Work

Degradation of organic micropollutants in urban tertiary treated wastewater by dielectric barrier discharge plasma: chemical removal and cyanobacteria toxicity reduction

Year: 2026

Type: article

Abstract: Discharge of organic micropollutants (OMPs) from urban wastewater treatment plants (WWTPs) poses a growing environmental concern, as effluents contain complex mixtures of pharmaceuticals, pesticides, and per - and polyfluoroalkyl substances (PFAS). This study evaluated nonthermal dielectric barrier discharge (DBD) plasma as a reagent-free advanced oxidation process (AOP) for OMP removal and ecotoxicity reduction in unspiked tertiary treated wastewater. Of 343 targeted compounds, 67 were detected; 15 of 28 quantified compounds exceeded the limit of quantification prior to treatment. At 16 kV, 30 min of plasma treatment achieved >90% removal of most quantified OMPs, including clarithromycin, carbamazepine, diclofenac, and venlafaxine, with a median electrical energy per order (EEO) of 4.8 kWh m −3 order −1 . Extending treatment to 90 min yielded no proportional improvement in removal efficiency. PFAS, particularly perfluorooctanoic acid (PFOA), were recalcitrant to DBD treatment under the conditions tested. The untreated effluent had an EC10 of 6.9 ± 1.1 relative enrichment factor (REF), whereas the EC10 exceeded 100 REF after treatment, corresponding to >93% reduction in cyanobacterial growth inhibition. Four antibiotics and herbicides explained 63.8% of the observed toxicity, with clarithromycin contributing 52.6%. All four compounds fell below detection or quantification limits after treatment. By integrating native OMP mixtures, energy demand, and biological effects, a more environmentally relevant picture of DBD plasma performance is provided than by chemical removal data alone. Broader validation across trophic levels and endpoints is necessary before conclusions on ecological safety or full-scale readiness can be drawn.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2026.181241