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 EPA/540/R-04/507

 

Electrochemical Remediation Technologies (ECRTs) - In Situ Remediation of Contaminated Marine Sediments Innovative Technology Evaluation Report
June 2007
Bulletin (540/MR-04/507)

This Innovative Technology Evaulation Report summarizes the results of the evaluation of the Electrochemical Remediation Technologies (ECRTs) process, developed by P2-Soil Remediation, Inc. (in partnership with Weiss Associates and Electro-Petroleum, Inc.). This evaluation was conducted between August 2002 and March 2003 in cooperation with the Washington State Department of Ecology (Ecology). The ECRTs demonstration consisted of an evaluation of ECRTs' process to utilize a DC/AC current passed between an electrode pair (anode and cathode) in sediment in order to mineralize organic contaminants through an ElectroChemicalGeoOxidation(ECGO) process, orcomplex, mobilize, and remove metal contaminants deposited at the electrodes through the Induced Complexation (IC) process. The demonstration of the ECRTs process was conducted at the Georgia Pacific, Inc. (G-P) Log Pond located along the Whatcom Waterway in Bellingham Bay, Bellingham, Washington. This demonstration was designed to assess and evaluate the ability of the ECRTs process to reduce concentrations of mercury, PAHs, and phenolic compounds.

For the demonstration project, Weiss Associates, (Emeryville, CA) installed, operated, and removed the ECRTs pilot test equipment from the Log Pond site. Faulk Doering, electrochemical processes (ECP; Stuttgart, Germany) provided oversight and consultation for the system installation and operation. Installation of pilot study infrastructure involved placing 9 anode (steel plates) and 9 cathode (graphite plates) electrodes, in two parallel rows, into the sediments.

The G-P Log Pond is a marine embayment that served as a former log storage and handling area and receiving water for facility effluent and stormwater runoff. The ECRTs project area was designated as an approximately 50-feet (ft) by 50-ft area within a pre-characterized area of the G-P Log Pond known to contain elevated concentrations of mercury, phenolics, and PAHs. However, based on results from a preliminary survey, mercury was identified as the most ubiquitous and consistently elevated contaminant relative to Washington State Sediment Management Standards (SMS) Sediment Quality Standards (SQS) and Cleanup Screening Levels (CSL) which are used in Puget Sound to determine impacted sediments that require remediation under State law.

The primary technical objective of the demonstration was to determine whether there was a significant trend in the reduction of sediment mercury concentrations over the period of the demonstration. Reference area samples were collected for comparison to determine whether treatment differed from natural attenuation. The experimental design was based upon significant mercury reduction from baseline to a post-treatment sampling event. The primary objective is not associated with a percent reduction but instead the primary objective is to determine a statistically significant negative trend over time. Samples of the cap material and the underlying native material were used to evaluate potential migration of all contaminants, including mercury (primary objective), PAHs, and phenolics.

An assessment of the sediment chemistry results indicated a less than anticipated performance due in part to system operational problems encountered during the course of the demonstration. Electrical readings collected by the technology's sponsor indicated a steady degradation of system performance throughout the duration of the demonstration, resulting in an early shutdown of the system prior to completion of the planned test period. In addition, when the electrodes were removed from the test plot, it was evident that the connections between the electrical supply and anode electrode plates had completely corroded to the point that a viable contact had not been maintained.

For more information on this and similar research, please visit our research web site.

Contact

Randy Parker

Office of Research & Development | National Risk Management Research Laboratory


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