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We demonstrate the potential of partial denitrification-anammox filters to retrofit plants into sustainable and cost-effective nitrogen removal systems.

This study focused on evaluating the feasibility of expanded clay and sand as media types for mainstream partial denitrification-anammox (PdNA) in deep-bed single-media polishing filters under nitrogen and solids loading rates as well as backwash conditions similar to conventional denitrification filters. The surface roughness and iron content of the expanded clay were hypothesized to allow for enhanced anammox retention, nitrogen removal rates, and runtimes. However, under the tested loading rates and backwash conditions, no clear benefit of expanded clay was observed compared with conventional sand. This study showed the feasibility of PdNA in filters with both sand and expanded clay with PdN efficiencies of 76% and 77%, PdNA rates of 840 and 843 g N/m

Retrofitting conventional denitrification filters into partial denitrification-anammox (PdNA)- or anammox (AnAOB)-based filters will reduce the needs for external carbon addition. The success of AnAOB-based filters depends on anammox growth and retention within such filters. Studies have overlooked the importance of media selection and its impact on AnAOB capacity, head loss progression dynamics, and shear conditions applied onto the AnAOB biofilm. The objective of this study was to evaluate viable media types (10 types) that can enhance AnAOB rates for efficient nitrogen removal in filters. Given the higher backwash requirement and lower AnAOB capacity of the conventionally used sand, expanded clay (3-5 mm) was recommended for AnAOB-based filters in this study. Owing to its surface characteristics, expanded clay had higher AnAOB activity (304- vs. 104-g NH

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel member of the Coronaviridae family, has been identified as the etiologic agent of an ongoing pandemic of severe pneumonia known as COVID-19.(1) To date there have been millions of cases of COVID-19 diagnosed in 184 countries with case fatality rates ranging from 1.8% in Germany to 12.5% in Italy.(2) Limited diagnostic testing capacity and asymptomatic and oligosymptomatic infections result in significant uncertainty in the estimated extent of SARS-CoV-2 infection.(3) Recent reports have documented that infection with SARS-CoV-2 is accompanied by persistent shedding of virus RNA in feces in 27%(4) to 89% of patients at densities from 0.8 to 7.5 log10 gene copies per gram.(5) The presence of SARS-CoV-2 RNA in feces raises the potential to survey sewage for virus RNA to inform epidemiological monitoring of COVID-19, which we refer to as wastewater-based epidemiology (WBE),(6) but is also known as environmental surveillance.(7) Several studies have reported the detection of SARS-CoV-2 RNA in wastewater in the early stages of local outbreaks, further supporting the technical viability of WBE.(8−10) WBE could be especially informative given that asymptomatic and oligosymptomatic infections are unlikely to be detected during clinical surveillance. In such instances, WBE can be used to determine the burden of undiagnosed infections at the population level, which is critical to refining estimates of case-fatality rates. Additionally, wastewater offers an aggregate sample from an entire community that is more easily accessible than pooled clinical samples.(11) Along with clinical data and other technological approaches, such as contact tracing, WBE could provide critical monitoring of SARS-CoV-2 transmission within a community including the beginning, tapering, or re-emergence of an epidemic (Figure 1). This approach mirrors previous efforts in environmental monitoring, for example poliovirus RNA, to inform mechanistic models of pathogen transmission dynamics.(12)

A sensor‐mediated strategy was applied to a laboratory‐scale granular sludge reactor (GSR) to demonstrate that energy‐efficient inorganic nitrogen removal is possible with a dilute mainstream wastewater. The GSR was fed a dilute wastewater designed to simulate an A‐stage mainstream anaerobic treatment process. DO, pH, and ammonia/nitrate sensors measured water quality as part of a real‐time control strategy that resulted in low‐energy nitrogen removal. At a low COD (0.2 kg m−3 day−1) and ammonia (0.1 kg‐N m−3 day−1) load, the average degree of ammonia oxidation was 86.2 ± 3.2% and total inorganic nitrogen removal was 56.7 ± 2.9% over the entire reactor operation. Aeration was controlled using a DO setpoint, with and without residual ammonia control. Under both strategies, maintaining a low bulk oxygen level (0.5 mg/L) and alternating aerobic/anoxic cycles resulted in a higher level of nitrite accumulation and supported shortcut inorganic nitrogen removal by suppressing nitrite oxidizing bacteria. Furthermore, coupling a DO setpoint aeration strategy with residual ammonia control resulted in more stable nitritation and improved aeration efficiency. The results show that sensor‐mediated controls, especially coupled with a DO setpoint and residual ammonia controls, are beneficial for maintaining stable aerobic granular sludge. Practitioner points Tight sensor‐mediated aeration control is need for better PN/A.Low DO intermittent aeration with minimum ammonium residual results in a stable N removal.Low DO aeration results in a stable NOB suppression.Using sensor‐mediated aeration control in a granular sludge reactor reduces aeration cost., Multiple metabolic pathways and competition for nitrite exist in the treatment of anaerobically pretreated mainstream wastewater using a granular sludge reactor.

This protocol describes the concentration and extraction methods for influent wastewater samples at Howard University for SARS-CoV-2 measurements in wastewater. This protocol is intended for research purposes to quantify SARS-CoV-2 and additional targets in RNA extracted from wastewater. It is not intended for diagnostic purposes.

This protocol describes the reverse transcription quantitative polymerase chain reaction (RT-qPCR) methods at Howard University for SARS-CoV-2 measurements in wastewater.

Cross-feeding of metabolites between coexisting cells leads to complex and interconnected elemental cycling and microbial interactions. These relationships influence overall community function and can be altered by changes in substrate availability. Here, we used isotopic rate measurements and metagenomic sequencing to study how cross-feeding relationships changed in response to stepwise increases of sulfide concentrations in a membrane-aerated biofilm reactor that was fed with methane and ammonium. Results showed that sulfide: (i) decreased nitrite oxidation rates but increased ammonia oxidation rates; (ii) changed the denitrifying community and increased nitrous oxide production; and (iii) induced dissimilatory nitrite reduction to ammonium (DNRA). We infer that inhibition of nitrite oxidation resulted in higher nitrite availability for DNRA, anammox, and nitrite-dependent anaerobic methane oxidation. In other words, sulfide likely disrupted microbial cross-feeding between AOB and NOB and induced cross-feeding between AOB and nitrite reducing organisms. Furthermore, these cross-feeding relationships were spatially distributed between biofilm and planktonic phases of the reactor. These results indicate that using sulfide as an electron donor will promote N2O and ammonium production, which is generally not desirable in engineered systems.

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 (KI) 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.

Summary In 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.

Accurate predictions across multiple fields of microbiome research have far-reaching benefits to society, but there are few widely accepted quantitative tools to make accurate predictions about microbial communities and their functions. More discussion is needed about the current state of microbiome analysis and the tools required to overcome the hurdles preventing development and implementation of predictive analyses., Accurate predictions across multiple fields of microbiome research have far-reaching benefits to society, but there are few widely accepted quantitative tools to make accurate predictions about microbial communities and their functions. More discussion is needed about the current state of microbiome analysis and the tools required to overcome the hurdles preventing development and implementation of predictive analyses. We summarize the ideas generated by participants of the Mid-Atlantic Microbiome Meet-up in January 2019. While it was clear from the presentations that most fields have advanced beyond simple associative and descriptive analyses, most fields lack essential elements needed for the development and application of accurate microbiome predictions. Participants stressed the need for standardization, reproducibility, and accessibility of quantitative tools as key to advancing predictions in microbiome analysis. We highlight hurdles that participants identified and propose directions for future efforts that will advance the use of prediction in microbiome research.

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 energy- and 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 trea...