Jefferson Hannover Faustino Magalhães, Letícia Nunes Bezerra, Anna Luísa Beserra Santos, C. Silveira, Ana Bárbara de Araújo Nunes, I. E. L. Neto
We conducted field, laboratory and modeling studies to evaluate the efficiency of a new solar disinfection (SODIS) device called Aqualuz for the removal of Escherichia coli (EC) from cistern water in the Brazilian semiarid, for different solar exposure–water temperature conditions. The results indicated EC contamination (100–300 MPN/100 mL) in all tests performed. As compared to the literature, lower exposure times (2.5–4.0 h) and solar radiations (250–410 W/m²) were sufficient for EC elimination. Then, assuming the complete-mix approach and first-order kinetics, it was possible to adjust EC decay rate constants (k) considering three different models: constant k-value, k as a function of water temperature and a new formulation for k as a function of both solar radiation and water temperature. All models performed well with normalized root mean squared logarithmic error (NRMSLE) lower than 20%, but the best fitting was obtained with the new approach. A new relationship between solar radiation and water temperature was also obtained, which allowed model simulations of EC decay for 34 municipalities in the Brazilian northeast, resulting in a color map for the region depicting the exposure periods of 1.8–5.6 h for reaching a 3-log reduction.
{"title":"Aqualuz: a new solar disinfection device for treatment of cistern water","authors":"Jefferson Hannover Faustino Magalhães, Letícia Nunes Bezerra, Anna Luísa Beserra Santos, C. Silveira, Ana Bárbara de Araújo Nunes, I. E. L. Neto","doi":"10.2166/aqua.2022.092","DOIUrl":"https://doi.org/10.2166/aqua.2022.092","url":null,"abstract":"\u0000 We conducted field, laboratory and modeling studies to evaluate the efficiency of a new solar disinfection (SODIS) device called Aqualuz for the removal of Escherichia coli (EC) from cistern water in the Brazilian semiarid, for different solar exposure–water temperature conditions. The results indicated EC contamination (100–300 MPN/100 mL) in all tests performed. As compared to the literature, lower exposure times (2.5–4.0 h) and solar radiations (250–410 W/m²) were sufficient for EC elimination. Then, assuming the complete-mix approach and first-order kinetics, it was possible to adjust EC decay rate constants (k) considering three different models: constant k-value, k as a function of water temperature and a new formulation for k as a function of both solar radiation and water temperature. All models performed well with normalized root mean squared logarithmic error (NRMSLE) lower than 20%, but the best fitting was obtained with the new approach. A new relationship between solar radiation and water temperature was also obtained, which allowed model simulations of EC decay for 34 municipalities in the Brazilian northeast, resulting in a color map for the region depicting the exposure periods of 1.8–5.6 h for reaching a 3-log reduction.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74285735","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 freshwater production in a conventional solar still (CSS) is very less and it can be enhanced by either enhancing evaporation or condensation rates or both in the solar still. Therefore, the current investigation focused on enhancing both the evaporation rate in the absorber basin and the condensation rate over the top glass simultaneously. In this regard, the evaporation rate is enhanced by using a hollow-finned absorber basin with energy storage and novel pond fibres in the absorber basin. Likewise, the sisal fibre with a water dripping arrangement is utilized for enhancing the condensation over the top glass. The investigations on the CSS and the modified solar still (MSS) with hollow fins and energy storage, pond fibres, and sisal fibres are conducted to analyze the effect of energy storage and natural fibres on the distillate production. It is observed that the water temperatures of the MSS are increased by 12% and the glass temperatures of the MSS are reduced by 30% relative to the CSS. The outcomes reported that the productivity of the MSS is enhanced by 126%. Furthermore, the cost per litre (CPL) and the payback period (PP) of the MSS are 38.5 and 49.3% lesser than the CPL and the PP of the CSS, respectively.
{"title":"Combined enhancement of evaporation and condensation rates in the solar still for augmenting the freshwater productivity using energy storage and natural fibres","authors":"Subbarama Kousik Suraparaju, S. Natarajan","doi":"10.2166/aqua.2022.017","DOIUrl":"https://doi.org/10.2166/aqua.2022.017","url":null,"abstract":"\u0000 The freshwater production in a conventional solar still (CSS) is very less and it can be enhanced by either enhancing evaporation or condensation rates or both in the solar still. Therefore, the current investigation focused on enhancing both the evaporation rate in the absorber basin and the condensation rate over the top glass simultaneously. In this regard, the evaporation rate is enhanced by using a hollow-finned absorber basin with energy storage and novel pond fibres in the absorber basin. Likewise, the sisal fibre with a water dripping arrangement is utilized for enhancing the condensation over the top glass. The investigations on the CSS and the modified solar still (MSS) with hollow fins and energy storage, pond fibres, and sisal fibres are conducted to analyze the effect of energy storage and natural fibres on the distillate production. It is observed that the water temperatures of the MSS are increased by 12% and the glass temperatures of the MSS are reduced by 30% relative to the CSS. The outcomes reported that the productivity of the MSS is enhanced by 126%. Furthermore, the cost per litre (CPL) and the payback period (PP) of the MSS are 38.5 and 49.3% lesser than the CPL and the PP of the CSS, respectively.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"142 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73477835","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 UN Sustainability Goals address measures to reduce environmental pollution. Water distribution systems (WDSs) use electric energy, which pollutes the atmosphere through, at least partly, the burning of coal. This study simulates, through modeling, variable-speed pumps (VSPs) on 15 different real WDSs on the network solver EPANET and analyzes the payback period. An algorithm is introduced here to select the optimal pump speed pattern to save the most energy while satisfying the constrain of sufficient pressure at all times and all locations. It was found that five of the 15 systems operated unsuccessfully using a VSP, due to the VSP operating at lower speeds causing a lower pressure than normal, thereby causing the pressure to become negative. Additionally, a new chart that compares the payback period, project life, and energy costs between the base case and the VSP case was developed and different regions on the chart reflect different decision criteria.
{"title":"Economic feasibility analysis of variable-speed pumps by simulating 15 multiple water distribution systems","authors":"Conrad B. Truettner, B. Barkdoll","doi":"10.2166/aqua.2022.032","DOIUrl":"https://doi.org/10.2166/aqua.2022.032","url":null,"abstract":"\u0000 The UN Sustainability Goals address measures to reduce environmental pollution. Water distribution systems (WDSs) use electric energy, which pollutes the atmosphere through, at least partly, the burning of coal. This study simulates, through modeling, variable-speed pumps (VSPs) on 15 different real WDSs on the network solver EPANET and analyzes the payback period. An algorithm is introduced here to select the optimal pump speed pattern to save the most energy while satisfying the constrain of sufficient pressure at all times and all locations. It was found that five of the 15 systems operated unsuccessfully using a VSP, due to the VSP operating at lower speeds causing a lower pressure than normal, thereby causing the pressure to become negative. Additionally, a new chart that compares the payback period, project life, and energy costs between the base case and the VSP case was developed and different regions on the chart reflect different decision criteria.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80122937","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}
Cha Zhang, Haixing Liu, Shengwei Pei, Mengke Zhao, Huicheng Zhou
Resilience has currently attracted increasing interest in the optimization of water distribution systems (WDSs). Most research mainly focuses on optimal design problems. However, the system operation has not been investigated adequately regarding resilience. Therefore, we proposed an integral format of the demand-weighted modified resilience index (IMRI), which can capture the overall resilient performance throughout the operational period. This indicator was incorporated into the multi-objective operation optimization model as one of the objectives. Two benchmark networks were considered as case studies. The resulting Pareto fronts show a clear competing relationship between cost and resilience. Operating conditions in pumps, reservoirs and tanks at each regulation step were characterized by methods of resilience decomposition, which proved valuable intuitively for resilience regulation. A framework for explicit resilience assessment was also developed to examine directly the overall performance in statistics about those optimal solutions obtained. Explicit resilience results show that the IMRI can effectively quantify the resilience of system operation in the temporal dimension. Furthermore, scheduling more pumps, higher trigger-on levels of tanks and a wider range of trigger-level control could yield a more resilient solution to the operation of WDSs.
{"title":"Multi-objective operational optimization toward improved resilience in water distribution systems","authors":"Cha Zhang, Haixing Liu, Shengwei Pei, Mengke Zhao, Huicheng Zhou","doi":"10.2166/aqua.2022.136","DOIUrl":"https://doi.org/10.2166/aqua.2022.136","url":null,"abstract":"\u0000 Resilience has currently attracted increasing interest in the optimization of water distribution systems (WDSs). Most research mainly focuses on optimal design problems. However, the system operation has not been investigated adequately regarding resilience. Therefore, we proposed an integral format of the demand-weighted modified resilience index (IMRI), which can capture the overall resilient performance throughout the operational period. This indicator was incorporated into the multi-objective operation optimization model as one of the objectives. Two benchmark networks were considered as case studies. The resulting Pareto fronts show a clear competing relationship between cost and resilience. Operating conditions in pumps, reservoirs and tanks at each regulation step were characterized by methods of resilience decomposition, which proved valuable intuitively for resilience regulation. A framework for explicit resilience assessment was also developed to examine directly the overall performance in statistics about those optimal solutions obtained. Explicit resilience results show that the IMRI can effectively quantify the resilience of system operation in the temporal dimension. Furthermore, scheduling more pumps, higher trigger-on levels of tanks and a wider range of trigger-level control could yield a more resilient solution to the operation of WDSs.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"107 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88146468","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 is necessary for human health, economic success, and happiness, as well as other developmental goals such as proper diet, gender equality, education, and poverty reduction. Drinking water is a common problem in Ejere Town. The primary goal of this study was to investigate the accessibility of the town's drinking water distribution system. To achieve this research goal, the hydraulic performance of the town's water distribution system and the level of customers’ satisfaction were assessed. A total of 374 sampled households were randomly chosen from a total of 13,380 to measure the degree of customer satisfaction with the town's water supply services, and the hydraulic performance of the town's water distribution system was analyzed using the WaterGEMS software. Of the 374 customers surveyed for the study, 85 (22.7%) were satisfied and 289 (77.3%) were dissatisfied, implying that the satisfaction levels were below average. The WaterGEMS hydraulic model was calibrated (R2 = 0.94) using measured data from nine randomly chosen nodes. According to the model results, a great amount of the velocity and pressure in the water distribution system was below the minimum recommended limits. These minimum pressures and velocity levels indicate that there is not enough water pressure in the distribution network to reach all parts of Ejere Town. Finally, it was concluded that there was insufficient access to drinking water in the town.
{"title":"Assessment of accessibility and hydraulic performance of the water distribution system of Ejere Town","authors":"Girma Tufa, B. Abate","doi":"10.2166/aqua.2022.012","DOIUrl":"https://doi.org/10.2166/aqua.2022.012","url":null,"abstract":"\u0000 Water is necessary for human health, economic success, and happiness, as well as other developmental goals such as proper diet, gender equality, education, and poverty reduction. Drinking water is a common problem in Ejere Town. The primary goal of this study was to investigate the accessibility of the town's drinking water distribution system. To achieve this research goal, the hydraulic performance of the town's water distribution system and the level of customers’ satisfaction were assessed. A total of 374 sampled households were randomly chosen from a total of 13,380 to measure the degree of customer satisfaction with the town's water supply services, and the hydraulic performance of the town's water distribution system was analyzed using the WaterGEMS software. Of the 374 customers surveyed for the study, 85 (22.7%) were satisfied and 289 (77.3%) were dissatisfied, implying that the satisfaction levels were below average. The WaterGEMS hydraulic model was calibrated (R2 = 0.94) using measured data from nine randomly chosen nodes. According to the model results, a great amount of the velocity and pressure in the water distribution system was below the minimum recommended limits. These minimum pressures and velocity levels indicate that there is not enough water pressure in the distribution network to reach all parts of Ejere Town. Finally, it was concluded that there was insufficient access to drinking water in the town.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79304156","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 increasing popularity of long-distance water supply projects and the development of materials technology, the variation of water hammer characteristics in the viscoelastic pipeline has become the focus of researchers. To find out the mechanism of water hammer in the viscoelastic pipe of both elastic and viscous properties, an experiment was set up to study the direct water hammer generated by rapid closure of the downstream valve in the polymethyl methacrylate (PMMA) pipe, with six flow velocities in nearly 70 tests. The experimental results showed that the maximum water hammer pressure generated in the viscoelastic pipe in all flow velocities was (20% at most) greater than the traditional value of Joukowsky's formula. A faster closing time of the valve caused a higher water hammer pressure. The difference in water hammer pressure generated between the fastest and the slowest closing time of the valve was 14–17% at each flow velocity. Based on the relationship between the stress and strain of the pipe wall in the viscoelastic pipe, the reason that the water hammer characteristic in the viscoelastic pipeline was different from the traditional value was explained. The study provides a reference for the mechanism of transient flow in viscoelastic pipelines.
{"title":"Experimental study on pressure characteristics of direct water hammer in the viscoelastic pipeline","authors":"Xiaoying Zhang, Shengbin Chen, Tingyu Xu, Jian Zhang","doi":"10.2166/aqua.2022.005","DOIUrl":"https://doi.org/10.2166/aqua.2022.005","url":null,"abstract":"\u0000 With the increasing popularity of long-distance water supply projects and the development of materials technology, the variation of water hammer characteristics in the viscoelastic pipeline has become the focus of researchers. To find out the mechanism of water hammer in the viscoelastic pipe of both elastic and viscous properties, an experiment was set up to study the direct water hammer generated by rapid closure of the downstream valve in the polymethyl methacrylate (PMMA) pipe, with six flow velocities in nearly 70 tests. The experimental results showed that the maximum water hammer pressure generated in the viscoelastic pipe in all flow velocities was (20% at most) greater than the traditional value of Joukowsky's formula. A faster closing time of the valve caused a higher water hammer pressure. The difference in water hammer pressure generated between the fastest and the slowest closing time of the valve was 14–17% at each flow velocity. Based on the relationship between the stress and strain of the pipe wall in the viscoelastic pipe, the reason that the water hammer characteristic in the viscoelastic pipeline was different from the traditional value was explained. The study provides a reference for the mechanism of transient flow in viscoelastic pipelines.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86534881","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}
A finite-volume second-order Godunov-type scheme (GTS) combining the unsteady friction model (UFM) is introduced to simulate free surface flow in pipelines. The exact solution to the Riemann problem calculates the mass and momentum fluxes while considering the Brunone unsteady friction factor. One simple boundary treatment with double virtual cells is proposed to ensure the whole computation domain with second-order accuracy. Results of various transient free-surface flows achieved by the proposed models are compared with exact solution, experimental data, the four-point implicit Preissmann scheme solution, as well as predictions by the classic Method of Characteristics (MOC). Results show that the proposed second-order GTS UFMs are accurate, efficient, and stable even for Courant numbers less than one and sparse grid. The four-point implicit Preissmann scheme may produce severe numerical attenuation in the case of large time steps and unsuitable weighting factors, while the MOC scheme may produce severe numerical attenuation in the case of a low Courant number and could not maintain mass conservation. The numerical simulations considering the unsteady friction factor are closer to the measured water depth variations. The effect of unsteady friction becomes more important as the initial water depth difference increases significantly.
{"title":"Godunov-type solutions for free surface transient flow in pipeline incorporating unsteady friction","authors":"Yinying Hu, Ling Zhou, Tianwen Pan, Haoyu Fang, Yunjie Li, Deyou Liu","doi":"10.2166/aqua.2022.161","DOIUrl":"https://doi.org/10.2166/aqua.2022.161","url":null,"abstract":"\u0000 A finite-volume second-order Godunov-type scheme (GTS) combining the unsteady friction model (UFM) is introduced to simulate free surface flow in pipelines. The exact solution to the Riemann problem calculates the mass and momentum fluxes while considering the Brunone unsteady friction factor. One simple boundary treatment with double virtual cells is proposed to ensure the whole computation domain with second-order accuracy. Results of various transient free-surface flows achieved by the proposed models are compared with exact solution, experimental data, the four-point implicit Preissmann scheme solution, as well as predictions by the classic Method of Characteristics (MOC). Results show that the proposed second-order GTS UFMs are accurate, efficient, and stable even for Courant numbers less than one and sparse grid. The four-point implicit Preissmann scheme may produce severe numerical attenuation in the case of large time steps and unsuitable weighting factors, while the MOC scheme may produce severe numerical attenuation in the case of a low Courant number and could not maintain mass conservation. The numerical simulations considering the unsteady friction factor are closer to the measured water depth variations. The effect of unsteady friction becomes more important as the initial water depth difference increases significantly.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86550531","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 recent years, the widespread of antibiotic resistance genes (ARGs) has brought tremendous risk to the biological safety of drinking water. With the increasing demand for drinking water quality, ARGs have been regarded as a new pollutant that may cause serious public health problems. A large number of studies showed that the disinfection process of drinking water treatment plants can remove ARGs. However, the effects of traditional disinfection methods on ARGs have their own disadvantages. Tea polyphenols have attracted more and more researchers’ attention as a green, efficient and non-disinfection by-products disinfectant. The effect of the ozone–tea polyphenols disinfection process on ARGs in filtered effluent of waterworks was analyzed by using the metagenomic sequencing. The result shows that the ozone–tea polyphenols disinfection process is suitable for specific raw water containing more tetracycline, sulfonamide, β-lactam, and aminoglycoside resistance genes, and the removal rate of total resistance genes in water is higher than the traditional disinfection process. The effect of the ozone–tea polyphenols disinfection process on ARGs is to reduce the transfer of ARGs by destroying ARGs molecules and inhibiting the proliferation of ARGs host cells. As an assistant disinfectant, tea polyphenols have significance for the ability to remove ARGs during traditional disinfection.
{"title":"Effect of ozone–tea polyphenols as a drinking water disinfection process on antibiotic resistance genes","authors":"Cuilan Feng, Hongri Yu, Ting Wang, Jing Li, Lihua Sun, Xing-cheng Tao","doi":"10.2166/aqua.2022.147","DOIUrl":"https://doi.org/10.2166/aqua.2022.147","url":null,"abstract":"\u0000 In recent years, the widespread of antibiotic resistance genes (ARGs) has brought tremendous risk to the biological safety of drinking water. With the increasing demand for drinking water quality, ARGs have been regarded as a new pollutant that may cause serious public health problems. A large number of studies showed that the disinfection process of drinking water treatment plants can remove ARGs. However, the effects of traditional disinfection methods on ARGs have their own disadvantages. Tea polyphenols have attracted more and more researchers’ attention as a green, efficient and non-disinfection by-products disinfectant. The effect of the ozone–tea polyphenols disinfection process on ARGs in filtered effluent of waterworks was analyzed by using the metagenomic sequencing. The result shows that the ozone–tea polyphenols disinfection process is suitable for specific raw water containing more tetracycline, sulfonamide, β-lactam, and aminoglycoside resistance genes, and the removal rate of total resistance genes in water is higher than the traditional disinfection process. The effect of the ozone–tea polyphenols disinfection process on ARGs is to reduce the transfer of ARGs by destroying ARGs molecules and inhibiting the proliferation of ARGs host cells. As an assistant disinfectant, tea polyphenols have significance for the ability to remove ARGs during traditional disinfection.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76373011","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 research, an M5 model tree is employed for the prediction of removal efficiency of azithromycin antibiotics by multi-wall carbon nanotubes (MWCNTs), based on experimental data sets from a laboratory column mode. The effect of total flow time (0–260 min), influent flow rates (0.5, 1, and 1.5 mL min−1), bed depths (2, 4, and 6 cm), initial azithromycin concentrations (25, 50, and 100 mg L−1), and pHs (2, 4, 6, 8, and 10) was considered in the adsorption process. Based on the obtained structures, three linear equations (LM, LM2, and LM3) were developed. The root mean square error (RMSE) of 9.89% and determination coefficient (R2) of 0.946 were determined for predicting azithromycin removal by the M5 model tree. The results indicated that contact time was more important in the adsorption process, relative to other operating conditions. This research showed that the M5 model tree could be an accurate and faster alternative to the available mathematical models to estimate removal rates of pollutants. The results obtained from the FTIR technique confirmed that the O–H groups on the MWCNTs surface have an important role in azithromycin adsorption.
本研究基于实验室柱模式的实验数据集，采用M5模型树预测多壁碳纳米管(MWCNTs)对阿奇霉素类抗生素的去除效率。在吸附过程中考虑了总流动时间(0-260 min)、进水流速(0.5、1和1.5 mL min - 1)、床层深度(2、4和6 cm)、初始阿奇霉素浓度(25、50和100 mg L - 1)和ph值(2、4、6、8和10)的影响。在此基础上，建立了LM、LM2和LM3三个线性方程。M5模型树预测阿奇霉素去除率的均方根误差(RMSE)为9.89%，决定系数(R2)为0.946。结果表明，相对于其他操作条件，接触时间在吸附过程中更为重要。这项研究表明，M5模型树可以是一个准确和更快的替代现有的数学模型来估计污染物的去除率。FTIR技术的结果证实了MWCNTs表面的O-H基团对阿奇霉素的吸附有重要作用。
{"title":"Assessment of M5 model tree for prediction of azithromycin antibiotic removal by multi-wall carbon nanotubes in a fixed-bed column system","authors":"M. Amiri, M. Bahrami, Sara Rajabi","doi":"10.2166/aqua.2022.157","DOIUrl":"https://doi.org/10.2166/aqua.2022.157","url":null,"abstract":"\u0000 In this research, an M5 model tree is employed for the prediction of removal efficiency of azithromycin antibiotics by multi-wall carbon nanotubes (MWCNTs), based on experimental data sets from a laboratory column mode. The effect of total flow time (0–260 min), influent flow rates (0.5, 1, and 1.5 mL min−1), bed depths (2, 4, and 6 cm), initial azithromycin concentrations (25, 50, and 100 mg L−1), and pHs (2, 4, 6, 8, and 10) was considered in the adsorption process. Based on the obtained structures, three linear equations (LM, LM2, and LM3) were developed. The root mean square error (RMSE) of 9.89% and determination coefficient (R2) of 0.946 were determined for predicting azithromycin removal by the M5 model tree. The results indicated that contact time was more important in the adsorption process, relative to other operating conditions. This research showed that the M5 model tree could be an accurate and faster alternative to the available mathematical models to estimate removal rates of pollutants. The results obtained from the FTIR technique confirmed that the O–H groups on the MWCNTs surface have an important role in azithromycin adsorption.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77932175","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}
Phytoplankton communities can be classified into different groups based on physiological, morphological, and ecological functions. In this study, the responses of phytoplankton functional groups (PFGs) to physicochemical variables and hydraulic regimes were investigated and used as ecological indicators in the Tri An Reservoir (TAR), a eutrophic tropical floodplain reservoir located in southern Vietnam. Altogether, 148 phytoplankton taxa were identified and assigned to 16 PFGs; the four predominant PFG groups were M (Microcystis spp.), MP (filamentous cyanobacteria: Oscillatoria spp., and some other diatoms: Gomphonema angustatum, Navicula sp.), J (green algae: Coelastrum spp., Cosmarium spp., Pediastrum spp., Scenedesmus spp., Staurastrum spp., Tetradesmus spp., Tetraëdron spp., and Xanthidium spp.), and P (Closterium spp., Aulacoseira granulata, Fragilaria spp., Pinnularia spp., and Desmidium baileyi). The average PFG biovolume ranged from 79.6 ± 20.2 to 230.1 ± 69.1 mg/L with M being the dominant group. The trophic state index (TSI) indicated that the water condition was light-eutrophic to hyper-eutrophic. It was found that the large water level fluctuation resulted in seasonal nutrient dynamics, with higher nutrient concentrations and higher turbidity during the low water level period and vice versa. The redundancy analysis (RDA) indicated that the nutrient concentrations, water level fluctuation, and mixing regimes were critical factors in the PFG selection in the TAR. Therefore, we assumed that water level fluctuation management coupled with biological competition have the potential to control toxic cyanobacteria in the TAR. In conclusion, the PFGs are suitable for examining the effects of environmental conditions on phytoplankton dynamics in tropical floodplain reservoirs, but their sensitivity to long-term changes in water quality and eutrophication requires further investigation.
{"title":"Factors affecting the seasonal succession of phytoplankton functional groups in a tropical floodplain reservoir in Vietnam","authors":"T. Pham, T. Tran, T. Tran","doi":"10.2166/aqua.2022.110","DOIUrl":"https://doi.org/10.2166/aqua.2022.110","url":null,"abstract":"\u0000 Phytoplankton communities can be classified into different groups based on physiological, morphological, and ecological functions. In this study, the responses of phytoplankton functional groups (PFGs) to physicochemical variables and hydraulic regimes were investigated and used as ecological indicators in the Tri An Reservoir (TAR), a eutrophic tropical floodplain reservoir located in southern Vietnam. Altogether, 148 phytoplankton taxa were identified and assigned to 16 PFGs; the four predominant PFG groups were M (Microcystis spp.), MP (filamentous cyanobacteria: Oscillatoria spp., and some other diatoms: Gomphonema angustatum, Navicula sp.), J (green algae: Coelastrum spp., Cosmarium spp., Pediastrum spp., Scenedesmus spp., Staurastrum spp., Tetradesmus spp., Tetraëdron spp., and Xanthidium spp.), and P (Closterium spp., Aulacoseira granulata, Fragilaria spp., Pinnularia spp., and Desmidium baileyi). The average PFG biovolume ranged from 79.6 ± 20.2 to 230.1 ± 69.1 mg/L with M being the dominant group. The trophic state index (TSI) indicated that the water condition was light-eutrophic to hyper-eutrophic. It was found that the large water level fluctuation resulted in seasonal nutrient dynamics, with higher nutrient concentrations and higher turbidity during the low water level period and vice versa. The redundancy analysis (RDA) indicated that the nutrient concentrations, water level fluctuation, and mixing regimes were critical factors in the PFG selection in the TAR. Therefore, we assumed that water level fluctuation management coupled with biological competition have the potential to control toxic cyanobacteria in the TAR. In conclusion, the PFGs are suitable for examining the effects of environmental conditions on phytoplankton dynamics in tropical floodplain reservoirs, but their sensitivity to long-term changes in water quality and eutrophication requires further investigation.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83337243","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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