AbstractThe removal of 10 pharmaceuticals and 3 of their metabolites from municipal wastewater by ultraviolet irradiation at a wavelength of 254 nm (UVC) and UV/H2O2 were investigated in this study. Experiments were conducted at a full-scale test facility embedded in an operating wastewater treatment plant. The results give a uniquely clear representation of the effectiveness of these processes for full implementation. Parametric studies on UV intensity and H2O2 dosage were performed, with accompanying analysis of feed water variability. Removal by UV photolysis was compound specific, with more than 70% sulfamethoxazole, caffeine, ciprofloxacin, fluoxetine, and norfluoxetine being removed with 1,400 kJ/m3 of UV fluence. Under similar conditions, 20%–70% removal of metformin, acetaminophen, cotinine, and erythromycin occurred, while <20% removal of trimethoprim, venlafaxine, O-desmethylvenlafaxine, and carbamazepine was found. The addition of H2O2 provided little benefit over UV irradiation alone. Therefore, the addition of H2O2 to UV treatment is only marginally beneficial over UV photolysis for degradation of very low concentrations of pharmaceuticals in municipal wastewater. UV/H2O2 is expected to be more effective in waters with higher concentrations of pharmaceuticals, such as reverse osmosis reject water.