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Electrodialytic soil remediation is a newly developed method for removal of heavy metal from polluted soil. The method is based on a combination of the electrokinetic movement of ions in soil with the principle of electrodialysis. The principle was tested in six experiments using laboratory cells on a copper-polluted Danish loamy sand. The duration of the experiments was varied, and the development of concentration profiles in the soil after the remediation was investigated for two different dc currents (0.1 and 0.2 mA/ cm 2 of soil). The rate of Cu removal was about doubled when doubling the current. It was found that Cu content was reduced to a level below 100 mg of Cu/kg of dry soil in the section closest to the anode and that the Cu removed was accumulated in the next section in the direction of the cathode. The accumulation zone was moving in the direction of the cathode during the application of an electric current. When the remediation ended, all Cu could be found in the cathode compartment, and results showed that it was possible to decontaminate the soil from 1360 to below 40 mg of Cu/kg of dry soil.

Electrodialytic remediation of heavy metal polluted soil is a method which combines the technique of electrodialysis with the electromigration of ions in the polluted soil. Results from laboratory-scale remediation experiments of soil samples from three real contaminated sites with di †erent heavy metals are presented. In the three cases it was possible to mobilize and reduce the amount of the pollutants in the soil. The pollutants were (1) copper and chromium, (2) mercury and (3) copper, lead and zinc. For a loamy sand polluted with copper and chromium it was possible to decontaminate the soil to an extent lower than the recommended critical values for metal concentration in soil. Parameters that were identiÐed as important for the efficiency of the electrodialytic remediation method were pH in the soil, lime content and speciation of the heavy metal.

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