGO technology. Some audience members indicated that Myers’ six sampling events, with five cores per event, may not give a large enough sample size to utilize the analysis of variance technique upon which his conclusion lies.

Development of a Framework for Evaluation of Electrochemical Remediation Technologies for Treatment of In Situ Sediments at the Log Pond Site, Puget Sound, WA
Randy Parker, NRMRL, EPA

Parker, a program manager in EPA’s Superfund Innovative Technology Evaluation (SITE) program, explained that SITE encourages the development and implementation of innovative treatment technologies for hazardous waste site remediation. He added that the SITE team intends to create an evaluation framework based on electrochemical technologies used as part of a demonstration project in Puget Sound, Washington. Parker emphasized that the challenge to drafting this framework has been obtaining site-specific characterization data to support experimental plan development. While obtaining a proper sample size was difficult, his team found that baseline, intermediate, and final mercury and semi-volatile organic compound (SVOC) concentrations showed no change. In addition, Parker noted that system operational issues resulted in the early termination of his team’s demonstration project.

Limnofix In Situ Sediment Treatment Technology
J. Stephen Goudey, Golder Associates Inc.

Goudey gave a brief history of Limnofix and expanded on the numerous in situ treatment technologies the company utilizes. He presented a variety of Limnofix case studies, including efforts made in Hamilton Harbor (Ontario, Canada), the Shing Mun river (Hong Kong), and the Salem intertidal estuary (Salem, Massachusetts). Goudey’s presentation focused on the three main challenges associated with in situ treatment technolgies: (1) emplacing remedial technologies into the sediment, (2) containing the remedy to the sediment, and (3) assessing the effectiveness of the remedy.

Recap of Day 1 of the In Situ Treatment Technologies Workshop
John Davis, The Dow Chemical Company

Davis provided a comprehensive summary of the major findings presented on day 1 of the workshop (see Attachment M (PDF, 8 pp., 100 KB)). He noted that the first session stressed the importance of preparing a technology for the field and determining how to deliver reagents, catalysts, or substrates and nutrients to sediments. In addition, Davis said, the first session emphasized emplacement/containment issues and discussed how bioavailability affects remedial effectiveness. He noted that the second session focused more on case study analysis of in situ treatment technologies and the difficulties that arise when evaluating the effectiveness of each strategy.

Throughout day 1, presenters referred to design and delivery as the keys to a successful treatment technology. To be successful, developers must determine: (1) how to get to the sediment, (2) what depth to treat, and (3) how to minimize sediment resuspension. Davis noted that researching these questions is the key to successful treatment development and implementation. The recap concluded with a brief brainstorming session summarizing the characteristics of an ideal pilot site. The audience agreed that an ideal site will (1) contain high concentrations of organic carbon, (2) include cohesive sediments, (3) be located in shallow water, and (4) have low-energy, depositional characteristics.

Panel 3: Sequestration/Immobilization Approaches

In Situ Stabilization of Persistent Organic Contaminants in Marine Sediments
Upal Ghosh, University of Maryland

Ghosh’s presentation focused on understanding (1) where PCBs and PAHs bind in sediment, (2) what types of compounds these contaminants bind to, and finally (3) what organisms can be used to invade these compounds and breakdown PCBs and PAHs (see Attachment N (PDF, 34 pp., 2,345 KB)). His study utilized a Navy shipyard in San Francisco Bay to study these compounds at the particle scale. His team determined that PCBs and PAHs preferentially accumulate in coal, charcoal, and coke, where they are strongly bound and less bioavailable. With this in mind, the team set out to determine whether they could enhance the binding process by adding granular activated carbon (GAC).

Using three types of benthic organisms (indigenous bivalves, estuarine amphipods, and infaunal deposit feeding polychaete worms), the team was able to study PCB and PAH bioaccumulation reduction with the addition of GAC. After a month of exposure, Ghosh found that the addition of GAC reduces PCB bioaccumulation in all three benthic organisms. The test was repeated using a semi-permeable membrane device that simulates absorption into lipids of an organism. After a month of exposure, Ghosh once again found that GAC reduces PCB uptake.

Ghosh emphasized the challenges associated with injecting GAC into the sediment. The team tested a number of different mixing technologies with goals of (1) minimizing resuspension, (2) assessing the erosion potential of sediments mixed with GAC, and (3) evaluating the cost effectiveness of GAC injection to see if a large-scale study is feasible. Technologies tested included:

• Rotovator
• Tilling/disking equipment
• Low ground-pressure vehicles
• Dry solid injection
• Slurry injection
• Auger mixer

Ghosh noted that any action taken to reduce benthic uptake of PCBs/PAHs is beneficial, and at a cost of 40 to 70 cents per pound, GAC is a cost-effective way to accomplish just that.

Application of In Situ Solidification/Stabilization at the Koppers Co. Ashley River Superfund Site
Craig Zeller, Region 4, U.S. EPA

Zeller provided an update on an EPA effort to clean up a 102-acre site along the Ashley River in South Carolina (see Attachment O (PDF, 26 pp., 1,967 KB)). The 3-acre area of potential ecological concern (APEC) is heavily contaminated with NAPL and lies along 1500 feet of the Ashley River shoreline. The NAPL is at times over 15 feet deep, making dredging impossible and limiting the team’s remedial options.

Zeller’s team attempted to use enhanced sedimentation as well as a subaqueous cap, but external circumstances made these options infeasible. Instead, the team chose a 2-acre subaqueous sand/geotextile cap that is (1) less permeable than sand so it contains the NAPL problem, (2) at a minimal elevation so barges can travel the river unobstructed, and (3) a more cohesive layer that will withstand erosion. Zeller indicated that the cost of the project is approximately $230 per cubic yard and shows how solidification and stabilization can be possible.

Deep Soil Mixing in Solidification of Contaminated Sediments
Scott Douglas, Office of Maritime Resources, New Jersey Department of Transportation (NJDOT)

Douglas provided an update of NJDOT’s efforts to treat contaminated sediment in the NY/NJ Harbor and Passaic River (see Attachment P (PDF, 31 pp., 1,590 KB)). He indicated that NY/NJ Harbor contains 2 to 4 million cubic yards of contaminated sediment that is frequently dredged to enable marine travel, making resuspension a critical concern. NJDOT focuses on hot spots within the harbor, of which the Passaic River is of highest concern.

The Passaic River’s highest area of concern lies along the banks of a Brownfield site formally home to the pesticides manufacturer Diamond Alkali. The sediments along the banks contain high concentrations of mercury, lead, dioxins, PCBs, and PAHs. Douglas indicated that NJDOT plans to remove 300,000 cubic yards of contaminated sediment from the riverbed, and his team has instituted a pilot project utilizing deep soil mixing treatment technology to do so. During this process, NJDOT injects mixed slurry into the contaminated sediment, generating a stable/solid material that can be removed. The pilot has been tested in the port of Oakland, California, and Douglas hopes to replicate the process in NY/NJ Harbor. Issues that first must be resolved include:

• Determining an optimum slurry ratio.
• Determining an optimum curing time.
• Proving that hardened sediments can be efficiently excavated (with minimal sediment loss) using traditional dredging equipment.
• Documenting improved handling characteristics of hardened sediments.

Panel 4: Coupling Existing Approaches with In Situ Treatment

Enhancement of In Situ Biodegradation Rates of Hydrocarbons Through Innovative Cap Designs
Clay Patmont, Anchor Environmental, LLC

Patmont shared a number of case studies with the group focusing on the use of cap designs to enhance in situ biodegradation rates (see Attachment Q (PDF, 23 pp., 757 KB)). Patmont presented studies from Eagle Harbor, Washington, Duluth, Minnesota, and Seattle, Washington,with major findings including:

• Placement of a cap depresses PAH biodegradation rates by a factor of 10 due to reduced oxygen and sulfate supply.
• Nitrate amendments prove to be ineffective.
• Sulfate amendments show the potential to be effective.
• Cap-induced reduction of subsurface biodegradation rates is balanced by effective exposure and risk controls.

Patmont concluded that there is ample opportunity to enhance and/or maintain hydrocarbon biodegradation rates through innovative cap design. To be successful, he said, one needs to (1) identify the biodegradation rate limiting amendments, (2) incorporate these amendments below the capping layer, and (3) minimize cap thickness/maximize cap grain size for oxygen and sulfate diffusion from the overlying water column.

Update on Reactive Capping Project in the Anacostia River
David Constant, Hazardous Substance Research Center S and SW, Louisiana State University
Danny Reible, Louisiana State University

Constant provided an overview of the ongoing remediation project in the Anacostia River in Washington, DC (see Attachment R (PDF, 38 pp., 1,114 KB)). He noted that the site has varying concentrations of PCBs, PAHs, mercury, and 13 EPA priority metals. His team is interested in comparing the effectiveness of traditional and innovative capping methods and will set up numerous test cells for different cap designs beginning in March 2004. Constant indicated that his team will utilize monitoring instruments to measure river flow current, the benthic layer, cap stability, and seepage rates.

Constant concluded by sharing a number of lessons learned from the development of the Anacostia River project:

• Communication with and information transfer to stakeholders is key.
• Site selection and characterization is critical to progress.
• Technology testing is necessary.
• The permit approval process can be long and tedious.
• Use of a staging area is critical.
• Documentation of characterization, construction, and monitoring is essential.

Group Discussion and Wrap Up
Dennis Timberlake, U.S. EPA
John Davis, The Dow Chemical Company
Kelly Madalinski, U.S. EPA
Nancy Grosso, Dupont Corporate Remediation

The organizers for the workshop led a wrap-up discussion designed to help capture the state of development for in situ treatment technologies. Grosso indicated that the RTDF will post a meeting summary, including presentations, to the RTDF Web site in March 2004. In addition, the group intends to create a white paper capturing the ideas discussed during the workshop. Madalinski, Davis, Grosso, and Timberlake led a brainstorming session to highlight the ideas presented at the conference and determine a forward path. Discussion topics included:

• The importance of technology delivery and placement.
• The difficulties of expanding a technology to encompass a larger siteCmany technologies work in the laboratory, but how can success be ensured in the field?
• The importance of choosing what metrics and/or monitoring data to use.
• The limited resources available to conduct research and development projects for technologies.
• The potential to incorporate technological advances from other fields into sediment remediation.
• The difficulties and frustrations that arise with the pace of technological innovation.
• The need to address spatial variability.
• The choice of pilot study sizeCappropriate scale is often difficult to determine.

Madalinski concluded by thanking the speakers for presenting, the audience for attending, and the group members for organizing the two-day session. He added that he, Grosso, Davis, and Timberlake will be creating a white paper based on the ideas discussed and asked that the audience contact him by email if they are interested in participating.

ATTACHMENTS A THROUGH R

SUMMARY OF THE REMEDIATION TECHNOLOGIES DEVELOPMENT FORUM
SEDIMENTS REMEDIATION ACTION TEAM MEETING
Radisson Plaza Lord Baltimore
Baltimore, Maryland
February 18-19, 2004