Pub Date : 2025-03-24DOI: 10.1016/j.watres.2025.123541
Yu-Qi Wang , Hong-Cheng Wang , Zi-Jie Xiao , Ling-Jun Bu , Jiuling Li , Xiao-Chi Feng , Bin Liang , Wen-Zong Liu , Fei-Yun Sun , Shi-Qing Zhou , Ai-Jie Wang
The integration of machine learning into urban drinking water treatment plants (DWTPs) offers a transformative pathway to ensure drinking water safety while promoting the development of smart, low-carbon cities. However, the effectiveness of these systems is frequently hindered by challenges related to data security and reliability, including imprecise control logic, sensor inconsistencies, and data transmission errors. In this study, we introduce a novel progressive Step-by-Step (SBS) machine learning strategy, initially applied to precise disinfectant dosage control in drinking water treatment and subsequently extended to enhance the data security of the entire water supply system. Among eight evaluated methods, the deep neural network integrated with the SBS strategy demonstrated superior performance. In a real-world DWTP, the SBS model significantly outperformed manual fuzzy control, reducing disinfectant dosage by 22.0 % and effluent turbidity by 16.0 %. Furthermore, through simulations of extreme data-missing scenarios and the application of SBS-based corrections, the robustness and security of DWTPs were maintained. The integration of the SBS strategy has the potential to significantly improve emergency management in urban water systems and elevate the intelligence of water supply networks. This approach not only strengthens urban resilience but also supports the safe and sustainable evolution of smart urban water systems.
{"title":"Machine learning strategy secures urban smart drinking water treatment plant through incremental advances","authors":"Yu-Qi Wang , Hong-Cheng Wang , Zi-Jie Xiao , Ling-Jun Bu , Jiuling Li , Xiao-Chi Feng , Bin Liang , Wen-Zong Liu , Fei-Yun Sun , Shi-Qing Zhou , Ai-Jie Wang","doi":"10.1016/j.watres.2025.123541","DOIUrl":"10.1016/j.watres.2025.123541","url":null,"abstract":"<div><div>The integration of machine learning into urban drinking water treatment plants (DWTPs) offers a transformative pathway to ensure drinking water safety while promoting the development of smart, low-carbon cities. However, the effectiveness of these systems is frequently hindered by challenges related to data security and reliability, including imprecise control logic, sensor inconsistencies, and data transmission errors. In this study, we introduce a novel progressive Step-by-Step (SBS) machine learning strategy, initially applied to precise disinfectant dosage control in drinking water treatment and subsequently extended to enhance the data security of the entire water supply system. Among eight evaluated methods, the deep neural network integrated with the SBS strategy demonstrated superior performance. In a real-world DWTP, the SBS model significantly outperformed manual fuzzy control, reducing disinfectant dosage by 22.0 % and effluent turbidity by 16.0 %. Furthermore, through simulations of extreme data-missing scenarios and the application of SBS-based corrections, the robustness and security of DWTPs were maintained. The integration of the SBS strategy has the potential to significantly improve emergency management in urban water systems and elevate the intelligence of water supply networks. This approach not only strengthens urban resilience but also supports the safe and sustainable evolution of smart urban water systems.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123541"},"PeriodicalIF":11.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678093","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 : 2025-03-24DOI: 10.1016/j.watres.2025.123548
Christian Krohn , Leadin Khudur , Sali Khair Biek , Jake AK Elliott , Seyedali Tabatabaei , Chenjing Jiang , Jennifer L. Wood , Daniel Anthony Dias , Morten K.D. Dueholm , Catherine A. Rees , Denis O'Carroll , Richard Stuetz , Damien J. Batstone , Aravind Surapaneni , Andrew S. Ball
Foaming during anaerobic digestion (AD) of sewage sludge is poorly understood and remains an uncontrollable operational obstacle for sewage treatment systems globally, causing mechanical damage, increased hazards and reduced biogas recovery. Foams during AD commonly occur after process disturbances, such as organic loading shocks. However, it is still unclear whether these foam events are biologically driven and linked to the abundance of organisms like filamentous or hydrophobic bacteria. A time-series study was conducted, comparing digestion performance, microbial community succession, metagenomes, and metabolomes in six anaerobic continuous stirred-tank reactors (CSTRs): a control group fed normally (n = 3), and one treated group inhibited through organic shock loading of more than twice the steady state loading rate with glycerol (treatment, n = 3). As soon as microbial activity and methanogenesis recovered after inhibition, significant volumes of foam accumulated simultaneously in the reactor headspace of the three treated CSTRs. Microbial abundance profiles (16S rRNA, V3-V4) from 165 days of operation showed that filamentous or mycolic acid-producing organisms were not associated with this foam event. Shock loading led to acidification, biomass decline and microbial imbalance, contributing indirectly to the foam event. During that period, metabolomes and functional pathway abundances indicated that the stressed microbial biomass was enriched in long-chain fatty acids prior to foaming. This biomass, combined with pH changes, may have modified the physicochemical properties of sludge, leading to the fractionation of organic mass once gas production resumed. More research is needed to understand how abiotic and biotic interactions contribute to foam formation.
{"title":"Microbial population shifts during disturbance induced foaming in anaerobic digestion of primary and activated sludge","authors":"Christian Krohn , Leadin Khudur , Sali Khair Biek , Jake AK Elliott , Seyedali Tabatabaei , Chenjing Jiang , Jennifer L. Wood , Daniel Anthony Dias , Morten K.D. Dueholm , Catherine A. Rees , Denis O'Carroll , Richard Stuetz , Damien J. Batstone , Aravind Surapaneni , Andrew S. Ball","doi":"10.1016/j.watres.2025.123548","DOIUrl":"10.1016/j.watres.2025.123548","url":null,"abstract":"<div><div>Foaming during anaerobic digestion (AD) of sewage sludge is poorly understood and remains an uncontrollable operational obstacle for sewage treatment systems globally, causing mechanical damage, increased hazards and reduced biogas recovery. Foams during AD commonly occur after process disturbances, such as organic loading shocks. However, it is still unclear whether these foam events are biologically driven and linked to the abundance of organisms like filamentous or hydrophobic bacteria. A time-series study was conducted, comparing digestion performance, microbial community succession, metagenomes, and metabolomes in six anaerobic continuous stirred-tank reactors (CSTRs): a control group fed normally (<em>n</em> = 3), and one treated group inhibited through organic shock loading of more than twice the steady state loading rate with glycerol (treatment, <em>n</em> = 3). As soon as microbial activity and methanogenesis recovered after inhibition, significant volumes of foam accumulated simultaneously in the reactor headspace of the three treated CSTRs. Microbial abundance profiles (16S rRNA, V3-V4) from 165 days of operation showed that filamentous or mycolic acid-producing organisms were not associated with this foam event. Shock loading led to acidification, biomass decline and microbial imbalance, contributing indirectly to the foam event. During that period, metabolomes and functional pathway abundances indicated that the stressed microbial biomass was enriched in long-chain fatty acids prior to foaming. This biomass, combined with pH changes, may have modified the physicochemical properties of sludge, leading to the fractionation of organic mass once gas production resumed. More research is needed to understand how abiotic and biotic interactions contribute to foam formation.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"281 ","pages":"Article 123548"},"PeriodicalIF":11.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-rate activated sludge operated at <2 days biomass age enhances carbon recovery from wastewater, but simultaneous biological recovery of phosphorus remains unachieved. Addressing the reported loss of phosphorus accumulating organisms (PAO) at such short biomass ages, this study investigated the integration of moving bed biofilms into high-rate activated sludge to enhance PAO retention. The results demonstrated sustained biofilm-based PAO activity and complete orthoP removal under short anaerobic-aerobic cycles with a hydraulic retention time of 2.7 h matching high-rate conditions. When combined with high-rate activated sludge in a sequencing batch reactor fed with acetate, complete orthoP removal was sustained. However, using synthetic wastewater promoted the growth of competing heterotrophic bacteria, reducing orthoP removal to 50–65 %. Biofilms served as a continuous source of PAO for the suspended biomass, which contributed to 46–55 % of the overall orthoP removal, even below 2 days biomass age. While acetate-fed microbial communities included known PAOs, using complex feed shifted the community toward less understood putative PAOs. Competition for acetate was likely compensated by a high fermentability of high-rate activated sludge, as PAO activity was maintained while reducing the acetate load in the feed from 20:1 to 5:1 g acetate⋅g P-1. P release and uptake rates were accurately described by the biomass-specific acetate loading rate and the depletion of intracellular polyphosphate, respectively, providing predictive relationships for process optimization. Imposing an anaerobic-aerobic regime enhanced the carbon recovery of high-rate activated sludge from about 37 to 60 %. Integrating biofilms enabled efficient phosphorus removal while maintaining carbon recovery rates of 41–53 %, highlighting the synergistic benefits of this approach.
{"title":"Synergizing carbon and phosphorus recovery from wastewater: Integrating biofilm-based phosphorus removal in high-rate activated sludge","authors":"Rellegadla Sandeep , Jakob Schelde Madsen , Ugo Marzocchi , Leendert Vergeynst","doi":"10.1016/j.watres.2025.123546","DOIUrl":"10.1016/j.watres.2025.123546","url":null,"abstract":"<div><div>High-rate activated sludge operated at <2 days biomass age enhances carbon recovery from wastewater, but simultaneous biological recovery of phosphorus remains unachieved. Addressing the reported loss of phosphorus accumulating organisms (PAO) at such short biomass ages, this study investigated the integration of moving bed biofilms into high-rate activated sludge to enhance PAO retention. The results demonstrated sustained biofilm-based PAO activity and complete orthoP removal under short anaerobic-aerobic cycles with a hydraulic retention time of 2.7 h matching high-rate conditions. When combined with high-rate activated sludge in a sequencing batch reactor fed with acetate, complete orthoP removal was sustained. However, using synthetic wastewater promoted the growth of competing heterotrophic bacteria, reducing orthoP removal to 50–65 %. Biofilms served as a continuous source of PAO for the suspended biomass, which contributed to 46–55 % of the overall orthoP removal, even below 2 days biomass age. While acetate-fed microbial communities included known PAOs, using complex feed shifted the community toward less understood putative PAOs. Competition for acetate was likely compensated by a high fermentability of high-rate activated sludge, as PAO activity was maintained while reducing the acetate load in the feed from 20:1 to 5:1 g acetate⋅g P<sup>-1</sup>. P release and uptake rates were accurately described by the biomass-specific acetate loading rate and the depletion of intracellular polyphosphate, respectively, providing predictive relationships for process optimization. Imposing an anaerobic-aerobic regime enhanced the carbon recovery of high-rate activated sludge from about 37 to 60 %. Integrating biofilms enabled efficient phosphorus removal while maintaining carbon recovery rates of 41–53 %, highlighting the synergistic benefits of this approach.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123546"},"PeriodicalIF":11.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-23DOI: 10.1016/j.watres.2025.123544
Sining Zhong , Bin Li , Qian Chen , Jinzheng zhang , Hetong Cai , Rui An , Guohong Liu , Shungui Zhou
Groundwater ecosystems face increasing threat from declining water quality due to intensified urbanization, agricultural, and industrial activities. Accurately identifying anthropogenic disturbances remains challenging, and their effects on microbial nitrogen cycling are still largely unknown. Here, by collecting 64 groundwater samples from an aquifer beneath the Tanghe sewage reservoir in the North China Plain, we conducted a full-spectrum screening of 228 physiochemical indices, 47 nitrogen cycling genes (NCGs) and 2182 metagenome-assembled genomes (MAGs) harboring NCGs. Unmix model identified antibiotic usage, industrial manufacturing, and agricultural practices as the predominant pollution sources, explaining 49.6–92.2 % (averaged 81.0 %) of the variations in aquifer attributes. These activities were primary drivers governing distributions of groundwater NCGs and NCG-hosts, with fragmented denitrification processes being prevalent. Antibiotic usage and industrial activities were probably associated with suppressed nitrogen cycling, while agriculture had a positive effect. Notably, we observed enhanced mutualistic interactions within NCG-hosts and increased enrichment of NCG-antibiotic resistance gene (ARG), NCG-mental resistance gene (MRG), and NCG-ARG-MRG co-hosts under high anthropogenic stresses, suggesting microbial adaptation to optimize nutrient and energy metabolism. This study provided new insight into how groundwater nitrogen cycling responds to anthropogenic disturbances, offering valuable information for developing groundwater management and pollution control strategies.
{"title":"Identifying groundwater anthropogenic disturbances and their predominant impact on microbial nitrogen cycling at a former contamination site adjacent to Baiyangdian Lake","authors":"Sining Zhong , Bin Li , Qian Chen , Jinzheng zhang , Hetong Cai , Rui An , Guohong Liu , Shungui Zhou","doi":"10.1016/j.watres.2025.123544","DOIUrl":"10.1016/j.watres.2025.123544","url":null,"abstract":"<div><div>Groundwater ecosystems face increasing threat from declining water quality due to intensified urbanization, agricultural, and industrial activities. Accurately identifying anthropogenic disturbances remains challenging, and their effects on microbial nitrogen cycling are still largely unknown. Here, by collecting 64 groundwater samples from an aquifer beneath the Tanghe sewage reservoir in the North China Plain, we conducted a full-spectrum screening of 228 physiochemical indices, 47 nitrogen cycling genes (NCGs) and 2182 metagenome-assembled genomes (MAGs) harboring NCGs. Unmix model identified antibiotic usage, industrial manufacturing, and agricultural practices as the predominant pollution sources, explaining 49.6–92.2 % (averaged 81.0 %) of the variations in aquifer attributes. These activities were primary drivers governing distributions of groundwater NCGs and NCG-hosts, with fragmented denitrification processes being prevalent. Antibiotic usage and industrial activities were probably associated with suppressed nitrogen cycling, while agriculture had a positive effect. Notably, we observed enhanced mutualistic interactions within NCG-hosts and increased enrichment of NCG-antibiotic resistance gene (ARG), NCG-mental resistance gene (MRG), and NCG-ARG-MRG co-hosts under high anthropogenic stresses, suggesting microbial adaptation to optimize nutrient and energy metabolism. This study provided new insight into how groundwater nitrogen cycling responds to anthropogenic disturbances, offering valuable information for developing groundwater management and pollution control strategies.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123544"},"PeriodicalIF":11.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678096","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 : 2025-03-23DOI: 10.1016/j.watres.2025.123518
Huanran Liu , Qinyan Yang , Chen Wang , Yang Wu , Li Liu , Guoqing Shen , Qincheng Chen
Microbial fuel cells (MFCs) offer great potential for simultaneous wastewater treatment and energy generation, yet the development of cost-effective and efficient carbon-based cathode alternatives to Pt/C for oxygen reduction reactions remains challenging. This study presents a novel single-atom Fe-decorated N-doped porous carbon (Fe-SA/NBC) synthesized from biogas residue for wastewater treatment. The Fe-SA/NBC demonstrated superior catalytic performance, achieving a kinetic current density of 18.89 mA·cm-² compared to 10.38 mA·cm-² for Pt/C, and an enhanced electrochemical surface area with a Cdl of 1.81 mF·cm-² versus 1.76 mF·cm-² for Pt/C. When integrated into an MFC air-cathode under actual sewage, Fe-SA/NBC outperformed Pt/C, achieving a 22.6 % higher power density (882.92 mW·m-² vs. 719.81 mW·m-²), a higher output voltage (0.53 V vs. 0.47 V), and a longer operational duration (3.6 days vs. 3.2 days). Additionally, Fe-SA/NBC exhibited superior removal efficiencies for chemical oxygen demand and ammonia nitrogen during sewage treatment. In practical applications, MFCs equipped with Fe-SA/NBC successfully powered diodes and timers in series-connected configurations. This study introduces an innovative method for producing cost-effective and efficient cathode catalysts from waste biomass, offering significant potential for wastewater treatment and power generation systems.
{"title":"Single-atom Fe-decorated N-doped porous carbon from waste biomass as a high-performance air-cathode for wastewater treatment in microbial fuel cells","authors":"Huanran Liu , Qinyan Yang , Chen Wang , Yang Wu , Li Liu , Guoqing Shen , Qincheng Chen","doi":"10.1016/j.watres.2025.123518","DOIUrl":"10.1016/j.watres.2025.123518","url":null,"abstract":"<div><div>Microbial fuel cells (MFCs) offer great potential for simultaneous wastewater treatment and energy generation, yet the development of cost-effective and efficient carbon-based cathode alternatives to Pt/C for oxygen reduction reactions remains challenging. This study presents a novel single-atom Fe-decorated N-doped porous carbon (Fe-SA/NBC) synthesized from biogas residue for wastewater treatment. The Fe-SA/NBC demonstrated superior catalytic performance, achieving a kinetic current density of 18.89 mA·cm<sup>-</sup>² compared to 10.38 mA·cm<sup>-</sup>² for Pt/C, and an enhanced electrochemical surface area with a C<sub>dl</sub> of 1.81 mF·cm<sup>-</sup>² versus 1.76 mF·cm<sup>-</sup>² for Pt/C. When integrated into an MFC air-cathode under actual sewage, Fe-SA/NBC outperformed Pt/C, achieving a 22.6 % higher power density (882.92 mW·m<sup>-</sup>² vs. 719.81 mW·m<sup>-</sup>²), a higher output voltage (0.53 V vs. 0.47 V), and a longer operational duration (3.6 days vs. 3.2 days). Additionally, Fe-SA/NBC exhibited superior removal efficiencies for chemical oxygen demand and ammonia nitrogen during sewage treatment. In practical applications, MFCs equipped with Fe-SA/NBC successfully powered diodes and timers in series-connected configurations. This study introduces an innovative method for producing cost-effective and efficient cathode catalysts from waste biomass, offering significant potential for wastewater treatment and power generation systems.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123518"},"PeriodicalIF":11.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675511","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 : 2025-03-22DOI: 10.1016/j.watres.2025.123537
Yongheng Wang , Qingtao Zhang , Jingkun Zhang , Kairong Lin
Urban flooding poses a serious threat to both the ecological environment and human society. Previous studies identified natural and anthropogenic factors as contributors to urban flooding, but little attention has been paid to the influence of urban horizontal and vertical factors. To address this gap, we conducted a comparative analysis of the patterns in spatial distribution of urban flooding in two megacities in eastern China (Beijing and Guangzhou). We then used Pearson's correlation to investigate the associations between flooding events and multiple influencing factors. Finally, two scenarios were designed to quantify the relative contributions of each driver using the Light Gradient Boosting Machine (LightGBM) and Shapley (SHAP) interpretable models. The results show that: (1) urban flooding points in Guangzhou and Beijing are predominantly clustered in central areas, with mid-rise and high-density buildings presenting the highest flood risk. (2) in the base scenario, Annual precipitation (AP) is the primary influencing factor for urban flooding in both Beijing and Guangzhou. However, in the enhanced scenario, the addition of 2D and 3D (two-dimensional and three-dimensional) metrics shifts the main drivers to factors like Aggregation index (AI), Patch density (PD), and Building density (BD), significantly impacting urban flooding. This study highlights the critical impacts of horizontal and vertical urban structures and layouts, emphasizing the need for comprehensive urban planning and design strategies to effectively mitigate flood risk. It also provides new perspectives on urban flood risk management.
{"title":"Impact of 2D and 3D factors on urban flooding: Spatial characteristics and interpretable analysis of drivers","authors":"Yongheng Wang , Qingtao Zhang , Jingkun Zhang , Kairong Lin","doi":"10.1016/j.watres.2025.123537","DOIUrl":"10.1016/j.watres.2025.123537","url":null,"abstract":"<div><div>Urban flooding poses a serious threat to both the ecological environment and human society. Previous studies identified natural and anthropogenic factors as contributors to urban flooding, but little attention has been paid to the influence of urban horizontal and vertical factors. To address this gap, we conducted a comparative analysis of the patterns in spatial distribution of urban flooding in two megacities in eastern China (Beijing and Guangzhou). We then used Pearson's correlation to investigate the associations between flooding events and multiple influencing factors. Finally, two scenarios were designed to quantify the relative contributions of each driver using the Light Gradient Boosting Machine (LightGBM) and Shapley (SHAP) interpretable models. The results show that: (1) urban flooding points in Guangzhou and Beijing are predominantly clustered in central areas, with mid-rise and high-density buildings presenting the highest flood risk. (2) in the base scenario, Annual precipitation (AP) is the primary influencing factor for urban flooding in both Beijing and Guangzhou. However, in the enhanced scenario, the addition of 2D and 3D (two-dimensional and three-dimensional) metrics shifts the main drivers to factors like Aggregation index (AI), Patch density (PD), and Building density (BD), significantly impacting urban flooding. This study highlights the critical impacts of horizontal and vertical urban structures and layouts, emphasizing the need for comprehensive urban planning and design strategies to effectively mitigate flood risk. It also provides new perspectives on urban flood risk management.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123537"},"PeriodicalIF":11.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675403","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 : 2025-03-22DOI: 10.1016/j.watres.2025.123530
Wentao Li , Yue Hu , Yangang Li , Wenzhen Zhang , Mengkai Li , Jun Hu , Weiwei Ben , Zhimin Qiang
This study investigated the impacts of rainstorms on the performance of a combined ultrafiltration (UF)-ozonation (O3) process for micropollutant removal and risk mitigation during municipal wastewater reclamation. Results reveal that the rainstorm triggered a substantial surge in dissolved organic matter (DOM) in secondary effluent, primarily composed of protein-like substances and terrestrial humus. Meanwhile, 12 commonly detected pharmaceuticals and personal care products (PPCPs) were found at concentrations slightly lower than in normal weather, ranging from 5.0 to 545.0 ng L−1. Following the rainstorm, the overall removals of PPCPs spanned a wide range of 14.8 %–77.7 %, where a significantly lower retention of high molecular-weight pollutants (e.g., ≥ 400 Da) was observed for UF. For the ozonation unit, the removals remained comparable, while the relative contribution of radical oxidation increased. This shift was related to the enhanced generation of HO• and/or other reactive species, driven by the enrichment of unsaturated proteins (originating from upstream sludge loss) as precursors. Higher concentrations of disinfection by-products (DBPs), reaching up to 1372.5 μg L−1, were observed in chlorinated effluents after the rainstorm, ascribing to the elevated content of terrestrial humus persisting through the treatments. While the risks associated with PPCPs were negligible, the formed DBPs posed considerable risks to human health (with cancer risk at 10−5) and aquatic ecosystem (with risk quotient up to 13.6), particularly post ozonation. These findings highlight the role of rainstorm-fueled DOM in reclaimed water quality and provide insights into ensuring reclaimed water safety under different weather conditions.
{"title":"Performance of ultrafiltration-ozonation for municipal wastewater reclamation under rainstorm conditions: Impacts of DOM surge on micropollutant removal and associated risks","authors":"Wentao Li , Yue Hu , Yangang Li , Wenzhen Zhang , Mengkai Li , Jun Hu , Weiwei Ben , Zhimin Qiang","doi":"10.1016/j.watres.2025.123530","DOIUrl":"10.1016/j.watres.2025.123530","url":null,"abstract":"<div><div>This study investigated the impacts of rainstorms on the performance of a combined ultrafiltration (UF)-ozonation (O<sub>3</sub>) process for micropollutant removal and risk mitigation during municipal wastewater reclamation. Results reveal that the rainstorm triggered a substantial surge in dissolved organic matter (DOM) in secondary effluent, primarily composed of protein-like substances and terrestrial humus. Meanwhile, 12 commonly detected pharmaceuticals and personal care products (PPCPs) were found at concentrations slightly lower than in normal weather, ranging from 5.0 to 545.0 ng L<sup>−1</sup>. Following the rainstorm, the overall removals of PPCPs spanned a wide range of 14.8 %–77.7 %, where a significantly lower retention of high molecular-weight pollutants (e.g., ≥ 400 Da) was observed for UF. For the ozonation unit, the removals remained comparable, while the relative contribution of radical oxidation increased. This shift was related to the enhanced generation of HO<sup>•</sup> and/or other reactive species, driven by the enrichment of unsaturated proteins (originating from upstream sludge loss) as precursors. Higher concentrations of disinfection by-products (DBPs), reaching up to 1372.5 μg L<sup>−1</sup>, were observed in chlorinated effluents after the rainstorm, ascribing to the elevated content of terrestrial humus persisting through the treatments. While the risks associated with PPCPs were negligible, the formed DBPs posed considerable risks to human health (with cancer risk at 10<sup>−5</sup>) and aquatic ecosystem (with risk quotient up to 13.6), particularly post ozonation. These findings highlight the role of rainstorm-fueled DOM in reclaimed water quality and provide insights into ensuring reclaimed water safety under different weather conditions.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123530"},"PeriodicalIF":11.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675368","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 : 2025-03-22DOI: 10.1016/j.watres.2025.123539
Zhaoxu Peng , Yuemei Lin , Mark C.M. van Loosdrecht , Merle K. de Kreuk
The aerobic granular sludge (AGS) is an emerging technology widely spread, since most organic matters in actual domestic sewage were particulate matters, this study aims to determine whether the attachment between micro particles and different sized AGS was influenced by granule surface area. The attachment of micro particles by different sized AGS (2.0–5.0 mm) were investigated. Furthermore, to simulate the attachment by broken fragments of AGS, complete 4.0–5.0 mm AGS were cut into 2,4, and 8 pieces, and the attachment performance between the broken pieces and similar sized complete AGS were compared. Fourier transform infrared (FTIR) and fluorescence staining were applied to analyze the chemical bonds and amyloid-glucan like structure of AGS from outside to inside. The results showed the 3.1–4.0 mm AGS had the best surface area attachment of micro particles, followed by the 2.5–3.1 mm AGS. The attachment performance of micro particles was not determined by specific surface area, but was closely related to the surface roughness caused by the amyloid-glucan like structure. The distribution density of amyloid-glucan like structure decreased from outside to inside, and if an granule was broken into pieces during aeration, micro particles were preferential to be attached by the outer layer of the broken pieces from the initial granule. The micro particles attachment showed little relationship with the hydrophilicity of AGS surface, either the outer layer or the inner layer. This study highlighted the crucial role of AGS outer layer in micro particle attachment, particularly the broken pieces from the original AGS outer layer, which facilitate to attach micro particles and contribute to form new granules.
{"title":"Attachment performance between micro particles and different sized aerobic granular sludge - from outside to inside","authors":"Zhaoxu Peng , Yuemei Lin , Mark C.M. van Loosdrecht , Merle K. de Kreuk","doi":"10.1016/j.watres.2025.123539","DOIUrl":"10.1016/j.watres.2025.123539","url":null,"abstract":"<div><div>The aerobic granular sludge (AGS) is an emerging technology widely spread, since most organic matters in actual domestic sewage were particulate matters, this study aims to determine whether the attachment between micro particles and different sized AGS was influenced by granule surface area. The attachment of micro particles by different sized AGS (2.0–5.0 mm) were investigated. Furthermore, to simulate the attachment by broken fragments of AGS, complete 4.0–5.0 mm AGS were cut into 2,4, and 8 pieces, and the attachment performance between the broken pieces and similar sized complete AGS were compared. Fourier transform infrared (FTIR) and fluorescence staining were applied to analyze the chemical bonds and amyloid-glucan like structure of AGS from outside to inside. The results showed the 3.1–4.0 mm AGS had the best surface area attachment of micro particles, followed by the 2.5–3.1 mm AGS. The attachment performance of micro particles was not determined by specific surface area, but was closely related to the surface roughness caused by the amyloid-glucan like structure. The distribution density of amyloid-glucan like structure decreased from outside to inside, and if an granule was broken into pieces during aeration, micro particles were preferential to be attached by the outer layer of the broken pieces from the initial granule. The micro particles attachment showed little relationship with the hydrophilicity of AGS surface, either the outer layer or the inner layer. This study highlighted the crucial role of AGS outer layer in micro particle attachment, particularly the broken pieces from the original AGS outer layer, which facilitate to attach micro particles and contribute to form new granules.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123539"},"PeriodicalIF":11.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-22DOI: 10.1016/j.watres.2025.123536
Yu Bai , Dandan Shen , Dongjing Huang
Artificial floating beds are widely recognized as an effective ecological approach for river water quality management. However, prior research has predominantly focused on pollutant retention efficiency across vegetation types, leaving the pollutant diffusion dynamics influenced by flexible-rooted vegetation underexplored. This study bridges this gap by investigating solute transport mechanisms in artificial floating bed channels with flexible vegetation roots through integrated indoor flume experiments and numerical simulations. A novel hybrid model, combining the lattice Boltzmann method for hydrodynamic simulation and the random displacement model for solute transport, was developed to quantify the vertical heterogeneity of pollutant diffusion coefficients. Experiments involved three bionic vegetation types with varying root morphologies, and solute transport was monitored using planar laser-induced fluorescence. Key findings revealed that flow velocity within the vegetation root zone was significantly reduced, particularly for vegetation with higher drag coefficients (e.g., Plant 2). The characteristic root diameter d50 was identified as the optimal parameter for simulating diffusion coefficients, achieving high accuracy. Vertical root distribution variance was incorporated into the diffusion model, enhancing simulation precision. Results demonstrated distinct pollutant dispersion patterns depending on source depth and vegetation type, with non-vegetated zones adhering to Gaussian concentration distributions. This study provides critical theoretical insights into pollutant transport mechanisms in flexible-rooted artificial floating beds, offering a foundation for optimizing artificial floating beds design and placement to improve water quality management strategies. Future work should validate these findings through outdoor experiments and integrate pollutant retention modules for practical applications.
{"title":"Vertical heterogeneity and flexible root dynamics in pollutant transport: A hybrid lattice Boltzmann method - random displacement model approach for optimizing artificial floating bed design","authors":"Yu Bai , Dandan Shen , Dongjing Huang","doi":"10.1016/j.watres.2025.123536","DOIUrl":"10.1016/j.watres.2025.123536","url":null,"abstract":"<div><div>Artificial floating beds are widely recognized as an effective ecological approach for river water quality management. However, prior research has predominantly focused on pollutant retention efficiency across vegetation types, leaving the pollutant diffusion dynamics influenced by flexible-rooted vegetation underexplored. This study bridges this gap by investigating solute transport mechanisms in artificial floating bed channels with flexible vegetation roots through integrated indoor flume experiments and numerical simulations. A novel hybrid model, combining the lattice Boltzmann method for hydrodynamic simulation and the random displacement model for solute transport, was developed to quantify the vertical heterogeneity of pollutant diffusion coefficients. Experiments involved three bionic vegetation types with varying root morphologies, and solute transport was monitored using planar laser-induced fluorescence. Key findings revealed that flow velocity within the vegetation root zone was significantly reduced, particularly for vegetation with higher drag coefficients (e.g., Plant 2). The characteristic root diameter <em>d</em><sub>50<!--> </sub> was identified as the optimal parameter for simulating diffusion coefficients, achieving high accuracy. Vertical root distribution variance was incorporated into the diffusion model, enhancing simulation precision. Results demonstrated distinct pollutant dispersion patterns depending on source depth and vegetation type, with non-vegetated zones adhering to Gaussian concentration distributions. This study provides critical theoretical insights into pollutant transport mechanisms in flexible-rooted artificial floating beds, offering a foundation for optimizing artificial floating beds design and placement to improve water quality management strategies. Future work should validate these findings through outdoor experiments and integrate pollutant retention modules for practical applications.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123536"},"PeriodicalIF":11.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675370","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 : 2025-03-22DOI: 10.1016/j.watres.2025.123540
Xinyi Wang , Jiyang Liu , Songyang Li , Yaqin Miao , Yuting Shen , Hu Cui , Shengnan Hou , Hui Zhu
Reactive intermediates (RIs) are critical in nutrient cycling and pollution mitigation, yet their behavior in salinized agricultural waters remains underexplored. This study investigates RIs formation in rice cultivation water from a typical saline-alkali region in China. Singlet oxygen was more pH-sensitive than hydroxyl radical (•OH), while triplet excited-state dissolved organic matter were more influenced by salinity. Steady-state •OH concentration ([•OH]ss) correlated strongly with concentrations of nitrite ([NO2--N]) and nitrate ([NO3--N]), with photolysis of NO2- and NO3-, and DOM contributing 19.50 %, 6.93 %, and 73.57 % to •OH formation, respectively. [RIs]ss positively correlated with fluorescence index and negatively with autochthonous index, indicating exogenous DOM as a major RIs source. Additionally, [•OH]ss was linked to aromatic content and DOM molecular weight, highlighting the importance of DOM structure in •OH production. These findings clarify the formation pathways of RIs in saline-alkali waters, informing ecological restoration and environmental management.
{"title":"Mechanisms of reactive intermediates formation in saline-alkali agricultural waters","authors":"Xinyi Wang , Jiyang Liu , Songyang Li , Yaqin Miao , Yuting Shen , Hu Cui , Shengnan Hou , Hui Zhu","doi":"10.1016/j.watres.2025.123540","DOIUrl":"10.1016/j.watres.2025.123540","url":null,"abstract":"<div><div>Reactive intermediates (RIs) are critical in nutrient cycling and pollution mitigation, yet their behavior in salinized agricultural waters remains underexplored. This study investigates RIs formation in rice cultivation water from a typical saline-alkali region in China. Singlet oxygen was more pH-sensitive than hydroxyl radical (•OH), while triplet excited-state dissolved organic matter were more influenced by salinity. Steady-state •OH concentration ([•OH]<sub>ss</sub>) correlated strongly with concentrations of nitrite ([NO<sub>2</sub><sup>-</sup>-N]) and nitrate ([NO<sub>3</sub><sup>-</sup>-N]), with photolysis of NO<sub>2</sub><sup>-</sup> and NO<sub>3</sub><sup>-</sup>, and DOM contributing 19.50 %, 6.93 %, and 73.57 % to •OH formation, respectively. [RIs]<sub>ss</sub> positively correlated with fluorescence index and negatively with autochthonous index, indicating exogenous DOM as a major RIs source. Additionally, [•OH]<sub>ss</sub> was linked to aromatic content and DOM molecular weight, highlighting the importance of DOM structure in •OH production. These findings clarify the formation pathways of RIs in saline-alkali waters, informing ecological restoration and environmental management.</div></div>","PeriodicalId":443,"journal":{"name":"Water Research","volume":"280 ","pages":"Article 123540"},"PeriodicalIF":11.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675366","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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