Geotechnical and Geochemical Assessments of Shales in Anambra Basin, Southeastern Nigeria, as Landfill Liners

Abstract

Background The use of landfills as containment for municipal solid waste management has received wide acceptance the world over. Its development in countries like Nigeria is constrained by high cost and scarcity of synthetic liners in the local markets. Exploration of the abundant locally available clay deposits in the country's sedimentary Basins will prove economical, provided it satisfies the standard specifications for design and construction of landfill liners. Purpose This study thus evaluates the suitability of shales from three formations (Enugu, Ameki and Imo) within Anambra Basin of Southeastern Nigeria as liner materials. Method Geotechnical tests such as particle size distribution, Atterberg's limits, compaction, coefficient of permeability and consolidation were performed on the shale samples. Geochemical analyses involving the inductively coupled plasma emission spectroscopy (ICPES) and cation exchange capacity (CEC) were also conducted; all employing standard methods. Results Based on the Unified Soil Classification System (USCS), Enugu and Imo shales contain high-plastic inorganic clay, while Ameki shales comprise low-mediumplastic inorganic clay. Coefficient of permeability result ranging from 9.12 9 10 −6 to 2.14 9 10 −6 cm/s indicates an increase above the standard specification. Expectedly, the cation exchange capacity (CEC), compressibility and plasticity index of the shales are positively related suggesting strong influence of the geotechnical properties on their sorption potentials. Overall assessment revealed that the high hydraulic conductivity and swelling potentials of the shales are not suitable for natural clay liners. Nevertheless, Enugu and Imo shales can further be stabilized chemically to the desired hydraulic conductivity of liners considering other suitable geotechnical properties and their CECs.

Role of smectite-rich shales in frequent foundation failures in southeast Nigeria

“…The predominant soil type underlying the problematic engineering structures in the present study area is clay belonging to the Awgu Shale group in the Anambra Basin. Among all tested expansive clay units (Asu-River, Imo, Enugu and Nkporo formations) underlying the Anambra Basin, Awgu Shale exhibited the highest expansive nature and consequently, lower strength characteristics (Adesina et al 2012;Ekeocha 2014). Aghamelu et al (2011a) suggested that the conversion of high expansive clay into less expansive types could be the reason for lower plasticity index of the Imo Shale.…”

Geochemical Appraisal of Termite-Reworked Clay Soils from Basement Complex Terrain: Implications as Landfill Liners

“…Landfills are covered with liners or covered with an underlayment to lessen the issues caused by leachate coming into touch with groundwater. In most cases, liners consist of a bottom liner, a geosynthetic clay liner (GCL), a geological barrier, and compacted clay and geomembrane (Declan and Paul, 2003;Leite et al, 2003;Frempong and Yanful, 2008;Budihardjo, 2015;Adesina and Tijani, 2017). According to Adesina and Tijani (2017), shales and other geologic materials have also been used as landfill liners.…”

“…In most cases, liners consist of a bottom liner, a geosynthetic clay liner (GCL), a geological barrier, and compacted clay and geomembrane (Declan and Paul, 2003;Leite et al, 2003;Frempong and Yanful, 2008;Budihardjo, 2015;Adesina and Tijani, 2017). According to Adesina and Tijani (2017), shales and other geologic materials have also been used as landfill liners. These materials have demonstrated their suitability by effectively combating the soil and groundwater contamination often associated with waste management techniques (Adesina and Tijani, 2017).…”

“…According to Adesina and Tijani (2017), shales and other geologic materials have also been used as landfill liners. These materials have demonstrated their suitability by effectively combating the soil and groundwater contamination often associated with waste management techniques (Adesina and Tijani, 2017). According to numerous studies (Gullick and Weber, 2001;Tijani and Bolaji, 2007;Charlermyanont et al, 2009;Ige, 2011;Ojuri et al, 2017;Daramola et al, 2018), clay liners are exceptional because of their inherent low hydraulic, high attenuation capacity, affordability, and chemical sorption ability.…”

Geotechnical and Mineralogical Appraisal of Shale and Claystone Facies of the Maastrichtian Patti Formation, Bida Basin, Nigeria

“…Okogbue et al (2010) compared geotechnical properties of Abakaliki, Awgu and Enugu shale formations and their likely use for construction and suggested that Abakaliki shale may be satisfactory as fill and embankment material but may not be good as sub base material due to high liquid limit and plasticity index. Adeshina et al (2017) studied shales (Enugu, Ameki and Imo) in Anambra Basin for use as landfill liners and suggested that high hydraulic conductivity and swelling potentials of the shales would not make them suitable for natural clay liners. These aspects of research, however, have not been *Corresponding Author extended to the shales and claystone in the southern Bida Basin despite its substantial occurrence both in the subsurface and outcrop levels.…”