Removal of SARS-CoV-2 Viral Markers Through a Water Reclamation Facility.

Gharoon, Niloufar; Dewan, Aimee; Li, Lin; Haak, Laura; Mazurowski, Lauren; Guarin, Tatiana; Pagilla, Krishna

There have been multiple reports of COVID-19 virus, SARS-CoV-2 RNA presence in influent wastewater of water reclamation facilities (WRFs) across the world. In this study, the removal of SARS-CoV-2 RNA was investigated in a WRF by collecting samples from various stages relayed to hydraulic retention time (HRT) and analyzed for viral RNA (N1 and N2) gene markers and wastewater characteristics. SARS-CoV-2 RNA was detected in 28 out of 28 influent wastewater and primary effluent samples. Secondary effluent showed 4 out of 9 positive samples, and all tertiary and final effluent samples were below the detection limit for the viral markers. The reduction was significant (p-value < 0.005, one-way ANOVA test) in secondary treatment, ranging from 1.4-2.0 log10 removal. Adjusted N1 viral marker had a positive correlation with total suspended solids, total Kjeldahl nitrogen and ammonia concentrations (Spearman's ρ = 0.61, 0.67, and 0.53, respectively, p-value < 0.05), while demonstrating a strongly negative correlation with HRT (Spearman's ρ = -0.58, p-value < 0.01).