Improving landfill liner performance with bentonite-slag blend permeated with ammonia for a Municipal solid waste landfill

• Published in: Journal of environmental management 2024-09, Vol.367, p.122013, Article 122013
• Main Authors: C. M, Aswathy, Sunil, B.M.
• Format: Article
• Language: English
• Subjects: adsorption; Ammonia; bentonite; clay; compression strength; furnaces; Granulated blast furnace slag; groundwater; hydraulic conductivity; landfill liner; landfills; leachates; Lithomargic clay; municipal solid waste; Reactive barrier; slags; soil amendments; Waste management; water content
• ISSN: 0301-4797; 1095-8630; 1095-8630
• DOI: 10.1016/j.jenvman.2024.122013

Leachate emanating from landfills contains ammonia which may cause serious health effects on living things. An effectively designed clay barrier should not allow the contaminant to infiltrate the soil and groundwater systems. The utilization of certain industrial by-products in engineered landfill barriers, not only reduces the need for conventional liner materials but also helps in sustainable waste management. This study investigated the hydraulic conductivity, unconfined compressive strength, compaction, and adsorption characteristics of lithomargic clay blended with an optimum percentage of bentonite (10%) and granulated blast furnace slag (15%) permeated with ammonia. The results revealed that increasing the content of granulated blast furnace slag decreased the maximum dry density while increasing the optimum moisture content. In comparison to lithomargic clay, the hydraulic conductivity of the amended soil liner permeated with ammonia decreased from a value of 3 × 10−8 m/s to 5 × 10−10 m/s. The unconfined compressive strength of the amended soil specimens showed an increasing trend with curing times (i.e., 0, 14, 28, and 56 days). The batch adsorption results revealed that Freundlich and Langmuir's isotherm fits the equilibrium adsorption data and the adsorption of ammonia on clay liner follows non-linear behaviour. Overall, the experimental results implied that lithomargic clay blended with 10% bentonite and 15% granulated blast furnace slag can be used as an impermeable soil reactive barrier in engineered landfills. [Display omitted] •Sustainable clay liner for engineered landfills using industrial by-product.•Reduction in hydraulic conductivity for slag-amended liner.•Adsorption characteristics of slag amended liner are commendable.•Strength improvement due to pozzolanic reaction of granulated blast furnace slag.