A New Landfill Liner to Reduce Ground-Water Contamination from Heavy Metals

Abstract

A series of permeameters (columns) was used to evaluate the effects of the percolation of water and 1,000 μg/mL of zinc chloride solution through a mixture of montmorillonite clay, sand, and lime. The column test results show that the addition of lime changes the chemical and physical properties of the clay. The hydraulic conductivities for the mixture of clay with different percentages of lime at first increases with increasing lime and then decreases with increasing lime. The breakthrough curves indicate that the Zn(II) capture is increased and Zn(II) breakthrough is delayed with increasing lime addition. Lime also enhances the clay/lime mixture's ability to resist puncture by sharp objects. Based on the effects of lime on Zn(II) captured by the clay, an explanation for the interacting effects of lime and Zn(II) capture on changing hydraulic conductivity is suggested. The results of this research demonstrate the potential of using lime-treated clay liners for landfills. Such liners would have lower hydraulic conductivity, better resistance to puncture, and enhanced ability to capture heavy metals.