Abstract :
[en] Advances in geosciences and diverse non-invasive geophysical methods have demonstrated to be useful for landfill exploration, characterization and monitoring. Their use allows to reduce the costs and environmental footprint of conventional characterization surveys, to increase gas production in the case of landfill bioreactors, and to better address and assesss the environmental effects associated with landfills. Geophysical methods can provide valuable decision support tools in applying the concept of Dynamic Landfill Management (DLM), which includes the resource recovery-driven landfill mining to support the transition to a circular low-carbon economy. However, it is important to know beforehand the applicability of the distinct geophysical methods under specific conditions of different landfills and/or DLM projects. In this work, we present an approach to guide the selection of the most suitable combination of geophysical methods considering three aspects of implementation. The first relates to the available historical information of the site, e.g. type, age and morphology of waste deposits, and presence of geomembranes. The second aspect accounts for the current physical structure of the site and its surroundings including the host geology, topography and vegetation. The third aspect covers the most commonly used surface geophysical exploration methods, namely magnetic, electromagnetic (e.g. frequency-domain electromagnetics, ground penetrating radar), electrical (e.g., electrical resistivity tomography), passive and active source seismic methods (e.g. refraction, horizontal to vertical spectral ratio) and the physical properties they target (e.g., electrical conductivity, magnetic susceptibility, elastic moduli, density) which in turn may be translated into parameters of interest (e.g., waste volume, water content, metallic content). The use of this approach can help optimizing the design of geophysical surveys where individual methods can be combined to bring complementary information and achieve a more complete characterization. Finally, we exemplify this approach with two of the landfill sites studied in the RAWFILL project, which are located in Belgium. We expose the motivation to investigate these sites, some geophysical results, their interpretation and following validation through conventional sampling.
Disciplines :
Physical, chemical, mathematical & earth Sciences: Multidisciplinary, general & others