Improvement of attenuation functions of a clayey sandstone for landfill leachate containment by bentonite addition.

Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions.

The performance of natural clay as a barrier to the diffusion of municipal solid waste landfill leachates.

In this paper, the diffusion of solutes in natural clay from a concentrated solution consisting primarily of ammonium, sodium and chloride ions at a pH level of 8 was studied and was based on an existing 20-year-old landfill. Contaminant transport through clay liners was predicted using transport and reaction geochemical codes to help explain the experimental data. The model predicted the chloride anion diffusion and cation exchange processes for three different experiments: (1) small-scale interactions in compacted clay, (2) 1:1 European Union (EU) Directive demonstration experiments (0.