K. Ikehata, Noriaki Nakamura, H. Kulkarni, Yuanyuan Zhao, N. Maleky, Shinya Sato, Han Gao
Recently, the use of brackish diatoms has been proposed to remove various inorganic constituents, such as dissolved silica, nutrients, calcium, and bicarbonate, to enhance the freshwater recovery in reverse osmosis (RO). In this study, nine strains of brackish diatoms isolated from water and sediment samples from several evaporation ponds in California and Arizona were examined for their ability to assimilate silica and remove other constituents from RO concentrate. In addition to two previously reported strains, namely Gedaniella flavovirens PEWL001 and Nitzschia communis PEWL002, several new isolates including Halamphora sydowii PEWL004, Nitzschia sp. PEWL008, and Halamphora sp. PEWL011 were found to remove more than 95% of silica, 95% of ammonia and orthophosphate, and more than 50% of calcium and carbonate within 6 days. Two additional G. flavovirens strains (Psetr3 and Psetr7) collected from a brackish lake in Aomori, Japan, also showed rapid dissolved silica uptake (32 mg L−1 day−1) comparable to the one isolated from an agricultural drainage water evaporation pond in the Central Valley, California. This study demonstrated that the brackish diatoms isolated from the evaporation ponds could be useful for the treatment of RO concentrate, which would possibly enable more sustainable desalination processes.
{"title":"Isolation and evaluation of brackish diatoms for the photobiological treatment of reverse osmosis concentrate","authors":"K. Ikehata, Noriaki Nakamura, H. Kulkarni, Yuanyuan Zhao, N. Maleky, Shinya Sato, Han Gao","doi":"10.2166/aqua.2022.082","DOIUrl":"https://doi.org/10.2166/aqua.2022.082","url":null,"abstract":"\u0000 Recently, the use of brackish diatoms has been proposed to remove various inorganic constituents, such as dissolved silica, nutrients, calcium, and bicarbonate, to enhance the freshwater recovery in reverse osmosis (RO). In this study, nine strains of brackish diatoms isolated from water and sediment samples from several evaporation ponds in California and Arizona were examined for their ability to assimilate silica and remove other constituents from RO concentrate. In addition to two previously reported strains, namely Gedaniella flavovirens PEWL001 and Nitzschia communis PEWL002, several new isolates including Halamphora sydowii PEWL004, Nitzschia sp. PEWL008, and Halamphora sp. PEWL011 were found to remove more than 95% of silica, 95% of ammonia and orthophosphate, and more than 50% of calcium and carbonate within 6 days. Two additional G. flavovirens strains (Psetr3 and Psetr7) collected from a brackish lake in Aomori, Japan, also showed rapid dissolved silica uptake (32 mg L−1 day−1) comparable to the one isolated from an agricultural drainage water evaporation pond in the Central Valley, California. This study demonstrated that the brackish diatoms isolated from the evaporation ponds could be useful for the treatment of RO concentrate, which would possibly enable more sustainable desalination processes.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85077247","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}
Air valves are used to suppress negative water pressures in water transmission pipelines. They also play a key role during the water filling and drainage stages in pipeline systems. However, systematic guidelines for the selection of air valve parameters are lacking. In practical engineering applications, the selection is mainly based on personal experience. If the selected parameters are not appropriate, negative pressures can occur in a pipeline due to insufficient air inflow or destructive water hammer pressures with column separation and rejoinder, which are caused by rapid air discharge. Given the subjectivity of the selection of air valve parameters in engineering applications, this paper introduces the structure and working principle of two different types of air valves. Combined with engineering examples, the one-dimensional transient flow elastic model and the characteristic method are used to conduct numerical simulations in MATLAB to investigate the influences of the air valve type, the inlet and outlet orifice diameters, and the inflow and outflow discharge coefficients on protection against water hammer with column separation and rejoinder. The inflow and outflow coefficients of the anti-slam air valve have a slight influence on preventing water hammers with column separation and rejoinder. The research results provide a theoretical basis for the rational selection of air valves in practical engineering applications.
{"title":"Study on the factors influencing air valve protection against water hammer with column separation and rejoinder","authors":"Xiaozhou Li, Tao Wang, Yanhe Zhang, P. Guo","doi":"10.2166/aqua.2022.165","DOIUrl":"https://doi.org/10.2166/aqua.2022.165","url":null,"abstract":"\u0000 Air valves are used to suppress negative water pressures in water transmission pipelines. They also play a key role during the water filling and drainage stages in pipeline systems. However, systematic guidelines for the selection of air valve parameters are lacking. In practical engineering applications, the selection is mainly based on personal experience. If the selected parameters are not appropriate, negative pressures can occur in a pipeline due to insufficient air inflow or destructive water hammer pressures with column separation and rejoinder, which are caused by rapid air discharge. Given the subjectivity of the selection of air valve parameters in engineering applications, this paper introduces the structure and working principle of two different types of air valves. Combined with engineering examples, the one-dimensional transient flow elastic model and the characteristic method are used to conduct numerical simulations in MATLAB to investigate the influences of the air valve type, the inlet and outlet orifice diameters, and the inflow and outflow discharge coefficients on protection against water hammer with column separation and rejoinder. The inflow and outflow coefficients of the anti-slam air valve have a slight influence on preventing water hammers with column separation and rejoinder. The research results provide a theoretical basis for the rational selection of air valves in practical engineering applications.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87439266","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}
With the burgeoning population worldwide, the demand for freshwater supply is increasing, mostly in urban areas, due to the influx of people for better livelihood. To mitigate this burden of freshwater demand and build a sustainable water management system, harvesting rainwater during the rainfall season is a viable option. Runoff estimation studies in the past are time-intensive as parameter estimation for an area is complex by the conventional method. In this study, the Motilal Nehru National Institute of Technology (MNNIT), Allahabad campus was selected as a pilot project to assess a methodology that uses Google Earth images for obtaining the runoff coefficients. This method is easy and consumes less time in runoff estimation. This was compared with the conventional method. Using the conventional method (Arc-GIS), the equivalent runoff coefficients for these catchments were found to be 0.2780, 0.3553, and 0.4111, respectively. The range of error (compared to the traditional method) in runoff obtained from the proposed method with a default k value (0.8) was found to be 8.16–13.55%, with an average value of 9.91%. However, with a slightly modified value of k (0.9), the errors were significantly reduced to 1.94–3.32%, with an average of 2.15%.
{"title":"Runoff estimation using digital image processing for residential areas","authors":"Pramod Soni, Hemanta Medhi, Anitya Sagar, Pulkit Garg, Abhay Singh, Umesh Karna","doi":"10.2166/aqua.2022.070","DOIUrl":"https://doi.org/10.2166/aqua.2022.070","url":null,"abstract":"\u0000 With the burgeoning population worldwide, the demand for freshwater supply is increasing, mostly in urban areas, due to the influx of people for better livelihood. To mitigate this burden of freshwater demand and build a sustainable water management system, harvesting rainwater during the rainfall season is a viable option. Runoff estimation studies in the past are time-intensive as parameter estimation for an area is complex by the conventional method. In this study, the Motilal Nehru National Institute of Technology (MNNIT), Allahabad campus was selected as a pilot project to assess a methodology that uses Google Earth images for obtaining the runoff coefficients. This method is easy and consumes less time in runoff estimation. This was compared with the conventional method. Using the conventional method (Arc-GIS), the equivalent runoff coefficients for these catchments were found to be 0.2780, 0.3553, and 0.4111, respectively. The range of error (compared to the traditional method) in runoff obtained from the proposed method with a default k value (0.8) was found to be 8.16–13.55%, with an average value of 9.91%. However, with a slightly modified value of k (0.9), the errors were significantly reduced to 1.94–3.32%, with an average of 2.15%.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83672941","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}
Chen Song, Yajun Shi, Hongjie Gao, H. Ren, Xiaoling Liu
S2− is one of the common pollutants in heavily polluted rivers. A pump-and-treat ex-situ process with enriched consortium (PEPEC) was used to remove S2− in this study. The kinetic model of S2− removal was developed, and the inflow ratio of the PEPEC was analyzed according to the results of the kinetic models. The results showed that the S2− removal ratio could reach 97.5% 5 0.5%, when the inflow ratio was controlled at 2% for the PEPEC operation. Meanwhile, the removal efficiency and operation performance were assessed for both the simulating ex-situ and in-situ bench-scale tests. Compared with the in-situ processes, the PEPEC showed a stable operation performance during 120 h of bio-treatment, and the concentrations of S2−, COD, NH3-N and TP in the effluent reached approximately 0.5, 20, 0.5 and 0.5 mg/L, respectively. The time consumption (8 h for one batch) and consortium dosage (3 g for the whole operation) in the PEPEC were significantly less than those in the in-situ processes. The PEPEC presented some potential advantages for the bio-treatment of a heavily polluted river.
S2−是重污染河流中常见的污染物之一。在本研究中，采用泵-处理富集联合体法(PEPEC)去除S2−。建立了S2−去除的动力学模型，并根据动力学模型的结果分析了PEPEC的入流比。结果表明，PEPEC作业中，当进水比控制在2%时，S2−去除率可达97.5% ~ 0.5%。同时，通过模拟离地试验和现场试验，对其去除效果和运行性能进行了评价。与原位工艺相比，在120 h的生物处理过程中，PEPEC表现出稳定的运行性能，出水中S2−、COD、NH3-N和TP的浓度分别约为0.5、20、0.5和0.5 mg/L。PEPEC工艺的时间(8 h /批)和联合体投加量(3 g /批)明显低于原位工艺。PEPEC对重污染河流的生物处理具有潜在的优势。
{"title":"Enhanced removal of dissolved S2− from a river by the pump-and-treat ex-situ process with enriched consortium","authors":"Chen Song, Yajun Shi, Hongjie Gao, H. Ren, Xiaoling Liu","doi":"10.2166/aqua.2022.152","DOIUrl":"https://doi.org/10.2166/aqua.2022.152","url":null,"abstract":"\u0000 S2− is one of the common pollutants in heavily polluted rivers. A pump-and-treat ex-situ process with enriched consortium (PEPEC) was used to remove S2− in this study. The kinetic model of S2− removal was developed, and the inflow ratio of the PEPEC was analyzed according to the results of the kinetic models. The results showed that the S2− removal ratio could reach 97.5% 5 0.5%, when the inflow ratio was controlled at 2% for the PEPEC operation. Meanwhile, the removal efficiency and operation performance were assessed for both the simulating ex-situ and in-situ bench-scale tests. Compared with the in-situ processes, the PEPEC showed a stable operation performance during 120 h of bio-treatment, and the concentrations of S2−, COD, NH3-N and TP in the effluent reached approximately 0.5, 20, 0.5 and 0.5 mg/L, respectively. The time consumption (8 h for one batch) and consortium dosage (3 g for the whole operation) in the PEPEC were significantly less than those in the in-situ processes. The PEPEC presented some potential advantages for the bio-treatment of a heavily polluted river.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90206187","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}
Tianbao Xu, W. Ma, Yao Cheng, Dexuan Qi, Lei Sun, Fengqin Chang
The Three Gorges Reservoir on the Yangtze River is the largest water control project in the world. While exerting great benefits (i.e., flood control, hydropower generation, inland river navigation and scenic tourism), the eutrophication of the tributary bay of the Three Gorges Reservoir has become one of the main environmental problems. This paper is to study the causes of water environment evolution in the tributary bay and investigate the driving force of eutrophication succession after the Three Gorges Reservoir enters the regular operation. By considering the Meixi River on the left bank of the mainstream of the Three Gorges Reservoir area (a typical tributary), this paper developed a three-dimensional hydrodynamic, water quality and water eutrophication mathematical model for the Meixi tributary bay, calibrated with measured data about hydrological regime (water level, flow), hydrodynamic factors (velocity) and water quality (water temperature, Chl-a, TP, TN, etc.). The annual variation of Chl-a concentration in the tributary bay was simulated, and the response relationship between the variation of Chl-a concentration and water conditions of the mainstream and tributary bay (e.g., reservoir water level, reservoir bay velocity, exogenous nutrient input, water temperature stratification and other factors) was analyzed. Results show that the water storage operation of the Three Gorges Reservoir contributes to the low flow velocity maintenance (≤0.05 m/s) in the tributary bay, the backward flow of the mainstream and the sufficient nutrients carried by the tributary water; the water temperature stratification is more likely to occur in the slow detention area in the middle-upper part of the bay in spring and summer, which provides a potential driving force for algae blooms. With the continuous decline of pollution load input in the reservoir basin, the algae blooms in tributary bay was the result of the combined action of low water level operation, low flow velocity (≤0.02 m/s), a large number of non-point source loads input with rainfall and runoff (the proportion of wet year is >70%), and obvious water temperature stratification in shallow water area, and the suitable meteorological conditions are the main inducing factors. Therefore, since the ecological regulation cannot be applied to the multitudinous tributary bays, the non-point source pollution control in the tributary bay is the key to controlling factor.
{"title":"How has the eutrophication evolved in the tributary bay of the Three Gorges Reservoir area","authors":"Tianbao Xu, W. Ma, Yao Cheng, Dexuan Qi, Lei Sun, Fengqin Chang","doi":"10.2166/aqua.2022.026","DOIUrl":"https://doi.org/10.2166/aqua.2022.026","url":null,"abstract":"\u0000 The Three Gorges Reservoir on the Yangtze River is the largest water control project in the world. While exerting great benefits (i.e., flood control, hydropower generation, inland river navigation and scenic tourism), the eutrophication of the tributary bay of the Three Gorges Reservoir has become one of the main environmental problems. This paper is to study the causes of water environment evolution in the tributary bay and investigate the driving force of eutrophication succession after the Three Gorges Reservoir enters the regular operation. By considering the Meixi River on the left bank of the mainstream of the Three Gorges Reservoir area (a typical tributary), this paper developed a three-dimensional hydrodynamic, water quality and water eutrophication mathematical model for the Meixi tributary bay, calibrated with measured data about hydrological regime (water level, flow), hydrodynamic factors (velocity) and water quality (water temperature, Chl-a, TP, TN, etc.). The annual variation of Chl-a concentration in the tributary bay was simulated, and the response relationship between the variation of Chl-a concentration and water conditions of the mainstream and tributary bay (e.g., reservoir water level, reservoir bay velocity, exogenous nutrient input, water temperature stratification and other factors) was analyzed. Results show that the water storage operation of the Three Gorges Reservoir contributes to the low flow velocity maintenance (≤0.05 m/s) in the tributary bay, the backward flow of the mainstream and the sufficient nutrients carried by the tributary water; the water temperature stratification is more likely to occur in the slow detention area in the middle-upper part of the bay in spring and summer, which provides a potential driving force for algae blooms. With the continuous decline of pollution load input in the reservoir basin, the algae blooms in tributary bay was the result of the combined action of low water level operation, low flow velocity (≤0.02 m/s), a large number of non-point source loads input with rainfall and runoff (the proportion of wet year is >70%), and obvious water temperature stratification in shallow water area, and the suitable meteorological conditions are the main inducing factors. Therefore, since the ecological regulation cannot be applied to the multitudinous tributary bays, the non-point source pollution control in the tributary bay is the key to controlling factor.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77916386","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}
F. B. Banadkooki, Yong Xiao, H. Malekinezhad, Mohammad Mehdi Sharifi Hosseini
Viewing water management as a multifaceted issue is critical to achieving sustainable water management. This paper proposes an integrated optimal allocation model for aquifer sustainability and environmental benefits when managing conjunctive water resources. Optimization techniques such as genetic algorithm (GA) and non-dominated sorting genetic algorithm (NSGA-II) are used to balance economic benefit and demand management based on decision makers’ preferences. The findings indicate that less water was allocated to industries with high water demand. The value of the allocated water to these industries is between 34 and 52%. Thus, it concluded that specific industries are unsustainable when environmental damage is considered. From the scenarios examined, scenario 10 (water resource conditions and water demands are determined based on existing conditions, considering domestic water management and aquifer restoration) was found to be the optimal water management scenario. The indicators of Integrated Water Resources Management (IWRM) for this scenario are 0.30, 0.15, 190, 40.9, and 0.55 for relative water stress, aquifer sustainability, aquifer attenuation period, aquifer recovery potential, and agricultural water productivity, respectively. This finding implies that considering demand management, wastewater treatment, and the absence of industrial development in development scenarios, it will be possible to conserve aquifers and meet water demands.
{"title":"Optimal allocation of regional water resources in an arid basin: insights from Integrated Water Resources Management","authors":"F. B. Banadkooki, Yong Xiao, H. Malekinezhad, Mohammad Mehdi Sharifi Hosseini","doi":"10.2166/aqua.2022.029","DOIUrl":"https://doi.org/10.2166/aqua.2022.029","url":null,"abstract":"\u0000 Viewing water management as a multifaceted issue is critical to achieving sustainable water management. This paper proposes an integrated optimal allocation model for aquifer sustainability and environmental benefits when managing conjunctive water resources. Optimization techniques such as genetic algorithm (GA) and non-dominated sorting genetic algorithm (NSGA-II) are used to balance economic benefit and demand management based on decision makers’ preferences. The findings indicate that less water was allocated to industries with high water demand. The value of the allocated water to these industries is between 34 and 52%. Thus, it concluded that specific industries are unsustainable when environmental damage is considered. From the scenarios examined, scenario 10 (water resource conditions and water demands are determined based on existing conditions, considering domestic water management and aquifer restoration) was found to be the optimal water management scenario. The indicators of Integrated Water Resources Management (IWRM) for this scenario are 0.30, 0.15, 190, 40.9, and 0.55 for relative water stress, aquifer sustainability, aquifer attenuation period, aquifer recovery potential, and agricultural water productivity, respectively. This finding implies that considering demand management, wastewater treatment, and the absence of industrial development in development scenarios, it will be possible to conserve aquifers and meet water demands.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84782929","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}
{"title":"Corrigendum: AQUA — Water Infrastructure, Ecosystems and Society 70 (4), 467–482: One water – evolving roles of our precious resource and critical challenges, Veera Gnaneswar Gude, http://dx.doi.org/10.2166/aqua.2021.154","authors":"","doi":"10.2166/aqua.2022.001","DOIUrl":"https://doi.org/10.2166/aqua.2022.001","url":null,"abstract":"","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82896202","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}
Water quality prediction is the basic work of water resource management and pollution control, and it is crucial to accurately predict the trend of pollutant concentration in water bodies over time. Water quality data prediction has an important significance, it provides data support for the effective estimation of water quality, and is also an indirect way to protect water resources and environment. At present there are a variety of water quality prediction methods, but these methods still have some shortcomings. In this paper, the main water quality pollution indicators such as the dissolved oxygen (DO), ammonia nitrogen (NH3-N) and total phosphorus (P) data were the object of study to build a water quality prediction model. The water quality prediction index contains numerous nonlinear correlation characteristics that results in low training efficiency on a large-scale data. Therefore, a combined water quality prediction model based on integrated ensemble empirical mode decomposition (EEMD) and cascade support vector machine (Cascade SVM) is proposed. First, the EEMD method is used to highlight the real characteristics of the original water quality data series. Then, the parallel training and prediction process are realized by the Spark, a distributed computing engine, to parallelize the traditional Cascade SVM. The experimental results show that the proposed combined model shows a strong superiority in many aspects of performance such as training efficiency and prediction accuracy.
{"title":"A combined water quality pollution prediction model based on the Spark big data platform","authors":"Zhihui Sun, Yiqing Fan","doi":"10.2166/aqua.2022.036","DOIUrl":"https://doi.org/10.2166/aqua.2022.036","url":null,"abstract":"\u0000 Water quality prediction is the basic work of water resource management and pollution control, and it is crucial to accurately predict the trend of pollutant concentration in water bodies over time. Water quality data prediction has an important significance, it provides data support for the effective estimation of water quality, and is also an indirect way to protect water resources and environment. At present there are a variety of water quality prediction methods, but these methods still have some shortcomings. In this paper, the main water quality pollution indicators such as the dissolved oxygen (DO), ammonia nitrogen (NH3-N) and total phosphorus (P) data were the object of study to build a water quality prediction model. The water quality prediction index contains numerous nonlinear correlation characteristics that results in low training efficiency on a large-scale data. Therefore, a combined water quality prediction model based on integrated ensemble empirical mode decomposition (EEMD) and cascade support vector machine (Cascade SVM) is proposed. First, the EEMD method is used to highlight the real characteristics of the original water quality data series. Then, the parallel training and prediction process are realized by the Spark, a distributed computing engine, to parallelize the traditional Cascade SVM. The experimental results show that the proposed combined model shows a strong superiority in many aspects of performance such as training efficiency and prediction accuracy.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76210600","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}
Alemu Gizaw, F. Zewge, Y. Chebude, Melakuu Tesfaye, A. Mekonnen
The calcium silicate hydrate (CSH) was synthesized from the solid waste residue (SWR) of the Alum Factory, and was used for phosphate abatement from an aqueous solution. Fixed-bed column adsorption experiments were conducted at different flow rates (5, 7.5, and 10 mL/min) and bed depths (6, 9, and 12 cm) at an initial pH and phosphate concentrations of 5 and 5.5 mg/L, respectively. The breakthrough curve analysis was developed and tabulated for the effects of the flow rate and bed depth. Fixed-bed adsorption models, namely the Thomas model, the Yoon–Nelson model, and Bed Depth Service Time (BDST) model were fitted to the experimental data. The R2 values observed for the Thomas model and the Yoon–Nelson model were 0.96 and 0.98, respectively, at the flow rate of 7.5 mL/min and bed depth of 9 cm with the breakthrough adsorption capacity of 5.67 mg/g. The synthesized CSH was also tested for its phosphate removal efficiency using local wastewater treatment plant effluent. About 1,658 mL of real wastewater was treated for 249 min before the standard threshold limit (1 mg/L) was reached. This study prevails that the synthesized CSH could be applied to remove phosphate from real wastewater under a continuous flow adsorption system.
{"title":"A fixed-bed column study of solid waste-based calcium silicate hydrate for the phosphate removal","authors":"Alemu Gizaw, F. Zewge, Y. Chebude, Melakuu Tesfaye, A. Mekonnen","doi":"10.2166/aqua.2022.167","DOIUrl":"https://doi.org/10.2166/aqua.2022.167","url":null,"abstract":"\u0000 The calcium silicate hydrate (CSH) was synthesized from the solid waste residue (SWR) of the Alum Factory, and was used for phosphate abatement from an aqueous solution. Fixed-bed column adsorption experiments were conducted at different flow rates (5, 7.5, and 10 mL/min) and bed depths (6, 9, and 12 cm) at an initial pH and phosphate concentrations of 5 and 5.5 mg/L, respectively. The breakthrough curve analysis was developed and tabulated for the effects of the flow rate and bed depth. Fixed-bed adsorption models, namely the Thomas model, the Yoon–Nelson model, and Bed Depth Service Time (BDST) model were fitted to the experimental data. The R2 values observed for the Thomas model and the Yoon–Nelson model were 0.96 and 0.98, respectively, at the flow rate of 7.5 mL/min and bed depth of 9 cm with the breakthrough adsorption capacity of 5.67 mg/g. The synthesized CSH was also tested for its phosphate removal efficiency using local wastewater treatment plant effluent. About 1,658 mL of real wastewater was treated for 249 min before the standard threshold limit (1 mg/L) was reached. This study prevails that the synthesized CSH could be applied to remove phosphate from real wastewater under a continuous flow adsorption system.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74467224","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 this paper, information entropy was proposed to measure water quality reliability in a water distribution system (WDS), which had been applied to evaluate hydraulic reliability in the WDS. In the water quality reliability evaluation, residual chlorine is a representative of water quality, and a first-order decay model was usually adopted. The water quality reliability (R) based on water quality entropy (WQE) and improved water quality reliability (Rd) based on improved water quality entropy (IWQE) were proposed and compared for three networks. The method was developed based on the EPANET toolkit and MATLAB environment. The results indicated that flow entropy (FE) is strongly related to WQE, and improved flow entropy (IFE) is also strongly related to IWQE. In addition, Rd can reflect the effect of pipe velocity, whereas R can only reflect the effects of pipe flow and the WDS layout. The novelty of this paper is to develop the entropy with consideration of the pipe velocity to measure water quality liability as a surrogate index, which can reduce the calculation load and can be applied to a nonlinear system. The proposed water quality reliability evaluation method based on information entropy can help design, analyze, and improve the water quality in the WDS.
{"title":"Water quality reliability based on an improved entropy in a water distribution system","authors":"Yumin Wang, Jianguo Zhu, G. Zhu","doi":"10.2166/aqua.2022.066","DOIUrl":"https://doi.org/10.2166/aqua.2022.066","url":null,"abstract":"\u0000 In this paper, information entropy was proposed to measure water quality reliability in a water distribution system (WDS), which had been applied to evaluate hydraulic reliability in the WDS. In the water quality reliability evaluation, residual chlorine is a representative of water quality, and a first-order decay model was usually adopted. The water quality reliability (R) based on water quality entropy (WQE) and improved water quality reliability (Rd) based on improved water quality entropy (IWQE) were proposed and compared for three networks. The method was developed based on the EPANET toolkit and MATLAB environment. The results indicated that flow entropy (FE) is strongly related to WQE, and improved flow entropy (IFE) is also strongly related to IWQE. In addition, Rd can reflect the effect of pipe velocity, whereas R can only reflect the effects of pipe flow and the WDS layout. The novelty of this paper is to develop the entropy with consideration of the pipe velocity to measure water quality liability as a surrogate index, which can reduce the calculation load and can be applied to a nonlinear system. The proposed water quality reliability evaluation method based on information entropy can help design, analyze, and improve the water quality in the WDS.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85584536","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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