Remediation of phenanthrene contaminated soil by coupling soil washing with Tween 80, oxidation using the UV/S2O82− process and recycling of the surfactant

•Spent TW 80 was recovered by selective oxidation of PHE with sulfate radicals.•PHE degradation products were identified and corresponding degradation pathways proposed.•The recovered TW 80 was effective in flushing PHE from “contaminated” soil.