Effect of Perfluorooctanoic Acid on Denitrifying Phosphorus Removal System under Short-Term Stress

Perfluorooctanoic acid (PFOA), a novel contaminant, is extensively found in aquatic environments. However, the capability of the denitrifying phosphorus removal process to treat PFOA-containing wastewater, as well as its response mechanisms, are unclear. This study used batch experiments to assess the short-term impact of PFOA on denitrifying phosphorus removal systems. During a single cycle, the addition of PFOA predominantly enhanced phosphate removal in the system mainly by the anaerobic phosphorus release pathway, but had no substantial effect on nitrogen removal. COD removal efficiency has a substantial positive correlation with C6-HSL and C8-HSL concentrations. As the PFOA concentration increased, the ROS concentration and enzyme activity also increased, while the PN/PS ratio decreased, causing the sludge to become looser. At the beginning of the second cycle, the impact of PFOA on phosphorus removal efficiency shifted from promotion to inhibition. These findings shed fresh light on the influence of PFOA on the denitrifying phosphorus removal mechanism, potentially furthering its use in the treatment of fluoride-containing wastewater.