Pub Date : 2025-04-23DOI: 10.1016/j.watres.2025.123667
Peiyi Zhao, Ziyue Li, Ai Chen, Yongze Liu, Fangshu Qu, Dan Qu, Xinying Liu
The anaerobic membrane bioreactor (AnMBR) technology is increasingly applied in the treatment of municipal wastewater. However, its application in cold region still faces many challenges including low anaerobic digestion efficiency and high concentrations of dissolved methane (D-CH4). In this study, powdered activated carbon (PAC) was incorporated into AnMBR operated under wave-pulse mixing mode (P-W-AnMBR) to enhance the operational performance under low temperature condition. As temperature decreased and organic loading rate (OLR) elevated, the COD removal efficiency in the P-W-AnMBR maintained at a high level (93.4%∼95.8%) and exhibited favorable stability. The P-W-AnMBR could effectively prevent volatile fatty acid (VFA) accumulation with the lowest VFA concentrations of 22.0±3.9 mg·L-1. Correspondingly, the methane yield in P-W-AnMBR system reached high as 0.22±0.04 L·g-1 which was 1.5 times of that in conventional biogas-recirculation mixing AnMBR (B-AnMBR), while the D-CH4 supersaturation was only ∼1.05, showing a 52.4% decrease compared to B-AnMBR. According to higher electron transfer system activity and Cyt-C content, electron transfer process was enhanced in P-W-AnMBR, accounting for superior organics conversion to methane. Through a high average KLa as 4.50 h⁻¹, the D-CH4 readily transfer to the gas phase, thereby reducing the concentration of D-CH4 as well as increasing the proportion of gaseous methane. Energy analysis showed generation of methane energy could be augmented in P-W-AnMBR as OLR was elevated at 15 °C, thereby significantly reducing the net energy consumption. The combination of wave-pulse mixing and conductive PAC within AnMBR provides insights into low temperature resource recovery from municipal wastewater.
{"title":"Wave-pulse mixing coupled with powdered activated carbon enhances AnMBR in treating low temperature municipal wastewater and recovering dissolved CH4","authors":"Peiyi Zhao, Ziyue Li, Ai Chen, Yongze Liu, Fangshu Qu, Dan Qu, Xinying Liu","doi":"10.1016/j.watres.2025.123667","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123667","url":null,"abstract":"The anaerobic membrane bioreactor (AnMBR) technology is increasingly applied in the treatment of municipal wastewater. However, its application in cold region still faces many challenges including low anaerobic digestion efficiency and high concentrations of dissolved methane (D-CH<sub>4</sub>). In this study, powdered activated carbon (PAC) was incorporated into AnMBR operated under wave-pulse mixing mode (P-W-AnMBR) to enhance the operational performance under low temperature condition. As temperature decreased and organic loading rate (OLR) elevated, the COD removal efficiency in the P-W-AnMBR maintained at a high level (93.4%∼95.8%) and exhibited favorable stability. The P-W-AnMBR could effectively prevent volatile fatty acid (VFA) accumulation with the lowest VFA concentrations of 22.0±3.9 mg·L<sup>-1</sup>. Correspondingly, the methane yield in P-W-AnMBR system reached high as 0.22±0.04 L·g<sup>-1</sup> which was 1.5 times of that in conventional biogas-recirculation mixing AnMBR (B-AnMBR), while the D-CH<sub>4</sub> supersaturation was only ∼1.05, showing a 52.4% decrease compared to B-AnMBR. According to higher electron transfer system activity and Cyt-<em>C</em> content, electron transfer process was enhanced in P-W-AnMBR, accounting for superior organics conversion to methane. Through a high average K<sub>La</sub> as 4.50 h⁻¹, the D-CH<sub>4</sub> readily transfer to the gas phase, thereby reducing the concentration of D-CH<sub>4</sub> as well as increasing the proportion of gaseous methane. Energy analysis showed generation of methane energy could be augmented in P-W-AnMBR as OLR was elevated at 15 °C, thereby significantly reducing the net energy consumption. The combination of wave-pulse mixing and conductive PAC within AnMBR provides insights into low temperature resource recovery from municipal wastewater.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"44 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866785","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}
Reverse osmosis (RO) system, extensively utilized in desalination process, faced multiple challenges of various membrane fouling, including scaling and biofouling. The development of multifunctional, environmentally benign antiscalants presents a promising avenue to address these issues. In this study, a series of carboxymethyl cellulose-graft-gallic acid (CMC-g-GA) polymers were prepared by varying the mass ratio of carboxymethyl cellulose to gallic acid (GA), employed for the inhibition of calcium sulphate scale and bacteria. Static scale inhibition and RO experiments were conducted to comprehensively investigate the scale inhibition properties and mechanisms of CMC-g-GA. Results revealed that the static scale inhibition efficiency of CMC-g-GA reached 98.5% at the optimal dosage of 10 mg/L. Furthermore, the membrane flux was sustained at 82.9% after 3 h of RO operation using 2 mg/L CMC-g-GA, far higher than 14.4% observed in the control group without antiscalant, which exhibited a pronounced flux decline. Molecular dynamics simulations and crystal characterization results confirmed that the effectiveness of CMC-g-GA was attributed to its carboxyl and phenolic hydroxyl groups, which bonded calcium ions and interacted with calcium sulphate crystals, preventing scale formation and distorting normal crystal growth. Additionally, the incorporation of GA endowed CMC-g-GA with robust antibacterial properties. These findings provided novel insights for the design and optimization of antiscalants to improve their functionality and broaden their potential applications.
{"title":"Bio-derived carboxymethyl cellulose-graft-gallic acid antiscalant with remarkable antibacterial activity for reverse osmosis scaling and biofouling control","authors":"Liping Xiong, Wei Yu, Chenglin Ji, Longyufan Liu, Jiaheng Teng, Cheng Chen, Hongjun Lin, Liguo Shen","doi":"10.1016/j.watres.2025.123716","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123716","url":null,"abstract":"Reverse osmosis (RO) system, extensively utilized in desalination process, faced multiple challenges of various membrane fouling, including scaling and biofouling. The development of multifunctional, environmentally benign antiscalants presents a promising avenue to address these issues. In this study, a series of carboxymethyl cellulose-<em>graft</em>-gallic acid (CMC-<em>g</em>-GA) polymers were prepared by varying the mass ratio of carboxymethyl cellulose to gallic acid (GA), employed for the inhibition of calcium sulphate scale and bacteria. Static scale inhibition and RO experiments were conducted to comprehensively investigate the scale inhibition properties and mechanisms of CMC-<em>g</em>-GA. Results revealed that the static scale inhibition efficiency of CMC-<em>g</em>-GA reached 98.5% at the optimal dosage of 10 mg/L. Furthermore, the membrane flux was sustained at 82.9% after 3 h of RO operation using 2 mg/L CMC-<em>g</em>-GA, far higher than 14.4% observed in the control group without antiscalant, which exhibited a pronounced flux decline. Molecular dynamics simulations and crystal characterization results confirmed that the effectiveness of CMC-<em>g</em>-GA was attributed to its carboxyl and phenolic hydroxyl groups, which bonded calcium ions and interacted with calcium sulphate crystals, preventing scale formation and distorting normal crystal growth. Additionally, the incorporation of GA endowed CMC-<em>g</em>-GA with robust antibacterial properties. These findings provided novel insights for the design and optimization of antiscalants to improve their functionality and broaden their potential applications.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"108 3 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866470","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 : 2025-04-23DOI: 10.1016/j.watres.2025.123717
Qiuling Ma, Xiangqian Tan, Miao Fang, Zhiyuan Ning, He Guo, Guodong Zhang, Jian Zhou, Tiecheng Wang
Water temperature fluctuations directly impact pollutant decomposition processes in wastewater. Thermoelectric effect is considered an alternative to utilize these temperature variations for pollution control. In this study, a system for persulfate (PS) activation by Ag2Se thermoelectric catalyst under water temperature gradients (Ag₂Se/ΔT/PS) was developed for humic acid (HA) degradation in water. The experimental results showed that the Ag2Se/ΔT/PS system achieved a 90.7% HA removal efficiency, outperforming both PS/ΔT (PS with temperature gradients) and Ag2Se/ΔT systems. Thermoelectric simulations indicated that Ag2Se generated an electric field under temperature variations, with higher current density at surface pores where polarized charges efficiently activated PS. Density functional theory calculations revealed that the thermoelectric effect of Ag2Se lowered the energy barriers for PS activation and ·SO4− generation. Different from ·OH-led decomposition of HA in the Ag₂Se/ΔT system, ·SO4− and ·OH dominated HA decomposition in the Ag₂Se/ΔT/PS system, and ¹O₂ also contributed this process. Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed that oxidation, decarboxylation, and sulfidation were the primary pathways driving HA degradation, leading to decreases in CHO-containing compounds and formation of S-rich byproducts. These findings highlighted the potential of thermoelectric catalysts in advancing water treatment technologies.
{"title":"Built-in electric field of Ag2Se thermoelectric effect activated persulfate for humic acid decomposition in water: Molecular transformation mechanism","authors":"Qiuling Ma, Xiangqian Tan, Miao Fang, Zhiyuan Ning, He Guo, Guodong Zhang, Jian Zhou, Tiecheng Wang","doi":"10.1016/j.watres.2025.123717","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123717","url":null,"abstract":"Water temperature fluctuations directly impact pollutant decomposition processes in wastewater. Thermoelectric effect is considered an alternative to utilize these temperature variations for pollution control. In this study, a system for persulfate (PS) activation by Ag<sub>2</sub>Se thermoelectric catalyst under water temperature gradients (Ag₂Se/ΔT/PS) was developed for humic acid (HA) degradation in water. The experimental results showed that the Ag<sub>2</sub>Se/ΔT/PS system achieved a 90.7% HA removal efficiency, outperforming both PS/ΔT (PS with temperature gradients) and Ag<sub>2</sub>Se/ΔT systems. Thermoelectric simulations indicated that Ag<sub>2</sub>Se generated an electric field under temperature variations, with higher current density at surface pores where polarized charges efficiently activated PS. Density functional theory calculations revealed that the thermoelectric effect of Ag<sub>2</sub>Se lowered the energy barriers for PS activation and ·SO<sub>4</sub><sup>−</sup> generation. Different from ·OH-led decomposition of HA in the Ag₂Se/ΔT system, ·SO<sub>4</sub><sup>−</sup> and ·OH dominated HA decomposition in the Ag₂Se/ΔT/PS system, and ¹O₂ also contributed this process. Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) revealed that oxidation, decarboxylation, and sulfidation were the primary pathways driving HA degradation, leading to decreases in CHO-containing compounds and formation of S-rich byproducts. These findings highlighted the potential of thermoelectric catalysts in advancing water treatment technologies.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"40 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866569","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 : 2025-04-23DOI: 10.1016/j.watres.2025.123713
Yue Wang, Yihan Bai, Liang Xu, Junfeng Su, Jingting Feng, Ying Zhang, Wenjing Cheng, Jiangtao Bai
The co-contamination of hexavalent chromium (Cr(VI)) and ammonium (NH4+-N) in industrial wastewater has attracted considerable attention due to its serious threats to both ecological systems and public health. Manganese(IV) (Mn(IV))-driven NH4+-N oxidation (Mnammox) coupled with Mn(II)-mediated denitrification (MnOD), built on the Mn redox cycle, is a promising nitrogen removal process, where Mn(II) and NOx−-N generated during Mnammox were effectively controlled by MnOD. Herein, a bioreactor integrating Mnammox and MnOD for NH4+-N and Cr(VI) removal was constructed utilizing core-shell gel beads embedded with two core strains and δ-MnO2. When the C/N was 1.5, pH was 6.5, and HRT was 20 h, the removal efficiencies for Cr(VI) and NH4+-N reached 96.3 and 91.3%, respectively. Cr(VI) can be bioreduced to Cr(III) in bioreactors. Additionally, the microbial activity and electron transfer properties in the Mn redox system were studied under varying Cr(VI) concentrations. High-throughput data revealed that high Cr(VI) concentrations significantly impacted microbial community diversity, while Aromatoleu and Zoogloea consistently remaining the dominant species in the bioreactor. KEGG database analysis showed that appropriately increasing C/N promoted the expression of genes related to nitrification and Mn redox cycling. This study provides novel perspectives on the application of the Mnammox coupled MnOD process driven by the Mn redox cycle for treating NH4+-N and Cr(VI) co-contaminated industrial wastewater.
{"title":"Mechanistic insights and performance of Mn redox cycling in a dual-bacteria bioreactor for ammonium and Cr(VI) removal","authors":"Yue Wang, Yihan Bai, Liang Xu, Junfeng Su, Jingting Feng, Ying Zhang, Wenjing Cheng, Jiangtao Bai","doi":"10.1016/j.watres.2025.123713","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123713","url":null,"abstract":"The co-contamination of hexavalent chromium (Cr(VI)) and ammonium (NH<sub>4</sub><sup>+</sup>-N) in industrial wastewater has attracted considerable attention due to its serious threats to both ecological systems and public health. Manganese(IV) (Mn(IV))-driven NH<sub>4</sub><sup>+</sup>-N oxidation (Mnammox) coupled with Mn(II)-mediated denitrification (MnOD), built on the Mn redox cycle, is a promising nitrogen removal process, where Mn(II) and NO<sub>x</sub><sup>−</sup>-N generated during Mnammox were effectively controlled by MnOD. Herein, a bioreactor integrating Mnammox and MnOD for NH<sub>4</sub><sup>+</sup>-N and Cr(VI) removal was constructed utilizing core-shell gel beads embedded with two core strains and δ-MnO<sub>2</sub>. When the C/N was 1.5, pH was 6.5, and HRT was 20 h, the removal efficiencies for Cr(VI) and NH<sub>4</sub><sup>+</sup>-N reached 96.3 and 91.3%, respectively. Cr(VI) can be bioreduced to Cr(III) in bioreactors. Additionally, the microbial activity and electron transfer properties in the Mn redox system were studied under varying Cr(VI) concentrations. High-throughput data revealed that high Cr(VI) concentrations significantly impacted microbial community diversity, while <em>Aromatoleu</em> and <em>Zoogloea</em> consistently remaining the dominant species in the bioreactor. KEGG database analysis showed that appropriately increasing C/N promoted the expression of genes related to nitrification and Mn redox cycling. This study provides novel perspectives on the application of the Mnammox coupled MnOD process driven by the Mn redox cycle for treating NH<sub>4</sub><sup>+</sup>-N and Cr(VI) co-contaminated industrial wastewater.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"63 1 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862692","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 : 2025-04-23DOI: 10.1016/j.watres.2025.123630
Hanson Appiah-Twum, Tim Van Winckel, Julia Santolin, Jolien De Paepe, Stefanie Hellweg, Tove A. Larsen, Kai M. Udert, Siegfried E. Vlaeminck, Marc Spiller
As municipal wastewater treatment regulations become more stringent, integrating source-separated urine treatment into centralized urban wastewater management offers a ‘hybrid’ solution. However, it is not clear how the environmental impacts of such hybrid systems compare to highly efficient centralized wastewater treatment plants (WWTPs) with low N2O emissions and electricity use. In this study, a consequential life cycle assessment was used to compare the environmental impact of three urine separation hybrid wastewater treatment systems – which combine decentralized urine treatment with a highly efficient central WWTP– to a centralized WWTP treating mixed wastewater (baseline). The studied urine treatment systems include partial nitrification & distillation, struvite precipitation & stripping/scrubbing, and partial nitritation/anammox. Additionally, the environmental impact of urine pre-treatment by calcium hydroxide and electrochemical alkalinization methods on the partial nitrification & distillation system was evaluated. The results show that all hybrid scenarios have a lower environmental impact in the freshwater ecotoxicity, marine toxicity, freshwater eutrophication and marine eutrophication categories compared to the baseline. However, all hybrid scenarios resulted in higher impacts on global warming compared to the baseline, with direct N2O emissions being a key variable. Additionally, it was identified that urine alkalinization increased the environmental impact of the treatment system in 7 out of the 10 impact categories. A Pareto frontier analysis was developed to guide decision makers on where hybrid solutions could be used as a strategy to reduce global warming impacts of conventional WWTPs. Using N2O emission factors of 75 WWTPs, 87% of centralized WWTPs had lower global warming impact compared to partial nitrification & distillation, and 91% compared to partial nitritation/anammox hybrid solutions. However, at energy demands of 1 kWh/PE and 1.5 kWh/PE, both hybrid solutions showed lower global warming impact than all the studied WWTPs. The study highlights the potential of hybrid wastewater treatment solutions as a strategy to reduce global warming impacts in WWTPs with high N2O emissions and electricity use as well as a mean to reduce marine eutrophication (i.e. nitrogen pollution).
{"title":"Environmental impact of integrating decentralized urine treatment in the urban wastewater management system: A comparative life cycle assessment","authors":"Hanson Appiah-Twum, Tim Van Winckel, Julia Santolin, Jolien De Paepe, Stefanie Hellweg, Tove A. Larsen, Kai M. Udert, Siegfried E. Vlaeminck, Marc Spiller","doi":"10.1016/j.watres.2025.123630","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123630","url":null,"abstract":"As municipal wastewater treatment regulations become more stringent, integrating source-separated urine treatment into centralized urban wastewater management offers a ‘hybrid’ solution. However, it is not clear how the environmental impacts of such hybrid systems compare to highly efficient centralized wastewater treatment plants (WWTPs) with low N<sub>2</sub>O emissions and electricity use. In this study, a consequential life cycle assessment was used to compare the environmental impact of three urine separation hybrid wastewater treatment systems – which combine decentralized urine treatment with a highly efficient central WWTP– to a centralized WWTP treating mixed wastewater (baseline). The studied urine treatment systems include partial nitrification & distillation, struvite precipitation & stripping/scrubbing, and partial nitritation/anammox. Additionally, the environmental impact of urine pre-treatment by calcium hydroxide and electrochemical alkalinization methods on the partial nitrification & distillation system was evaluated. The results show that all hybrid scenarios have a lower environmental impact in the freshwater ecotoxicity, marine toxicity, freshwater eutrophication and marine eutrophication categories compared to the baseline. However, all hybrid scenarios resulted in higher impacts on global warming compared to the baseline, with direct N<sub>2</sub>O emissions being a key variable. Additionally, it was identified that urine alkalinization increased the environmental impact of the treatment system in 7 out of the 10 impact categories. A Pareto frontier analysis was developed to guide decision makers on where hybrid solutions could be used as a strategy to reduce global warming impacts of conventional WWTPs. Using N<sub>2</sub>O emission factors of 75 WWTPs, 87% of centralized WWTPs had lower global warming impact compared to partial nitrification & distillation, and 91% compared to partial nitritation/anammox hybrid solutions. However, at energy demands of 1 kWh/PE and 1.5 kWh/PE, both hybrid solutions showed lower global warming impact than all the studied WWTPs. The study highlights the potential of hybrid wastewater treatment solutions as a strategy to reduce global warming impacts in WWTPs with high N<sub>2</sub>O emissions and electricity use as well as a mean to reduce marine eutrophication (i.e. nitrogen pollution).","PeriodicalId":443,"journal":{"name":"Water Research","volume":"35 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143866571","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}
Microalgae, ammonia-oxidizing bacteria (AOB), and anaerobic ammonium-oxidizing bacteria (AnAOB) have been proven to form an integrated algal-bacterial biofilm system with over 93% of total nitrogen removal. Compared to conventional nitrification-denitrification process, this system operated without additional organic carbon or aeration. In order to understand the interaction mechanisms between bacteria and algae, this study investigated microbial community succession, the changes in metabolic pathways and the potential role of acyl-homoserine lactone (AHL)-mediated quorum sensing (QS) during the formation of the algae/partial nitrification/anammox biofilm system. Within this algal-bacterial symbiotic biofilm, the dominant genera identified were Candidatus_Brocadia (AnAOB), Nitrosomonas (AOB), and Geitlerinema (microalgae), with relative abundances of 13.86%, 6.37%, and 2.88%, respectively. Compared with the first two stages, the abundance of genes related to nitrogen metabolism pathways (anaerobic ammonium oxidation, denitrification, and ammonia assimilation) increased, indicating enhanced nitrogen transformation capacity in the algal-bacterial symbiotic stage. Co-occurrence network analysis also revealed enhanced microbial interactions, with increased negative correlations (from 36.07% to 39.38%), high average standard betweenness centrality (from 0.193 to 0.304), and reduced community vulnerability (from 0.037 to 0.028), contributing to biofilm stability and resilience. The variations in AHLs provided direct evidence for more frequent interspecies communication, facilitating the ecological reconfiguration in the biofilm. Overall, the close synergistic relationship between microalgae and bacteria supports stable biofilm development and high nitrogen removal efficiency.
{"title":"AHL-Mediated Quorum Sensing Drives Microbial Community Succession and Metabolic Pathway in Algal-Bacterial Biofilm System","authors":"Zuocheng Liu, Ting Zeng, Jinlong Wang, Zongping Wang, Daotong Zhao, Junchi Wei, Yongzhen Peng, Lei Miao","doi":"10.1016/j.watres.2025.123702","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123702","url":null,"abstract":"Microalgae, ammonia-oxidizing bacteria (AOB), and anaerobic ammonium-oxidizing bacteria (AnAOB) have been proven to form an integrated algal-bacterial biofilm system with over 93% of total nitrogen removal. Compared to conventional nitrification-denitrification process, this system operated without additional organic carbon or aeration. In order to understand the interaction mechanisms between bacteria and algae, this study investigated microbial community succession, the changes in metabolic pathways and the potential role of acyl-homoserine lactone (AHL)-mediated quorum sensing (QS) during the formation of the algae/partial nitrification/anammox biofilm system. Within this algal-bacterial symbiotic biofilm, the dominant genera identified were <em>Candidatus</em>_Brocadia (AnAOB), <em>Nitrosomonas</em> (AOB), and <em>Geitlerinema</em> (microalgae), with relative abundances of 13.86%, 6.37%, and 2.88%, respectively. Compared with the first two stages, the abundance of genes related to nitrogen metabolism pathways (anaerobic ammonium oxidation, denitrification, and ammonia assimilation) increased, indicating enhanced nitrogen transformation capacity in the algal-bacterial symbiotic stage. Co-occurrence network analysis also revealed enhanced microbial interactions, with increased negative correlations (from 36.07% to 39.38%), high average standard betweenness centrality (from 0.193 to 0.304), and reduced community vulnerability (from 0.037 to 0.028), contributing to biofilm stability and resilience. The variations in AHLs provided direct evidence for more frequent interspecies communication, facilitating the ecological reconfiguration in the biofilm. Overall, the close synergistic relationship between microalgae and bacteria supports stable biofilm development and high nitrogen removal efficiency.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"11 10 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858134","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 : 2025-04-22DOI: 10.1016/j.watres.2025.123707
De Wang, Jing Wang, Di Zhang, Jiaxing Li
Through the design of flow electrodes, flow electrode capacitive deionization (FCDI) enables the efficient remediation of uranium-contaminated water to meet World Health Organization (WHO) standards (uranium ≤ 30 ppb), while concurrently facilitating the recovery of uranium from the flow electrode slurry. In this work, the phosphate-functionalized magnetic carbon-based flow electrode (OMPAC) was synthesized by simply co-precipitation and oxygen plasma treatment. The enhanced conductivity of OMPAC accelerated the efficient remediation of surface water contaminated with multiple nuclides, due to the improved charge-transfer capability facilitated by the introduced magnetic particles (Fe, Fe3O4, Fe3C) and heteroatoms (O, P). The uranium in feed solution was selectively adsorbed by OMPAC in flow electrode slurry, benefiting from the multiple strong sorption interactions between U(VI) and C=O/P=O /P–O groups, as well as the redox reactions between U(VI) and Fe (0/II). After four batch cycles, the average uranium removal rate by OMPAC was maintained at 97.84 %, while the recovery rate of uranium from OMPAC reached 78.2 %, demonstrating the excellent long-term performance and synchronous uranium recovery capability in FCDI. This study provides feasibility guidance for the remediation of radioactive pollution and the strategic reuse of resources via the FCDI technology.
{"title":"Efficient Remediation and Synchronous Recovery of Uranium by Phosphate-Functionalized Magnetic Carbon-based Flow Electrode Capacitive Deionization","authors":"De Wang, Jing Wang, Di Zhang, Jiaxing Li","doi":"10.1016/j.watres.2025.123707","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123707","url":null,"abstract":"Through the design of flow electrodes, flow electrode capacitive deionization (FCDI) enables the efficient remediation of uranium-contaminated water to meet World Health Organization (WHO) standards (uranium ≤ 30 ppb), while concurrently facilitating the recovery of uranium from the flow electrode slurry. In this work, the phosphate-functionalized magnetic carbon-based flow electrode (OMPAC) was synthesized by simply co-precipitation and oxygen plasma treatment. The enhanced conductivity of OMPAC accelerated the efficient remediation of surface water contaminated with multiple nuclides, due to the improved charge-transfer capability facilitated by the introduced magnetic particles (Fe, Fe<sub>3</sub>O<sub>4</sub>, Fe<sub>3</sub>C) and heteroatoms (O, P). The uranium in feed solution was selectively adsorbed by OMPAC in flow electrode slurry, benefiting from the multiple strong sorption interactions between U(VI) and C=O/P=O /P–O groups, as well as the redox reactions between U(VI) and Fe (0/II). After four batch cycles, the average uranium removal rate by OMPAC was maintained at 97.84 %, while the recovery rate of uranium from OMPAC reached 78.2 %, demonstrating the excellent long-term performance and synchronous uranium recovery capability in FCDI. This study provides feasibility guidance for the remediation of radioactive pollution and the strategic reuse of resources via the FCDI technology.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"7 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862724","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 : 2025-04-22DOI: 10.1016/j.watres.2025.123710
Jie Liu, Yang Liu, Zi Zhang, Yangfan Deng, Guanghao Chen
Microorganisms capable of anaerobic ammonia oxidation (anammox), or the conversion of nitrite and ammonium to dinitrogen, tend to aggregate and form a granular sludge in anammox reactors. This anammox granular sludge is a potential source of polysaccharides due to its richly diverse microbial community and abundant polymers. In this study, anammox polysaccharide (APS) was extracted from anammox granular sludge, and its potential to form hydrogels with alginate was investigated. The yield of APS was 9.91% ± 0.12%. The three main monosaccharides in APS were glucose (60.63% ± 3.45%), glucuronic acid (13.81% ± 0.31%), and rhamnose (18.88% ± 0.22%). The antioxidant potential of APS was evaluated through three antioxidant assays, which revealed significant antioxidant benefits at APS concentrations between 100 and 500 mg/L. Furthermore, L929 mouse fibroblasts exhibited high survival rates (>85%) under different APS concentrations (1–50 μg/mL), indicating the good biological compatibility of APS. A series of hydrogels were prepared by mixing alginate with APS in different ratios (10:0, 9:1, 8:2, 7:3, and 6:4). The swelling ability of the prepared hydrogels in simulated gastric fluid varied between 1.4 and 2.0. In contrast, the swelling ability increased significantly to 10.37 ± 0.01 in simulated intestinal fluid when the ratio of alginate to APS in the hydrogel was 8:2. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were also used to analyse the functional groups and specific chemical bonds in the hydrogels. Subsequent loading experiments using bovine serum albumin (BSA) demonstrated that an alginate:APS ratio of 8:2 exhibited the highest loading efficiency for BSA, reaching 80.59% ± 1.46%. As the quantity of APS was increased, the release of BSA into simulated gastric fluid was effectively inhibited, with an alginate:APS ratio of 6:4 resulting in the lowest release amount (0.023% in dry state, 0.11% in wet state). Overall, this study highlights the derivation of a valuable resource from anammox sludge and offers insights into its potential applications in drug delivery.
{"title":"Characterisation of polysaccharide from anammox granular sludge and potential application in hydrogel preparation","authors":"Jie Liu, Yang Liu, Zi Zhang, Yangfan Deng, Guanghao Chen","doi":"10.1016/j.watres.2025.123710","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123710","url":null,"abstract":"Microorganisms capable of anaerobic ammonia oxidation (anammox), or the conversion of nitrite and ammonium to dinitrogen, tend to aggregate and form a granular sludge in anammox reactors. This anammox granular sludge is a potential source of polysaccharides due to its richly diverse microbial community and abundant polymers. In this study, anammox polysaccharide (APS) was extracted from anammox granular sludge, and its potential to form hydrogels with alginate was investigated. The yield of APS was 9.91% ± 0.12%. The three main monosaccharides in APS were glucose (60.63% ± 3.45%), glucuronic acid (13.81% ± 0.31%), and rhamnose (18.88% ± 0.22%). The antioxidant potential of APS was evaluated through three antioxidant assays, which revealed significant antioxidant benefits at APS concentrations between 100 and 500 mg/L. Furthermore, L929 mouse fibroblasts exhibited high survival rates (>85%) under different APS concentrations (1–50 μg/mL), indicating the good biological compatibility of APS. A series of hydrogels were prepared by mixing alginate with APS in different ratios (10:0, 9:1, 8:2, 7:3, and 6:4). The swelling ability of the prepared hydrogels in simulated gastric fluid varied between 1.4 and 2.0. In contrast, the swelling ability increased significantly to 10.37 ± 0.01 in simulated intestinal fluid when the ratio of alginate to APS in the hydrogel was 8:2. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were also used to analyse the functional groups and specific chemical bonds in the hydrogels. Subsequent loading experiments using bovine serum albumin (BSA) demonstrated that an alginate:APS ratio of 8:2 exhibited the highest loading efficiency for BSA, reaching 80.59% ± 1.46%. As the quantity of APS was increased, the release of BSA into simulated gastric fluid was effectively inhibited, with an alginate:APS ratio of 6:4 resulting in the lowest release amount (0.023% in dry state, 0.11% in wet state). Overall, this study highlights the derivation of a valuable resource from anammox sludge and offers insights into its potential applications in drug delivery.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"690 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862696","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 : 2025-04-22DOI: 10.1016/j.watres.2025.123697
Dong Li, Laurie C. Van De Werfhorst, Rachel T. Noble, Denene Blackwood, Jared Ervin, Brandon Steets, Jen Smith, Patricia A. Holden
Assessing human fecal contamination of recreational beach waters is a public health challenge owing to multiple sources and environmental conditions affecting indicator, pathogen, and source marker relationships. Human fecal-associated markers, such as HF183, accurately indicate human waste, but reliance on individual markers risks false negative diagnoses, owing to marker source loading variations and attenuation. Bacterial community analysis is a data-dense approach that could improve the accuracy of human waste detection, but relatedness to actual human health hazards under complex coastal water conditions is unproven. Here, two Malibu and one Pacific Palisades, CA recreational beaches differing in urbanization and sewerage were studied over two years across varying seasonal rainfall, and beach berm, conditions. Fecal indicator bacteria (FIB), HF183, and human norovirus concentrations were quantified and related to bacterial community 16S rRNA gene sequences which were further analyzed for putative human pathogens and sewage proportions. All lower watersheds harbored human fecal sources, and surf zone contamination was enhanced by rainfall runoff with berm breaching, which intensified with urbanization. Notably, for sequenced surf zone waters sampled across all weather conditions (n = 36), sequence-based putative pathogen proportions correlated with qPCR HF183 concentrations (w/ and w/o PMA treatment; p = 0.0) and with human norovirus G1concentrations (p = 0.04) which also correlated with HF183 sequence abundance in bacterial communities (p = 0.02). Although human fecal sources appeared to vary seasonally and a range of physical conditions influenced surf zone fecal contamination, human fecal contamination and associated health hazard were reliably evidenced by bacterial community analysis in this study.
{"title":"Bacterial Community Analysis of Recreational Beach Waters Reveals Human Fecal Contamination and Pathogenicity across Varying Field Conditions","authors":"Dong Li, Laurie C. Van De Werfhorst, Rachel T. Noble, Denene Blackwood, Jared Ervin, Brandon Steets, Jen Smith, Patricia A. Holden","doi":"10.1016/j.watres.2025.123697","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123697","url":null,"abstract":"Assessing human fecal contamination of recreational beach waters is a public health challenge owing to multiple sources and environmental conditions affecting indicator, pathogen, and source marker relationships. Human fecal-associated markers, such as HF183, accurately indicate human waste, but reliance on individual markers risks false negative diagnoses, owing to marker source loading variations and attenuation. Bacterial community analysis is a data-dense approach that could improve the accuracy of human waste detection, but relatedness to actual human health hazards under complex coastal water conditions is unproven. Here, two Malibu and one Pacific Palisades, CA recreational beaches differing in urbanization and sewerage were studied over two years across varying seasonal rainfall, and beach berm, conditions. Fecal indicator bacteria (FIB), HF183, and human norovirus concentrations were quantified and related to bacterial community 16S rRNA gene sequences which were further analyzed for putative human pathogens and sewage proportions. All lower watersheds harbored human fecal sources, and surf zone contamination was enhanced by rainfall runoff with berm breaching, which intensified with urbanization. Notably, for sequenced surf zone waters sampled across all weather conditions (n = 36), sequence-based putative pathogen proportions correlated with qPCR HF183 concentrations (w/ and w/o PMA treatment; <em>p</em> = 0.0) and with human norovirus G1concentrations (<em>p</em> = 0.04) which also correlated with HF183 sequence abundance in bacterial communities (<em>p</em> = 0.02). Although human fecal sources appeared to vary seasonally and a range of physical conditions influenced surf zone fecal contamination, human fecal contamination and associated health hazard were reliably evidenced by bacterial community analysis in this study.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"13 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862695","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 : 2025-04-22DOI: 10.1016/j.watres.2025.123698
Zhaoxu Peng, Antonella L. Piaggio, Guilherme Lelis Giglio, Sara Toja Ortega, Mark C.M. van Loosdrecht, Merle K. de Kreuk
More than 50% of the organic matter in sewage consist of particulate chemical oxygen demand (pCOD). This study used 250 μm fluorescent microbeads, 130±58 μm microparticles and 100 nm nanobeads to simulate sewage particles, and investigated the fate of these particles under both plug flow feeding and aeration phases in an aerobic granular sludge (AGS) system. Filtration performance was dominantly influenced by the particle size rather than the upflow velocity (Vupflow). The microbeads exhibited 95±3 % filtration efficiency with obvious accumulation around the AGS bed bottom, even as slight fluidization started at the Vupflow of 5.0 m·h-1. In contrast, the nanobeads filtration efficiency was significantly lower (43±6 %). During the aeration phase, the attachment efficiency increased with the decrease of particle size. The microbeads attachment efficiency variated between 39-49 %, whereas the microparticles and nanobeads achieved better attachment of 89.4-95.2 % and 98.8-99.3 %, respectively. Furthermore, aeration batch tests showed both nanobeads and the irregular microparticles attachment by AGS was strong, and the detach-attach of nanobeads/microparticles between different sized AGS was very limited duration aeration. This work provides insight into the fate of particles in AGS system. The optimal sludge treatment was also evaluated in the scope of this removal of non-biodegradable, and potentially harmful particles.
{"title":"Interaction of non-biodegradable particles and granular sludge in Nereda®—— from nanoparticles to microparticles","authors":"Zhaoxu Peng, Antonella L. Piaggio, Guilherme Lelis Giglio, Sara Toja Ortega, Mark C.M. van Loosdrecht, Merle K. de Kreuk","doi":"10.1016/j.watres.2025.123698","DOIUrl":"https://doi.org/10.1016/j.watres.2025.123698","url":null,"abstract":"More than 50% of the organic matter in sewage consist of particulate chemical oxygen demand (pCOD). This study used 250 μm fluorescent microbeads, 130±58 μm microparticles and 100 nm nanobeads to simulate sewage particles, and investigated the fate of these particles under both plug flow feeding and aeration phases in an aerobic granular sludge (AGS) system. Filtration performance was dominantly influenced by the particle size rather than the upflow velocity (V<sub>upflow</sub>). The microbeads exhibited 95±3 % filtration efficiency with obvious accumulation around the AGS bed bottom, even as slight fluidization started at the V<sub>upflow</sub> of 5.0 m·h<sup>-1</sup>. In contrast, the nanobeads filtration efficiency was significantly lower (43±6 %). During the aeration phase, the attachment efficiency increased with the decrease of particle size. The microbeads attachment efficiency variated between 39-49 %, whereas the microparticles and nanobeads achieved better attachment of 89.4-95.2 % and 98.8-99.3 %, respectively. Furthermore, aeration batch tests showed both nanobeads and the irregular microparticles attachment by AGS was strong, and the detach-attach of nanobeads/microparticles between different sized AGS was very limited duration aeration. This work provides insight into the fate of particles in AGS system. The optimal sludge treatment was also evaluated in the scope of this removal of non-biodegradable, and potentially harmful particles.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"65 1 1","pages":""},"PeriodicalIF":12.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862698","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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