Reuse of calcium carbide and water treatment residues in the bottom clay liner of a municipal solid waste landfill

In this work, calcium carbide residue (CCR) and water treatment residue (WTR) were used in combination with clay to produce a composite bottom clay liner for sanitary landfills. The effects of these two residues on the performance of a composite bottom clay liner by means of compressive strength development and the coefficient of perme- ability were studied. The WTR was classified as high plasticity silt according to the Uni- fied Soil Classification System and was used to replace clay with clay:WTR ratios of 0:100, 30:70, 50:50, 70:30, and 100:0, whereas CCR was used at 0, 10, 20, and 30 wt%. The experimental results showed that the optimum mix proportions of a composite clay liner containing clay, WTR, and CCR at 40, 40, and 20 wt% gave a 56-day compressive strength of 2.95 MPa and a coefficient of permeability value of 6.6 × 10−8 cm/s.