Chelating agents supported solar photo-Fenton and sunlight/H2O2 processes for pharmaceuticals removal and resistant pathogens inactivation in quaternary treatment for urban wastewater reuse
Pellegrino La Manna, Marco De Carluccio, Patrizia Iannece, Giovanni Vigliottá, Antonio Proto, Luigi Rizzo
Abstract
In this work, Fe3+-iminodisuccinic acid (Fe:IDS) based solar photo Fenton (SPF), an Italian patented method, was investigated in quaternary treatment of real urban wastewater and compared to Fe3+-ethylenediamine-N,N′-disuccinic acid (Fe:EDDS) for the first time. Three pharmaceuticals (PCs) (sulfamethoxazole, carbamazepine and trimethoprim) and four pathogens (Escherichia coli, somatic and F-plus coliphages, Clostridium perfringens, consistently with the new EU regulation for wastewater reuse (2020/741)), were chosen as target pollutants. SPF with Fe:EDDS was more effective in PCs removal (80%, 10 kJ L−1) than the SPF with Fe:IDS (58%), possibly due to the higher capability of generating hydroxyl radicals. On the contrary, Fe:IDS was more effective (4.3 log inactivation for E. coli) than Fe:EDDS (1.9 log) in pathogens inactivation, possibly due to a lower iron precipitation and turbidity which finally promoted an improved intracellular photo-Fenton mechanism. Fe:L based SPF was subsequently coupled to sunlight/H2O2. Interestingly, while its combination with Fe:EDDS based SPF slightly increased disinfectant efficacy (2.3 vs 1.9 log inactivation for E. coli), the combination with Fe:IDS decreased inactivation efficiency (3.4 vs 4.3 log reduction). In conclusion, due to the good compromise between PCs removal and disinfection efficiency, Fe:IDS SPF alone is an attractive option for quaternary treatment for urban wastewater reuse.