The Effects on Hydraulic Conductivity of the Geosynthetic Clay Liner (GCL) with Humic Substances of Leachate in the Landfill

摘要

The Geosynthetic clay liner (GCL) have widely used as one of the hydraulic barrier materials in waste landfills; however, it also has a potential problem when exposed to some organic and inorganic leachate. The major component of the GCL is bentonite. The hydraulic conductivity of GCL might be easily changed due to bentonite, if it is permeated with various components of the leachate. Especially, the humic materials of landfill lechate closely interact with clay particles in bentonite. This study was performed to characterize the humic materials composed of two kinds of landfill leachate; the first one was a leachate of old-landfill (O-landfill) and the other one was a leachate of young-landfill (Y-landfill). Also, the GCL was evaluated to find the effect of humic materials on the swelling and hydraulic conductivity of GCL. The result of the swelling tests represented that the amount of humic materials and high electrical conductivity caused a decrease of the swelling of bentonite. This was expected to increase the hydraulic characteristics of GCL. The increase in hydraulic conductivity of GCL permeated with O-leachate was significantly higher than that with Y-leachate. This result means that the humic materials have an effect on the hydraulic conductivity of GCL. Therefore, the potential danger of increasing hydraulic conductivity of GCL permeated with the landfill leachate has to be considered when you construct the GCL in the waste landfill.