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Stabilized red soil—an efficient liner system for landfills containing hazardous materials

Gopinath, R., Poopathi, R., Vasanthavigar, M., Arun, R., Mahadevan, M.
Environmental monitoring and assessment 2018 v.190 no.10 pp. 590
Prosopis juliflora, aquifers, clay, hydrologic models, landfills, leaching, permeability, plasticity, polyethylene, scanning electron microscopy, shrinkage, soil, soil stabilization, subtropics, toxic substances, wastes, woody weeds
In recent decades, disposal of hazardous material has become a challenging task especially in case of landfills where leaching out of waste is possible. In such cases, an efficient and economical liner system using locally available material is very essential. In this paper, an attempt has been made to study the suitability of red soil stabilized using lime and Prosopis juliflora fibers as liner material for landfills. Prosopis is a woody weed available abundantly in tropical and subtropical regions of the world. The fibers were used at 0.0%, 0.25%, 0.50%, 0.75%, and 1.0% by weight of the soil and the amount of lime used was kept constant as 4%. Tests results revealed decrease in plasticity index, increase in UCC strength, ductile behavior, decrease in consolidation settlement, reduction in permeability and shrinkage, and increase in CBR resistance in soils treated with both lime and Prosopis fibers. SEM images of stabilized soil revealed adherence of hydrated products of lime on the fiber surface, which facilitate efficient stress transfer between the soil and fibers. A single composite liner system was modeled using Visual MODFLOW by replacing the compacted clay layer with the stabilized red soil below the HDPE liner and the model was simulated. The simulation result showed that the performance of liner system with stabilized red soil is good and could prevent the aquifer from contamination. From the study, it can be concluded that stabilized red soil possesses the geotechnical properties required for an efficient liner system.