Process intensification strategies for potable and non-potable wastewater reuse: multitarget assessment of O3/H2O2/UV coupled with biofiltration

The present work aims at identifying sustainable solutions to produce and meet the current and future drinking water demand in Apulia while protecting the quality of receiving water bodies. Three treatment schemes were investigated on a pilot scale. In particular, an innovative patented technology that allows the simultaneous dosage of H2O2/O3 under high-mixing and optimal mass-transfer conditions, MITO3X®, was compared with the UV/H2O2 treatment, both followed by granular carbon biofiltration. Moreover, a third line consisting of ultrafiltration followed by UV disinfection and reverse osmosis was also used as a comparative line of the two advanced oxidation lines. All pilot lines were fed with the tertiary treated wastewater obtained from the municipal wastewater treatment plant located in Fasano (Apulia, Italy). Treatment performance were assessed in terms of removal of: a list of contaminants of emerging concern (CECs), a panel of microbiological parameters (Coliformi, Escherichia coli, Enterococchi, Pseudomonas aeruginosa, Salmonella spp, Staphylococcus aureus, Clostridium perfringens, enteric virus, HAV, HEV, Adenovirus, Enterovirus, Norovirus, Rotavirus and Peppervirus) and for mutagenic bioassay response. The occurrence of CECs in the sampling sites was investigated by UPLC-QTOF/MS/MS. Thirty (30) CECs were detected in a wide range of concentrations in the influent wastewater. The pilot line employing the MITO3X® technology showed an overall greater removal efficiency against the monitored CECs (compared to the UV/H2O2 line), even when the UV/H2O2 doses were doubled. Moreover, microbiological results demonstrated that the obtained water, from all investigated lines, met the potability standards required by D.Lgs 31/01 for both virus and bacteria except for P. aeruginosa (an unregulated parameter) which appeared to be present at the effluent points of all sample lines likely due to biofilm growth within the pilot pipes. Selected samples generated in this study were subjected to the SOS Chromotest and indicated no genotoxic response, despite multiple concentration factors up to 1000 were applied to increase the sensitivity of the bioassay test.