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

Abstract

COVID‐19 wastewater‐based epidemiology has been performed in catchments of various sizes and sewer types with many short‐term studies available and multi‐seasonal studies emerging. The objective of this study was to compare weekly observations of SARS‐CoV‐2 genes in municipal wastewater across multiple seasons for different systems as a factor of sewer type (combined, separate sanitary) and system size. Sampling occurred following the first wave of SARS‐CoV‐2 cases in the study region (June 2020) and continued through the third wave (May 2021), the period during which clinical testing was widely available and different variants dominated clinical cases. The strongest correlations were observed between wastewater N1 concentrations and the cumulative clinical cases reported in the 2 weeks prior to wastewater sampling, followed by the week prior, new cases, and the week after wastewater sampling. Sewer type and size did not necessarily explain the strength of the correlations, indicating that other non‐sewer factors may be impacting the observations. In‐system sampling results for the largest system sampled are presented for 1 month. Removing wet weather days from the data sets improved even the flow‐normalized correlations for the systems, potentially indicating that interpreting results during wet weather events may be more complicated than simply accounting for dilution. Practitioner Points SARS‐CoV‐2 in wastewater correlated best with total clinical cases reported in 2 weeks before wastewater sampling at the utility level. Study performed when clinical testing was widespread during the year after the first COVID‐19 wave in the region. Sewer type and size did not necessarily explain correlation strength between clinical cases and wastewater‐based epidemiology results. Removing wet weather days improved correlations for 3/4 utilities studied, including both separate sanitary and combined sewers.

Changes in Prevalence but Not Hosts of Antibiotic Resistance Genes during the COVID-19 Pandemic versus Prepandemic in Wastewater Influent

“…There was a consistent drop in U.S migration from 2019 to 2021, and the local mobility (movement within the country) also dropped . Drastic changes in movement compared to baseline were reported in the sewer catchments studied here for residential, workplace, and transit (Figure S11 ) during the pandemic. Notably, both WWTP studied here have regional rail lines, airports, and travelers/commuters in the densely populated study region.…”

“…Water quality parameters monitored in the pandemic wastewater samples included pH, total suspended solids (TSS), and chemical oxygen demand (COD), as previously described. 36 qPCR was performed for 16S rRNA gene 38 and for select resistance genes. ARGs analyzed included sul1, 39 tet(G), 40 blaTEM, 41 and qacE.…”

“…A oneway.test was used with a posthoc pairwise t test (pairwise.t.test) with Bonferroni correction for qPCR data that were normal but did not have equal variance (i.e., tet(G)). Spearman's correlations were tested between the qPCR measured concentration of ARGs and the number of COVID-19 cases reported in the sewer catchment one week prior to the date of sampling (previously shown to have moderate correlation with the SARS-CoV-2 N1 gene copies per capita per day 36 ). PERMANOVA (adonis) analysis was performed to understand the relative importance of factors (pH, conductivity, COD, TSS, COVID-19 cases, season, time phase) impacting qPCR measured ARG concentrations.…”

Wastewater-based surveillance of COVID-19 and removal of SARS-CoV-2 RNA across a major wastewater treatment plant in San Antonio, Texas

“…Our study was able to capture wastewater surveillance data from the third major COVID-19 pandemic wave (Delta variant) that ran from June 15, 2021, to August 31, 2021,. 48,49 During this period, wastewater surveillance data collected in the first week of August had the peak weekly average reported concentrations for N1 (Fig. 3, Table S2†).…”

Monitoring hospital effluents through physico‐chemical characterization and genotoxic testing

“…The treated wastewater recycling becomes increasingly important and necessary due to increased climate change, droughts, and water scarcity (Eze et al, 2016), but at the same time, it is risky to use the recycled waters specially when it comes from health care establishments because it may pose serious health problems to the environment, human, and animals. Monitoring, therefore, becomes of utmost importance (Parashar et al, 2022) wherein quality of water can be checked at different times in a year and its toxicity testing should be done from time to time (Fahrenfeld et al, 2022). In this direction, Mathur et al, 2022 performed battery of bioassays to check the efficiency of the treatment plants installed at various health care establishments.…”