Removal of pharmaceuticals using combination of UV/H2O2/O3 advanced oxidation process

Water and wastewater effluents contain a vast range of pharmaceutical chemicals. The present study aims to determine the potential of the advanced oxidation technology UV/H2O2/O3 and its sub-processes (i.e. UV, UV/H2O2, UV/O3, O3 and H2O2/O3) for the degradation of the antibiotics ciprofloxacin (CIP) and trimethoprim (TMP), and the antineoplastic drug cyclophosphamide (CPD) from water. Creating AOP conditions improved in most cases the degradation rate of the target compounds (compared with O3 and UV alone). H2O2 concentration was found to be an important parameter in the UV/H2O2 and H2O2/O3 sub-processes, acting as •OH initiator as well as •OH scavenger. Out of the examined processes, O3 had the highest degradation rate for TMP and H2O2/O3 showed highest degradation rate for CIP and CPD. The electrical energy consumption for both CIP and CPD, as calculated using the EEO parameter, was in the following order: UV > UV/O3 > UV/H2O2/O3 > O3 > H2O2/O3. Whereas for TMP O3 was shown to be the most electrical energy efficient. Twelve degradation byproducts were identified following direct UV photolysis of CIP.