Design of Landfill Leachate-Collection Filters

Geotextile-filter design for the leachate-collection system in a municipal solid-waste landfill is quite different from that of a geotextile-filter design for other conventional geotechnical drainage applications. This is primarily due to the nature of the permeating liquid. Clearly, leachate is not ground water. Leachate has high suspended solids as well as high organic content. As a result, filters can excessively clog when permeated with leachate over long periods of time. The essential question, which is answered in this paper, is what defines "excessive" clogging. A design equation for geotextile filters or graded granular soils used in landfill leachate-collection systems is proposed in the paper.