Monitoring of electrokinetic treatment of landfill leachate-contaminated clay in Portugal

This paper describes how electrokinetic treatment (EKT) was used to decontaminate compacted kaolin artificially contaminated with leachate obtained from a landfill waste site near Lisbon, Portugal. An experimental test was conducted on a laboratory-scale set-up with focus on monitoring the electrochemical properties of the soil and pore fluid during the treatment, as these are the most usual in-situ-monitored parameters. The test comprised three sets, each with 3 d of duration, where different operating conditions were applied simulating real cases. EKT treatment effectiveness is analysed through changes in the electrical conductivity and pH of the pore fluid and changes in the electrical resistivity of the soil. With EKT, it was possible to remove inorganic content (metals) from the soil, a result confirmed through chemical analysis of some components. The results of the experimental tests performed helped in discussing how operating conditions and monitoring provisions, usually taken when applying EKT to decontaminate clayey soils, can be useful in optimising EKT.