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We propose a minimum set of meta-information to accompany the reporting of SARS-CoV-2 occurrence in wastewater for improved data interpretation.

Growing interest in the anaerobic treatment of domestic wastewater requires a parallel focus on developing downstream technologies that address nitrogen pollution, especially for treatment systems located in eutrophication-impacted watersheds. Anaerobic effluents contain sulfide and hydrogen sulfide (a corrosive gas), dissolved methane (a potent greenhouse gas), ammonium, and residual organic carbon predominantly in the form of volatile fatty acids. Conventional approaches to nitrogen removal are energyand chemical-intensive and are not appropriate for application to anaerobic effluents. Innovative, energy efficient nitrogen removal processes are being developed and involve several novel chemotrophic processes. This review provides information about these processes, identifies how to control and retain the most desirable microorganisms, and considers the impact of reactor configuration on performance. Given the complexity of the technologies under development that remove nitrogen from anaerobically treated domestic wastewater, we conclude that computational models can support their development and that sensor-mediated controls are essential to achieving energy efficiency.

SummaryIn addition to removing organics and other nutrients, the microorganisms in wastewater treatment plants (WWTPs) biotransform many pharmaceuticals present in wastewater. The objective of this study was to examine the relationship between pharmaceutical biotransformation and biodiversity in WWTP bioreactor microbial communities and identify taxa and functional genes that were strongly associated with biotransformation. Dilution‐to‐extinction of an activated sludge microbial community was performed to establish cultures with a gradient of microbial biodiversity. Batch experiments were performed using the dilution cultures to determine biotransformation extents of several environmentally relevant pharmaceuticals. With this approach, because the communities were all established from the same original community, and using sequencing of the 16S rRNA and metatranscriptome, we identified candidate taxa and genes whose activity and transcript abundances associated with the extent of individual pharmaceutical biotransformation and were lost across the biodiversity gradient. Metabolic genes such as dehydrogenases, amidases and monooxygenases were significantly associated with pharmaceutical biotransformation, and five genera were identified whose activity significantly associated with pharmaceutical biotransformation. Understanding how biotransformation relates to biodiversity will inform the design of biological WWTPs for enhanced removal of chemicals that negatively impact environmental health.

Increasingly, technologies that use sulfide as an electron donor are being considered for nitrogen removal; however, our understanding of how sulfide affects microbial communities in nitrifying treatment processes is limited. In this study, we used batch experiments to quantify sulfide inhibition of both ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) using activated sludge from two full-scale treatment plants with distinct treatment processes. The batch experiments showed that NOB were more vulnerable to sulfide inhibition than AOB, and that inhibition constants (K) for NOB were distinct between the two treatment plants, which also had distinct nitrite oxidizing microbial communities. A Nitrospira-rich, less diverse NOB community was inhibited more by sulfide than a more diverse community rich in Nitrotoga and Nitrobacter. Therefore, sulfide-induced nitritation may be more successful in less diverse, Nitrospira-rich communities. Additionally, sulfide significantly influenced the activity of non-nitrifying microbial community members, as measured by 16S rRNA cDNA sequencing. Overall, these results indicate that sulfide has a strong impact on both nitrification and the activity of the underlying microbial communities, and that the response is community-specific.