Electrokinetic remediation of contaminated soils using acid and alkaline media: Laboratory experiments with synthetic soils

Metal contamination is a common problem at hazardous waste sites. There are several techniques that can be applied for the remediation of metal contaminated soil and groundwater. When low permeability soils and in situ treatments are considered, the number of applicable technologies is reduced. One emerging technology promises successful results in these scenarios - electrokinetic remediation. Electrokinetic remediation relies on the application of low intensity direct current between electrodes placed in the soil. Contaminants are mobilized in the form of charged species, particles or ions, transported to the electrodes and subsequently treated above ground. Electrokinetic remediation can also be used to slow or to prevent migration of contaminants. This practice is termed 'electrokinetic fencing'. The range of potential contaminants that could be removed or captured is wide: heavy metals, nonmetallic toxic elements, radionucleides, some organic compounds (chlorinated volatile compounds, solvents, BTEX, phenols ...), etc. The technology can be used with several types of soils: sands, silts, fine-grained clays and sediments. This paper presents a description, results and conclusions of laboratory experiments developed to optimise the design of a electrokinetic remediation system applying acid medium and basic medium to the soil.