Geomechanics of Landfills—Innovative Technology for Liners

Abstract

Cracks in clayey landfill liner, which cannot be closed up upon re-wetting, affect the long-term performance of a landfill. In this paper, the mixture bentonite-zeolite (BEZ) is presented as a potential liner material due to its plastic properties. Also, it may fulfill an existing demand, in developing countries, for liners that are cost-effective, natural and in compliance with environmental regulations. Traditional liners have shortcomings: (i) clayey soil is suitable for liners if the temperature and moisture fluctuations are not high; otherwise, they may form cracks; (ii) geomembranes, considered as the best alternatives for liners, are out of reach of most underdeveloped countries for their high price, and do not last more than 4 years; (iii) the interface of a CGL (clay geosynthetic liner) is susceptible to sliding. In the studies performed, the low volumetric shrinkage of the BEZ indicates that it is not affected by moisture content fluctuations, and its hydraulic conductivity in the order of 10 −10 cm/s meets regulatory agency requirements. Also, its inherent chemical properties (specially clinoptilolite zeolite) and its natural selectivity indicates that it will adsorb heavy metals such as Pb 2+ , Zn 2+ , Cd 2+ , Ni 2+ ,Fe 2+ , and Mn 2+ that may be present in leachate. Therefore, BEZ is a potential innovative material for liners in landfills.