Capacity of existing wastewater treatment plants to treat SARS-CoV-2. A review

Water is one of many viral transmission routes, and the presence of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) in wastewater has brought attention to its treatment. SARS CoV-2 primarily transmits in the air but the persistence of the virus in the water possibly can serve as a secondary source even though current studies do not show this. In this paper, an evaluation of the current literature with regards to the treatment of SARS-CoV-2 in wastewater treatment plant (WWTP) effluents and biosolids is presented. Treatment efficiencies of WWTPs are compared for viral load reduction on the basis of publicly available data. The results of this evaluation indicate that existing WWTPs are effectively removing 1–6 log₁₀ viable SARS-CoV-2. However, sludge and biosolids provide an umbrella of protection from treatment and inactivation to the virus. Hence, sludge treatment factors like high temperature, pH changes, and predatory microorganisms can effectively inactivate SARS-CoV-2.