SARS-CoV-2 RNA Persistence in Municipal Wastewater Treatment Systems Proves Wastewater Surveillance Is an Effective Tool for Monitoring COVID-19 Community Health Burdens

Abstract

Wastewater surveillance of SARS-CoV-2 is used worldwide to track COVID-19 infection trends. However, there is no standard method for SARS-CoV-2 measurement from wastewater, and uncertainties of pre-analytical influences from the wastewater collection system persist. This study builds upon the growing body of knowledge surrounding wastewater surveillance and aims to understand how wastewater measurements relate to other public health metrics, explain the influence of wastewater conveyance systems, and improve SARS-CoV-2 detection and quantification from wastewater. Our laboratory has been part of the ongoing Wisconsin SARS-CoV-2 wastewater surveillance program since August 2020, analyzing almost 4,000 samples to date. Through various experiments, our findings demonstrated that monitoring variants in wastewater using RT-ddPCR can outperform clinical sequencing. Temperature was the only parameter that significantly influenced SARS-CoV-2 decay in the wastewater matrix. Travel time, flow rate, BOD, and TSS, did not significantly influence SARS-CoV-2 decay or detection. Additionally, extracting RNA from primary settled solids improved detection sensitivity.