ACS ES&T water最新文献

The ability of dissolved organic matter (DOM) to mediate the reduction of ionic Ag to silver nanoparticles (AgNPs) in sunlit water has been validated, however, there remains a paucity of knowledge regarding the environmental fates of both naturally occurring and engineered AgNPs. This study systematically investigates the aggregation and stabilization mechanisms of AgNPs synthesized by plant-derived DOM under critical environmental stressors. The results indicate that both freezing and the presence of coexisting ions significantly enhance the aggregation of AgNPs. Specifically, anions such as Cl^– and SO₄^2– facilitate aggregation through electrostatic interactions, while divalent cations like Ca²⁺ and Mg²⁺ further promote aggregation via bridging effects and accelerate the reduction of DOM, which indirectly compromises the stability of AgNPs. Notably, AgNPs synthesized from Eriobotrya japonica demonstrate remarkable colloidal stability under various environmental stressors, a phenomenon attributed to specific components within macromolecular DOM (>30 kDa). These components may provide multifunctional protection through mechanisms such as π-Ag coordination, steric hindrance, and the formation of hydration shells. Furthermore, sucrose-6-acetic ester appears to enhance medium viscosity, thereby reducing diffusion during freeze–thaw cycles. These findings are significant for understanding of the diverse roles of plant-derived DOM in controlling fates of AgNPs in DOM-rich surface water.

Integrated fixed-film activated sludge (IFAS) systems provide an energy-efficient method for nitrogen removal in aniline wastewater treatment. However, the effects of low SGV on microbial community dynamics and electron transfer under aniline stress in continuous-flow IFAS systems remain insufficiently understood. Herein, we systematically evaluated IFAS performance under varying SGVs (0.15, 0.10, and 0.04 cm/s) in treating 400 mg/L aniline wastewater. Aniline removal remained consistently high (>99%) across all conditions, while the total nitrogen removal efficiency declined from 82.65% at 0.15 cm/s to 46.58% at 0.04 cm/s. Reduced SGV, a key determinant of dissolved oxygen (DO), induced metabolic stress on microbial consortia and suppressed nitrification by reducing ammonia-oxidizing bacteria (AOB) abundance and downregulating amoA and hao. Community assembly analyses revealed a shift from deterministic selection at higher SGVs to stochastic processes (ecological drift and dispersal limitation) at lower SGVs. Microbial compositional shifts were observed, with Actinobacteria (aniline degraders) enrichment at reduced SGVs. Across all conditions, biofilms demonstrated a dominant role in nitrogen removal over suspended sludge. Electron transfer adaptations exhibited a strategic microbial response, characterized by the recovery of related functional gene abundance under lower SGVs.

The electrochemically driven UV light-emitting diode/chlorine (UV-LED/EC-Cl₂) process represents an emerging advanced oxidation technology capable of simultaneously removing microorganisms and micropollutants, making it particularly suited for decentralized water treatment in rural areas (utilized naturally occurring Cl^– in water). This research systematically investigated the removal efficiency and underlying mechanisms of the UV-LED/EC-Cl₂ process for the selected microorganisms (Aspergillus niger spores) and herbicides (atrazine (ATZ) and 2,4-dichlorophenoxyacetic acid (2,4-D)). The results demonstrated a significant synergistic effect in fungal spore inactivation, primarily attributed to the generation of reactive radical species, which induced severe membrane disruption and elevated intracellular reactive oxygen species levels. Furthermore, the UV-LED/EC-Cl₂ process exhibited exceptional herbicide removal efficiency, achieving over 90% degradation within 37 min. The coexistence of A. niger spores reduced the herbicide degradation efficiency by approximately 10%, with the degradation products of ATZ exhibiting increased molecular weight and toxicity. Even in actual groundwater, the UV-LED/EC-Cl₂ process maintained a high removal efficiency. Additionally, the electrical energy per log removal of herbicide ranged from 18.3 to 32.5 kWh/m³-log, lower than that of the standalone processes. These findings underscore the potential of the UV-LED/EC-Cl₂ process as an effective and energy-efficient solution for simultaneous microorganisms and micropollutant removal in decentralized water treatment.

This study investigates 16 locations sampled along a 50-mile stretch of the Schuylkill River, a major drinking water source, to examine the presence, spatial distribution, and risk assessment of PFAS. The most prevalent compounds were PFBA, 6:2 FTS, PFOA, and PFOS, which were detected in nearly 100% of the samples. The Risk Quotient (RQ) method, which was applied to conduct risk assessments according to the EPA’s 2016 guidelines, indicated that more than 61% of the samples showed a medium-risk profile. However, the 2024 EPA regulations resulted in a high-risk profile for all February samples for PFOA, with 67.7% and 87% of the May and July samples also categorized as high-risk. In the same vein, a high-risk profile for PFOS was observed in 61.5–81% of the samples. Furthermore, the Hazard Index (HI) was evaluated to assess the cumulative hazard of PFNA, GenX Chemicals, PFHxS, and PFBS; notably, 19% of July samples exceeded the HI threshold, indicating increased health risks. Potential PFAS contamination pathways were investigated. These results emphasize the critical importance of ongoing monitoring and mitigation strategies to protect public health and guarantee the safety of water resources.

Microplastics (MPs) pollution has become an urgent global environmental issue due to its widespread distribution and persistence in aquatic ecosystems. Although there is growing interest in remediation technologies, effective methods for microplastic (MP) removal remain limited. In this study, we report for the first time the application of bath-type ultrasonication for MP remediation, representing a novel and chemical-free approach in this field. Results demonstrated that ultrasonic treatment effectively removed MPs from water within 5 s, with removal efficiency positively correlated with particle concentration and strongly influenced by material density─achieving over 90% removal for high-density polyvinyl chloride (PVC), while only ∼13% for low-density polyethylene (PE). Interestingly, under the tested power level of 500 W, the removal efficiency was largely independent of treatment duration, and no significant difference was observed between 200 and 500 W. The removal mechanism was attributed to ultrasound-induced particle motion that facilitated agglomeration and subsequent sedimentation. This pioneering work fills a critical knowledge gap in the ultrasonic remediation of MPs pollution and introduces a new physical treatment method for addressing this pressing environmental challenge.

Antibiotic resistance is a growing threat to public health, and environmental factors, including metals in drinking water distribution systems, are increasingly recognized as contributors to the spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Zinc orthophosphate, a common corrosion inhibitor, and copper corrosion products (CuO and Cu₂O) are frequently present in drinking water systems. While each has been shown to increase ARB and ARGs individually, their combined effects remain unknown. The objective of this study was to evaluate the combined impact of copper corrosion products and the corrosion inhibitor zinc orthophosphate on antibiotic resistance. Two sets of lab-scale microcosms were used, in which CuO and Cu₂O were added with and without zinc orthophosphate, and impacts on ARB abundance, ARG abundance, and microbial community structure were assessed. Overall, the combined addition of copper corrosion products and corrosion inhibitor increased ARB and ARGs, coinciding with changes to the microbial community’s β-diversity. In most cases, the coaddition of the corrosion product with the corrosion inhibitor resulted in greater changes in antibiotic resistance abundance than the addition of the corrosion product alone. This research improves our understanding of how the coexistence of metal corrosion products and corrosion inhibitors in drinking water pipes can impact antibiotic resistance.

The coexposure of copper corrosion products and zinc orthophosphate, common in drinking water systems, increases antibiotic-resistant bacteria and antibiotic-resistant genes and alters microbial communities.

Most data on laboratory-scale experiments evaluating E. coli and enterococci disinfection are from experiments conducted using laboratory-cultured bacteria. However, environmental bacteria, such as those in wastewater, have potential to be more resistant to disinfection than their laboratory-cultured counterparts. Additionally, most Enterococcus disinfection studies have only evaluated E. faecalis despite the diversity of Enterococcus species in the environment. In this study, we evaluated inactivation kinetics of wastewater-sourced E. coli and enterococci, laboratory-cultured E. coli, and three species of laboratory-cultured Enterococcus with exposure to free chlorine, monochloramine, UVC, and simulated sunlight. All bacteria were purified and suspended in a chlorine-demand-free buffer with minimal light attenuation to allow comparison between populations without confounding matrix effects. Laboratory-cultured bacteria were more susceptible to the oxidants than the wastewater-sourced bacteria, highlighting that research using reference-strain bacteria in the laboratory may not reflect inactivation kinetics in the environment. When exposed to the light-based disinfectants, only laboratory-cultured E. coli and E. faecalis were more susceptible than the wastewater-sourced bacteria. Notably, different laboratory-cultured Enterococcus species had different inactivation rates, with E. faecalis being the most susceptible. These findings highlight the importance of incorporating indigenous environmental bacteria in laboratory studies and assessing a variety of Enterococcus species in disinfection research.

Environmental bacteria in wastewater can have slower disinfection kinetics than bacteria grown in the laboratory and should be included in laboratory-based experiments evaluating the mechanisms and kinetics of disinfection.

Landfill leachate is a major source of refractory dissolved organic nitrogen (rDON), which can exacerbate eutrophication and harmful algal blooms in downstream aquatic ecosystems. This study evaluates the effectiveness of two advanced physicochemical treatments─Fenton oxidation and granular activated carbon (GAC) adsorption─for rDON removal from biologically treated landfill leachate blended with sewage, and their impacts on the estuarine algal (phytoplankton) community with in situ algal bioassays. Fenton oxidation achieved 52%–60% rDON removal by converting rDON into ammonium nitrogen (NH₄⁺-N), enhancing its biodegradability and suitability for subsequent biological treatments. In contrast, GAC adsorption achieved higher removal efficiencies (86%–92%) by physically adsorbing nitrogenous species, including rDON and NH₄⁺-N, without altering their chemical structure. We deployed in situ algal bioassays to analyze the impacts of advanced wastewater treatment processes on the algal growth dynamics. Bioassays revealed distinct effects on algal growth: Fenton treatment temporarily increased algal biomass due to elevated NH₄⁺-N levels, while GAC treatment mitigated nutrient availability, inhibiting algal proliferation. While GAC was more effective overall, its regeneration requirements and associated costs pose applicability challenges. Fenton treatment is best suited as a pretreatment step to enhance rDON biodegradability.

This study evaluated two advanced treatment technologies for refractory dissolved organic nitrogen and analyzed their impacts on algal (phytoplankton) growth dynamics with the application of an in situ algal bioassay.

Thallium (Tl) is a toxic element typically enriched in sulfide minerals and ferromanganese oxides, and its immobilization depends largely on the stability of thallium sulfide (Tl₂S) under various environmental conditions. This study examines Tl(I) immobilization using ferromanganese sulfides, focusing on the effects of Fe/Mn/S molar ratios, oxygenation levels, and stirring intensity on Tl₂S stability. Under anaerobic conditions, Tl(I) immobilization efficiency reached 96.1 ± 0.3% in 14 days and increased to 99.4 ± 0.2% over 6 months. Under microaerobic and aerobic conditions, efficiencies decreased to 85.7 ± 0.4 and 83.4 ± 0.8%, respectively. Oxygen facilitated the formation of Fe/Mn (oxyhydr)oxides, a sink for Tl(I), primarily present as ≡FeOTl and ≡MnOTl. Continuous stirring enhanced the removal of Tl(I) under anaerobic conditions, whereas static conditions favored Tl(I) immobilization in aerobic environments. Under aerobic conditions, sulfides were oxidized into elemental sulfur (77.2%) and sulfate (11.7%), leading to Tl(I) dissolution and an impact on its immobilization dynamics. Pb²⁺, Hg²⁺, Cu²⁺, Ni²⁺, and Zn²⁺ further promoted Tl(I) dissolution through competitive adsorption and a reduction in solution pH. Key strategies for Tl(I) immobilization include maintaining low dissolved oxygen and redox potential levels, enhancing surface hydroxyl complexation, and promoting sulfide-induced precipitation and electrostatic adsorption. This study provides insights into Tl(I) immobilization dynamics within complex Fe–Mn–S systems subjected to redox cycling and varied environmental conditions.

Electrodialysis (ED) is a promising technology for the recovery of ammonia from wastewater. However, separating ammonia directly from complex wastewater mixtures using ED is challenging due to membrane scaling, low selectivity, and high energy consumption. Here, we evaluate the potential of electrodialysis for ammonia recovery from simulated and real wastewater mixtures. The specific energy consumption (SEC) of electrodialysis exceeded 31 kWh/kg-N for simulated wastewater but decreased 4-fold to 7 kWh/kg-N after hardness removal. Concentration factors (CFs), the final concentration relative to the initial concentration, of NH₄⁺ for real wastewater after ultrafiltration and for synthetic wastewater without hardness were 7.5 and 10, comparable to the CF of 9 for single-salt solutions (nonmixtures). We find that the concentrated product after ED with real and simulated synthetic wastewater includes K⁺ and Na⁺, as cation exchange membranes exhibit K⁺/NH₄⁺ and Na⁺/NH₄⁺ selectivities near one. Thus, if the concentrated product is directly used as an aqueous fertilizer, the resulting product will be 30/30/30 for Na⁺, K⁺, and NH₄⁺. Finally, staged electrodialysis achieved a CF of ∼50 (2.42 N wt %) with SECs of 15.2–18.1 kWh/kg-N for synthetic wastewater without hardness, demonstrating promise for recovering ammonia from wastewater with a high concentration and low energy demand.

Recovering ammonia from wastewater with electrodialysis requires pretreatment of hardness to reduce energy consumption.