Does Landfill Leachate Make Clay Liners More Permeable

Abstract

Most environmental regulations require that clay liners exhibit permeabilities less than 1 x 10/u-\u7 cm/sec. While permeability is typically determined using pure water, the leachate to which clay liners are exposed are usually either highly contaminated water or organic liquids. Studies going back 40 years have found that clay can be as much as 1 million times more permeable to organic liquids than to water. Regulations governing the disposal of liquids in landfills have alternated between a complete ban and allowing the practice to continue unabated. If liquids are to be placed in landfills, a minimum requirement should be that the permeability of the liners be evaluated with whatever leachates to which the liners would be exposed.