Landfill characterization with a multi-method geophysical approach - A case study from Emersons Green, UK

For a large number of landfills, basic knowledge about extent, waste composition or environmental impact is incomplete. Therefore, effective tools are required for landfill characterization to be able to identify landfills with high priority for remediation or high potential for landfill mining. In contrast to conventional ground-truth methods, geophysical methods are relatively inexpensive and since they are minimally invasive, they entail less risk for environmental contamination. With our case study on the landfill in Emersons Green UK, we tested the effectiveness of multiple geophysical methods for landfill characterization. Electromagnetics (EM) and Magnetics (Mag) were able to provide a rapid overview of the landfill structure, and detected areas with higher metal content. Induced Polarization (IP) was the most suitable method to delineate the extent of the waste layer whereas Electrical Resistivity Tomography (ERT) seemed more sensitive to changes in moisture content. This study has shown that a multi-method geophysical approach in combination with targeted sampling is essential to avoid misinterpretations. Furthermore, planning the profile location of the more time-consuming methods such as IP and ERT based on the results of the rapid mapping methods such as EM and Mag can improve the survey efficiency.