Membrane behavior of an exhumed geosynthetic clay liner – preliminary analysis

抄録

Membrane behavior of a geosynthetic clay liner (GCL) exhumed from a bottom liner system at a municipal solid waste landfill in California, USA was investigated in this study. The GCL was installed as part of a geomembrane-GCL bottom liner system at a newly constructed cell at the landfill. The cell was not filled subsequent to the construction of the liner system and the geosynthetics were exposed to the atmosphere for 12 years. Preliminary data on the membrane behavior of GCL samples exhumed from the liner system are provided herein. Laboratory multi-stage membrane behavior tests were used to determine membrane efficiency coefficients (ω) of the GCL for potassium chloride source solutions. Measurable membrane behavior was confirmed in the laboratory tests for the exposed GCLs. Even though membrane behavior was shown to still exist in the GCL after 12 years of exposure, values of ω were very low (0.1 – 5.4 %). Bentonite migration and cation exchange likely contributed to the significantly lower ω for the exposed GCLs relative to values reported in the literature for virgin/unexposed GCLs.