New findings on the occurrence, removal, and ecological risk assessment of micropollutants in publicly owned industrial wastewater treatment plants

Previous research on micropollutants (MPs) in wastewater treatment facilities has mainly focused on pharmaceuticals and personal care products in sewage treatment plants. This study presents the first comprehensive investigation into the occurrence, removal efficiency, and potential ecological risks of 34 unregulated inorganic and organic MPs in 12 publicly owned industrial wastewater treatment plants (POIWTPs) in South Korea. These facilities, located in areas with high densities of industrial complexes, have treatment capacities ranging from 5,000 to 185,000 m³ /day. All MPs were analyzed using internationally accredited methods. Among the target compounds, 24 were detected in effluents, with inorganic MPs occurring more frequently than organic ones. Ecological risk assessment using hazard quotient (HQ) values identified selenium (Se) and nickel (Ni) as priority pollutants, with HQ values of 125.1 and 1.5, respectively, posing a “high hazard” for aquatic life. These substances showed low removal efficiencies through conventional coagulation–flocculation (CF) treatment, with average rates of only 7.9 % and 28.3 %. The findings underscore the need for regulatory attention and improved treatment strategies. This study contributes meaningful insights toward the effective management of policy-relevant MPs in POIWTPs and highlights the importance of optimizing treatment processes to reduce ecological risks posed by industrial effluents.