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 na tural zeolites of Gordes (Turkey) and the commercial powdered bentonit e were used in various experiments, such as compaction, hydraulic cond uctivity, and strength. Various ratios of bentonites and zeolites (B/Z ) compacted at the optimum water content (w(opt)) were tested to deter mine the strength parameters. The laboratory samples compacted under w (opt) and slightly higher water contents were tested for hydraulic con ductivity (k). For the bentonite content >5%, the resulting average k values ranged from 2 x 10(-8) to 4 x 10(-8) cm s(-1). Cation exchange capacity, an important chemical property of a liner material, of bento nite and natural zeolite were found to be 60 and 95 meq/100 g, respect ively. A B/Z ratio of 0.05-0.10 was found to be an ideal landfill line r material regarding its low hydraulic conductivity and high cation ex change capacity. The use of B/Z mixtures as an alternative to clay lin ers would significantly reduce the thickness of base liner for sanitar y landfills.