Potential use of calcareous mudstones in low hydraulic conductivity earthen barriers for environmental applications

Abstract

Earthen layers play a significant role in isolating contaminants in the subsurface, controlling the migration of contaminant plumes, and as landfill liners and covers. The physical, chemical and mineralogical properties of three calcareous mudstones from the Jagüel and Roca formations in North Patagonia, Argentina, are evaluated to determine their potential for the construction of liners. These mudstones were deposited in a marine environment in the Upper Cretaceous-Paleocene. The tested specimens mainly comprise silt and clay-sized particles, and their mineralogy is dominated by a smectite/illite mixed layer (70-90% Sm) and calcite in smaller proportion. Powdered mudstone samples have little viscosity and swelling potential when suspended in water. The hydraulic conductivity of compacted mudstones and sand-mudstone mixtures is very low (around 1-3 x 10(-10) m/s) and in good agreement with the expected hydraulic behaviour of compacted earthen layers. This behaviour can be attributed to the large amount of fine particles, high specific surface and the close packing of particles as confirmed by scanning electron microscope analysis. The tested materials also show a high cation exchange capacity (50-70 cmol/kg), indicating a high contaminant retardation capability. The calcareous mudstones show satisfactory mineralogical and chemical properties as well as an adequate hydraulic behaviour, demonstrating the potential use of these materials for the construction of compacted liners for the containment of leachate or as covers in landfills. These findings confirm the potential usage of marine calcareous mudstones as a low-cost geomaterial in environmental engineering projects.

Cu(II) and Zn(II) adsorption capacity of three different clay liner materials

“…The CATAE and KCE samples are of Upper Cretaceous age, while the NTOL sample is of Tertiary age. The main physical and geotechnical properties of these specimens are presented in Table 1, while their chemical composition can be found in Musso et al (2010Musso et al ( , 2013. These materials meet the technical requirements outlined in the European, Japanese and American legislations for use as clay liners (Chai and Miura, 2002), having hydraulic conductivities lower than 1 Â 10 À9 m/s (Musso et al, 2010(Musso et al, , 2013 (Table 1).…”

“…The voltage applied during the measurements was 60 V. These determinations were conducted under different pH conditions. The pH effect was evaluated, adjusting the pH of the dispersions in the range from 2.5 to 10.5 Table 1 Geotechnical and hydraulic properties of tested clays (data compiled from Musso et al, 2010Musso et al, , 2013 before each measurement. In this case, NaCl (0.08 M) was used to adjust the ionic strength of the aqueous solutions.…”

“…These bentonites, as well as the smectite-rich claystones, meet the common hydraulic requirements for use as part of compacted clay liners (Musso et al, 2012(Musso et al, , 2013. However, the adsorption of heavy metals by these natural Argentinean clays has not been extensively explored.…”

Arcillas Esmectíticas De La Región Norpatagónica Argentina Como Barreras Hidráulicas De Rellenos Sanitarios Y Agentes De Retención De Metales Pesados

“…Estos materiales fueron previamente caracterizados desde un punto de vista físico, químico y mineralógico (Musso et al 2010, Musso et al 2013. En el cuadro I se presentan sus principales propiedades mineralógicas, fisicas, químicas y geotécnicas.…”

Aptitud de suelos tropicales compactados para la construcción de barreras aislantes en rellenos sanitarios en Argentina

“…Los suelos compactados en muchos casos cumplen con las especificaciones mencionadas anteriormente, sin embargo, es necesario realizar estudios para la determinación de zonas óptimas en la curva Proctor para posteriormente realizar el control en campo (Daniel y Benson, 1990;Sharma y Reddy, 2004;Osinubi y Nwaiwu, 2006). En particular porque la mineralogía de la fracción fina del suelo influye significativamente en la conductividad hidráulica alcanzada (Montoro y Francisca;2010;Musso et al, 2013).…”