An Effective Electrode Configuration for the Detection of DNAPLs with Electrical Resistivity Tomography

Locating Dense Non-Aqueous Phase Liquids (DNAPLs) is often a bottleneck for the successful remediation and∕or control of polluted sites. Electrical Resistivity Tomography (ERT) between boreholes can detect DNAPLs because of their high electrical resistivity. In applying ERT the definition of the ‘best’ measurement schedule is a poorly resolved problem. In two case studies, and with synthetic modeling, the cross-hole tripole-pole electrode configuration is compared with the more widely used circulating dipole-dipole and cross-hole dipole-dipole electrode configurations. The case studies involved ERT measurements between five boreholes at two polluted sites with unconsolidated sediments in the Netherlands. The outcome of the modeled data and the field data show that a cross-hole tripole-pole electrode configuration is more effective in locating DNAPLs than the other configurations. The tomographic image from the cross-hole tripole-pole configuration shows clear horizontal patterns that are in accordance wit...