W astewater surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rapidly evolving as a public health tool that holds both promise and challenges (1-3). In concept, a sewer system contains biological waste from the human population it serves. Biological constituents, including pathogens, enter the sewer system through feces, urine, saliva, and other excreta, and the pathogen concentrations represent input from the human population served by the network of pipes within the sewershed. Given that SARS-CoV-2 RNA is shed in feces of persons with asymptomatic and symptomatic infections (4,5), the potential for coronavirus disease (COVID-19) community-level surveillance through wastewater has garnered much attention since the fi rst report of detection of SARS-CoV-2 RNA in wastewater in March 2020 (6).SARS-CoV-2 wastewater surveillance could be an important complement to existing public health surveillance for the COVID-19 response because it has

SARS-CoV-2 viral loads in New York City were significantly correlated with clinical case rates in corresponding sewersheds.

The process of air stripping/absorption was studied at pilot scale at temperatures ranging between 23 and 75°C using ammonia in artificial and natural centrate. The process was more effective at high temperatures and became pH insensitive beyond a critical pH, which was found to drop as the operating temperature increased. Thus, at high temperatures, shorter packing height and lower pH are required to achieve the same ammonia removal. The Onda correlations predicted well the mass‐transfer properties of 25 mm (1 in.) and 32 mm (1.25 in.) nominal size packing in the ranges of 40 to 60°C and 53 to 61°C, respectively. The Norman/Sherwood–Holloway correlations predicted well the mass‐transfer properties for the former and poorly underpredieted the latter packing. The Onda correlations are recommended for preliminary design of stripping/absorption systems within the preceding temperature ranges.

Biological nitrogen removal (BNR) strategies can contribute to atmospheric nitrous oxide (N2O). In the future, as BNR is implemented at more wastewater treatment plants (WWTPs) around the globe, the emission and release of these gases to the atmosphere is expected to increase. This study focused on the quantification of N2O emissions rates and inventory at several WWTPs using a newly developed, U.S. Environmental Protection Agency (Washington, D.C.) (U.S. EPA)‐reviewed protocol. Application of the protocol revealed nitrous oxide emissions from aerated zones therein, hitherto not considered in the current U.S. EPA approach to quantifying N2O fluxes from WWTPs. A high degree of diurnal variability in N2O fluxes was measured, which correlated well with diurnal total Kjeldahl nitrogen loadings. In combination, these results point to the diminishing utility of a single emission factor approach to estimate the N2O emissions from WWTPs, which has been followed to date.

Removal of hydrogen sulfide from anaerobic biogas is necessary to facilitate it's use as a fuel source and minimize sulfur dioxide emissions from wastewater treatment plants. A review of the state of the art in hydrogen sulfide removal is provided, and a new process integrating biological nutrient removal and hydrogen sulfide removal is presented. By utilizing nitrite produced in the separate nitrification of high ammonia in-plant recycles, hydrogen sulfide is converted to sulfate, at the expense of nitrite, while producing alkalinity that can be utilized in the nitrification process. Integration of this novel combined biological and chemical process, converts high-ammonia recycle streams into a resource that allow for removal of hydrogen sulfide from the biogas, while using biologically produced compounds from within the plant. This permits hydrogen sulfide removal with effectively no operating costs attached, while capital costs would be at a fraction of a system with equivalent capacity.