Geotechnical behaviour of low-permeability soils in surfactant-enhanced electrokinetic remediation

ABSTRACT

Electrokinetic processes provide the basis of a range of very interesting techniques for the remediation of polluted soils. These techniques consist of the application of a current field in the soil that develops different transport mechanisms capable of mobilizing several types of pollutants. However, the use of these techniques could generate nondesirable effects related to the geomechanical behavior of the soil, reducing the effectiveness of the processes. In the case of the remediation of polluted soils with plasticity index higher than 35, an excessive shrinkage can be observed in remediation test. For this reason, the continued evaporation that takes place in the sample top can lead to the development of cracks, distorting the electrokinetic transport regime, and consequently, the development of the operation. On the other hand, when analyzing silty soils, in the surroundings of injection surfactant wells, high seepages can be generated that give rise to the development of piping processes. In this article methods are described to allow a reduction, or to even eliminate, both problems.

Keywords:

• Low-permeability soils
• electrokinetic remediation
• cracked soil
• piping process

Acknowledgments

The collaboration of Oscar Merlo is truly appreciated.

Funding

This work has been supported by Spanish Government through the project CTM2013-45612-R and INNOCAMPUS and CYTEMA E2TP Programs of the University of Castilla La Mancha.