Research progress on occurrence characteristics， environmental impact and treatment technology of PAHs in wastewater treatment plants

As a typical persistent organic pollutant， polycyclic aromatic hydrocarbons （PAHs） have become a key challenge in global environmental governance due to their carcinogenicity， bioaccumulation， and long-distance migration ability. The occurrence of PAHs in wastewater treatment plants （WWTPs） across multiple countries was systematically analyzed in this study. The concentration distribution patterns were revealed： industrial-intensive regions exhibited significantly higher influent PAHs concentrations compared to domestic wastewater-dominant areas； in sludge， high molecular weight PAHs account for over 65% of the total PAHs. The removal mechanisms of PAHs at different wastewater treatment stages were comprehensively examined. Biological treatment achieved an average removal rate of approximately 60%. Although advanced oxidation technology has a beneficial treatment effect， it presents problems such as high cost and toxicity of by-products. Based on these findings， a full-chain governance framework was proposed， integrating “source apportionment， process interception， and intelligent regulation.” This study was conducted from multiple analytical perspectives. A theoretical framework and engineering strategies were established to achieve precise control and mitigate risks associated with PAHs in WWTPs.