Non-Destructive Test to Measure Pollutant Transport into Landfill Liners

In Algeria during ten year ago, waste disposal has become a particularly sensitive issue. A new legislation concerning landfill liner design was adopted. Traditional methods of landfills liners characterization involve soil sampling and chemical analysis, which are costly, destructive and time-consuming process. New techniques are being investigated to provide non-destructive, liners characterisation. This paper details technical aspect associated with electrical conductivity measurements within landfill liners and presents experimental work to show the direct application of electrical techniques to track ionic movement through sand bentonite liner under chemically induced flow. Samples of sand bentonite were mixed and compacted with NaCl electrolytes at different concentrations. Electrical conductivity of compacted specimens was measured with a two electrode cell. The effects frequency and electrolyte concentration are introduced on the conductivity measurement. Also relationship between soil electrical conductivity and NaCl electrolyte concentration in interstitial pore fluid are determined. The conductivity measurements were used to quantify the pore fluid concentration and effective diffusion coefficient of sand bentonite liners. It is concluded here that the electrical conductivity of compacted specimens depends mainly on the salt concentration in the pore fluid and it could be used to track ionic movement through liners during diffusion.