Remediation of soil contaminated by PAHs and TPH using alkaline activated persulfate enhanced by surfactant addition at flow conditions

BACKGROUND Remediation of a soil polluted with fuel oil #2 and polycyclic aromatic hydrocarbons (PAHs) has been carried out by alkaline activated persulfate (PS). Furthermore, the effect of surfactant addition on the abatement of TPH and PAHs was studied. Accordingly, four runs were performed at flow conditions using: 1) only water, 2) only surfactant (15 g L−1 of Verusol-3), 3) activated persulfate (210 mM PS and 840 mM NaOH) and 4) surfactant (15 g L−1 Verusol) with activated persulfate (210 mM PS and 840 mM NaOH). RESULTS Washing with water was found to achieve a negligible desorption of the pollutants. Washing with surfactant or a combination of surfactant and oxidant completely removed the contaminants from soil, however only the addition of oxidant yielded an aqueous effluent without the pollutants. When adding activated persulfate alone (without surfactant), about 30% residual contamination remains in the soil. CONCLUSION Results suggest that the combined application of surfactant and alkali persulfate produces a significant improvement in the elimination of organic compounds such as fuel oil #2 and PAHs.