Enhanced degradation of polycyclic aromatic hydrocarbons in aged subsurface soil using integrated persulfate oxidation and anoxic biodegradation

•Integrated PS oxidation and anoxic biodegradation of PAH in subsurface soil was investigated.•Soil bacterial abundance was negatively impacted by PS, but that can be restored.•Both PS oxidation and anoxic biodegradation contributed to PAH removal in the soil added 1% of PS.•PAH removal was primarily attributed to PS oxidation in soil added 1% of PS.•Combined treatment was more efficient for PAH removal than either one alone in the soil added 1% of PS.