Pub Date : 2025-03-20DOI: 10.1016/j.watres.2025.123524
Bingqian Yang, Peng Zhou, Long Tian, Nigel Graham, Guibai Li, Zhaoyang Su, Wenzheng Yu
Coagulation is a widely applied and important process for water treatment, and the development of improved coagulation reagents continues to be a practical objective. However, mechanisms guiding the development of composite coagulants remain insufficiently understood. In addressing this deficiency, this study has investigated the enhancement of conventional Fe(III) coagulation by composite coagulants that incorporate an additional metal salt (Me: Ca²⁺, Al³⁺, Ti⁴⁺, Zr⁴⁺), focusing on the mechanistic roles that Me constituents play in Fe-based coagulation. The effectiveness of composite coagulants was assessed through floc size and the removal of organics and phosphates. Results demonstrated that Me constituents enhance coagulation performances to varying extents, with Al³⁺ and Zr⁴⁺ showing the most significant improvements. FT-ICR MS analysis at the molecular scale reveals that additional Me facilitates the removal of humic acid, hydrophobic macromolecules, and highly aromatic organics containing polycarboxyl and secondary carbon structures. EXAFS results indicate that co-hydrolysis of Fe³⁺ with Me disrupts the formation of conventional ferrihydrite at the nanoscale of flocs and promotes the development of Fe-phosphate clusters. Me effectively reduces the corner- and edge-sharing coordination between FeO₆ octahedra within clusters, resulting in a more dispersed arrangement of FeO₆ polymers with available binding sites for the PO4 tetrahedron. The shortened Fe-P bond indicates that Me promotes a more compact link between FeO₆ octahedra and PO₄ tetrahedra. By revealing how cations in composite coagulants change the nanoscale structure of Fe flocs to affect macroscopic coagulation, this study enhances the understanding of metal ion interactions during co-hydrolysis and co-precipitation in natural systems.
{"title":"The nanoscale explanation of metal cations differences in enhancing the Fe(III) coagulation performance","authors":"Bingqian Yang, Peng Zhou, Long Tian, Nigel Graham, Guibai Li, Zhaoyang Su, Wenzheng Yu","doi":"10.1016/j.watres.2025.123524","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123524","url":null,"abstract":"Coagulation is a widely applied and important process for water treatment, and the development of improved coagulation reagents continues to be a practical objective. However, mechanisms guiding the development of composite coagulants remain insufficiently understood. In addressing this deficiency, this study has investigated the enhancement of conventional Fe(III) coagulation by composite coagulants that incorporate an additional metal salt (Me: Ca²⁺, Al³⁺, Ti⁴⁺, Zr⁴⁺), focusing on the mechanistic roles that Me constituents play in Fe-based coagulation. The effectiveness of composite coagulants was assessed through floc size and the removal of organics and phosphates. Results demonstrated that Me constituents enhance coagulation performances to varying extents, with Al³⁺ and Zr⁴⁺ showing the most significant improvements. FT-ICR MS analysis at the molecular scale reveals that additional Me facilitates the removal of humic acid, hydrophobic macromolecules, and highly aromatic organics containing polycarboxyl and secondary carbon structures. EXAFS results indicate that co-hydrolysis of Fe³⁺ with Me disrupts the formation of conventional ferrihydrite at the nanoscale of flocs and promotes the development of Fe-phosphate clusters. Me effectively reduces the corner- and edge-sharing coordination between FeO₆ octahedra within clusters, resulting in a more dispersed arrangement of FeO₆ polymers with available binding sites for the PO<sub>4</sub> tetrahedron. The shortened Fe-P bond indicates that Me promotes a more compact link between FeO₆ octahedra and PO₄ tetrahedra. By revealing how cations in composite coagulants change the nanoscale structure of Fe flocs to affect macroscopic coagulation, this study enhances the understanding of metal ion interactions during co-hydrolysis and co-precipitation in natural systems.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"49 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-20DOI: 10.1016/j.watres.2025.123516
Lenin Riascos-Flores, Long Ho, Wout Van Echelpoel, Marie Anne Eurie Forio, Stijn Bruneel, Niels De Troyer, Nancy de Saeyer, Rafael Bermudez, Wim Vanden Berghe, Luis Dominguez-Granda, Pascal Boeckx, Christine Van der heyden, Peter Goethals
The Galapagos Islands, known for their unique ecology, are confronted with significant challenges in water management and freshwater scarcity. These challenges are further exacerbated by a lack of comprehensive monitoring, assessment and understanding of the quality of water systems on inhabited islands. This study examines the urban and associated natural water systems of the remote volcanic islands of Floreana, Isabela, and Santa Cruz in the Pacific Ocean through an unprecedented combination of comprehensive physicochemical analysis, including nutrient measurements, microbiological analyses, and isotope-based source detection of nitrate (NO3−) contamination. A systematic monitoring campaign across 66 sites revealed critical anthropogenic impacts on water quality. This includes contamination by sewage and the presence of coliforms and/or Escherichia coli in groundwater, reservoirs, tap water and the receiving water bodies of the three evaluated islands. Major impacts are present in the most densely populated island (Santa Cruz), where about 39% of the monitoring sites are classified as polluted according to the Basic Prati Index, with the presence of E. coli in 57% (4/7) of the evaluated sites and NO3− contribution from sewage accounting for up to 57% of the NO3− in the receiving water body. In Isabela, treated wastewater is discharged about 300 meters from a recreational site, while it contains high ammonium concentrations (41.5 mg N L−1), E. coli and very low oxygen levels (< 0.5 mg O2 L−1). In Floreana, the groundwater (aquifer) closest to the urban area shows a NO3− contribution of up to 94% from sewage, while this figure is only 11% in the other islands. On top of this, water analyses in the drinking water reservoirs and tap water in the three islands indicate quality issues in the urban water provision system that could lead to human health impacts. The role of tourism, agriculture, urbanization and population growth exacerbates these issues, presenting urgent public health concerns and highlight the need for sustainable practices by stopping and treating the critical sources of pollution and contamination. These findings on the Galapagos emphasize the need for better water treatment and distribution, as well as sewage and agricultural management in islands to improve and protect the islands' highly vulnerable ecosystems and related water provisioning services.
{"title":"Chemical and microbiological analysis of urban and associated natural water systems of inhabited volcanic islands of the Galapagos (Ecuador)","authors":"Lenin Riascos-Flores, Long Ho, Wout Van Echelpoel, Marie Anne Eurie Forio, Stijn Bruneel, Niels De Troyer, Nancy de Saeyer, Rafael Bermudez, Wim Vanden Berghe, Luis Dominguez-Granda, Pascal Boeckx, Christine Van der heyden, Peter Goethals","doi":"10.1016/j.watres.2025.123516","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123516","url":null,"abstract":"The Galapagos Islands, known for their unique ecology, are confronted with significant challenges in water management and freshwater scarcity. These challenges are further exacerbated by a lack of comprehensive monitoring, assessment and understanding of the quality of water systems on inhabited islands. This study examines the urban and associated natural water systems of the remote volcanic islands of Floreana, Isabela, and Santa Cruz in the Pacific Ocean through an unprecedented combination of comprehensive physicochemical analysis, including nutrient measurements, microbiological analyses, and isotope-based source detection of nitrate (NO<sub>3</sub><sup>−</sup>) contamination. A systematic monitoring campaign across 66 sites revealed critical anthropogenic impacts on water quality. This includes contamination by sewage and the presence of coliforms and/or <em>Escherichia coli</em> in groundwater, reservoirs, tap water and the receiving water bodies of the three evaluated islands. Major impacts are present in the most densely populated island (Santa Cruz), where about 39% of the monitoring sites are classified as polluted according to the Basic Prati Index, with the presence of <em>E. coli</em> in 57% (4/7) of the evaluated sites and NO<sub>3</sub><sup>−</sup> contribution from sewage accounting for up to 57% of the NO<sub>3</sub><sup>−</sup> in the receiving water body. In Isabela, treated wastewater is discharged about 300 meters from a recreational site, while it contains high ammonium concentrations (41.5 mg N L<sup>−1</sup>), <em>E. coli</em> and very low oxygen levels (< 0.5 mg O<sub>2</sub> L<sup>−1</sup>). In Floreana, the groundwater (aquifer) closest to the urban area shows a NO<sub>3</sub><sup>−</sup> contribution of up to 94% from sewage, while this figure is only 11% in the other islands. On top of this, water analyses in the drinking water reservoirs and tap water in the three islands indicate quality issues in the urban water provision system that could lead to human health impacts. The role of tourism, agriculture, urbanization and population growth exacerbates these issues, presenting urgent public health concerns and highlight the need for sustainable practices by stopping and treating the critical sources of pollution and contamination. These findings on the Galapagos emphasize the need for better water treatment and distribution, as well as sewage and agricultural management in islands to improve and protect the islands' highly vulnerable ecosystems and related water provisioning services.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"22 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Currently, chemicals or nanoparticles are widely used for modifying membranes to improve their antifouling properties. However, the chemicals released, particularly during long-term water or wastewater filtration, are highly toxic to the environment and humans. Herein, an herb-inspired, green antibacterial membrane with exceptional sustainable antifouling properties was developed using aloin. The resultant membranes exhibited excellent bacterial inactivating efficiency because of the electrostatic interactions between the amine groups on the membrane and the bacterial cells, which contributed to cell deformation. The aloin molecules also significantly increased reactive oxygen species levels, causing oxidative damage to bacterial cells. Moreover, the functional decorative layer, which exhibited remarkable resistance to bacterial adhesion because of the abundant hydroxyl, carbonyl, and amino groups in aloin, endowed the as-prepared membranes with strong polarity, reducing bacterial adhesion and biofilm formation. When applied in a membrane bioreactor, the aloin-modified membranes demonstrated a >27.0% lower fouling rate than commercial microfiltration membranes. Overall, the successful fabrication strategy and material features described offer a green alternative for membrane development and provide new avenues for the design of healthcare materials such as wound dressings.
{"title":"Facile fabrication of antibacterial membranes with human-friendly aloin for water purification","authors":"Ji Qi, Shanshan Zhao, Jian Chen, Qiwei Guo, Yirong Hong, Fangang Meng","doi":"10.1016/j.watres.2025.123515","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123515","url":null,"abstract":"Currently, chemicals or nanoparticles are widely used for modifying membranes to improve their antifouling properties. However, the chemicals released, particularly during long-term water or wastewater filtration, are highly toxic to the environment and humans. Herein, an herb-inspired, green antibacterial membrane with exceptional sustainable antifouling properties was developed using aloin. The resultant membranes exhibited excellent bacterial inactivating efficiency because of the electrostatic interactions between the amine groups on the membrane and the bacterial cells, which contributed to cell deformation. The aloin molecules also significantly increased reactive oxygen species levels, causing oxidative damage to bacterial cells. Moreover, the functional decorative layer, which exhibited remarkable resistance to bacterial adhesion because of the abundant hydroxyl, carbonyl, and amino groups in aloin, endowed the as-prepared membranes with strong polarity, reducing bacterial adhesion and biofilm formation. When applied in a membrane bioreactor, the aloin-modified membranes demonstrated a >27.0% lower fouling rate than commercial microfiltration membranes. Overall, the successful fabrication strategy and material features described offer a green alternative for membrane development and provide new avenues for the design of healthcare materials such as wound dressings.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"59 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.watres.2025.123513
Eduardo De Gerónimo, Agustín Mosca, Franco M. Cabrerizo, Ronald Vargas
Chlorination is a common method for drinking water disinfection due to its efficiency and low cost. The strong oxidative properties of chlorine can lead to reactions with dissolved organic compounds, resulting in various transformation products. This study investigates the chlorination-induced degradation of the sulfonylurea herbicides metsulfuron-methyl and chlorimuron-ethyl, which are frequently found in surface and groundwater. The degradation of these herbicides follows a second-order kinetic model. The apparent second-order rate constants for metsulfuron-methyl range from 3.2 to 244 M⁻¹ s⁻¹, while those for chlorimuron-ethyl range from 2.2 to 287.7 M⁻¹ s⁻¹ within a pH range of 4 to 9. Reaction with HClO effectively reduced the concentration of pesticides. Under acidic conditions, the reaction was significantly enhanced, likely due to hydrolysis or changes in the speciation of the organic compounds. In fact, the rate constant under acidic conditions was approximately 35 and 27 times higher than the reaction rate at more neutral pH for chlorimuron-ethyl and metsulfuron-methyl, respectively. The reaction rate with ClO⁻ approached zero for both herbicides, suggesting a minor or negligible pathway involving the hypochlorite anion. Mass spectrometry identified six chlorination products for metsulfuron-methyl and five for chlorimuron-ethyl. Although the specific reaction mechanisms were not fully elucidated, these products provided valuable insights into the fate of sulfonylureas under chlorination. Under typical disinfection conditions (pH 7 and 4 mg L⁻¹ chlorine), the half-lives of 17.8 minutes for metsulfuron-methyl and 26.6 minutes for chlorimuron-ethyl demonstrate the potential for effective degradation in relatively short timeframes. This study underscores the potential for effective removal of these herbicides in drinking water treatment and highlights the importance of evaluating degradation products over time, as they remain detectable even after seven days.
{"title":"Insights into Chlorination-Induced Degradation of Sulfonylurea Herbicides: Unraveling Kinetics and Intermediates during Water Treatment","authors":"Eduardo De Gerónimo, Agustín Mosca, Franco M. Cabrerizo, Ronald Vargas","doi":"10.1016/j.watres.2025.123513","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123513","url":null,"abstract":"Chlorination is a common method for drinking water disinfection due to its efficiency and low cost. The strong oxidative properties of chlorine can lead to reactions with dissolved organic compounds, resulting in various transformation products. This study investigates the chlorination-induced degradation of the sulfonylurea herbicides metsulfuron-methyl and chlorimuron-ethyl, which are frequently found in surface and groundwater. The degradation of these herbicides follows a second-order kinetic model. The apparent second-order rate constants for metsulfuron-methyl range from 3.2 to 244 M⁻¹ s⁻¹, while those for chlorimuron-ethyl range from 2.2 to 287.7 M⁻¹ s⁻¹ within a pH range of 4 to 9. Reaction with HClO effectively reduced the concentration of pesticides. Under acidic conditions, the reaction was significantly enhanced, likely due to hydrolysis or changes in the speciation of the organic compounds. In fact, the rate constant under acidic conditions was approximately 35 and 27 times higher than the reaction rate at more neutral pH for chlorimuron-ethyl and metsulfuron-methyl, respectively. The reaction rate with ClO⁻ approached zero for both herbicides, suggesting a minor or negligible pathway involving the hypochlorite anion. Mass spectrometry identified six chlorination products for metsulfuron-methyl and five for chlorimuron-ethyl. Although the specific reaction mechanisms were not fully elucidated, these products provided valuable insights into the fate of sulfonylureas under chlorination. Under typical disinfection conditions (pH 7 and 4 mg L⁻¹ chlorine), the half-lives of 17.8 minutes for metsulfuron-methyl and 26.6 minutes for chlorimuron-ethyl demonstrate the potential for effective degradation in relatively short timeframes. This study underscores the potential for effective removal of these herbicides in drinking water treatment and highlights the importance of evaluating degradation products over time, as they remain detectable even after seven days.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"34 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microbial oxidation of short-chain gaseous alkanes (SCGAs, including ethane, propane and butane) are important sinks to mitigate the emission of SCGAs to the atmosphere. ‘Candidatus Alkanivorans nitratireducens’ has been discovered to be capable of utilizing nitrate as an electron acceptor to anaerobically oxidize these SCGAs. However, little is known about its metabolic diversity in sulfate reduction, despite sulfate being widely present in both marine and freshwater ecosystems. Here, we show that sulfate can be reduced by ‘Ca. A. nitratireducens’ and as an alternative electron acceptor. Genomic analysis confirmed that the genome of ‘Ca. A. nitratireducens’ harbour genes involved in sulfate reduction. Short-term incubation of the enriched ‘Ca. A. nitratireducens’ showed immediate consumption of propane and sulfate, suggesting the capability of ‘Ca. A. nitratireducens’ to utilize sulfate as an electron acceptor. Long-term incubation further confirmed its ability to utilize sulfate. However, propane oxidation rates and sulfate reduction rates gradually decreased during the long-term incubation, accompanied by the decrease of relative abundance of ‘Ca. A. nitratireducens’. After the long-term adaptation with sulfate as the sole acceptor, both anaerobic propane oxidation and nitrate reduction capability of ‘Ca. A. nitratireducens’ can be partly recovered by switching the electron acceptor back from sulfate to nitrate. Overall, this study indicates sulfate can be utilized but is not the preferred electron acceptor for ‘Ca. A. nitratireducens’. The findings deepen our understanding on the metabolic flexibility of ‘Ca. A. nitratireducens’.
{"title":"Sulfate-reducing capability of nitrate-dependent anaerobic gaseous alkanes degrader","authors":"Xiawei Liu, Zhiguo Yuan, Mengxiong Wu, Jianhua Guo","doi":"10.1016/j.watres.2025.123507","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123507","url":null,"abstract":"Microbial oxidation of short-chain gaseous alkanes (SCGAs, including ethane, propane and butane) are important sinks to mitigate the emission of SCGAs to the atmosphere. ‘<em>Candidatus</em> Alkanivorans nitratireducens’ has been discovered to be capable of utilizing nitrate as an electron acceptor to anaerobically oxidize these SCGAs. However, little is known about its metabolic diversity in sulfate reduction, despite sulfate being widely present in both marine and freshwater ecosystems. Here, we show that sulfate can be reduced by ‘<em>Ca.</em> A. nitratireducens’ and as an alternative electron acceptor. Genomic analysis confirmed that the genome of ‘<em>Ca.</em> A. nitratireducens’ harbour genes involved in sulfate reduction. Short-term incubation of the enriched ‘<em>Ca.</em> A. nitratireducens’ showed immediate consumption of propane and sulfate, suggesting the capability of ‘<em>Ca.</em> A. nitratireducens’ to utilize sulfate as an electron acceptor. Long-term incubation further confirmed its ability to utilize sulfate. However, propane oxidation rates and sulfate reduction rates gradually decreased during the long-term incubation, accompanied by the decrease of relative abundance of ‘<em>Ca.</em> A. nitratireducens’. After the long-term adaptation with sulfate as the sole acceptor, both anaerobic propane oxidation and nitrate reduction capability of ‘<em>Ca.</em> A. nitratireducens’ can be partly recovered by switching the electron acceptor back from sulfate to nitrate. Overall, this study indicates sulfate can be utilized but is not the preferred electron acceptor for ‘<em>Ca.</em> A. nitratireducens’. The findings deepen our understanding on the metabolic flexibility of ‘<em>Ca.</em> A. nitratireducens’.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"12 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.watres.2025.123512
R. Thomson, K. Close, A. Riley, D.J. Batstone, A. Oehmen
Existing enhanced biological phosphorus removal (EBPR) models do not fully describe the metabolism of fermentative polyphosphate accumulating organisms (fPAOs), particularly under mixed substrate conditions representative of fermentation-enhanced EBPR (F-EBPR) processes. This study presents a steady-state metabolic model integrating anaerobic amino acid (AA) fermentation and storage processes in fPAOs. The model identifies key metabolic interactions underlying fPAO metabolism, prioritising substrate accumulation over fermentation. This results in significant changes to ATP and reduction-oxidation (redox) flows as compared to when relying on previous AA fermentation models typically used to describe fPAO metabolism, with medium-chain-length (MCL) polyhydroxyalkanoate (PHA) formation and polyphosphate (polyP) consumption acting as important electron and energy management mechanisms, respectively. Succinate, rather than volatile fatty acids (VFAs), was identified as the more likely synergetic substrate between fermentative and conventional PAOs (cPAOs) under these conditions. Moreover, conditions favourable of VFA efflux by fPAOs may also favour a shift away from a polyP accumulation to a fermentation dominant metabolism. Further work is required to verify the role of MCL-PHA fractions, alongside the contribution of free intracellular AA accumulation as compared to polymers such as cyanophycin or polyglutamate on fPAO metabolism. This metabolic model provides a framework for better understanding the role of fPAOs and their interactions with cPAOs within EBPR processes, informing future modelling and optimisation of F-EBPR systems.
{"title":"Metabolic Modelling of Anaerobic Amino Acid Uptake and Storage by Fermentative Polyphosphate Accumulating Organisms","authors":"R. Thomson, K. Close, A. Riley, D.J. Batstone, A. Oehmen","doi":"10.1016/j.watres.2025.123512","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123512","url":null,"abstract":"Existing enhanced biological phosphorus removal (EBPR) models do not fully describe the metabolism of fermentative polyphosphate accumulating organisms (fPAOs), particularly under mixed substrate conditions representative of fermentation-enhanced EBPR (F-EBPR) processes. This study presents a steady-state metabolic model integrating anaerobic amino acid (AA) fermentation and storage processes in fPAOs. The model identifies key metabolic interactions underlying fPAO metabolism, prioritising substrate accumulation over fermentation. This results in significant changes to ATP and reduction-oxidation (redox) flows as compared to when relying on previous AA fermentation models typically used to describe fPAO metabolism, with medium-chain-length (MCL) polyhydroxyalkanoate (PHA) formation and polyphosphate (polyP) consumption acting as important electron and energy management mechanisms, respectively. Succinate, rather than volatile fatty acids (VFAs), was identified as the more likely synergetic substrate between fermentative and conventional PAOs (cPAOs) under these conditions. Moreover, conditions favourable of VFA efflux by fPAOs may also favour a shift away from a polyP accumulation to a fermentation dominant metabolism. Further work is required to verify the role of MCL-PHA fractions, alongside the contribution of free intracellular AA accumulation as compared to polymers such as cyanophycin or polyglutamate on fPAO metabolism. This metabolic model provides a framework for better understanding the role of fPAOs and their interactions with cPAOs within EBPR processes, informing future modelling and optimisation of F-EBPR systems.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"189 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.watres.2025.123511
Christopher Keneally, Daniel Chilton, Tyler N. Dornan, Stephen P. Kidd, Virginie Gaget, Adam Toomes, Charlotte Lassaline, Reuben Petrovski, Lisa Wood, Justin D. Brookes
Microorganisms drive essential biogeochemical processes in aquatic ecosystems and are sensitive to both salinity and hydrological changes. As climate change and anthropogenic activities alter hydrology and salinity worldwide, understanding microbial ecology and metabolism becomes increasingly important for managing aquatic ecosystems. Biogeochemical processes were investigated on sediment microbial communities during a significant flood event in the hypersaline Coorong lagoon, South Australia (the largest in the Murray-Darling Basin since 1956). Samples from six sites across a salinity gradient were collected before and during flooding in 2022. To assess changes in microbial taxonomy and metabolic function, 16S rRNA amplicon sequencing was employed alongside untargeted liquid chromatography–mass spectrometry (LC-MS) to assess changes in microbial taxonomy and metabolic function. Results showed a decrease in microbial richness and diversity during flooding, especially in hypersaline conditions. Pre-flood communities were enriched with osmolyte-degrading and methanogenic taxa, alongside osmoprotectant metabolites, such as glycine betaine and choline. Flood conditions favored taxa such as Halanaerobiaceae and Beggiatoaceae, inducing inferred metagenomic shifts indicative of sulfate and nitrogen reduction pathways, while also enriching a greater diversity of metabolites including Gly-Phe dipeptides and guanine. This study demonstrates that integrating metabolomics with microbial community analysis enhances understanding of ecosystem responses to disturbance. These findings suggest microbial communities rapidly change in response to salinity reductions while maintaining key biogeochemical functions. Such insights are valuable for ecosystem management and predictive modelling under environmental stressors such as flooding.
{"title":"Multi-Omics Reveal Microbial Succession and Metabolomic Adaptations to Flood in a Hypersaline Coastal Lagoon","authors":"Christopher Keneally, Daniel Chilton, Tyler N. Dornan, Stephen P. Kidd, Virginie Gaget, Adam Toomes, Charlotte Lassaline, Reuben Petrovski, Lisa Wood, Justin D. Brookes","doi":"10.1016/j.watres.2025.123511","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123511","url":null,"abstract":"Microorganisms drive essential biogeochemical processes in aquatic ecosystems and are sensitive to both salinity and hydrological changes. As climate change and anthropogenic activities alter hydrology and salinity worldwide, understanding microbial ecology and metabolism becomes increasingly important for managing aquatic ecosystems. Biogeochemical processes were investigated on sediment microbial communities during a significant flood event in the hypersaline Coorong lagoon, South Australia (the largest in the Murray-Darling Basin since 1956). Samples from six sites across a salinity gradient were collected before and during flooding in 2022. To assess changes in microbial taxonomy and metabolic function, 16S rRNA amplicon sequencing was employed alongside untargeted liquid chromatography–mass spectrometry (LC-MS) to assess changes in microbial taxonomy and metabolic function. Results showed a decrease in microbial richness and diversity during flooding, especially in hypersaline conditions. Pre-flood communities were enriched with osmolyte-degrading and methanogenic taxa, alongside osmoprotectant metabolites, such as glycine betaine and choline. Flood conditions favored taxa such as <em>Halanaerobiaceae</em> and <em>Beggiatoaceae</em>, inducing inferred metagenomic shifts indicative of sulfate and nitrogen reduction pathways, while also enriching a greater diversity of metabolites including Gly-Phe dipeptides and guanine. This study demonstrates that integrating metabolomics with microbial community analysis enhances understanding of ecosystem responses to disturbance. These findings suggest microbial communities rapidly change in response to salinity reductions while maintaining key biogeochemical functions. Such insights are valuable for ecosystem management and predictive modelling under environmental stressors such as flooding.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"197 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-18DOI: 10.1016/j.watres.2025.123514
Yoshiyasu Takefuji
This paper critically examines the analysis conducted by Maußner et al. on AI analysis, particularly their interpretation of feature importances derived from various machine learning models using SHAP (SHapley Additive exPlanations). Although SHAP aids in interpretability, it is subject to model-specific biases that can misrepresent relationships between variables. The paper emphasizes the lack of ground truth values in feature importance assessments and calls for careful consideration of statistical methodologies, including robust nonparametric approaches. By advocating for the use of Spearman's correlation with p-values and Kendall's tau with p-values, this work aims to strengthen the integrity of findings in machine learning studies, ensuring that conclusions drawn are reliable and actionable.
{"title":"Reevaluating Feature Importance in Machine Learning: Concerns Regarding SHAP Interpretations in the Context of the EU Artificial Intelligence Act","authors":"Yoshiyasu Takefuji","doi":"10.1016/j.watres.2025.123514","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123514","url":null,"abstract":"This paper critically examines the analysis conducted by Maußner et al. on AI analysis, particularly their interpretation of feature importances derived from various machine learning models using SHAP (SHapley Additive exPlanations). Although SHAP aids in interpretability, it is subject to model-specific biases that can misrepresent relationships between variables. The paper emphasizes the lack of ground truth values in feature importance assessments and calls for careful consideration of statistical methodologies, including robust nonparametric approaches. By advocating for the use of Spearman's correlation with p-values and Kendall's tau with p-values, this work aims to strengthen the integrity of findings in machine learning studies, ensuring that conclusions drawn are reliable and actionable.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"24 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-16DOI: 10.1016/j.watres.2025.123510
Ziyi Zhao, Yanan Mi, Shili Wang, Xuedong Du, Qingrui Zhang
We firstly present a novel strategy for enhancing fluoride removal from contaminated water using defect-engineered UiO-66 (Zr-MOFs), emphasizing the crucial role of pKa in modulator selection. By utilizing modulators with varying pKa values-specifically benzimidazole (BI), benzoic acid (BA), and acetic acid (AA)-we synthesized defect-rich Act-UiO-66-M(X). The higher pKa of BI facilitated greater defect formation, resulting in significantly improved adsorption capacity and faster diffusion rates. Act-UiO-66-BI(8), modulated with BI, showed a higher intensity peak at g = 2.003 in ESR analysis, indicating more oxygen vacancies. Its fluoride adsorption capacity reached 93.59 mg F/g, nearly six times higher than commercial ZrO2, with rapid kinetics—evidenced by a kinetic rate constant (kint) of 2.64 mg/g·min0.5 and equilibrium achieved within 10 minutes. The kinetic performance was enhanced by 270% compared to raw Act-UiO-66. Furthermore, Act-UiO-66-BI(8) demonstrated high selectivity and stability in high-salinity environments, with a Kd coefficient consistently exceeding 17,900 mL/g. The study highlights that selecting modulators based on pKa enhances defect formation, improving active site exposure and pore diffusion, as confirmed by DFT calculations and XPS analysis. The ability of Act-UiO-66-BI(8) to treat up to 1160 kg of wastewater per kg of adsorbent highlights its potential for large-scale water purification, showcasing a promising approach for developing high-performance MOF materials.
{"title":"The High pKa-Guided Defect Engineering: Improving Fluoride Removal in Actual Scenarios by Benzimidazole Modulated Metal-Organic Frameworks","authors":"Ziyi Zhao, Yanan Mi, Shili Wang, Xuedong Du, Qingrui Zhang","doi":"10.1016/j.watres.2025.123510","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123510","url":null,"abstract":"We firstly present a novel strategy for enhancing fluoride removal from contaminated water using defect-engineered UiO-66 (Zr-MOFs), emphasizing the crucial role of pKa in modulator selection. By utilizing modulators with varying pKa values-specifically benzimidazole (BI), benzoic acid (BA), and acetic acid (AA)-we synthesized defect-rich Act-UiO-66-M(X). The higher pKa of BI facilitated greater defect formation, resulting in significantly improved adsorption capacity and faster diffusion rates. Act-UiO-66-BI(8), modulated with BI, showed a higher intensity peak at g = 2.003 in ESR analysis, indicating more oxygen vacancies. Its fluoride adsorption capacity reached 93.59 mg F/g, nearly six times higher than commercial ZrO<sub>2</sub>, with rapid kinetics—evidenced by a kinetic rate constant (k<sub>int</sub>) of 2.64 mg/g·min<sup>0.5</sup> and equilibrium achieved within 10 minutes. The kinetic performance was enhanced by 270% compared to raw Act-UiO-66. Furthermore, Act-UiO-66-BI(8) demonstrated high selectivity and stability in high-salinity environments, with a K<sub>d</sub> coefficient consistently exceeding 17,900 mL/g. The study highlights that selecting modulators based on pKa enhances defect formation, improving active site exposure and pore diffusion, as confirmed by DFT calculations and XPS analysis. The ability of Act-UiO-66-BI(8) to treat up to 1160 kg of wastewater per kg of adsorbent highlights its potential for large-scale water purification, showcasing a promising approach for developing high-performance MOF materials.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"69 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143635596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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