Performance evaluation of permeable reactive barrier using zero-valent iron at a chlorinated solvents site

The present study illustrates the preliminary results of a long-term monitoring plan carried out in order to investigate the performance of a zero-valent iron permeable reactive barrier (PRB) at a chlorinated solvents’ site. The cleanup intervention has been undertaken at an industrial landfill located near the city of Turin (Italy) and represents the first full-scale application of this technology in Italy. The monitoring plan started in November 2005 with the aim to verify the attainment of the cleanup goals and to evaluate the efficiency of the PRB. The concentrations of the chlorinated compounds have been measured in a monitoring network across the PRB in order to assure that the dissolved plume is being adequately captured and treated without occurring of contaminant bypass/breakthrough. The hydraulic and chemical performances of the barrier are also monitored with the analysis of groundwater hydrochemistry with the purpose to evaluate the influence of secondary reactions (e.g. precipitation, microbially-mediated redox transformation). The medium and long-term effects of these processes on the PRB performances are simulated using geochemical equilibrium models.