Pub Date : 2024-11-19DOI: 10.1016/j.wroa.2024.100283
Gabriel López Porras , Patrick Allard
In response to water scarcity in Mexico´s urban areas, authorities have implemented significant measures to increase water access, primarily by overexploiting groundwater resources. However, this approach has unintentionally worsened human exposure to groundwater arsenic consumption, which is part of a broader phenomenon known as environmental problem shifting. This paper examines the public health implications of arsenic contamination in Mexico's groundwater. We particularly focus our analysis on urban areas to demonstrate the policy gap that leaves the issue of arsenic contamination caused by over-pumping, and its associated widespread health risks, largely unaddressed. We draw on evidence from Mexico, but also Bangladesh, to define and describe the issue of such problem-shifting and how it underlies the urgent need to develop integrative water management strategies that balance the demands of water access with the necessity of maintaining water quality. By analysing water data from Mexico, the paper calls for a reconsideration of water policies to prevent further health crises.
{"title":"Making waves: Public health risks from arsenic in Mexico's water extraction practices","authors":"Gabriel López Porras , Patrick Allard","doi":"10.1016/j.wroa.2024.100283","DOIUrl":"10.1016/j.wroa.2024.100283","url":null,"abstract":"<div><div>In response to water scarcity in Mexico´s urban areas, authorities have implemented significant measures to increase water access, primarily by overexploiting groundwater resources. However, this approach has unintentionally worsened human exposure to groundwater arsenic consumption, which is part of a broader phenomenon known as environmental problem shifting. This paper examines the public health implications of arsenic contamination in Mexico's groundwater. We particularly focus our analysis on urban areas to demonstrate the policy gap that leaves the issue of arsenic contamination caused by over-pumping, and its associated widespread health risks, largely unaddressed. We draw on evidence from Mexico, but also Bangladesh, to define and describe the issue of such problem-shifting and how it underlies the urgent need to develop integrative water management strategies that balance the demands of water access with the necessity of maintaining water quality. By analysing water data from Mexico, the paper calls for a reconsideration of water policies to prevent further health crises.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"26 ","pages":"Article 100283"},"PeriodicalIF":7.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-17DOI: 10.1016/j.wroa.2024.100281
Wei Wang , Zhongshi He , Junping Lv , Xudong Liu , Shulian Xie , Jia Feng
Phytoplankton are vital components of freshwater ecosystems, serving as primary producers and ecological indicators of freshwater health. While substantial research has explored the dynamics and potential drivers of phytoplankton communities in freshwater lakes, the influence of altitude—a crucial geographic factor—remains unelucidated. In this study, we investigated 26 lakes located along the eastern section of the Hu Line (Heihe–Tengchong Line) from China, focusing on how altitudinal gradients shape phytoplankton communities. Our findings reveal that cyanobacteria increasingly dominate community abundance with rising altitude. However, this dominance results in a reduction of community diversity, as cyanobacteria outcompete other taxa, thereby narrowing the ecological niches available. Further analysis indicates that the effects of altitude are mediated primarily by dominant cyanobacteria, which are equipped with gas vesicles that provide an adaptive advantage under low atmospheric pressure conditions associated with higher altitudes. This physiological trait allows cyanobacteria to maintain buoyancy and occupy favorable niches in the water column, enhancing their proliferation at the expense of overall community diversity. The study underscores the critical role of altitude in modulating phytoplankton community structure through its direct influence on cyanobacteria. These findings contribute new insights into the ecological processes that regulate freshwater ecosystems across altitudinal gradients, and highlight the need for targeted management strategies in regions where cyanobacterial dominance (cyanobacterial blooms) may compromise water quality and biodiversity.
{"title":"Cyanobacteria as dominant mediator of altitudinal gradient effects on phytoplankton community diversity in freshwater ecosystems: Evidences from the freshwater Lakes along the Hu Line","authors":"Wei Wang , Zhongshi He , Junping Lv , Xudong Liu , Shulian Xie , Jia Feng","doi":"10.1016/j.wroa.2024.100281","DOIUrl":"10.1016/j.wroa.2024.100281","url":null,"abstract":"<div><div>Phytoplankton are vital components of freshwater ecosystems, serving as primary producers and ecological indicators of freshwater health. While substantial research has explored the dynamics and potential drivers of phytoplankton communities in freshwater lakes, the influence of altitude—a crucial geographic factor—remains unelucidated. In this study, we investigated 26 lakes located along the eastern section of the Hu Line (Heihe–Tengchong Line) from China, focusing on how altitudinal gradients shape phytoplankton communities. Our findings reveal that cyanobacteria increasingly dominate community abundance with rising altitude. However, this dominance results in a reduction of community diversity, as cyanobacteria outcompete other taxa, thereby narrowing the ecological niches available. Further analysis indicates that the effects of altitude are mediated primarily by dominant cyanobacteria, which are equipped with gas vesicles that provide an adaptive advantage under low atmospheric pressure conditions associated with higher altitudes. This physiological trait allows cyanobacteria to maintain buoyancy and occupy favorable niches in the water column, enhancing their proliferation at the expense of overall community diversity. The study underscores the critical role of altitude in modulating phytoplankton community structure through its direct influence on cyanobacteria. These findings contribute new insights into the ecological processes that regulate freshwater ecosystems across altitudinal gradients, and highlight the need for targeted management strategies in regions where cyanobacterial dominance (cyanobacterial blooms) may compromise water quality and biodiversity.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"26 ","pages":"Article 100281"},"PeriodicalIF":7.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-12DOI: 10.1016/j.wroa.2024.100278
Jingyu Ge , Jiuling Li , Ruihong Qiu , Tao Shi , Zi Huang , Yanchen Liu , Zhiguo Yuan
Accurate diagnosis of sewer inflow and infiltration (I/I) is crucial for ensuring the safe transportation of sewage and the stability of wastewater treatment processes. Identifying periods impacted by I/I is essential for I/I diagnosis, but current methods lack a standard criterion and require adaptation to specific conditions, resulting in low accuracy, complexity, and limited generalizability. This paper proposes a novel approach to distinguish I/I periods from time series of sewer measurements based on anomaly detection theory through an iterative use of a time-series reconstruction model. This method eliminates the need for external data such as rainfalls and avoids intensive manual data analysis. Operating directly on in-sewer data, it enhances accuracy compared to existing approaches and is applicable to various external factors such as rainfall, snowmelt, and seawater intrusion. The method can be applicable to a broad range of monitoring data, including flow rate, temperature, and conductivity. Validated through simulation studies and demonstrated via real-life applications, this method offers an efficient solution for I/I detection, facilitating further I/I diagnosis, including I/I quantification and location identification.
{"title":"Identifying periods impacted by sewer inflow and infiltration using time series anomaly detection","authors":"Jingyu Ge , Jiuling Li , Ruihong Qiu , Tao Shi , Zi Huang , Yanchen Liu , Zhiguo Yuan","doi":"10.1016/j.wroa.2024.100278","DOIUrl":"10.1016/j.wroa.2024.100278","url":null,"abstract":"<div><div>Accurate diagnosis of sewer inflow and infiltration (I/I) is crucial for ensuring the safe transportation of sewage and the stability of wastewater treatment processes. Identifying periods impacted by I/I is essential for I/I diagnosis, but current methods lack a standard criterion and require adaptation to specific conditions, resulting in low accuracy, complexity, and limited generalizability. This paper proposes a novel approach to distinguish I/I periods from time series of sewer measurements based on anomaly detection theory through an iterative use of a time-series reconstruction model. This method eliminates the need for external data such as rainfalls and avoids intensive manual data analysis. Operating directly on in-sewer data, it enhances accuracy compared to existing approaches and is applicable to various external factors such as rainfall, snowmelt, and seawater intrusion. The method can be applicable to a broad range of monitoring data, including flow rate, temperature, and conductivity. Validated through simulation studies and demonstrated via real-life applications, this method offers an efficient solution for I/I detection, facilitating further I/I diagnosis, including I/I quantification and location identification.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100278"},"PeriodicalIF":7.2,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-10DOI: 10.1016/j.wroa.2024.100276
Gang Fang , Daoping Huang , Zhiying Wu , Yan Chen , Yan Li , Yiqi Liu
Real-time monitoring of key quality variables is essential and crucial for stable and safe operations of wastewater treatment plants (WWTPs). Next generation reservoir computing (NG-RC) has recently garnered significant attention in quality prediction, such as COD and BOD, as an effective alternative to traditional reservoir computing (RC), then is able to act as a data-driven soft sensor to twin a hardware sensor for quality variable measurements. Unlike RC, NG-RC does not require random sampling matrices to define the weights of recurrent neural networks and has fewer hyperparameters. However, NG-RC is usually used online but trained offline, thus leading to model degradation under dynamic scenarios. This paper proposes a sparse online NG-RC approach to meet the real-time requirements of WWTPs and mitigate the impact of measurement noise on the model. First, inspired by the Woodbury matrix identity, an incremental strategy is designed, using sequentially arriving data blocks to learn the output weights of NG-RC online. Then, an ensemble sparse strategy is combined to alleviate overfitting issues of the prediction model. Moreover, a soft sensor based on the ensemble sparse online NG-RC is developed to perform real-time prediction of quality indicators in wastewater treatment processes. Finally, two datasets from actual WWTPs are used to validate the effectiveness of the proposed model.
{"title":"Effluent quality soft sensor for wastewater treatment plant with ensemble sparse learning-based online next generation reservoir computing","authors":"Gang Fang , Daoping Huang , Zhiying Wu , Yan Chen , Yan Li , Yiqi Liu","doi":"10.1016/j.wroa.2024.100276","DOIUrl":"10.1016/j.wroa.2024.100276","url":null,"abstract":"<div><div>Real-time monitoring of key quality variables is essential and crucial for stable and safe operations of wastewater treatment plants (WWTPs). Next generation reservoir computing (NG-RC) has recently garnered significant attention in quality prediction, such as COD and BOD, as an effective alternative to traditional reservoir computing (RC), then is able to act as a data-driven soft sensor to twin a hardware sensor for quality variable measurements. Unlike RC, NG-RC does not require random sampling matrices to define the weights of recurrent neural networks and has fewer hyperparameters. However, NG-RC is usually used online but trained offline, thus leading to model degradation under dynamic scenarios. This paper proposes a sparse online NG-RC approach to meet the real-time requirements of WWTPs and mitigate the impact of measurement noise on the model. First, inspired by the Woodbury matrix identity, an incremental strategy is designed, using sequentially arriving data blocks to learn the output weights of NG-RC online. Then, an ensemble sparse strategy is combined to alleviate overfitting issues of the prediction model. Moreover, a soft sensor based on the ensemble sparse online NG-RC is developed to perform real-time prediction of quality indicators in wastewater treatment processes. Finally, two datasets from actual WWTPs are used to validate the effectiveness of the proposed model.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100276"},"PeriodicalIF":7.2,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-08DOI: 10.1016/j.wroa.2024.100274
Xiao Zhou , Yacan Man , Shuming Liu , Juan Zhang , Rui Yuan , Wei Wang , Kuizu Su
Data missing and anomalies in monitoring equipment have become critical barriers to developing intelligent Water Supply Systems (WSS). The valid data preceding and after the missing segments can be utilized to impute missing values. However, traditional imputation methods, such as linear interpolation and prediction-based methods, have limited capacity to use data relationships or can only utilize information before the missing values. Therefore, existing methods still need to work on efficiently and conveniently achieving high-accuracy imputation. According to the continuity and periodicity of WSS data, missing values often exhibit multi-level correlations with valid data. This paper innovatively employs graph structures to analyze the multi-level correlations at different timestamps and applies graph signal sampling algorithms to extract low-frequency features for imputation. A novel Graph-based Data Imputation (GDI) method has been developed, which leverages multi-level correlations to propagate information and completes imputation tasks without requiring complex feature engineering and pre-training processes. Results indicate that GDI outperforms Holt-Winters, Support Vector Regression, and Gated Recurrent Unit in the task of imputing continuous missing data. It can still achieve even when the proportion of missing values reaches 80 %. These results demonstrate that GDI ensures a more streamlined and efficient imputation with high robustness and accuracy.
{"title":"Leveraging multi-level correlations for imputing monitoring data in water supply systems using graph signal sampling theory","authors":"Xiao Zhou , Yacan Man , Shuming Liu , Juan Zhang , Rui Yuan , Wei Wang , Kuizu Su","doi":"10.1016/j.wroa.2024.100274","DOIUrl":"10.1016/j.wroa.2024.100274","url":null,"abstract":"<div><div>Data missing and anomalies in monitoring equipment have become critical barriers to developing intelligent Water Supply Systems (WSS). The valid data preceding and after the missing segments can be utilized to impute missing values. However, traditional imputation methods, such as linear interpolation and prediction-based methods, have limited capacity to use data relationships or can only utilize information before the missing values. Therefore, existing methods still need to work on efficiently and conveniently achieving high-accuracy imputation. According to the continuity and periodicity of WSS data, missing values often exhibit multi-level correlations with valid data. This paper innovatively employs graph structures to analyze the multi-level correlations at different timestamps and applies graph signal sampling algorithms to extract low-frequency features for imputation. A novel Graph-based Data Imputation (GDI) method has been developed, which leverages multi-level correlations to propagate information and completes imputation tasks without requiring complex feature engineering and pre-training processes. Results indicate that GDI outperforms Holt-Winters, Support Vector Regression, and Gated Recurrent Unit in the task of imputing continuous missing data. It can still achieve <span><math><mrow><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup><mo>></mo><mn>0.8</mn></mrow></math></span> even when the proportion of missing values reaches 80 %. These results demonstrate that GDI ensures a more streamlined and efficient imputation with high robustness and accuracy.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100274"},"PeriodicalIF":7.2,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-06DOI: 10.1016/j.wroa.2024.100277
Zhiqiang Zuo , Tianyi Zhang , Xin Huang , Xiaotong Cen , Xi Lu , Tao Liu , Ho Kyong Shon , Min Zheng
Nutrient resources contained in human urine have great potential to alleviate global agricultural fertilizer demand. Microbial nitrification is a recognized strategy for stabilizing urine ammonia into ammonium nitrate, a common fertilizer worldwide, but faces a core bottleneck of process instability due to microbial inhibition. This study reports a new approach by developing a hybrid oxidation process involving three stages—microbial ammonia oxidation, chemical nitrite oxidation and microbial nitrite oxidation. Candidatus Nitrosoglobus, a γ-proteobacterial ammonia oxidizer highly tolerant to free nitrous acid, was introduced in the first stage to oxidize half of the total ammonia in the influent (8 g NH4+-N/L) to nitrite. The nitrite was then chemically oxidized by using hydrogen peroxide via a rapid chemical reaction to form nitrate. The third stage, microbial nitrite oxidation, was employed to ensure the complete removal of residual nitrite following chemical oxidation. The overall concept demonstrated in this work showcased the robust performance of the hybrid system. Moreover, the system also had a dual advantage in achieving antimicrobial ability in the first and second stages, making treated urine a safe fertilizer.
{"title":"A hybrid oxidation approach for converting high-strength urine ammonia into ammonium nitrate","authors":"Zhiqiang Zuo , Tianyi Zhang , Xin Huang , Xiaotong Cen , Xi Lu , Tao Liu , Ho Kyong Shon , Min Zheng","doi":"10.1016/j.wroa.2024.100277","DOIUrl":"10.1016/j.wroa.2024.100277","url":null,"abstract":"<div><div>Nutrient resources contained in human urine have great potential to alleviate global agricultural fertilizer demand. Microbial nitrification is a recognized strategy for stabilizing urine ammonia into ammonium nitrate, a common fertilizer worldwide, but faces a core bottleneck of process instability due to microbial inhibition. This study reports a new approach by developing a hybrid oxidation process involving three stages—microbial ammonia oxidation, chemical nitrite oxidation and microbial nitrite oxidation. <em>Candidatus</em> Nitrosoglobus, a <em>γ</em>-proteobacterial ammonia oxidizer highly tolerant to free nitrous acid, was introduced in the first stage to oxidize half of the total ammonia in the influent (8 g NH<sub>4</sub><sup>+</sup>-N/L) to nitrite. The nitrite was then chemically oxidized by using hydrogen peroxide via a rapid chemical reaction to form nitrate. The third stage, microbial nitrite oxidation, was employed to ensure the complete removal of residual nitrite following chemical oxidation. The overall concept demonstrated in this work showcased the robust performance of the hybrid system. Moreover, the system also had a dual advantage in achieving antimicrobial ability in the first and second stages, making treated urine a safe fertilizer.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100277"},"PeriodicalIF":7.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-11-01DOI: 10.1016/j.wroa.2024.100275
Suwan Dai , Haixiao Guo , Yiming Li , Jiaqi Hou , Yufen Wang , Tingting Zhu , Bing-Jie Ni , Yiwen Liu
Sulfidogenic and methanogenic processes are undesirable in sewer management, yet the derived problems regarding organic losses are often neglected. Traditional chemical dosing methods aimed at sulfide and methane control commonly involve similar mechanisms of oxidation and/or precipitation. Moreover, previous focuses were centered on elevating control efficacy rather than investigating interactions between dosed chemicals and biofilms. In this work, organic silicon quaternary ammonium salt (QSA) of 75 mg-N/L was firstly applied in laboratory pressurized sewer reactors. After three dosing events, it took 20 days for sulfidogenic activities to recover to 50 % without further elevations. Meantime, methanogenic activities were stable ca. 11 % without significant inclinations to recover. Notably, consumption rate of chemical oxygen demand (COD) was suppressed to 50 % at most, and no microbial resistance to QSA but better control efficacy was observed. Characterizations of physicochemistry, microbial community and metabolism were conducted to elucidate mechanisms. Results showed that QSA was attached on sewer biofilms via electrostatic attraction to exert enduring control efficacy. Biofilms tended to become more hydrophobic and compact after QSA exposure. Microbial analyses indicated that relative abundances of microbes regarding hydrolysis, acidogenesis and methanogenesis were sharply decreased together with down-regulation of pivotal enzymatic activities. Additionally, denitrification batch tests initially suggested that the biodegradability of effluent was significantly enhanced, which ensured the safety of QSA dosing into sewers. Overall, results of this work were expected to lay a theoretical foundation on employing QSA to wastewater management.
{"title":"Application of organic silicon quaternary ammonium salt (QSA) to reduce carbon footprint of sewers: Long-term inhibition on sulfidogenesis and methanogenesis","authors":"Suwan Dai , Haixiao Guo , Yiming Li , Jiaqi Hou , Yufen Wang , Tingting Zhu , Bing-Jie Ni , Yiwen Liu","doi":"10.1016/j.wroa.2024.100275","DOIUrl":"10.1016/j.wroa.2024.100275","url":null,"abstract":"<div><div>Sulfidogenic and methanogenic processes are undesirable in sewer management, yet the derived problems regarding organic losses are often neglected. Traditional chemical dosing methods aimed at sulfide and methane control commonly involve similar mechanisms of oxidation and/or precipitation. Moreover, previous focuses were centered on elevating control efficacy rather than investigating interactions between dosed chemicals and biofilms. In this work, organic silicon quaternary ammonium salt (QSA) of 75 mg-N/L was firstly applied in laboratory pressurized sewer reactors. After three dosing events, it took 20 days for sulfidogenic activities to recover to 50 % without further elevations. Meantime, methanogenic activities were stable ca. 11 % without significant inclinations to recover. Notably, consumption rate of chemical oxygen demand (COD) was suppressed to 50 % at most, and no microbial resistance to QSA but better control efficacy was observed. Characterizations of physicochemistry, microbial community and metabolism were conducted to elucidate mechanisms. Results showed that QSA was attached on sewer biofilms via electrostatic attraction to exert enduring control efficacy. Biofilms tended to become more hydrophobic and compact after QSA exposure. Microbial analyses indicated that relative abundances of microbes regarding hydrolysis, acidogenesis and methanogenesis were sharply decreased together with down-regulation of pivotal enzymatic activities. Additionally, denitrification batch tests initially suggested that the biodegradability of effluent was significantly enhanced, which ensured the safety of QSA dosing into sewers. Overall, results of this work were expected to lay a theoretical foundation on employing QSA to wastewater management.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100275"},"PeriodicalIF":7.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-30DOI: 10.1016/j.wroa.2024.100271
Kyle D. Rauch , Sean A. MacIsaac , Bailey Reid , Toni J. Mullin , Ariel J Atkinson , Anthony L Pimentel , Amina K. Stoddart , Karl G. Linden , Graham A. Gagnon
UV light emitting diode (LED) disinfection technologies have advanced over the last decade and expanded the design space for applications in point of use, industrial, and now full-scale water treatment. This literature review examines the progression of UV LED technologies from 2007 to 2023 using key features such as total optical power, price, and wall-plug efficiency. The review found that optical power is increasing while the price per Watt is decreasing; however, the wall plug energy (WPE) is slowly improving over the last decade. These factors govern the feasibility of many UV LEDs applications and establish the current state of the art for these technologies. An analysis of inactivation rate constants for low-pressure, medium-pressure, and UV LED sources was undertaken and provides a comprehensive view of how current UV LED technologies compare to traditional technologies. This comparison found that UV LEDs perform comparably vs conventional UV technologies when disinfecting bacteria and viruses. Furthermore, comparison of reported reduction equivalent fluences for UV LED flow-through reactors at the bench-, pilot-, and full-scale were explored in this review, and it was found that LED treatment is becoming more effective at handling increased flowrates and has been proven to work at full-scale. UV LEDs do however require additional research into the impacts of water matrices at different wavelengths and the impact that each available LED wavelength has on disinfection. Overall, this work provides a broad assessment of UV disinfection technologies and serves as a state-of-the-art reference document for those who are interested in understanding this rapidly developing technology.
紫外线发光二极管 (LED) 消毒技术在过去十年中取得了长足进步，为使用点、工业以及现在的全面水处理应用拓展了设计空间。本文献综述利用总光功率、价格和壁插效率等关键特性，研究了紫外线 LED 技术从 2007 年到 2023 年的发展情况。综述发现，光功率在不断增加，而每瓦价格却在不断下降；不过，在过去十年中，壁插能量（WPE）却在缓慢提高。这些因素决定了许多紫外发光二极管应用的可行性，并确定了这些技术的现状。我们对低压、中压和紫外 LED 光源的灭活率常数进行了分析，全面了解了当前紫外 LED 技术与传统技术的比较情况。比较发现，紫外线 LED 与传统紫外线技术在消毒细菌和病毒方面的性能相当。此外，本综述还探讨了紫外 LED 直通式反应器在台式、中试和全规模试验中的减排等效通量比较，发现 LED 处理在处理增大的流速方面越来越有效，并已被证明可在全规模试验中发挥作用。不过，紫外线 LED 还需要进一步研究不同波长对水基质的影响，以及每种可用 LED 波长对消毒的影响。总之，这项研究对紫外线消毒技术进行了广泛的评估，为有兴趣了解这项快速发展的技术的人提供了最新的参考文件。
{"title":"A critical review of ultra-violet light emitting diodes as a one water disinfection technology","authors":"Kyle D. Rauch , Sean A. MacIsaac , Bailey Reid , Toni J. Mullin , Ariel J Atkinson , Anthony L Pimentel , Amina K. Stoddart , Karl G. Linden , Graham A. Gagnon","doi":"10.1016/j.wroa.2024.100271","DOIUrl":"10.1016/j.wroa.2024.100271","url":null,"abstract":"<div><div>UV light emitting diode (LED) disinfection technologies have advanced over the last decade and expanded the design space for applications in point of use, industrial, and now full-scale water treatment. This literature review examines the progression of UV LED technologies from 2007 to 2023 using key features such as total optical power, price, and wall-plug efficiency. The review found that optical power is increasing while the price per Watt is decreasing; however, the wall plug energy (WPE) is slowly improving over the last decade. These factors govern the feasibility of many UV LEDs applications and establish the current state of the art for these technologies. An analysis of inactivation rate constants for low-pressure, medium-pressure, and UV LED sources was undertaken and provides a comprehensive view of how current UV LED technologies compare to traditional technologies. This comparison found that UV LEDs perform comparably vs conventional UV technologies when disinfecting bacteria and viruses. Furthermore, comparison of reported reduction equivalent fluences for UV LED flow-through reactors at the bench-, pilot-, and full-scale were explored in this review, and it was found that LED treatment is becoming more effective at handling increased flowrates and has been proven to work at full-scale. UV LEDs do however require additional research into the impacts of water matrices at different wavelengths and the impact that each available LED wavelength has on disinfection. Overall, this work provides a broad assessment of UV disinfection technologies and serves as a state-of-the-art reference document for those who are interested in understanding this rapidly developing technology.</div></div>","PeriodicalId":52198,"journal":{"name":"Water Research X","volume":"25 ","pages":"Article 100271"},"PeriodicalIF":7.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-30DOI: 10.1016/j.wroa.2024.100270
Dongdong Xu , Tao Liu , Chao Pan , Leiyan Guo , Jianhua Guo , Ping Zheng , Meng Zhang
Anammox granular sludge (AnGS) serves as an important platform for cost-effective nitrogen removal from wastewater. Different to the traditionally sphere-like granules, a novel type of AnGS in a unique ellipsoid-like shape was obtained through enhancing shear force. The ellipsoid-like AnGS significantly exhibited a smaller aspect ratio (-25.1 %) and granular size (-11.8 %), compared to traditional sphere-like AnGS (p < 0.01). Comprehensive comparisons showed that ellipsoid-like AnGS possessed a significantly higher extracellular polymeric substances (EPS) content and strength, as well as an enhanced mass transfer and a higher viable bacteria proportion due to the larger substrate permeable zone (p < 0.01). Additionally, the anammox bacterial abundance (Candidatus Kuenenia) was 12.2 % higher in ellipsoid-like AnGS than in sphere-like AnGS. All these characteristics of ellipsoid-like AnGS jointly increased the specific anammox activity by 29.0 % and nitrogen removal capacity by 22.6 %, compared to sphere-like AnGS. Further fluid field simulation suggested the enhanced flow shear on the side surface of AnGS likely drove the formation of ellipsoid-like AnGS. The higher shear force on the side surface led to an increase of EPS content (especially hydrophobic protein) and elastic modulus, thus constraining lateral expansion. This study sheds light on impacts of granular shape, an overlooked morphological factor, on anammox performance. The ellipsoid-like AnGS presented herein also offers a unique and promising aggregate to enhance anammox performance.
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Pub Date : 2024-10-29DOI: 10.1016/j.wroa.2024.100272
Jinhui Wang , Lina Chi , Shuai Liu , Jiao Yin , Youlin Zhang , Jian Shen , Xinze Wang
Lanthanum-modified-bentonite(LMB) has been applied for eutrophication management as a phosphate(P)-binding agent in many lakes. However, re-eutrophication took place several years or decades later after the first practice of capping due to dynamic environmental factors in the plateau lake. Here, we investigated the effect of long-term capping and integrated environmental factors in the plateau lake including alkalinity, organic matter, disturbance and photodegradation to the LMB immobilization. Long-term LMB immobilization exhibited C accumulation(82.3%), La depletion(53.5%) and lager size effect in the sediment particle, indicating the breakage of La-O-P bonds and the formation of La-O-C bonds over immobilization time. Additionally, pH(8–10) in the plateau lake could enhance the P desorption and decrease P adsorption through electrostatic repulsion enhancement with the zeta potential reduction(7.2 mV). Further disturbance experiment indicated a significant releasing trend of active P and DGT-labile P from the solid phase, pore water to the overlying water after disturbances due to resuspended releasing, particle size and amorphous Fe, Mn and Al's redistribution. Moreover, 31P NMR and EPR results indicated photodegradation after disturbance converted diester phosphate into orthophosphate with long-term LMB immobilization via the oxidation of ·OH in the sediment of the plateau lake. Therefore, management issues for Xingyun Lake may apply to other plateau lakes with low external P input, intermediate depth and intense disturbance.
镧改性膨润土（LMB）作为一种磷酸盐（P）结合剂，已被许多湖泊用于富营养化治理。然而，由于高原湖泊的动态环境因素，在首次实施封盖后的几年或几十年后，湖泊发生了再富营养化。在此，我们研究了高原湖泊长期封盖和综合环境因素（包括碱度、有机质、干扰和光降解）对 LMB 固定化的影响。LMB长期固定化表现出C积累（82.3%）、La耗竭（53.5%）和沉积物粒径变大效应，表明随着固定化时间的延长，La-O-P键断裂，La-O-C键形成。此外，高原湖泊中的 pH 值（8-10）可增强 P 的解吸作用，并通过静电斥力增强减少 P 的吸附，Zeta 电位降低（7.2 mV）。进一步的扰动实验表明，由于再悬浮释放、粒度和非晶态铁、锰、铝的重新分布，扰动后固相、孔隙水和上覆水中的活性 P 和 DGT 标记 P 有明显的释放趋势。此外，31P NMR 和 EPR 结果表明，扰动后的光降解作用通过高原湖泊沉积物中 -OH 的氧化作用将磷酸二酯转化为正磷酸盐，并使 LMB 长期固定。因此，兴云湖的管理问题可能适用于其他外部磷输入量低、水深中等、干扰强烈的高原湖泊。
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