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Polymer Enhanced Geosynthetic Clay Liners for Extreme Leachate Chemistries

Geosynthetic clay liners (GCLs) have been used for a quarter-century as a substitute for the compacted clay component of composite lining systems in various industrial applications. For waste storage, the primary use of GCLs has been as a component in the composite liner system of municipal solid waste landfills. GCLs have seen limited use in other applications that involve high salinity and/or high-/low-pH leachates due to the chemical compatibility limitations of the base bentonite. Research into blends of bentonite clay with tailored polymer systems has shown that the chemical compatibility can be extended to leachates with high-pH (>10) and low-pH (<4) solutions. The compatibility of these bentonite clay blends with tailored polymers was evaluated using site-specific leachate permeability tests for four different cases. The low-pH leachates involved in these studies were representative of those encountered in phosphogypsum storage, copper heap leach processing and other applications.