Highlights SARS-CoV-2 was quantified (10 1 -10 4 copies 100 mL −1 ) in southeast Virginia wastewater. RT-ddPCR was optimized to quantify SARS-CoV-2 from wastewater. 5.5 and 7.6% recoveries were observed for BCoV and BRSV, respectively. Trends in SARS-CoV-2 are apparent at the facility and regional scaleover a 21-week study.

This paper presents an up-to-date meta-analysis assessing per- and polyfluoroalkyl substance (PFAS) concentrations at wastewater treatment plants (WWTPs) as well as changes over time. PFAS concentrations were compiled for WWTPs in the United States from peer-reviewed studies, technical reports, and original data. Perfluorooctanoic acid (PFOA) increased by an average of 6.0 ± 1.6 ng/L from the influents to the effluents of WWTPs, but perfluorosulfonic acid (PFOS) did not significantly change, indicating sorption to sludge is offset by biotransformation of precursor compounds. The occurrence of individual PFAS may vary temporally; for example, perfluoropentanoic acid correlated weakly with seasonal temperatures at a site in Virginia. Wastewater effluent PFOA concentrations decreased at a site in Nevada from 2012 to February 2020 but appeared to increase during the COVID-19 pandemic. Effluent PFOA also declined nationally from 1999 to 2020 by ∼13% per year. Nevertheless, the national mean PFOA concentration was 8.4 ± 0.4 ng/L in data collected from 2013 to 2020 with outliers omitted, indicating persisting low-level occurrence. This would equate to 383 ± 20 kg of PFOA per year continuing to enter the environment via WWTP effluents.

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We hypothesized that mats of a nonnative macroalga, Gracilaria vermiculophylla, which is often found incorporated several centimeters into intertidal mudflat sediments, would increase net denitrification rates relative to bare sediments. At moderate densities (, 40 g dry weight [dry wt] m 22 ), net denitrification rates in June (182.37 6 16.87 mmol N-N 2 m 22 h 21 ), July (213.19 6 16.30 mmol N-N 2 m 22 h 21 ), and September (124.82 6 11.17 mmol N-N 2 m 22 h 21 ) were higher than rates previously documented with macroalgal mats. Compared with rates from bare sediment in June (25.48 6 15.09 mmol N-N 2 m 22 h 21 ) and September (46.47 6 15.79 mmol N-N 2 m 22 h 21 ), net denitrification was significantly higher when G. vermiculophylla was present. Rates measured on bare sediment in July (254.81 6 19.86 mmol N-N 2 m 22 h 21 ) were not significantly different from G. vermiculophylla counterparts, most likely because of highly reduced conditions in G. vermiculophylla cores, which could have limited nitrification. July incubations also demonstrate that at higher densities (, 120 g dry wt m 22 G. vermiculophylla), denitrification rates can drop, suggesting a potential biomass threshold for macroalgal enhancement of denitrification.

Hampton Roads Sanitation District recently initiated an indirect potable reuse project to recharge the Potomac Aquifer in southeastern Virginia, USA. Source control and granular activated carbon (GAC) treatment are employed to minimize per-and polyfluoroalkyl substances (PFAS) content in this water. Final purified water maintained low long-chain perfluoroalkyl acids (PFAAs; <8 ppt sum of PFOA, PFNA, PFDA, PFHxS, PFOS) and moderately low short-chain PFAAs (<118 ppt of sum PFBA, PFPeA, PFHxA, PFHpA, PFBS). High mobility of low concentrations of five PFAS (PFBS, PFPeA, PFHxA, PFHpA, PFOA) in the Potomac Aquifer was observed. Despite low concentrations relative to current guidelines, PFAS breakthrough and mobility support strict source control and the use of surrogates like total organic carbon to guide GAC operation at the installation.