Assessing the effectiveness of bentonite-FA and bentonite-marble dust in sustainable landfill liners compared to traditional bentonite-sand liner based on swelling and permeability property subjected to permeate solution

Abstract Landfill liners are crucial barriers against environmental contamination from wastes. This paper attempted to evaluate the suitability of two alternative materials, namely waste fly ash and marble dust amended with bentonite, as potential alternatives in landfill liners, considering mainly their swelling and permeability properties against the traditional, bentonite-sand liner. Laboratory experiments performed in the present research work for evaluating permeability and swelling properties of fly ash-sand-marble dust mixtures with bentonite. Under the permeate solutions conditions of CaCl 2 , HCl, and NaOH, the swelling and permeability behavior of the mixtures were studied. The experimental results and findings clearly show under the under the permeate solution of CaCl 2 , the mixtures 4OB+60MD, 40B+60FA, 25B+75S or 30B+70S, under the permeate solution of NaOH, the mixtures 35MD+65B, 35FA+65B, 20S+80B or 25S+75B and under the permeate solution of HCl, the mixtures 4OB+60MD, 40B+60FA, 25B+75S or 30B+70S under the concentration from 1N to 2 N gives optimum result based on requirement of EPA. Finally, the bentonite-amended waste fly ash and marble dust mixes could in the future become an effective, sustainable alternative to bentonite-amended sand in the landfill liners. Adopting these materials could reduce the environmental impact of landfill construction and promote a circular economy by repurposing industrial waste, thereby contributing to more sustainable landfill management practices.