Ex-situ DBD plasma discharge experiments were performed in model-NAPL contaminated soils in order to evaluate the remediation efficiency as a function of soil heterogeneity, NAPL concentration, injected energy density, and examine the degradation rate of each NAPL compound (n-decane, n-dodecane and n-hexadecane). It was found that NAPL removal efficiency reaches 97 to 99.7% for an energy density of 10000 J gsoil-1, indicating that all NAPL compounds (n-C10, n-C12 and n-C16) are oxidized, regardless of NAPL concentration and soil heterogeneity. For lower energy densities, the NAPL oxidation rate decreases as NAPL concentration increases and soil heterogeneity is enhanced. At high NAPL concentrations and for saturations that exceed the percolation threshold of the porosity, the remediation efficiency becomes independent of soil heterogeneity. Regarding the oxidation rate of each NAPL compound, it was found that the degradation rate decreases with the number of carbon atoms increasing in agreement with their volatility.

Soil Remediation, DBD Plasma, NAPL Oxidation, Removal Efficiency, Soil Heterogeneity