On Tuesday, November 14, 2000, members of the Remediation Technologies Development Forum’s (RTDF’s) Sediments Remediation Action Team met for a discussion. The Action Team meeting was held during a conference of the Society for Environmental Toxicology and Chemistry (SETAC). Attendees are listed in Attachment A.

DIRECT-CURRENT TECHNOLOGY

Dick Jensen welcomed the meeting participants and said the objective of the meeting was to decide whether RTDF should apply for funding from the Great Lakes National Program Office (GLNPO) to demonstrate a promising sediment remediation technology called direct-current technology. (Direct-current technology, a variant of conventional electrokinetic technologies, is currently being marketed by Weiss Associates and Electro-Petroleum, Inc.) Jensen wanted the group, in making its decision, to consider the technology’s viability.

Direct-current technology, first presented to the group at the September 2000 RTDF meeting in Wilmington, Delaware, by Joe Iovenitti, surpasses the conventional electrokinetic technologies demonstrated up to now. The most important way in which it does this is destroying organic chemicals, such as polycyclic aromatic hydrocarbons (PAHs), in situ. In addition, using the technology does not require adding chemicals or pumping contaminants from one electrode to another. Direct-current technologies have been demonstrated in Europe and will soon be tested here in the United States, in Seattle and New Jersey.

Joe Iovenitti and his business partner, Ken Wittle, provided an overview of the direct-current technology. Much of Iovenitti’s overview was repeated from the presentation he gave at the September 2000 meeting. During this discussion, though, Iovenitti and Wittle shared more details about the technology. For example, Wittle pointed out that the technology does not affect the pH of the soil being remediated. Iovenitti provided data on pH behavior at a field site in Germany to prove this. Jensen emphasized the importance of this fact. With conventional electrokinetic technologies, because pH does not remain near-neutral, metals tend to precipitate out randomly within the soil rather than at the electrodes themselves.

Iovenitti and Wittle mentioned other details about direct-current technology:

• While the technology is being used, reactions occur not only at the soil-water and contaminant-water interfaces but also at the electrodes.

• The time needed for remediation depends more on the contaminants involved than on the type of substrate. Iovenitti said it takes 75 to 90 days to remove fuel hydrocarbons and up to 275 days for polychlorinated biphenyls (PCBs).

• The technology requires moisture—water or humidified air—to operate.

• If the sediment is gravel or sand, carbon dioxide vacuum stripping wells must be used to deal with the aqueous phase.

• The amount of material needed for the process to work ex situ is 500 tons of soil (not 500,000 tons as reported in an earlier meeting summary).

• Wittle said an interesting phenomenon occurs when the technology is used: in the first 30 to 90 days, contaminant concentrations increase. Wittle attributed this to desorption of the soil.

Iovenitti also gave examples of successful field projects. In one case, the technology was used to remediate 500 tons of PAH-contaminated soil, reducing 16 PAHs from an average of 1,355 mg/kg to 55 mg/kg in 70 days. After 100 days, PAH levels were non-quantifiable. Almost all of the field projects have remediated upland soil, except for one sediment site at a canal in Scotland. Most of the contaminants have been PAHs, while two sites have involved PCBs. Data collected from the sites have been limited to changes in contaminant concentrations and sometimes temperatures: they have not included toxicity testing.

Iovenitti and Wittle described how they were gradually convinced the technology was valid. After an initial meeting with the developer of direct-current technology, Falk Doring, they investigated the validity of the technology by working with a geophysicist, who determined whether electricity could discharge in soil, and by researching the bioremediation literature for analogous reactions. (They pointed out that insurance companies have completed their own evaluation of the technology and back up its validity.)

Members of the group asked Iovenitti and Wittle a number of questions regarding the chemical processes involved in direct-current technology, the technology’s limitations, how the technology is different from conventional electrokinetics, and problems with demonstrating the technology at the bench scale.

Sabine Apitz expressed concern that the technology might increase toxicity: Did Iovenitti understand the mechanism by which organic chemicals break down, and did he know what forms PAHs were degrading to? Iovenitti said they have a general understanding but do not know the particular chemicals involved.

Regarding the technology’s limitations, Iovenitti said he was not sure if direct-current technology worked any better in sediment than in soil. The one field demonstration of the technology in sediment (at a canal in Scotland) removed 168 pounds of mercury in 26 days. Jensen did not believe there was any limit to the amount of pollution that could be remediated with this technology. In cases involving a high amount of contamination, as at New Bedford Harbor, the technology would still work but would take more time. Iovenitti stated that there appears to be no limit on the types of contaminants that could be removed with this technology.

The main difference between direct-current technology and conventional electrokinetics is the difference in amperage and voltage gradient. At higher currents, Iovenitti explained, electrochemical reactions take place in the pore water instead of at the pore scale; as a result, the induced polarization effect does not take place and the soil does not act as a capacitor. No discharge takes place, only a flow of electricity.

The group had major problems with the fact that direct-current technology cannot be demonstrated at the bench scale. This kind of demonstration is impossible, Iovenitti explained, because of the resistance of soil. The soil’s resistance is a function of the electrode array and the amount of soil involved. In the laboratory, the small soil volume creates high resistance, and therefore requires more power for reactions to take place. Because direct-current technology can only work in a low power regime, it is impossible to demonstrate it in the laboratory. In the laboratory, the reactions are not happening at the pore scale and are not the electrochemical reactions that are part of direct-current technology. Wittle pointed out that bench-scale studies of this technology have only destroyed organic chemicals at the electrodes, not between the electrodes.

Jensen and other meeting attendees had difficulty accepting that the technology could not be demonstrated in the laboratory. Wittle argued it was in their best interest commercially to prove the technology worked in the laboratory, so the fact they have not accomplished this should not disprove the validity of the technology. Wittle said his company has spent a half million dollars working with Lehigh University to try and duplicate field conditions in the laboratory, but they have been unsuccessful. In addition, the developer of this technology has worked very hard to demonstrate the technology at the bench scale in order to attain his Ph.D. in Europe; he too has been unsuccessful. Iovenitti said he would try to get a regulator from the New Jersey field site to provide an independent verification of the technology.

Wittle said, however, that with the expertise and resources of member organizations such as Battelle and DuPont, it could become possible to prove the technology at the bench scale. Jensen suggested that the group hold another session by phone that included experts in electronics, electronic materials, and physics. These experts might give the group insight into whether the technology could be demonstrated at the bench scale and, if not, whether it could still be considered a valid technology.

Jensen believed the group might feel more comfortable about the scientific validity of the technology if they had more of the information Iovenitti and Wittle are protecting as proprietary.

Having heard Iovenitti and Wittle’s presentation, Jensen felt that the group should assume that direct-current technology is valid and develop a proposal for a demonstration project. However, he also said the group’s proposal should include a paragraph explaining that, in addition to conducting a demonstration project, the RTDF would continue to explore the technology through a smaller-scale experiment that could provide proof of principle.

Jensen recommended that an Action Team member sign a confidentiality agreement and assume responsibility for this smaller-scale experiment as an in-kind contribution. With the missing proprietary information and the results of the experiment, this member could communicate to the group as an independent person and help validate the technology.

Apitz did not think it was necessary to carry out a smaller-scale experiment, since so many others have already tried and failed. In addition, GLNPO and the Superfund Innovative Technology Evaluation (SITE) program support technologies ready for field tests; it is not their mission to fund laboratory studies.

Apitz recommended the group’s proposal should show the field data, explain why laboratory tests do not represent what happens in the field, argue why the technology is ready for a field demonstration, and explain how the RTDF will conduct a number of critical analyses to show that contaminants do not volatilize and no toxic byproducts are generated. Apitz emphasized the need for expert opinion from a physicist who could explain why the technology cannot be demonstrated at the bench scale.

Jensen spoke about demonstrating direct-current technology. He believed the RTDF’s strong point is that it can bring a high level of assessment to a demonstration project. The project would determine whether the process actually removes organic chemicals in situ or whether contaminants are being volatilized. If the process actually removes organic chemicals in situ, the regulation that organic chemicals be transferred to the water phase before they are destroyed would not apply. Apitz said the assessment should also look at toxicity, bioavailability, the impact on biota, and fluxes of contaminants before, during, and after treatment. She explained that regulators and other stakeholders will want information of this type so they can weigh short-term impacts against long-term benefits. Victor Magar noted that toxicity testing would be necessary because a mass balance on organic chemicals would not be possible: they disappear in place, and labeled carbon could not be injected in the sediment.

To reach consensus on the design for the demonstration experiment, Apitz suggested that each member e-mail the group their view of the experiment’s critical parameters and the importance of particular design considerations. She reminded the group that it is important to be able to generalize the projects’ results to in situ use of the technology.

The group discussed many different design aspects, including:

• Should the experiment be conducted in situ, rather than ex situ or at a confined disposal facility (CDF)? Jensen believed the demonstration should be either ex situ or at a CDF, since this would mean more careful controls. Wittle argued the experiment should be in situ, but others thought the experimental design would be too complex and permitting would be required. In addition, Iovenitti noted that in an in situ experiment the group might have to consider impacts to fish that use electricity to hunt. The group then considered the benefits of a flooded CDF as opposed to an ex situ site. Jensen pointed out that using a flooded CDF would mean having to consider infiltration of contaminants, since the treated area would have an open bottom and there would be no control of downward fluxes. He recommended that the group conduct the experiment ex situ, creating a concrete bottom and then using a front-end loader to move earth onto the structure. Apitz believed a flooded CDF would provide more realism than an ex situ site, since the former would be more analogous to what the group intends to extrapolate to. She said a carefully monitored CDF could help the group get to the questions of toxicity and volatilization even if the material balance loop could not be closed entirely. Jensen agreed with Apitz and believed the group could afford to sacrifice total control of the material balance for more realism as long as top controls, such as an airtight tent, could be put in place to detect possible volatilization. Jensen also said that instead of containing the treated area, the group could sample the perimeter and perhaps core the CDF before and after the experiment. If the group decides to go with a CDF, Jensen said, they should plan to walk on the CDF before the experiment, put up an airtight tent, flood the site, and, after the experiment, drain the site so they can walk on the CDF again. For air monitoring, Jensen thought, an airtight tent would be better than a flux chamber. Iovenitti suggested using an aged CDF that is somewhat compacted. He also mentioned that the CDF would need to contain at least 500 tons of sediment for the technology to work.

• What types of analyses should be conducted? In addition to looking at toxicity, bioavailability, the impact on biota, and fluxes of contaminants before, during, and after treatment, the group mentioned examining the zone of influence around the target cell in a CDF and possibly doing geophysical monitoring to see how uniform the electrical field is in three dimensions. Iovenitti said a control area would have to be between 75 and 100 meters away from the target cell to not be affected by the zone of influence. Jensen said they could also use a plastic sheet pile to isolate the control area. To determine the impact of the technology on biota, members of the group proposed either in situ toxicity testing or examining changes in the sediment that might prevent a benthic invertebrate community from repopulating it.

• Should the system be complex or simple? Wittle asked the group to consider the higher energy costs required to remediate a complex system (i.e., one with more than one contaminant) instead of a simple one (i.e., one with only one contaminant). Apitz pointed out that a complex system might be more realistic and help the group assess the impact of the technology on both target and nontarget contaminants. However, Jensen believed treating one contaminant would be enough of an accomplishment. He also proposed tying the demonstration to other work currently being done on the bioavailability of PAHs (e.g., the Stanford research or research by Jeff Tahle at Notre Dame). Magar believed a simple system would make it easier for the group to understand and analyze their results.

• What types of contaminants should be examined? The group discussed whether, in a simple system, the group should examine PAHs or PCBs. One meeting attendee favored PAHs: their intermediate products are bioaccumulative, making the demonstration of greater interest to funding sources. Wittle argued that the mechanisms by which PAHs cleave and break down are much more complex than the corresponding mechanisms for PCBs, making PAHs more difficult to analyze. Magar pointed out, though, that there are a few laboratories that can analyze PAHs vigorously. Jensen believed that, as long as the group did toxicity testing, it would not matter what byproducts were created if the byproducts were nontoxic. He also noted that PCBs are just as important as PAHs from a national standpoint. Jensen mentioned New Bedford Harbor and Wittle mentioned the Peoli railyard as possible PCB sites to examine.

• How well does the site need to be characterized before the demonstration project begins? Apitz pointed out the need to characterize the chosen site in order to determine the heterogeneity and distribution of contaminants there. With this characterization, the group would have a "signal to noise" indication that would allow them to determine the significance of any trends they might see. Iovenitti suggested the group find a site that is already well characterized. Another method to increase homogeneity, Wittle proposed, is that the group could work with others to set up their own site within a CDF. The group could do this by depositing homogeneous material in particular areas or layers of a CDF.

Jensen asked Iovenitti for a rough estimate of the cost for demonstrating direct-current technology given that RTDF would be taking on the burden of assessment. Iovenitti thought it would cost $260,000 to remediate 500 tons or cubic yards of sediment. The group estimated that the proposed analyses would increase the cost to about $520,000.

Jensen let the group know that GLNPO funding is a good possibility: GLNPO has urged the RTDF to take advantage of this funding for a couple of years. It was also suggested that the group consider using the SITE program. The SITE program could provide matching funding, monitoring, and quality assurance, but it would not cover technology deployment. Iovenitti noted that Weiss Associates is working with a private-sector company that might support the demonstration project after they hear the RTDF has a lot of interest in the technology.

After discussing the many issues involved with testing direct-current technology in a demonstration project, Jensen asked the group to resolve to proceed with a proposal to GLNPO in January to test this technology and begin scouting for other sources of funding. Iovenitti said he would set up a schedule to get the proposal submitted, Dennis Timberlake agreed to find a demonstration site, and Magar and Apitz volunteered to develop a sampling and analysis plan. Jensen suggested Iovenitti take the lead on writing the proposal while others should contribute paragraphs on analyses and other issues. Iovenitti will e-mail the Weiss Associates Puget Sound proposal and monitoring plan to the group; it should help them prepare the proposal. Wittle suggested that the proposal list the questions the demonstration project will not address as well as the questions it will address.

The GLNPO proposal must be five pages long, and must be submitted by January 2001. Although a site does not have to be identified, having GLNPO funding would mean using a location in the Great Lakes area. The proposal requires a federal lead; the RTDF is not considered a federal lead. GLNPO probably has a matching requirement and will require the RTDF to provide in-kind services.

MISCELLANEOUS TOPICS

Jensen recommended natural recovery monitoring and assessment as the topics for the Action Team’s workshop in Seattle in January 2001.

Jensen mentioned the Anacostia project, saying it is still a good candidate for a capping proposal. He recommended the group set up an innovative technology subcommittee to identify acceptable technologies for the Anacostia Watershed Toxics Alliance to use.

ACTION ITEMS

• Iovenitti will try to get a regulator from the New Jersey field site to provide an independent verification of direct-current technology.

• Jensen recommended that an Action Team member sign a confidentiality agreement with Weiss Associates and Electro-Petroleum, Inc., and assume responsibility for a possible small-scale experiment as an in-kind contribution.

• Jensen suggested that the group hold another session by phone, one including experts in electronics, electronic materials, and physics. These experts might give the group insight on whether direct-current technology could be demonstrated at the bench scale—or, if not, why not and whether it should still be considered a valid technology. Jensen said DuPont will determine this.

• To reach consensus on the experimental design for the demonstration project, Apitz suggested that each member e-mail the group their view of the experiment’s critical parameters and the importance of particular design considerations.

• Jensen asked the group to resolve to proceed with a proposal to GLNPO in January to test direct-current technology and begin scouting for other sources of funding. Iovenitti will set up a schedule to get the proposal in place, Dennis Timberlake will find a demonstration site, and Magar and Apitz will develop a sampling and analysis plan. Iovenitti will take the lead on writing the proposal, while others should contribute paragraphs on analyses and other issues.

• Iovenitti will e-mail the Weiss Associates Puget Sound proposal and monitoring plan to the group. It should help them prepare the proposal.

• Natural recovery monitoring and assessment will be the topics for the Action Team’s workshop in Seattle in January 2001.

• Jensen recommended the group set up an innovative technology subcommittee to identify acceptable technologies for the Anacostia Watershed Toxics Alliance to use.