Detection of SARS-CoV-2 in hospital wastewater during the Covid-19 pandemic

Hospital sewage is believed to be an important source of the spread of pathogenic microorganisms including the emerging SARS-CoV-2 virus in the environment. In this study, the performance of wastewater treatment system of three hospitals dedicated to COVID-19 patients in Tehran in removal of SARS-CoV-2 was investigated.

Wastewater samples were collected from the influent and final effluent of two hospitals. Samples were characterized in terms of temperature, acidity, turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD) as well as total suspended solids (TSS). To concentrate RNA, Ultrafiltration and Polyethylene glycol (PEG) precipitation methods were done followed by RNA extraction and viral quantification using RT-qPCR. Finally, through Multiplex One Step q-Real Time PCR method, two N and RdRP regions in the genome of the SARS-CoV-2 were investigated.

The reduction of organic load (BOD and COD) and TSS content of wastewater show that wastewater treatment of hospital 1 was more efficient. Moreover, the results of this study show that concentrating by using both methods of Ultrafiltration and PEG precipitation method has been successful in tracking the presence of the viral RNA in wastewater. The presence of SARS-CoV-2 genome has been confirmed in influent and final effluent of two hospitals.

SARS-CoV-2 in the hospital effluents can be a warning for sanitation authorities to establish new standards for hospital wastewater management. Besides, monitoring of sewage can be considered as a tool for early warning of the outbreak of pandemics.