Modeling SARS-CoV-2 RNA degradation in small and large sewersheds

Abstract

Wastewater-based epidemiology has played a significant role in monitoring the COVID-19 pandemic, yet little is known about degradation of SARS-CoV-2 in sewer networks. Here, we used advanced sewershed modeling software...

The dynamic relationship between COVID-19 cases and SARS-CoV-2 wastewater concentrations across time and space: Considerations for model training data sets

“…Concentration of SARS-CoV-2 in wastewater is affected by the number of infected individuals and their respective viral shedding dynamics, but also by precipitation events, infiltration and inflow ( McCall et al, 2022 ), industrial flow contributions, and many other factors ( Soller et al, 2022 ; Wade et al, 2022 ; de Araújo et al, 2023 ; Mitranescu et al, 2022 ). Flow rates at wastewater sampling sites can be used to adjust for dilution, but flow data is not always available, especially for samples collected from manholes or small wastewater treatment facilities where no flow meter is present.…”

Year‐long wastewater monitoring for SARS‐CoV‐2 signals in combined and separate sanitary sewers

“…Therefore, as noted by others, sewer size sewer type did not necessarily explain the strength of the correlations with clinical cases observed (Ai et al, 2021 ; Feng et al, 2021 ). While one may expect the longer transport time in larger sewer systems to potentially decay SARS‐CoV‐2 gene copies, as previously demonstrated for a one‐system study (McCall et al, 2022 ), the travel times in the present study were shorter than those reported to result in significant decay by McCall et al It is possible that the correlations were affected in this present study by the sampling design (once per week rather than multiple weekly sampling) and/or the factors beyond the sewer itself (e.g., demographic/geospatial variation in testing) that could impact the clinical testing data accuracy, discussed further below. The latter may be a motivation for exploring alternative clinical metrics for comparison, such as hospitalization rates or intensive care unit admissions (Galani et al, 2022 ), that may be less biased.…”

“…Other factors that may impact the interpretation of sewage for system‐wide WBE could be system size/hydraulics, age, and sewer type, among others. Sewer system size was demonstrated to be sufficient to facilitate decay and therefore may impact interpretation in collection systems with longer travel times for dry weather flows with a maximum of ~1200 min (McCall et al, 2022 ) but was not a factor that explained the varying strength of correlations with case data across different sewer systems (Feng et al, 2021 ). Understanding the potential impact of sewer type is limited to select US studies that included both combined and separate sanitary sewers where no differences in correlations with cases were reported by sewer type (Ai et al, 2021 ; Feng et al, 2021 ).…”

Assessing the Removal Efficiency of Murine Norovirus 1, Hepatitis A Virus, and Human Coronavirus 229E on Dish Surfaces Through General Wash Program of Household Dishwasher

“…Though viral RNA remained on the surface of the dishes and in the wastewater, the viral viability was lost in the general wash program. Simultaneously, it cannot pose a threat to the safety of food tableware and human health because naked residual viral RNA has no infectious ability and degrades rapidly in the environment (McCall et al, 2021 ). The correlation between residual food contaminants and viruses; the ability of dishwashers to remove them in mixed form; the associated experimental processing method require further research in household dishwashers for considering commercial purposes.…”