Investigation of Clay Liner Permeability Changes Subject to Municipal Waste Leachate (Case Study: Kahrizak Landfill)

Due to availability of proper materials in landfills (at most parts of Iran especially in Kahrizak) and also less expenditure of this liner in comparison with other liners it can be count as an acceptable choice. Different studies imply that one of the most important factors for soil liner selection is local conditions and also liner compatibility with generated leachate in studied site. Hydraulic behavior of soil liner, which can be condensed in liner permeability, in reaction with municipal solid waste leachate depends on properties of used leachate and liner's soil. This issue is very important, especially in the case of soil with high degree of salinity. Because of this, changes of compacted soil liner permeability were measured by use of Kahrizak landfill soil in contact with leachate in laboratory scale. Permeability test was done based on falling head method and by using of soil samples which was compacted in permeameter and real leachate which sampled from Kahrizak landfill. Result imply that however, liner permeability shows little increase by passing the time but this amount is one or two order of magnitude less than required permeability for liners (1*10-9 m sec-1). So this soil liner has needful competence for controlling of leachate permeation and it can be used as a material creating compacted soil liner according to related standards for Kahrizak landfill.