Life Cycle Assessment of UV-C based treatment systems for the removal ofcompounds of emerging concern from urban wastewater br

In the last decades particular attention is being paid to the efficient and effective removal of compounds of emergingconcern (CECs) present in wastewater before their eventual reuse or disposal. Several technologies have been devel-oped for the degradation of CECs in aqueous matrix, in this regard advanced oxidation processes (AOPs) represent anascent technological solution developed on a laboratory scale with applications on a prototype scale. The experimen-tal evidences have shown that AOPs processes can oxidize numerous organic compounds in a much faster and moreefficient way than that of the most common disinfection processes. The most common AOPs processes are thosethat involve the use of H2O2/UV, O3/UV, H2O2/O3,H2O2/O3/UV, Fenton and photo-Fenton. The aim of this work isto illustrate the results of a comparative LCA study of a laboratory scale UV-C photoreactor for the tertiary treatmentof urban wastewater of three treatment systems (UV-C, UV-C + H2O2e UV-C + TiO2). In particular, the specificobjective is to evaluate, fromanenvironmentalpoint ofview, aninnovative advanced oxidation system based on nano-structures TiO2immobilized on a stainless steel mesh. Compared to the UV-C photolysis reference system, the additionof hydrogen peroxide reduces the total environmental impact of the system by almost 75 %, while the use of thestainless-steel mesh coated by the nanostructures titanium dioxide reduces the UV-C environmental impact by 30 %. These results are due to the lower energy consumption of these last treatments compared to photolysis alone.The main impacts of the three systems are related to the electric power consumption of the centrifugal pump(63-64 %) and of the UV-C lamp (32-33 %). The LCA applied to these systems has shown that TiO2assistedphotocatalysis is not yet advantageous from an environmental point of view and that, therefore, the efficiency ofthe system needs to be improved