Water transport in electrokinetic remediation of unsaturated kaolinite. Experimental and numerical study

This work evaluated water transport that occurs in a partially saturated soil of low hydraulic permeability when undergoing an electrokinetic remediation process. The soil used was a compacted kaolinite. To evaluate a wide range of possible conditions, soil with three different initial water contents (10, 15 and 20%) was used, obtaining a range of dry densities of 1300-1600 kg m−3. The tests were performed using a lab-scale setup with a soil capacity of 675 cm3 and applying different electrical potential gradients (0.5, 1, 1.5 and 2 V cm−1). The experimental results obtained were used to validate a conceptual model implemented in COMSOL. The validated model was used to conduct a detailed interpretation of the observed water transport processes and to perform a study of the hydraulic behaviour of the soil as a function of the initial conditions of compaction, water saturation and applied electrical potential gradient.