Removal of SARS-CoV-2 Viral Markers Through Truckee Meadows Water Reclamation Facility
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Authors
Dewan, Aimee
Issue Date
2021
Type
Thesis
Language
Keywords
Enveloped virus , SARS-CoV-2 , Wastewater , WBE
Alternative Title
Abstract
Wastewater treatment technology is relied upon to prevent the spread of human pathogenic viruses through waterborne transmissions. Variable trends in the reduction of viral genomic concentrations are commonly observed following treatment, leading to the conclusion that wastewater treatment processes are not always consistent. Research on the existence and fate of viruses in wastewater has focused on enteric, non-enveloped viruses. The COVID-19 pandemic called for a rapid shift in focus from the research community to investigate the behavior of enveloped viruses within wastewater reclamation facilities (WRFs), with a focus on the SARS-CoV-2 virus.Following multiple reports of SARS-CoV-2 presence in influent wastewaters of WRFs, this study investigated the removal of SARS-CoV-2 RNA markers in Truckee Meadows WRF in Washoe County, Nevada. Samples from the treatment train, as relayed to hydraulic retention time (HRT), were collected and analyzed for viral RNA N1 and N2 gene markers and wastewater characteristics. Wastewater samples were processed through a series of pre-treatment, virus concentration and RNA extraction methodologies. SARS-CoV-2 genetic markers were then quantified using reverse transcription quantitative polymerase chain reaction (RT-qPCR). SARS-CoV-2 RNA was detected in 28 out of 28 influent wastewater and primary effluent samples. Secondary effluent showed 4 positives out of 9 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 across the treatment process. Wastewater viral RNA concentrations measured at each sampling site allowed the development of relationships between physical, chemical, and biological constituents in wastewater and transport of SARS-CoV-2 through the collection systems. Primarily, Total Suspended Solids and HRT are the most significantly correlated wastewater characteristics with the removal of SARS-CoV-2 genetic markers. Determining the safety of treated wastewater in light of the viral loads occurring during a pandemic is a necessary step for public health and public confidence in wastewater treatment effectiveness. This research has provided a basis for further research on the fate and removal of enveloped viruses during wastewater treatment.