Small scale monitoring of a bioremediation barrier using miniature electrical resistivity tomography

The aim of this study was to assess, in the laboratory, the efficiency of a barrier of oxygen release compound (ORC) to block and divert a diesel plumemigration in a scaled aquifermodel usingminiature electrical resistivity tomography (ERT) as themonitoring system. Two plumes of contaminant (diesel) were injected in a soil model made of local sand and clay. The diesel plumesmigrationwas imaged andmonitored using aminiature resistivity array systemthat has proved to be accurate in soil resistivity variations in small-scaledmodels of soil. ERT results reflected the lateral spreading and diversion of the diesel plumes in the unsaturated zone. One of the contaminant plumes was partially blocked by the ORC barrier and a diversion and reorganisation of the diesel in the soil matrix was observed. The technique of time-lapse ERT imaging showed that a dense non-aqueous phase liquid (DNAPL) contaminant like diesel can be monitored through a bioremediation barrier and the technique is well suited to monitor the efficiency of the barrier. Therefore, miniature ERT as a small-scale modelling tool could complement conventional techniques, which require more expensive and intrusive site investigation prior to remediation