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

   https://doi.org/10.1002/wer.10768  

   Fahrenfeld, Nicole L. ; Morales Medina, William R. ; D'Elia, Stephanie ; Deshpande, Aishwarya S. ; Ehasz, Genevieve ( August 2022 , Water Environment Research)

   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.

   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.

    

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2. The fate and removal of pharmaceuticals and personal care products within wastewater treatment facilities discharging to the Great Bay Estuary

   https://doi.org/10.1002/wer.1680  

   Hidrovo, Alexandria ; Luek, Jenna L. ; Antonellis, Carmela ; Malley, Jr., James P. ; Mouser, Paula J. ( January 2022 , Water Environment Research)

   Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging concern that derive primarily in the water environment from combined sewer overflows and discharges from industrial and municipal wastewater treatment facilities (WWTFs). Due to incomplete removal during wastewater treatment, PPCP impacts to aquatic ecosystems are a major concern. The Great Bay Estuary (New Hampshire, USA) is an important ecological, commercial, and recreational resource where upstream WWTFs have recently been under pressure to reduce nitrogen loading to the estuary and consequently upgrade treatment systems. Therefore, we investigated the distribution and abundance of 18 PPCPs and three flame retardants within the Great Bay Estuary and WWTFs discharging to the estuary to examine how WWTF type influenced PPCP removal. All 21 analytes were frequently detected at μg/L to ng/L concentrations in influent and effluent and ng/kg in sludge. WWTFs with enhanced nutrient removal and longer solids retention times correlated to higher PPCP removal, indicating facility upgrades may have benefits related to PPCP removal. Understanding PPCP fate during treatment and in downstream waters informs our ability to assess the environmental and ecological impacts of PPCPs on estuarine resources and develop mitigation strategies to better protect marine ecosystems from emerging contaminant exposure.

   PPCP removal positively correlated with solids retention time and varied by treatment facility and compound.

   Upgrade of WWTFs for biological nitrogen removal may also increase PPCP removal.

   Surface water fluoxetine concentrations may present an ecological risk to the Great Bay Estuary.

    

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3. Sewage spills are a major source of titanium dioxide engineered (nano)-particle release into the environment

   https://doi.org/10.1039/c8en01376d  

   Loosli, Frédéric ; Wang, Jingjing ; Rothenberg, Sarah ; Bizimis, Michael ; Winkler, Christopher ; Borovinskaya, Olga ; Flamigni, Luca ; Baalousha, Mohammed ( March 2019 , Environmental Science: Nano)

   Sanitary sewer overflows (SSOs) are a common problem across the United States. An estimated number of 23 000–75 000 SSOs occurred in 2004, discharging between 11 and 38 billion liters of untreated wastewater to receiving waters. SSOs release many contaminants, including engineered nanomaterials (ENMs), to receiving water bodies. Measuring ENM concentrations in environmental samples remains a key challenge in environmental nanotechnology and requires the distinction between natural and engineered particles. This distinction between natural and engineered particles is often hampered by the similarities in the intrinsic properties of natural and engineered particles, such as particle size, composition, density, and surface chemistry, and by the limitations of the available nanometrology tools. To overcome these challenges, we applied a multi-method approach to measure the concentrations and properties of TiO 2 engineered particles ( e.g. , ENMs and pigments) including: 1) multi element-single particle-inductively coupled plasma-mass spectrometry (ME-SP-ICP-MS) to identify elemental associations and to determine elemental ratios in natural particles, 2) calculation of total elemental concentrations and ratios from total metal concentrations measured following total sample digestion to estimate engineered particle concentrations, and 3) transmission electron microscopy (TEM) to characterize engineered particle size and morphology. ME-SP-ICP-MS analysis revealed that natural TiO 2 particles are often associated with at least one of the following elements: Al, Fe, Ce, Si, La, Zr, Nb, Pb, Ba, Th, Ta, W and U, and that elemental ratios of Ti to these elements, except Pb, are typical of riverine particulates and the average crustal ratios. High TiO 2 engineered particle concentrations up to 100 μg L −1 were found in SSO-impacted surface waters. TEM analysis demonstrated the presence of regular-shape TiO 2 particles in SSO-impacted surface waters. This study provides a comprehensive approach for measuring TiO 2 engineered particle concentrations in surface waters. The quantitative data produced in this work can be used as input for modeling studies and pave the way for routine monitoring of ENMs in environmental systems, validation of ENM fate models, and more accurate ENM exposure and risk assessment. 

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4. Optimal Control of Combined Sewer Systems to Minimize Sewer Overflows by Using Reinforcement Learning

   https://doi.org/10.1061/9780784484852.067  

   Yin, Zeda ; Leon, Arturo S. ; Sharifi, Abbas ; Amini, M. Hadi ( May 2023 , World Environmental and Water Resources Congress 2023)

   A combined sewer system (CSS) collects rainwater runoff, domestic sewage, and industrial wastewater in the same pipe. The volume of wastewater can sometimes exceed the system capacity during heavy rainfall events. When this occurs, untreated stormwater and wastewater discharge directly to nearby streams, rivers, and other water bodies. This would threaten public health and the environment, contributing to drinking water contamination and other concerns. Minimizing sewer overflows requires an optimization method that can provide an optimal sequence of decision variables at control gates. Conventional strategies use classical optimization algorithms, such as genetic algorithms and pattern search, to find the optimal sequence of decision variables. However, these conventional frameworks are very time-consuming, and it is almost impossible to achieve near real-time optimal control. This paper presents a faster optimization framework by using a new optimal control tool: reinforcement learning. The environment (flow modeler) used in this paper is the numerical model: Environmental Protection Agency’s Storm Water Management Model (EPA SWMM) to ensure the accuracy of environment response. The reward function is constructed based on the calculated water depth and overflow rate from SWMM. The process keeps minimizing the reward function to obtain the optimal flow release sequence at each controlled orifice gate. The combined sewer system (CSS) of the Puritan-Fenkell 7-mile facility in Detroit, MI, is chosen as the case study. 

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5. Regression modeling of combined sewer overflows to assess system performance

   https://doi.org/10.2166/wst.2022.362  

   A. Bizer, Matthew ; Kirchhoff, Christine J. ( November 2022 , Water Science and Technology)

   Combined sewer overflows (CSOs) occur when untreated raw sewage mixed with rainwater, runoff, or snowmelt is released during or after a storm in any community with a combined sewer system (CSS). Climate change makes CSOs worse in many locales; as the frequency and severity of wet weather events increases, so do the frequency and volume of CSO events. CSOs pose risks to humans and the environment, and as such, CSS communities are under regulatory pressure to reduce CSOs. Yet, CSS communities lack the tools needed, such as performance indicators, to assess CSS performance. Using the city of Cumberland, Maryland as a case study, we use public data on CSOs and precipitation over a span of 16 years to identify a new critical rainfall intensity threshold that triggers likely CSO incidence, and a multiple linear regression model to predict CSO volume using rainfall event characteristics. Together, this indicator and modeling approach can help CSS communities assess the performance of their CSS over time, especially to evaluate the effectiveness of efforts to reduce CSOs.

    

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