ACS ES&T water最新文献

The UV-based advanced reduction processes (ARPs) have emerged as an effective strategy to degrade PFAS contaminants in water. This study investigates PFAS degradation by integrating far-UVC irradiation at 222 nm with sulfite-based ARPs. Comparative analysis of UV222/sulfite and conventional UV254/sulfite revealed that UV222/sulfite systems significantly improve the performance by generation of more hydrated electrons (e_aq ^-), the primary reactive species driving PFAS degradation, and exhibit superior energy efficiency, characterized by lower electrical energy per order (E _EO ). The higher efficiency of UV222/sulfite can be attributed to stronger light absorption of sulfite and higher photon energy at 222 nm. Under optimized stepwise sulfite dosing conditions, the UV222/sulfite ARP achieved high perfluorooctyl sulfonic acid (PFOS) removal efficiency, nearly 85% reduction in parent compound and 66% defluorination within a 6 h period, while the degradation of shorter-chain PFHxS and PFBS was slower. Real water matrix components can influence treatment efficiency. The impacts of nitrate/nitrite were transient and diminished after rapid photolysis at 222 nm, while dissolved organic matter and carbonates exerted strong reactive species scavenging effects. This study establishes UV222/sulfite ARP as a promising strategy to enhance PFAS degradation. Careful optimization of UV222/sulfite system parameters and water matrices will increase the adaptability for environmental PFAS remediation.

Microbially mediated transformations, such as nitrification and biodegradation, play a crucial role in removing pollutants from rivers. Although in-stream removal rate coefficients are often assumed to be spatially and temporally constant, they are likely affected by the channel shape and size because these factors control contact between the water column and fixed biofilms. Here, we test the hypothesis that transformation rate constants are inversely proportional to the hydraulic radius (R: ratio of the channel cross-sectional area to wetted perimeter) in dye tracing experiments conducted in two U.K. rivers with contrasting morphologies: (1) the River Maun (shallow: mean bankfull R = 1.25 m) and (2) the River Calder (deep: mean bankfull R = 3 m). In each case, a slug of rhodamine WT was injected upstream of a wastewater outfall, and samples were collected downstream, staggered by the rhodamine travel time. Rate constants were derived for sucralose, ammonium, caffeine, and linear alkylbenzenesulfonate. Sucralose (persistent, hydrophilic, and exclusively of wastewater origin) was used as a conservative tracer to adjust model fits for dilution. Higher rate coefficients were observed for all biotransformed pollutants in the Maun compared to the Calder, supporting the hypothesis and highlighting the need to consider geomorphology in models of chemical behavior.

In drinking water distribution systems (DWDS), skin-friction drag in turbulent pipe flows contributes significantly to energy losses. Passive drag-reducing surfaces, such as shark-skin-inspired riblets, have shown promise in controlled environments but often underperform under variable flow conditions. This study addresses this limitation by developing and experimentally evaluating a Hierarchical Step-shaped Riblet (HSR) design aimed at sustaining drag reduction under the variable and fluctuating flow conditions typical of water pipelines. Building on conventional riblets (CR) and hierarchical riblets (HR), the HSR configuration introduces progressively tapered riblet tips to the hierarchical design to reduce shear-exposed surface area while maintaining effective interaction with vortices of varying size. Riblet designs were fabricated using high-resolution 3D printing and tested in variable flow conditions, simulating the flows in typical drinking water distribution networks. Drag reduction performance was evaluated across a Reynolds number range of 4200 to 20,000 using friction factor analysis and nondimensional riblet spacing. The HSR design achieved the highest peak drag reduction of 11.2% and sustained favorable performance across a broader range of flow conditions than the CR and HR designs. The results demonstrate that multiscale geometric tuning, combined with reduced shear exposure, enhances drag reduction across a broadened operational range suitable for drinking water distribution pipes.

Installation of advanced filtration technologies for removing perfluoroalkyl and polyfluoroalkyl substances (PFAS) from drinking water presents an opportunity for considerable improvement in public drinking water quality. The U.S. Environmental Protection Agency’s drinking water standards published in 2024 for six PFAS were calculated to provide nationwide health benefits due to concurrent reduction in PFAS as well as total trihalomethanes (TTHMs or THM4), a group of carcinogenic disinfection byproducts. Here, we present a disinfection byproduct case study analysis of 19 community water systems that installed treatment to remove PFAS between 2018 and 2022. Fifteen case study systems observed reductions in THM4, and 15 observed reductions in haloacetic acids (HAA5) following the installation of PFAS treatment. Average reductions were 42% for THM4 (range: 9%–95%) and 50% for HAA5 (range: 2%–97%). Tap water served by 690 of the 1,083 systems with a single PFAS concentration exceeding the 2024 standards also contains co-occurring contaminants from four groups: disinfection byproducts, metals, nitrate/nitrite, and organic contaminants. Analysis of community water system treatment information and PFAS occurrence data from the U.S. EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR5) program suggests that a new regulatory framework based on treatment standards for multiple co-occurring contaminants would lead to a wide scope of potential health benefits due to simultaneous contaminant removal.

Analysis of U.S. water systems shows that PFAS treatment can reduce co-occurring contaminants, supporting benefits beyond those considered in the 2024 PFAS standards.

Bacteria and free-living protozoa (FLP) have been coevolving in a predator–prey relationship for well over a billion years, facilitating an array of “arms race” mechanisms, including antimicrobial resistance (AMR). This perspective explores the role of FLP, including free-living amoebae (FLA), in promoting AMR with a focus on wastewater treatment plants (WWTPs), recognized hotspots for the release of AMR. Technological advances in WWTPs have changed ecological niches, impacting their microbial communities. Each process alters the diversity, abundance, and activity of FLP/FLA and bacteria, generally increasing the potential for horizontal gene transfer of antibiotic resistance genes (ARGs). Further, disinfection treatments such as chlorination, UV irradiation, and ozonation may inadvertently select for antibiotic-resistant bacteria (ARB) and multidrug resistance through natural stress responses, which are also enhanced and protected within FLP. Overall, there is a critical need to better understand the ecological impacts of biological wastewater treatment technologies and their associated interactions between FLP/FLA and ARB, and their pathways of AMR dissemination through engineered and natural water systems. This perspective underscores the importance of going beyond fecal indicator-ARG monitoring to control AMR in wastewater treatments and water reuse to mitigate risks associated with the dissemination of AMR via the environment.

Wastewater-based epidemiology is an efficient method for monitoring the transmission of diverse pathogens in communities. While various concentration methods are used, most were selected to detect SARS-CoV-2 and other respiratory viruses. Research is needed to guide the method selection for monitoring diverse pathogens in wastewater. In this study, a head-to-head comparison of six different concentration methods was performed, including direct extraction (with and without bead beating), electronegative (HA) filtration, solid concentration, and magnetic bead-based concentration (using Nanotrap particles; with and without bead beating). Methods were assessed for sensitivity, inhibitor removal, recovery rates, and cost, targeting 14 microorganisms including viruses, bacteria, and fungal pathogens. Results showed that the concentration method selection significantly impacts the sensitivity and economic costs of the wastewater monitoring workflow. While no single method was optimal for all targets, combining HA filtration and solid methods in parallel for the same sample is recommended to sensitively detect viruses, bacteria, and fungal pathogens. The magnetic bead-based method can be automated but costs more per sample and is less sensitive for some targets. This study provides data-driven insights to enhance the reliability and cost-effectiveness of wastewater surveillance systems that can support public health responses for a broad range of diseases.

In this study, cobalt–gallium layered double hydroxide (CoGa LDH) was synthesized using the coprecipitation technique. The characteristics of the prepared LDH were assessed in detail using various analytical techniques, including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N₂ adsorption/desorption, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, energy-dispersive X-ray spectroscopy, elemental dot mapping, and X-ray photoelectron spectroscopy. 2-Mercaptobenzoxazole (MBO), an organosulfur model pollutant, was utilized to investigate the sonocatalytic capability of CoGa LDH. The effect of the operational parameters, including catalyst dosage, pollutant concentration, and pH, on the performance of the sonocatalytic system was investigated. The results showed that CoGa LDH with a catalyst dosage of 0.5 g/L exhibited considerable sonocatalytic activity (80.9%) for the removal of MBO, compared to adsorption (17.9%) and sonolysis (30.4%) within 120 min. A plausible sonocatalytic degradation mechanism was proposed using the gas chromatography–mass spectrometry method. The developed sonocatalytic system showed high performance in the degradation of diverse mercaptan derivatives, including 2-mercaptobenzimidazole (71.2%) and 2-mercaptobenzothiazole (100%), and also pharmaceutical pollutants, including oxytetracycline (100%), tilmicosin (100%), and levofloxacin (86.1%). The findings revealed that CoGa LDH is a durable and efficient sonocatalyst for environmental remediation and wastewater treatment.

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants that are subject to increasingly restrictive regulations. This study characterized the occurrence of 77 PFAS compounds in raw and treated water from 15 drinking water treatment plants (WTPs) in the Greater Montreal Area, including an urban creek receiving airport runoff. A total of 32 compounds were detected at least once, representing diverse classes and carbon chain lengths. This helped to identify trends and precursor impacts on the PFAS profiles. Perfluoroalkyl carboxylic acids (PFCA) and perfluoroalkyl sulfonic acids (PFSA) were the most frequently detected. The highest concentrations occurred in WTPs drawing from the St. Lawrence River, while the Ottawa and L’Assomption Rivers demonstrated the occurrence of localized contamination. Conventional treatment showed negligible PFAS removal. WTPs drawn from the same water source were generally correlated. Correlation analyses also demonstrated that some plants are influenced by both the Ottawa and St. Lawrence Rivers. Airport-related PFAS compounds, such as those from aqueous firefighting foam and hydraulic fluids, were detected in downstream WTPs. Seasonal trends suggest that temperature and flow variations might affect PFAS concentrations. These findings illustrate the challenges when protecting water sources against PFAS at a basin scale while offering insights into how their patterns can assist with the identification of local contamination sources.

This study has shown that the existing conventional treatment processes are not efficient for PFAS removal. The highest PFAS concentrations were observed in the St. Lawrence River. While airport runoff, aqueous film-forming foams (AFFFs), and hydraulic fluids contribute to PFAS contamination, trends on PFAS classes and chain lengths related to sources and mixing of rivers were established.

In this work, we developed the long-term photoaging of polyethylene microplastics (PE MPs) in coastal seawater ecosystems, focusing on pigment-dependent effects. After 0.5 g of MP was exposed to 20 mL of coastal seawater and underwent 12-day simulated ultraviolet (UV) irradiation (UV₃₆₅ = 10 mW/cm²), the intensity of crystalline region peaks in the PE MPs decreased in the following order: red (6.11%) > blue (2.11%) > green (0.45%), corresponding to the increase in carbonyl index after UV aging (red (298.6%) > blue (376.4%) > green (192.9%)). This disparity can be attributed to the susceptibility of the red pigment adhered to the surface of MPs, which is more prone to absorb UV light photons under sunlight irradiation, leading to the generation of higher levels of oxidative free radicals, including hydroxyl radicals (^·OH, red: 7.67 × 10^–15 M; green: 3.43 × 10^–15 M; blue: 5.34 × 10^–15 M) and superoxide anions (O₂^·–, red: 120.62 ± 9.31 μM; green: 66 ± 1.32 μM; blue: 95.97 ± 0.88 μM), thereby accelerating the photoaging of MPs during prolonged exposure in coastal seawater. Regarding color, which is regarded as a significant yet often overlooked factor influencing MP phototransformation, the obtained findings herein provide methodological strategies to elucidate the formation and ecological risks associated with MPs and nanoplastics in marine environments.

Bisphenol A (BPA) is a pervasive environmental contaminant known for its detrimental effects on human health. However, its impact on multiple generations of microorganisms and the biogeochemical cycles they mediate, particularly at environmentally relevant concentrations, remains poorly understood. This study explores the effects of BPA on Roseovarius nubinhibens, a crucial bacterium in the global sulfur cycle, under both short-term (F0 generation) exposure at the observed-effect concentration (26 mg/L) and long-term (F20 generation) exposure at an environmentally relevant concentration (0.06 mg/L). Short-term exposure to the observed-effect concentration significantly inhibited bacterial growth by 12.9%, while long-term exposure at the environmentally relevant concentration induced notable morphological changes without affecting growth. BPA at the observed-effect concentration also disrupted extracellular polymeric substance (EPS) production and protein structures, particularly in the soluble-EPS (S-EPS) fraction, leading to impaired bacterial flocculation. Additionally, BPA at both exposure levels decelerated the conversion of dimethylsulfoniopropionate (DMSP), with the observed-effect concentration particularly affecting the cleavage pathway, reducing dimethyl sulfide (DMS) production. This study provides the first direct experimental evidence that BPA disrupts the metabolic equilibrium of sulfur cycling. These findings underscore the need for deeper exploration of BPA’s environmental risks, especially at environmentally relevant concentrations, and its potential to interfere with microbial-driven sulfur biogeochemistry.