Environmental monitoring using Electrical Resistance Tomography

Abstract

Landfill sites and saline disposal basins are just two of the numerous situations in which escape of fluids from the system can contaminate soils and groundwater. Techniques to map fluid flow, delineate the extent of contamination and monitor changes during remediation are needed for environmental monitoring applications. Theoretical and laboratory-based testing of Electrical Resistance Tomography (ERT) was undertaken to examine the capabilities and limitations of this method. The performance of a series of two-dimensional numerical models led to the conclusions that a contaminant plume can be imaged, that downhole current transmission sites with both downhole and surface potential measurement sites is preferable and that smaller scale fingering effects associated with free convection are not readily resolved. It also highlighted the importance of electrode configuration for successful ERT surveying. An ERT survey conducted in a glass tank to monitor the development of a dense, saline plume was also conducted. Visual comparison of photographs with ERT images agreed with theoretical results.