Comparison of UV, Peracetic Acid and Sodium Hypochlorite Treatment in the Disinfection of Urban Wastewater

• Main Authors: Silvia Bonetta, Cristina Pignata, Sara Bonetta, Giulia Amagliani, Giorgio Brandi, Giorgio Gilli, Elisabetta Carraro
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Pathogens
• Subjects: wastewater; disinfection; <i>Campylobacter</i>; <i>Salmonella</i> spp.; <i>E. coli</i> O157:H7; STEC
• Online Access: https://www.mdpi.com/2076-0817/10/2/182

One source of water contamination is the release of wastewater that has not undergone efficient treatment. The aim of this study was to evaluate the reduction obtained with sodium hypochlorite (NaClO), UV and peracetic acid disinfection treatment of <i>Salmonella</i> spp., pathogenic <i>Campylobacter</i>, STEC and bacterial indicators in three full-scale municipal wastewater plants. A general reduction in <i>Salmonella</i> was observed after disinfection, but these bacteria were detected in one UV-treated sample (culture method) and in 33%, 50% and 17% of samples collected after NaClO, UV and PAA disinfection treatments, respectively (PCR method). A better reduction was also observed under NaClO disinfection for the microbial indicators. Independent of the disinfection treatment, <i>E. coli</i> O157:H7 was not detected in the disinfected samples, whereas some samples treated with UV and PAA showed the presence of the <i>stx1</i> gene. No reduction in the presence of <i>stx2</i> genes was verified for any of the disinfection treatments. <i>Campylobacter</i> was not detected in any of the analysed samples. The overall results highlight a better reduction in microbiological parameters with a NaClO disinfection treatment in a full-scale municipal wastewater plant compared with UV and PAA. However, the results indicate that a complete and specific monitoring program is necessary to prevent a possible risk to public health.