Leachate Adsorption/Desorption Dynamics and their Influence on Dumpsites Soil Properties and Environmental Risk

Abstract

Landfill leachate, a contaminated liquid containing dissolved organic and inorganic matter, poses a significant environmental threat. This study investigated the interplay between leachate adsorption/desorption dynamics on dumpsites' soil properties and the consequent impact on environmental risk. The research focused on common cations and anions within the leachate composition and batch adsorption experiments was used to investigate the impact of leachate containing the ions on the key geotechnical soil properties like void ratio, porosity, degree of saturation, and dry density. Analysis of the leachate composition identified the presence of common cations (K⁺, Na⁺, Ca²⁺, Mg²⁺) and anions (SO₄^2– and Cl^–). The dumpsites’ soil samples were characterized by low affinity or adsorption coupled with high desorption rate of these ions, which demonstrably influenced the geotechnical properties and environmental risk of the soils of the dumpsites. The increased mobility of these ions within the dumpsites’ soil systems is potentially leading to contamination of surrounding soil and water resources. Therefore, this knowledge can inform strategies for mitigating environmental risks associated with leachate migration. The findings can guide approaches for leachate treatment, landfill design, and the selection of suitable cover materials to minimize contaminant movement and ensure long-term environmental protection. Hence, to maintain a balanced ecosystem, the study emphasizes the need for engineered landfills with a higher capacity for ions adsorption.