Engineering aspects of a novel landfill liner material: bentonite-amended natural zeolite

This study aims at investigating certain features of a novel material proposed to serve as an impervious liner in sanitary landfills. The natural zeolites of Gordes (Turkey) and the commercial powdered bentonite were used in various experiments, such as compaction, hydraulic conductivity, and strength. Various ratios of bentonites and zeolites (B/Z) compacted at the optimum water content (wopt) were tested to determine the strength parameters. The laboratory samples compacted underwopt and slightly higher water contents were tested for hydraulic conductivity (k). For the bentonite content > 5%, the resulting averagek values ranged from 2 × 10−8 to 4 × 10−8 cm s−1. Cation exchange capacity, an important chemical property of a liner material, of bentonite and natural zeolite were found to be 60 and 95 meq/100 g, respectively. AB/Z ratio of 0.05–0.10 was found to be an ideal landfill liner material regarding its low hydraulic conductivity and high cation exchange capacity. The use ofB/Z mixtures as an alternative to clay liners would significantly reduce the thickness of base liner for sanitary landfills.