title: Improvement of attenuation functions of a clayey sandstone for landfill leachate containment by bentonite addition.
abstract: Enhanced sand-clay mixtures have been prepared by using a sandstone arkosic material and have been evaluated for consideration as landfill liners. A lab-scale test was carried out under controlled conditions with different amended natural sandstones whereby leachate was passed through the compacted mixtures. The compacted samples consisted of siliceous sand (quartz-feldspar sand separated from the arkose sandstone) and clay (purified clay from arkose sandstone and two commercial bentonites) materials that were mixed in different proportions. The separation of mineral materials from a common and abundant natural source, for soil protection purposes, is proposed as an economic and environmentally efficient practice. The liner qualities were compared for their mineralogical, physicochemical and major ions transport and adsorption properties. Although all samples fulfilled hydraulic conductivity requirements, the addition of bentonite to arkose sandstone was determined to be an effective strategy to decrease the permeability of the soil and to improve the pollutants retention. The clay materials from arkose sandstone also contributed to pollutant retention by a significant improvement of the cation exchange capacity of the bulk material. However, the mixtures prepared with clay materials from the arkose, exhibited a slight increase of hydraulic conductivity. This effect has to be further evaluated.
authors.affiliation: Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, Facultad de Ciencias, Campus de Cantoblanco, 28049 Madrid, Spain. anai.ruiz@uam.es
authors.forename: Ana I
authors.initials: AI
authors.lastname: Ruiz
authors.forename: Raúl
authors.initials: R
authors.lastname: Fernández
authors.forename: Nicanor
authors.initials: N
authors.lastname: Sánchez Jiménez
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez Rastrero
authors.forename: Mercedes
authors.initials: M
authors.lastname: Regadío
authors.forename: Isabel S
authors.initials: IS
authors.lastname: de Soto
authors.forename: Jaime
authors.initials: J
authors.lastname: Cuevas
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry*; D004058:Diffusion; D010539:Permeability; D000644:Quaternary Ammonium Compounds / Q000032:analysis / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution / Q000517:prevention & control*
chemical_list: D000644:Quaternary Ammonium Compounds; D014874:Water Pollutants, Chemical; D001546:Bentonite; D012822:Silicon Dioxide