Pharmaceuticals degradation and pathogens inactivation in municipal wastewater: A comparison among UVC photo-Fenton with chelating agents, UVC/H2O2 and ozonation

Abstract

In this work, emerging advanced oxidation processes (AOPs), namely UVC photo-Fenton with two chelating agents at neutral pH, were compared for the first time to consolidated AOPs, namely, UVC/H2O2 and Ozonation (O3) in the degradation of three pharmaceuticals (PhCs) and pathogens inactivation, in real municipal wastewater (RMWW) at pilot scale. Conventional UVC based AOP (UVC/H2O2 at 50 mg/L of H2O2) was faster, being able to degrade 80% of the sum of PhCs in RMWW after 2.5 min, while the same treatment time was required to achieve 60% removal by photo-Fenton. 60% removal of the sum of PhCs in RMWW by O3 was achieved only after 75 min, at the highest dose investigated (0.45 g O3/ L h). The detection limit (1 CFU/100 mL) for pathogens inactivation was achieved after 120 min by O3 for E. coli, while more time was required for Enterococcus (10 CFU/100 mL after 120 min). Faster inactivation was observed for UVC/H2O2 (15 mg/L), the DL being achieved just within 5 and 10 min for E. coli and Enterococcus, respectively. Accordingly, UVC/H2O2 at 15 mg/L would be an effective solution for simultaneous PhCs removal and bacteria inactivation, showing better performance compared to O3 and UVC photo-Fenton like process.