Photocatalytic Disinfection and Removal of Emerging Pollutants from Effluents of Biological Wastewater Treatments, Using a Newly Developed Large-Scale Solar Simulator

The reuse of sewage water treatment is becoming a priority, especially in arid regions, where water is scarce. However, there is increasing concern about the presence of emerging micropollutants refractory to the conventional treatments in wastewater treatment plants. Solar TiO₂ heterogeneous photocatalysis provides a valuable alternative for the simultaneous oxidation of chemical and inactivation of microorganisms. However, the variability of solar irradiance hinders the study of the process under controlled ultraviolet (UV) irradiance. This work reports the development of an innovative solar simulator and its validation against the use of natural sunlight in photocatalytic disinfection applications with simultaneous removal of emerging contaminants. The significant impact of osmotic and mechanical stress on the viability of E. coli bacteria was confirmed. UV irradiance and total-to-illuminated volume ratio showed no impact on the dependence of the bacteria inactivation kinetics on the energy accumulated in the system, indicating that the possible existence of dark repair mechanisms can be neglected within the studied irradiance range (20–60 W m^–2). Average results show that after an accumulated energy of 3 kJ L^–1, 5 logarithmic units (5-logs) of E. coli bacteria are inactivated, whereas a removal efficiency of >80% is achieved for the micropollutants.