SARS-CoV-2 in sewer systems and connected facilities.

• SARS-CoV-2 has been found in faeces and, in some cases, urine of infected people. • Wastewater and sewage sludge from infected area can contain SARS-CoV-2 RNA. • To date, virulence of SARS−COV-2 in sewage sludge has not been determined. • Wastewater monitoring could help to understand epidemic situation of urban areas. • Identify and sharing protocols for SARS-CoV-2 detection and analysis are fundamental. As for the SARS coronavirus in the 2003 epidemic, the presence of SARS-CoV-2 has been demonstrated in faeces and, in some cases, urine of infected people, as well as in wastewater. This paper proposes a critical review of the state of the art regarding studies on the presence of SARS-CoV-2 in wastewater and sewage sludge, the factors affecting its inactivation and the main proposed treatments. In-vitro tests demonstrated low resistance of SARS-CoV-2 to high temperature, while even significant changes in pH would not seem to determine the disappearance of the virus. In real wastewater and in sewage sludge, to date studies on the influence of the different parameters on the inactivation of SARS-CoV-2 are not available. Therefore, studies involving other HCoVs such as SARS-CoV and HCoV-229E have been also considered, in order to formulate a hypothesis regarding its behaviour in sewage and throughout the steps of biological treatments in WWTPs. Finally, SARS-CoV-2 in wastewater might track the epidemic trends: although being extremely promising, an effective and wide application of this approach requires a deeper knowledge of the amounts of viruses excreted through the faeces and the actual detectability of viral RNA in sewage. [ABSTRACT FROM AUTHOR]