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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.

Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote reuse. The authors have studied the electrodialytic removal of Cu, Cr, and As from CCA-treated timber waste. The method uses a low-level direct current as the "cleaning agent", combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in four experiments using a laboratory cell on sawdust of an out-of-service CCA-treated Pinus pinaster Ait. pole. The duration of all the experiments was 30 days, and the current density was kept constant at 0.2 mA/ cm 2 . The experiments differ because in one the sawdust was saturated with water (experiment 1) and in the rest it was saturated with oxalic acid, 2.5, 5, and 7.5% (w/w), respectively, in experiments 2-4. The highest removal rates obtained were 93% of Cu, 95% of Cr, and 99% of As in experiment 2. Other experimental conditions might possibly optimize the removal rates.