Limestone liner for landfill leachates containing beryllium, cadmium, iron, nickel, and zinc

We evaluated the influence of crushed agricultural limestone, placed in a layer over six soils, on the rate of migration of beryllium, cadmium, iron, nickel, and zinc contained in municipal, solid-waste, landfill leachate. The limestone was highly effective in slowing the rate of migration of beryllium, cadmium, nickel, and zinc in all six soils, which represent five major soil orders of the United States. Not only breakthrough (C/C₀= 0.5) but also final breakthrough (C/C₀= 1) values were significantly delayed (twofold to threefold) over soil alone. The limestone effect was considerably more than additive, i.e., several times more than the sum of soil alone plus limestone alone. The limestone effects were not the same for the individual metals. Attenuation effects were greatest for beryllium and least for cadmium. The migration rate of iron, indigenous to the landfill leachate, also was favorably slowed by the limestone barrier layered over the soils.