Use of Ozone-Based Processes for the Removal of Pharmaceuticals Detected in a Wastewater Treatment Plant

Ozone (O-3)-based processes (O-3, O-3/H2O2, and O-3/UV) were investigated for the removal of pharmaceuticals in real wastewater using a bench-scale experimental setup. An ozone dose of 6 mg/L (contact time = 10 minutes) was found to reduce the concentration of most pharmaceuticals detected in secondary effluent. Caffeine, N,N-Diethyl-meta-toluamide (DEET), and cyclophosphamide were removed with efficiencies of 84, 89, and 46%, respectively, even with a contact time of 15 minutes (O-3 dose = 6 mg/L). In the case of the ozone process alone, the concentration of bromate ion in the effluent increased with longer contact time. On the other hand, it was found that the O-3/H2O2 and O-3/UV processes can be used as alternative processes for effective removal of pharmaceuticals, while leaving a low residual concentration of dissolved ozone in the system, thereby preventing bromate formation. Water Environ. Res., 82, 294 (2010).