Detection of landfill cover damage using geophysical methods

Abstract

International audienceOn closed landfills, impermeable covers are capping the waste in order to minimize water infiltration and accumulation of leachate inside the waste. In France, the cover composition depends notably on the kind of stored waste. In cases of hazardous waste, the cover must be composed of a drainage layer under the top soil and a geomembrane or a Geosynthetic Clay Liner (GCL) associated with an underlying 1.0 m thick low permeability material to ensure its tightness. However, this protection cover is sometimes damaged leading to an escape of landfill gazes and an unusual increase of leachate within the waste after rainy events. As leachate treatment is very expensive, it appears necessary to locate the weakness zones of the cover and assess their sizes in order to limit maintenance cost on landfills. In order to detect damages in the cover, the 2 following geophysical methods have been carried out on a French landfill: cartography with an Automatic Resistivity Profiling (ARP©), the Electrical Resistivity Tomography (ERT) and the Self Potential method (SP). The joint use of these methods has given us the opportunity to determine the contribution of each of them for cover's characterization. The ARP survey has put in evidence the lateral heterogeneity of cover materials on the whole landfill. The ERT has confirmed the variability of the cover composition but also provided information about the cover thickness and the damaging of the GCL. SP measurements have revealed a negative anomaly at the top of the landfill, possibly linked with a thin and damaged cover and therefore a greater proximity of waste. Finally, manual augers holes have enabled to associate electrical resistivity properties with different materials used in the cover and the damaged GCL. This study on a hazardous waste landfill shows that geophysical methods associated with manual auger holes have allowed to improve the knowledge of the cover. Thus, the damaged areas detected thanks to measurements performed on site may be useful for the landfill manager who can optimize the drilling survey necessary to check the nature of defects and then choose a suited remediation of the cover

Integrated Interpretation of Magnetic and ERT Data to Characterize a Landfill in the North-West of Cologne, Germany

“…Several geophysical techniques improved their power in detection the geometry of waste deposits in a faster, cheaper, and non-destructive way. Among these techniques are magnetic methods (Marchetti et al, 2002;Prezzi et al, 2005), electrical resistivity and electromagnetic prospecting (Baawain et al, 2018;Bernstone & Dahlin, 1997;Candansayar & Tezkan, 2006;De Carlo et al, 2013;Frangos, 1997;Helene et al, 2020;Karlik & Kaya, 2001;Martinho & Almeida, 2006;Morita et al, 2020;Saraev et al, 2020;Tezkan et al, 2000), ground penetration radar (GPR) (Orlando & Marchesi, 2001;Porsani et al, 2004;Wu & Huang, 2006), seismic methods (Carpenter et al 1991;De Laco et al, 2003;Missiaen & Feller, 2008) in addition to the use of a combination of more than one geophysical method (Appiah et al, 2018;Genelle et al, 2014;Tezkan et al, 1996;Yannah et al, 2019). Moreover, investigating leachates and locating possible paths of pollution plumes in landfill areas using near-surface geophysical techniques have been studied by several scientists (e.g.…”

Optimum reduction of sensing electrodes for delamination identification with electrical resistance tomography

“…Different sensing and electrode array configurations are used to examine the sample. Electric current and voltage electrodes can be placed on the surface, [30][31][32][33][34][35][36][37][38][39][40][41] inside borehole sites [42][43][44][45][46] or a combination of surface measurements with data from borehole samples 47,48 (see Figure 1b). ERT uses one electrode pair for current injection and one for voltage measurement.…”

Estudo de parâmetros geomecânicos de uma célula experimental de resíduos sólidos urbanos com métodos geofísicos

“…No estudo de Cardarelli & Di Filippo (2004) Os métodos geoelétricos são usados no estudo de RSU com objetivos variados, como por exemplo, na detecção de danos na cobertura dos aterros (Genelle et al, 2014;Carpenter et al, 1991), no mapeamento e monitoramento de umidade ou concentração de chorume (Melges Bortolin et al, 2010;Moura et al, 2003), assim como na obtenção do teor de umidade ( Dumont et al, 2016;Grellier et al, 2007;Feng et al, 2017). Este último objetivo é o mais complexo de se obter e são poucos os trabalhos encontrados que estabelecem alguma relação direta entre a resistividade e o teor de umidade dentro do corpo de resíduos.…”

“…Quando esses sistemas são danificados, o aquífero pode estar em risco devido a contaminação. Três fatores que podem causar dano nos sistemas de cobertura ou revestimento são apresentados no estudo deGenelle et al (2014), a saber: ▪ Ação de estresse mecânico, hidráulico e climático na superfície.▪ A incorreta preparação e instalação dos materiais de cobertura ou revestimento.▪ Uso de diferentes materiais de cobertura, como a mudança nas espessuras ou materiais com que foi iniciada a cobertura. O custo elevado de tratamento do chorume, assim como o de remediação por contaminação de chorume, fazem com que gastos em manutenção e monitoramento de danos nos sistemas sejam a melhor opção.…”

“…As áreas com resistividades maiores durante o clima seco foram designadas como fraturas dentro da cobertura. duas partes experimentais em um aterro de lixo industrial na França.Com o ensaio elétrico foi possível identificar as duas fissuras e outras caracteristicas como o contato entre a argila, cascalho argiloso condutor e o aluvião argiloso Genelle et al (2014). apresentam resultados de tomografia de resistência elétrica com a finalidade de obter modelos de resistividade 2D e achar zonas de dano na cobertura.…”