In this study, a fixed-bed biofilm membrane bioreactor was used to assess denitrification and carbon removal performance, membrane fouling, composition, and the dynamics of microbial communities across 10 salinity levels. As salinity levels increased (from 0 to 30 g/L), the removal efficiency of total nitrogen and chemical oxygen demand decreased from 98 and 86% in Phase I to 25 and 45% in Phase X, respectively. Beyond a salinity level of 10 g/L, membrane fouling accelerated considerably. The analysis of fouling resistance distribution suggested that soluble microbial products (SMPs) were the primary cause of this phenomenon. The irregularity in microbial community succession reflected the varying adaptability of different bacteria to different salinity levels. The relative abundance of Sulfuritalea, Lentimircobium, Thauera, and Pseudomonas increased from 20.2 to 47.7% as the experiments progressed. Extracellular polymeric substances-related analysis suggested that Azospirillum plays a positive role in preserving the structural integrity of the biofilm carrier. The SMP-related analysis showed a positive correlation between Lentimircobium, Thauera, Pseudomonas, and the SMP content. These results suggested that these three bacterial genera significantly promoted the release of SMP under salt stress, which in turn led to severe membrane fouling.
{"title":"Effect of salinity on denitrification, membrane fouling and bacterial community in a fixed-bed biofilm membrane reactor","authors":"Ning An, Lei Ma, Dameng Lian, Shuwei Wang","doi":"10.2166/wst.2024.050","DOIUrl":"https://doi.org/10.2166/wst.2024.050","url":null,"abstract":"\u0000 \u0000 In this study, a fixed-bed biofilm membrane bioreactor was used to assess denitrification and carbon removal performance, membrane fouling, composition, and the dynamics of microbial communities across 10 salinity levels. As salinity levels increased (from 0 to 30 g/L), the removal efficiency of total nitrogen and chemical oxygen demand decreased from 98 and 86% in Phase I to 25 and 45% in Phase X, respectively. Beyond a salinity level of 10 g/L, membrane fouling accelerated considerably. The analysis of fouling resistance distribution suggested that soluble microbial products (SMPs) were the primary cause of this phenomenon. The irregularity in microbial community succession reflected the varying adaptability of different bacteria to different salinity levels. The relative abundance of Sulfuritalea, Lentimircobium, Thauera, and Pseudomonas increased from 20.2 to 47.7% as the experiments progressed. Extracellular polymeric substances-related analysis suggested that Azospirillum plays a positive role in preserving the structural integrity of the biofilm carrier. The SMP-related analysis showed a positive correlation between Lentimircobium, Thauera, Pseudomonas, and the SMP content. These results suggested that these three bacterial genera significantly promoted the release of SMP under salt stress, which in turn led to severe membrane fouling.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"5 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139958238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the lack of theoretical guidance for sponge city construction (SCC) in China, this study introduces a method to evaluate the available water volume (AWV) in urban watersheds. This evaluation is based on the water balance relationship, water volume, and ecological water demand (EWD). The Xi'an urban area was selected as a case study due to its water shortage and flooding issues. Results show monthly surface and subsurface AWV ranging between 53.06 and 53.98 million m3 and between 8,701.89 and 8,898.14 million m3, respectively. By maximizing the potential for surface AWV, an annual water supply of 527.75 million m3 could be provided, surpassing the annual artificial water consumption of 394.20 million m3, effectively addressing water scarcity. During the rainy season, implementing measures such as employing permeable paving materials, establishing wetlands and rainwater gardens, and constructing lakes and reservoirs can mitigate flooding caused by rainfall exceeding 32.8 mm. While the subsurface space in Xi'an holds significant potential for subsurface AWV utilization, revitalizing the ecological environment of subsurface water is crucial. Overall, the AWV theoretical framework offers a comprehensive solution to water shortage and flooding issues in the Xi'an urban area, serving as a vital theory for SCC.
{"title":"Integrated assessment of available water volume for sustainable sponge city construction – a case study in Xi'an, China","authors":"Li Luo, Dong Su, Tong Wang, Wenshan Guo","doi":"10.2166/wst.2024.049","DOIUrl":"https://doi.org/10.2166/wst.2024.049","url":null,"abstract":"\u0000 \u0000 To address the lack of theoretical guidance for sponge city construction (SCC) in China, this study introduces a method to evaluate the available water volume (AWV) in urban watersheds. This evaluation is based on the water balance relationship, water volume, and ecological water demand (EWD). The Xi'an urban area was selected as a case study due to its water shortage and flooding issues. Results show monthly surface and subsurface AWV ranging between 53.06 and 53.98 million m3 and between 8,701.89 and 8,898.14 million m3, respectively. By maximizing the potential for surface AWV, an annual water supply of 527.75 million m3 could be provided, surpassing the annual artificial water consumption of 394.20 million m3, effectively addressing water scarcity. During the rainy season, implementing measures such as employing permeable paving materials, establishing wetlands and rainwater gardens, and constructing lakes and reservoirs can mitigate flooding caused by rainfall exceeding 32.8 mm. While the subsurface space in Xi'an holds significant potential for subsurface AWV utilization, revitalizing the ecological environment of subsurface water is crucial. Overall, the AWV theoretical framework offers a comprehensive solution to water shortage and flooding issues in the Xi'an urban area, serving as a vital theory for SCC.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"6 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139958754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The most important information required to successfully issue a flood warning is the quantitative precipitation forecasts (QPFs). This is important to run subsequent rainfall–runoff simulations. A rainfall–runoff simulation derives its accuracy mainly from the accuracy of the input QPFs. The dynamically based global numerical weather prediction models (NWPMs) are strong candidate sources of QPFs. A main problem is the real-time selection of which NWPM should be used to provide the QPFs for flood warning simulations. This paper develops an automated technique to solve this problem. The technique performs real-time comparisons with measured rainfall fields using a novel ‘tolerant’ hydrologic approach. The ‘tolerant’ approach performs the comparison on the basin scale and allows for timing shifts in the forecasts. This is because QPFs can be good but only a few hours early or late. Two events are used for illustration, and the proposed real-time application in flood warning is presented. The developed technique, employing the tolerant approach, could eliminate the effects of the timing shifts and, accordingly, succeeded to select the QPFs to be used. A Python package was developed for automation. The developed technique is expected to also be useful for offline assessments of historical performances of NWPMs.
{"title":"A tolerant hydrologic technique for real-time selection of optimum QPFs from NWPMs for flood warning applications","authors":"Mahmoud Salah, Ashraf El-Mostafa, Mohamed Abdel Hamid Gad","doi":"10.2166/wst.2024.046","DOIUrl":"https://doi.org/10.2166/wst.2024.046","url":null,"abstract":"\u0000 \u0000 The most important information required to successfully issue a flood warning is the quantitative precipitation forecasts (QPFs). This is important to run subsequent rainfall–runoff simulations. A rainfall–runoff simulation derives its accuracy mainly from the accuracy of the input QPFs. The dynamically based global numerical weather prediction models (NWPMs) are strong candidate sources of QPFs. A main problem is the real-time selection of which NWPM should be used to provide the QPFs for flood warning simulations. This paper develops an automated technique to solve this problem. The technique performs real-time comparisons with measured rainfall fields using a novel ‘tolerant’ hydrologic approach. The ‘tolerant’ approach performs the comparison on the basin scale and allows for timing shifts in the forecasts. This is because QPFs can be good but only a few hours early or late. Two events are used for illustration, and the proposed real-time application in flood warning is presented. The developed technique, employing the tolerant approach, could eliminate the effects of the timing shifts and, accordingly, succeeded to select the QPFs to be used. A Python package was developed for automation. The developed technique is expected to also be useful for offline assessments of historical performances of NWPMs.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"88 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139959454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this study is to explore the architecture and functioning of hybrid solar desalination systems and investigate their potential as a sustainable solution for water purification. The study reveals that solar-powered desalination systems offer a remarkable alternative to traditional methods, as they rely on clean solar energy and produce no noise or sound pollution. In addition, they have demonstrated cost-effectiveness in generating drinking water, especially in desert regions and inaccessible areas. Furthermore, the research highlights the significance of incorporating waste heat energy into the desalination process. Also shows that utilizing waste heat energy can significantly reduce expenses and enhance the overall effectiveness of water desalination. Through an in-depth analysis of the fundamental principles and real-world applications, this study underscores the importance and rationale for implementing hybrid solar desalination systems. By effectively utilizing solar energy, these systems provide a sustainable approach to address water scarcity and ensure the efficient management of water and energy resources. This study emphasizes the fundamental importance of the structure of hybrid solar desalination systems fueled by solar energy in the efficient management of water resources. By combining technological innovations with renewable energy sources, these systems pave the way for a sustainable future.
{"title":"A review of hybrid solar desalination systems: structure and performance","authors":"Mohammed A. Alghassab","doi":"10.2166/wst.2024.042","DOIUrl":"https://doi.org/10.2166/wst.2024.042","url":null,"abstract":"\u0000 The purpose of this study is to explore the architecture and functioning of hybrid solar desalination systems and investigate their potential as a sustainable solution for water purification. The study reveals that solar-powered desalination systems offer a remarkable alternative to traditional methods, as they rely on clean solar energy and produce no noise or sound pollution. In addition, they have demonstrated cost-effectiveness in generating drinking water, especially in desert regions and inaccessible areas. Furthermore, the research highlights the significance of incorporating waste heat energy into the desalination process. Also shows that utilizing waste heat energy can significantly reduce expenses and enhance the overall effectiveness of water desalination. Through an in-depth analysis of the fundamental principles and real-world applications, this study underscores the importance and rationale for implementing hybrid solar desalination systems. By effectively utilizing solar energy, these systems provide a sustainable approach to address water scarcity and ensure the efficient management of water and energy resources. This study emphasizes the fundamental importance of the structure of hybrid solar desalination systems fueled by solar energy in the efficient management of water resources. By combining technological innovations with renewable energy sources, these systems pave the way for a sustainable future.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"46 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139960450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rasikh Habib, Mai Phuong, Muhammad Bilal Asif, Guangming Jiang, M. Sivakumar
Fouling behaviour in membrane distillation (MD) processes plays a crucial role in determining their widespread acceptability. Most studies have primarily focused on model organic foulants, such as humic acid (HA) and sodium alginate (SA). This study investigates the fouling of a polytetrafluoroethylene membrane in a direct contact MD (DCMD) using model organics (i.e., HA and SA) and real wastewater. The results indicated that the flux decline (5–60%) was only observed during the initial phase of the operation with model organic foulants. In contrast, real wastewater caused a gradual decline in flux throughout the experiment in both the concentrate (40%) and continuous (90%) modes. The study also found significant differences in the fouling layer morphology, composition, and hydrophobicity between the model organic foulants and real wastewater. Fourier transform infrared spectroscopy findings demonstrated that the fouling layer formed by real wastewater varied significantly from model organics, which primarily comprised of protein-like and polysaccharide-like functional groups. Finally, liquid chromatography–organic carbon detection revealed that the fouling layer of the MD membrane with real wastewater was composed of 40.7% hydrophobic and 59.3% hydrophilic organics. This study suggests that model organics may not accurately reflect real wastewater fouling.
膜蒸馏（MD）过程中的污垢行为在决定其广泛可接受性方面起着至关重要的作用。大多数研究主要集中于有机污垢模型，如腐植酸（HA）和海藻酸钠（SA）。本研究使用模型有机物（即 HA 和 SA）和实际废水调查了直接接触 MD（DCMD）中聚四氟乙烯膜的污垢情况。结果表明，只有在使用模型有机污物的运行初期才会出现通量下降（5%-60%）。相比之下，真实废水在浓缩模式（40%）和连续模式（90%）的整个实验过程中都会导致通量逐渐下降。研究还发现，模型有机污垢剂和实际废水在污垢层形态、组成和疏水性方面存在显著差异。傅立叶变换红外光谱分析结果表明，真实废水形成的污垢层与模型有机物有显著差异，后者主要由蛋白质类和多糖类官能团组成。最后，液相色谱-有机碳检测显示，MD 膜与实际废水形成的污垢层由 40.7% 的疏水性有机物和 59.3% 的亲水性有机物组成。这项研究表明，模型有机物可能无法准确反映真实废水的污垢情况。
{"title":"Membrane distillation of wastewater: comparison of model and real organics","authors":"Rasikh Habib, Mai Phuong, Muhammad Bilal Asif, Guangming Jiang, M. Sivakumar","doi":"10.2166/wst.2024.045","DOIUrl":"https://doi.org/10.2166/wst.2024.045","url":null,"abstract":"\u0000 \u0000 Fouling behaviour in membrane distillation (MD) processes plays a crucial role in determining their widespread acceptability. Most studies have primarily focused on model organic foulants, such as humic acid (HA) and sodium alginate (SA). This study investigates the fouling of a polytetrafluoroethylene membrane in a direct contact MD (DCMD) using model organics (i.e., HA and SA) and real wastewater. The results indicated that the flux decline (5–60%) was only observed during the initial phase of the operation with model organic foulants. In contrast, real wastewater caused a gradual decline in flux throughout the experiment in both the concentrate (40%) and continuous (90%) modes. The study also found significant differences in the fouling layer morphology, composition, and hydrophobicity between the model organic foulants and real wastewater. Fourier transform infrared spectroscopy findings demonstrated that the fouling layer formed by real wastewater varied significantly from model organics, which primarily comprised of protein-like and polysaccharide-like functional groups. Finally, liquid chromatography–organic carbon detection revealed that the fouling layer of the MD membrane with real wastewater was composed of 40.7% hydrophobic and 59.3% hydrophilic organics. This study suggests that model organics may not accurately reflect real wastewater fouling.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"45 49","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139961483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
After the closure of the Yudong coal mine, the pH value was approximately 3.0, and the Fe and Mn concentrations reached 380 and 69 mg/L, respectively, in the acid mine drainage (AMD), causing serious pollution to the water bodies in the nearby watershed. Combined with the formation conditions of AMD, the comprehensive treatment technology of source reduction–end treatment is adopted to treat the AMD. The treatment area of the goaf is 0.3 km3, the filling and grouting volume is about 6.7 m3, and the curtain grouting volume is 4,000 m3. Through the grouting and sealing treatment in the goaf, the water volume is reduced to less than 85% of the initial volume (100 m3/h). After the end treatment, the pH value of the effluent is around 7.0, the content of Fe and Mn is less than 0.1 mg/L, and the removal rate is above 99%. The project was subsequently operated at RMB 0.85 yuan/t. This project is aimed at the treatment of AMD from small coal mines in complex terrain conditions. It has the characteristics of low cost and high efficiency and can provide an effective treatment technology for AMD in southwestern China and areas with the same geological conditions.
{"title":"Source reduction and end treatment of acid mine drainage in closed coal mines of the Yudong River Basin","authors":"Quanjia Wu, Xiangdong Li, Qiyan Feng, Xibin Li","doi":"10.2166/wst.2024.002","DOIUrl":"https://doi.org/10.2166/wst.2024.002","url":null,"abstract":"\u0000 \u0000 After the closure of the Yudong coal mine, the pH value was approximately 3.0, and the Fe and Mn concentrations reached 380 and 69 mg/L, respectively, in the acid mine drainage (AMD), causing serious pollution to the water bodies in the nearby watershed. Combined with the formation conditions of AMD, the comprehensive treatment technology of source reduction–end treatment is adopted to treat the AMD. The treatment area of the goaf is 0.3 km3, the filling and grouting volume is about 6.7 m3, and the curtain grouting volume is 4,000 m3. Through the grouting and sealing treatment in the goaf, the water volume is reduced to less than 85% of the initial volume (100 m3/h). After the end treatment, the pH value of the effluent is around 7.0, the content of Fe and Mn is less than 0.1 mg/L, and the removal rate is above 99%. The project was subsequently operated at RMB 0.85 yuan/t. This project is aimed at the treatment of AMD from small coal mines in complex terrain conditions. It has the characteristics of low cost and high efficiency and can provide an effective treatment technology for AMD in southwestern China and areas with the same geological conditions.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"103 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139391408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jidapa Plaimart, Kishor Acharya, Adrian Blackburn, Wojciech Mrozik, R. Davenport, David Werner
Regulators in England and Wales have set new targets under the Environment Act 2021 for freshwater quality by 2038 that include halving the length of rivers polluted by harmful metals from abandoned mines and reducing phosphorus loadings from treated wastewater by 80%. In this context, an intriguing win–win opportunity exists in the removal of iron from abandoned mines and phosphate from small sewage treatment plants by coprecipitation in constructed wetlands (CWs). We investigated such a CW located at Lamesley, Northeast England, which cotreats abandoned coal mine and secondary-treated sewage treatment plant effluents. We assessed the removal of nutrients, heavy metals, organic micropollutants, and faecal coliforms by the CW, and characterized changes in the water bacteriology comprehensively using environmental DNA. The CW effectively removed ammonium-nitrogen, phosphorus, iron, and faecal coliforms by an average of 86, 74, 98, and 75%, respectively, to levels below or insignificantly different from those in the receiving river. The CW also effectively removed micropollutants such as acetaminophen, caffeine, and sulpiride by 70–100%. Molecular microbiology methods showed successful conversion of sewage and mine water microbiomes into a freshwater microbiome. Overall, the CW significantly reduced impacts on the rural water environment with minimal operational requirements.
英格兰和威尔士的监管机构根据《2021 年环境法案》制定了到 2038 年淡水质量的新目标，其中包括将受废弃矿山有害金属污染的河流长度减少一半，并将经处理的废水中的磷负荷减少 80%。在此背景下，通过在人工湿地（CW）中进行共沉淀，去除废弃矿山中的铁和小型污水处理厂中的磷酸盐，是一个令人感兴趣的双赢机会。我们对位于英格兰东北部拉姆斯利的这样一个共沉淀湿地进行了调查，该湿地将废弃煤矿的废水和污水处理厂二级处理后的废水进行了共沉淀处理。我们评估了化武对营养物质、重金属、有机微污染物和粪大肠菌群的去除情况，并利用环境 DNA 全面描述了水体细菌学的变化。化武有效地去除了铵态氮、磷、铁和粪大肠菌群，平均去除率分别为 86%、74%、98%和 75%，去除水平低于受纳河流或与受纳河流相差不大。化武还能有效去除对乙酰氨基酚、咖啡因和舒必利等微污染物，去除率达 70%-100%。分子微生物学方法显示，污水和矿井水微生物群成功转化为淡水微生物群。总之，化学武器大大减少了对农村水环境的影响，而且操作要求极低。
{"title":"Effective removal of iron, nutrients, micropollutants, and faecal bacteria in constructed wetlands cotreating mine water and sewage treatment plant effluent","authors":"Jidapa Plaimart, Kishor Acharya, Adrian Blackburn, Wojciech Mrozik, R. Davenport, David Werner","doi":"10.2166/wst.2024.001","DOIUrl":"https://doi.org/10.2166/wst.2024.001","url":null,"abstract":"\u0000 \u0000 Regulators in England and Wales have set new targets under the Environment Act 2021 for freshwater quality by 2038 that include halving the length of rivers polluted by harmful metals from abandoned mines and reducing phosphorus loadings from treated wastewater by 80%. In this context, an intriguing win–win opportunity exists in the removal of iron from abandoned mines and phosphate from small sewage treatment plants by coprecipitation in constructed wetlands (CWs). We investigated such a CW located at Lamesley, Northeast England, which cotreats abandoned coal mine and secondary-treated sewage treatment plant effluents. We assessed the removal of nutrients, heavy metals, organic micropollutants, and faecal coliforms by the CW, and characterized changes in the water bacteriology comprehensively using environmental DNA. The CW effectively removed ammonium-nitrogen, phosphorus, iron, and faecal coliforms by an average of 86, 74, 98, and 75%, respectively, to levels below or insignificantly different from those in the receiving river. The CW also effectively removed micropollutants such as acetaminophen, caffeine, and sulpiride by 70–100%. Molecular microbiology methods showed successful conversion of sewage and mine water microbiomes into a freshwater microbiome. Overall, the CW significantly reduced impacts on the rural water environment with minimal operational requirements.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"120 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139391516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhiwei Li, Bing Wang, Fei Wang, Bin Sun, Shuaikang Zhao
The sediment accumulation in drainage pipes has long been recognized as a significant concern in the environmental field. This study addresses sediment accumulation in drainage pipes by introducing an innovative bioinspired approach using various shapes and angles of plates for long-term sediment reduction. Through experiments and numerical simulations, the velocity field, the turbulent kinetic energy, the head loss, and the dynamic pressure distribution in the pipeline with plates are analyzed. Results demonstrate significant increases in local velocity, dynamic pressure, and turbulence energy due to the presence of plates. The sediment reduction performance shows a positive correlation with the angle for folded plates and a non-linear relation with curvature for curved plates. Notably, the superior performance of folded plates is attributed to their exceptional ability to induce vortex formation. The head loss due to sediment reduction measures increases linearly as the angle and the curvature increase. Furthermore, the intentional induction of strong eddies and high shear flow using the undulating topography created by the locally installed folding plates in the pipeline was the main cause of sediment reduction. This novel approach holds promise for more efficient and sustainable sediment reduction in drainage systems.
{"title":"A novel measure for long-term sediment reduction inspired by dragonfly wings","authors":"Zhiwei Li, Bing Wang, Fei Wang, Bin Sun, Shuaikang Zhao","doi":"10.2166/wst.2023.403","DOIUrl":"https://doi.org/10.2166/wst.2023.403","url":null,"abstract":"The sediment accumulation in drainage pipes has long been recognized as a significant concern in the environmental field. This study addresses sediment accumulation in drainage pipes by introducing an innovative bioinspired approach using various shapes and angles of plates for long-term sediment reduction. Through experiments and numerical simulations, the velocity field, the turbulent kinetic energy, the head loss, and the dynamic pressure distribution in the pipeline with plates are analyzed. Results demonstrate significant increases in local velocity, dynamic pressure, and turbulence energy due to the presence of plates. The sediment reduction performance shows a positive correlation with the angle for folded plates and a non-linear relation with curvature for curved plates. Notably, the superior performance of folded plates is attributed to their exceptional ability to induce vortex formation. The head loss due to sediment reduction measures increases linearly as the angle and the curvature increase. Furthermore, the intentional induction of strong eddies and high shear flow using the undulating topography created by the locally installed folding plates in the pipeline was the main cause of sediment reduction. This novel approach holds promise for more efficient and sustainable sediment reduction in drainage systems.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"86 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139154888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zi-Fan Wu, Zhao-Long Li, Qing-Hua Liu, Zhi-Man Yang
Using a batch thermophilic anaerobic system established with 60 mL serum bottles, the mechanism on how microbial enrichments obtained from magnetite-amended paddy soil via repeated batch cultivation affected methane production from acetate was investigated. Magnetite-amended enrichments (MAEs) can improve the methane production rate rather than the methane yield. Compared with magnetite-unamended enrichments, the methane production rate in MAE was improved by 50%, concomitant with the pronounced electrochemical response, high electron transfer capacity, and fast acetate degradation. The promoting effects might be ascribed to direct interspecies electron transfer facilitated by magnetite, where magnetite might function as electron conduits to link the acetate oxidizers (Anaerolineaceae and Peptococcaceae) with methanogens (Methanosarcinaceae). The findings demonstrated the potential application of MAE for boosting methanogenic performance during thermophilic anaerobic digestion.
{"title":"Magnetite-boosted syntrophic conversion of acetate to methane during thermophilic anaerobic digestion","authors":"Zi-Fan Wu, Zhao-Long Li, Qing-Hua Liu, Zhi-Man Yang","doi":"10.2166/wst.2023.421","DOIUrl":"https://doi.org/10.2166/wst.2023.421","url":null,"abstract":"Using a batch thermophilic anaerobic system established with 60 mL serum bottles, the mechanism on how microbial enrichments obtained from magnetite-amended paddy soil via repeated batch cultivation affected methane production from acetate was investigated. Magnetite-amended enrichments (MAEs) can improve the methane production rate rather than the methane yield. Compared with magnetite-unamended enrichments, the methane production rate in MAE was improved by 50%, concomitant with the pronounced electrochemical response, high electron transfer capacity, and fast acetate degradation. The promoting effects might be ascribed to direct interspecies electron transfer facilitated by magnetite, where magnetite might function as electron conduits to link the acetate oxidizers (Anaerolineaceae and Peptococcaceae) with methanogens (Methanosarcinaceae). The findings demonstrated the potential application of MAE for boosting methanogenic performance during thermophilic anaerobic digestion.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"25 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139162158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In natural rivers, flow conditions are mainly dependent on flow resistance and type of roughness. The interactions among flow and bedforms are complex in nature as bedform dynamics primarily regulate the flow resistance. Manning's equation is the most frequently used equation for this purpose. Therefore, there is a need to develop alternate reliable techniques for adequate prediction of Manning's roughness coefficient (n) in alluvial channels with bedforms. Thus, the main objective of this study is to utilize machine learning (ML) models for predicting ‘n’ based on the six input features. The performance of ML models was assessed using Pearson's coefficient (R2), sensitivity analysis, Taylor's diagram, box plots, and K-fold method has been used for the cross-validation. Based on the output of the current work, models such as random forest, extra trees regression, and extreme gradient boosting performed extremely well (R2 ≥ 0.99), whereas, Lasso Regression models showed moderate efficiency in predicting roughness. The sensitivity analysis indicated that the energy grade line has a significant impact in predicting the roughness as compared to the other parameters. The alternate approach utilized in the present study provides insights into riverbed characteristics, enhancing the understanding of the complex relationship between roughness and other independent parameters.
在自然河流中，流动条件主要取决于流动阻力和粗糙度类型。由于床面动力学主要调节流动阻力，因此水流与床面之间的相互作用在本质上是复杂的。曼宁方程是最常用的计算公式。因此，有必要开发其他可靠的技术，以充分预测有床基的冲积河道中的曼宁粗糙度系数（n）。因此，本研究的主要目标是利用机器学习（ML）模型来预测基于六个输入特征的 "n"。使用皮尔逊系数（R2）、灵敏度分析、泰勒图、箱形图和 K-fold 交叉验证法评估了 ML 模型的性能。根据当前工作的结果，随机森林、额外树回归和极梯度提升等模型表现极佳（R2 ≥ 0.99），而拉索回归模型在预测粗糙度方面表现出中等效率。敏感性分析表明，与其他参数相比，能量品位线对粗糙度的预测有显著影响。本研究采用的替代方法有助于深入了解河床特征，加深对粗糙度与其他独立参数之间复杂关系的理解。
{"title":"Machine learning approaches for adequate prediction of flow resistance in alluvial channels with bedforms","authors":"A. Mir, M. Patel","doi":"10.2166/wst.2023.396","DOIUrl":"https://doi.org/10.2166/wst.2023.396","url":null,"abstract":"In natural rivers, flow conditions are mainly dependent on flow resistance and type of roughness. The interactions among flow and bedforms are complex in nature as bedform dynamics primarily regulate the flow resistance. Manning's equation is the most frequently used equation for this purpose. Therefore, there is a need to develop alternate reliable techniques for adequate prediction of Manning's roughness coefficient (n) in alluvial channels with bedforms. Thus, the main objective of this study is to utilize machine learning (ML) models for predicting ‘n’ based on the six input features. The performance of ML models was assessed using Pearson's coefficient (R2), sensitivity analysis, Taylor's diagram, box plots, and K-fold method has been used for the cross-validation. Based on the output of the current work, models such as random forest, extra trees regression, and extreme gradient boosting performed extremely well (R2 ≥ 0.99), whereas, Lasso Regression models showed moderate efficiency in predicting roughness. The sensitivity analysis indicated that the energy grade line has a significant impact in predicting the roughness as compared to the other parameters. The alternate approach utilized in the present study provides insights into riverbed characteristics, enhancing the understanding of the complex relationship between roughness and other independent parameters.","PeriodicalId":505935,"journal":{"name":"Water Science & Technology","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139162324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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