Determination of fluoroquinolone antibiotics in wastewater and transformation by UV and UV-H2O2 processes

Discharge of antibiotics from wastewater treatment plants represents a threat to both human and ecological health. Elevated levels of fluoroquinolone antibiotics have been detected in wastewater effluent. A novel solid-phase extraction, high performance liquid chromatography with fluorescence detection method was developed and used to measure concentrations of nine fluoroquinolones in a water reclamation plant. Based on that data, UV disinfection was identified as having a high potential for transformation of fluoroquinolones. For that reason, UV irradiation and UV-H2O2 advanced oxidation were studied for several fluoroquinolones. The quantum yield at 254nm and the fluence-based pseudo-first order rate constant were determined for select fluoroquinolones. Significant variation in photoreactivity was observed for fluoroquinolones at pH > 6.5; however, expected transformation efficiencies during UV disinfection processes were relatively low (e.g., 14-36%). Addition of hydrogen peroxide enabled higher transformation efficiencies, indicating that UV-coupled processes could help overcome the challenges associated with wastewater treatment of antibiotics.