The Suitability of Marine Clay–Zeolite Mix as Landfill Liners

Feasibility of using marine clay modified with zeolite for the construction of landfill liner was studied. Compacted natural clays are commonly used as liner material due to their high containment, attenuation and cost-effectiveness. The material chosen for liner construction has to satisfy the standards set by Environmental Protection Agency (EPA), based on plasticity characteristics, hydraulic conductivity and shear strength. As per EPA standards, the hydraulic conductivity of the liner material should be less than 1 × 10–7 cm/sec. The feasibility of using marine clay–zeolite mixtures as landfill liner material is presented in this study, and the most acceptable zone was obtained for the same. The liner material was prepared by mixing marine clay with various percentages of zeolite (0–25%). Initially, the suitability of moist and sun-dried marine clay was assessed, because marine clay exhibits different index properties in the natural moist condition and dried condition. Experimental programme involved laboratory tests to determine the index properties, compaction characteristics, hydraulic conductivity and shear strength of marine clay and marine clay–zeolite mix. In order to study the strength development, samples were kept for curing for 7 days, 28 days and 3 months. From the results, 15–20% zeolite content in sun-dried marine clay was found to be optimum.