Feasibility of Advanced Oxidation Processes as an upgrade for Microcontaminants removal at municipal Wastewater Treatment Plants

Benzotriazole, carbamazepine, clarithromycin and diclofenac have been identified as microcontaminants of concern in Luxembourgish wastewaters, thus the implementation of photo-Fenton processes at natural pH has been proposed for their removal. In the present work, the effectiveness of a pilot scale photo-Fenton system (500W Medium Pressure) has been evaluated according to the reagent dosage and toxicity of the treated effluent. With this treatment, 80% degradation is achieved in 15 minutes even with 5 and 3 mg/L of iron (40 mg/L H2O2), but 5 mg/L can have a negative effect on the growth of Sorghum saccharatum in Phytotoxicity tests. In comparison UV-C/H2O2 (40W Low Pressure; 40 mg/L H2O2) process needs longer treatment time and generates degradation by-products causing a growth inhibition of Sorghum saccharatum. The combination of both lamps can lead to a better performance of the reagents allowing to reach the 80% target in less time and to reduce the dosage.