H. Shon, S. Phuntsho, D. Chaudhary, S. Vigneswaran, Jaeweon Cho
Abstract. The application of membrane technology in water and wastewater treatment is increasing due to stringent water quality standards. Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination. NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates. This paper briefly reviews the application of NF for water and wastewater treatment including fundamentals, mechanisms, fouling challenges and their controls.
{"title":"Nanofiltration for water and wastewater treatment – a mini review","authors":"H. Shon, S. Phuntsho, D. Chaudhary, S. Vigneswaran, Jaeweon Cho","doi":"10.5194/dwes-6-47-2013","DOIUrl":"https://doi.org/10.5194/dwes-6-47-2013","url":null,"abstract":"Abstract. The application of membrane technology in water and wastewater treatment is increasing due to stringent water quality standards. Nanofiltration (NF) is one of the widely used membrane processes for water and wastewater treatment in addition to other applications such as desalination. NF has replaced reverse osmosis (RO) membranes in many applications due to lower energy consumption and higher flux rates. This paper briefly reviews the application of NF for water and wastewater treatment including fundamentals, mechanisms, fouling challenges and their controls.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"5 1","pages":"47-53"},"PeriodicalIF":0.0,"publicationDate":"2013-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221586","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}
Abstract. The global population is increasingly concentrated in cities. Cities and urban areas face many challenges – economic, social, health and environmental – which are often exacerbated by an increase in the frequency of natural disasters. Together, these challenges call for a shift towards sustainable cities which reduce their impact on the surrounding environment, whilst at the same time succeeding to make resources available to their increasing number of inhabitants. This study explores the state of the art of water management practices of the highly urbanised Northern Italian region and plans and scope for the future development of water management. Although the region is at present not under severe water stress, recently some cities faced water scarcity problems and were forced to implement water rationing. We assessed the vulnerability of Parma and Ferrara to a water crisis, together with the regular and emergency adaptation measures already in place, and the forecast for the near future. In two workshops, the authors adapted the Australian concept of water sensitive urban design for the Italian context. Although the population remains generally unaware of the impact of the two latest severe drought events (2003 and 2006/7), many adaptation measures towards a more sustainable use of the water resource are already in place – technically, institutionally, and individually. Water managers consider however that the drastic and definite changes needed to integrate the urban water management cycle, and which minimise the ecological footprint of urban spaces, lay far in the future.
{"title":"Present challenges for future water sustainable cities: a case study from Italy","authors":"L. Bonzanigo, G. Sinnona","doi":"10.5194/DWES-7-35-2014","DOIUrl":"https://doi.org/10.5194/DWES-7-35-2014","url":null,"abstract":"Abstract. The global population is increasingly concentrated in cities. Cities and urban areas face many challenges – economic, social, health and environmental – which are often exacerbated by an increase in the frequency of natural disasters. Together, these challenges call for a shift towards sustainable cities which reduce their impact on the surrounding environment, whilst at the same time succeeding to make resources available to their increasing number of inhabitants. This study explores the state of the art of water management practices of the highly urbanised Northern Italian region and plans and scope for the future development of water management. Although the region is at present not under severe water stress, recently some cities faced water scarcity problems and were forced to implement water rationing. We assessed the vulnerability of Parma and Ferrara to a water crisis, together with the regular and emergency adaptation measures already in place, and the forecast for the near future. In two workshops, the authors adapted the Australian concept of water sensitive urban design for the Italian context. Although the population remains generally unaware of the impact of the two latest severe drought events (2003 and 2006/7), many adaptation measures towards a more sustainable use of the water resource are already in place – technically, institutionally, and individually. Water managers consider however that the drastic and definite changes needed to integrate the urban water management cycle, and which minimise the ecological footprint of urban spaces, lay far in the future.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"39 1","pages":"35-40"},"PeriodicalIF":0.0,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71222149","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}
Abstract. New behavioral indexes including combined index (CI), distribution index (DI), toxic index (TI), and altitude index (AI) for a biological early warning system (BEWS) were developed and evaluated using Daphnia magna in this study. The sensitivity and stability of each index were compared to evaluate the performance of the indexes through a real-time exposure test with a synthetic copper solution. The applicability of the CI to the field sample was evaluated through an effluent exposure test. The proportional relationship between toxicity level and magnitude of response was much lower in the effluent due to the complexity of water than in the copper solution. The results showed that the CI was most sensitive among the three indexes, while the DI was confirmed as the most useful index among the individual indexes. The combined index (CI) shows not only sensitivity but also stability in normal conditions below the statistically significant threshold (p 0.01). The CI improved performance of the BEWS in terms of sensitivity and stability, and it was confirmed as the higher correlation coefficient between the magnitude of the index and the toxicity level of the water sample.
{"title":"Development and evaluation of new behavioral indexes for a biological early warning system using Daphnia magna","authors":"T. Jeong, Jun-Hyuk Jeon, S. D. Kim","doi":"10.5194/DWES-7-1-2014","DOIUrl":"https://doi.org/10.5194/DWES-7-1-2014","url":null,"abstract":"Abstract. New behavioral indexes including combined index (CI), distribution index (DI), toxic index (TI), and altitude index (AI) for a biological early warning system (BEWS) were developed and evaluated using Daphnia magna in this study. The sensitivity and stability of each index were compared to evaluate the performance of the indexes through a real-time exposure test with a synthetic copper solution. The applicability of the CI to the field sample was evaluated through an effluent exposure test. The proportional relationship between toxicity level and magnitude of response was much lower in the effluent due to the complexity of water than in the copper solution. The results showed that the CI was most sensitive among the three indexes, while the DI was confirmed as the most useful index among the individual indexes. The combined index (CI) shows not only sensitivity but also stability in normal conditions below the statistically significant threshold (p 0.01). The CI improved performance of the BEWS in terms of sensitivity and stability, and it was confirmed as the higher correlation coefficient between the magnitude of the index and the toxicity level of the water sample.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"208 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2013-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221940","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}
Sedimentation in drinking water networks can lead to discolouration complaints. A sufficient criterion to prevent sedimentation in the Dutch drinking water networks is a daily maximum velocity of 0.25 m s?1. Flushing experiments have shown that this criterion is a sufficient condition for a clean network, but not a necessary condition. Drinking water networks include many locations with a maximum velocity well below 0.25 m s?1 without accumulated sediments. Other criteria need to be developed to predict which locations are susceptible to sedimentation and to prevent sedimentation in future networks. More distinctive criteria are helpful to prioritise flushing operations and to prevent water quality complaints. The authors use three different numerical modelling approaches – quasi-steady, rigid column and water hammer – with a temporal discretisation of 1 s in order to assess the influence of unsteady flows on the wall shear stress, causing resuspension of sediment particles. The model predictions are combined with results from flushing experiments in the drinking water distribution system of Purmerend, the Netherlands. The waterhammer model does not result in essentially different flow distribution patterns, compared to the rigid column and quasi-steady modelling approach. The extra information from the waterhammer model is a velocity oscillation of approximately 0.02 m s?1 around the quasi-steady solution. The presence of stagnation zones and multiple flow direction reversals seem to be interesting new parameters to predict sediment accumulation, which are consistent with the observed turbidity data and theoretical considerations on critical shear stresses.
饮用水网中的沉淀物会引起变色投诉。在荷兰的饮用水网络中，防止沉积的一个充分标准是每日最大流速为0.25 m s?1。冲洗实验表明，该准则是清洁网络的充分条件，但不是必要条件。饮用水网络包括许多最大流速远低于0.25 m / s的地点。1 .无沉积物堆积。需要制定其他标准，以预测哪些地点容易淤积，并防止未来水网淤积。制订更有特色的准则，有助安排冲厕作业的先后次序，以及防止有关水质的投诉。作者使用三种不同的数值模拟方法-准稳定、刚性柱和水锤-具有1 s的时间离散，以评估非定常流对壁面剪切应力的影响，导致泥沙颗粒的再悬浮。模型预测与荷兰Purmerend饮用水分配系统的冲洗实验结果相结合。与刚性柱和准稳态建模方法相比，水锤模型没有产生本质上不同的流动分布模式。来自水锤模型的额外信息是大约0.02 m / s的速度振荡。1绕准稳态解。停滞带和多次水流方向逆转的存在似乎是预测沉积物堆积的有趣的新参数，这与观测到的浊度数据和临界剪应力的理论考虑一致。
{"title":"Dynamic hydraulic models to study sedimentation in drinking water networks in detail","authors":"I. Pothof, E. Blokker","doi":"10.5194/DWES-5-87-2012","DOIUrl":"https://doi.org/10.5194/DWES-5-87-2012","url":null,"abstract":"Sedimentation in drinking water networks can lead to discolouration complaints. A sufficient criterion to prevent sedimentation in the Dutch drinking water networks is a daily maximum velocity of 0.25 m s?1. Flushing experiments have shown that this criterion is a sufficient condition for a clean network, but not a necessary condition. Drinking water networks include many locations with a maximum velocity well below 0.25 m s?1 without accumulated sediments. Other criteria need to be developed to predict which locations are susceptible to sedimentation and to prevent sedimentation in future networks. More distinctive criteria are helpful to prioritise flushing operations and to prevent water quality complaints. The authors use three different numerical modelling approaches – quasi-steady, rigid column and water hammer – with a temporal discretisation of 1 s in order to assess the influence of unsteady flows on the wall shear stress, causing resuspension of sediment particles. The model predictions are combined with results from flushing experiments in the drinking water distribution system of Purmerend, the Netherlands. The waterhammer model does not result in essentially different flow distribution patterns, compared to the rigid column and quasi-steady modelling approach. The extra information from the waterhammer model is a velocity oscillation of approximately 0.02 m s?1 around the quasi-steady solution. The presence of stagnation zones and multiple flow direction reversals seem to be interesting new parameters to predict sediment accumulation, which are consistent with the observed turbidity data and theoretical considerations on critical shear stresses.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"5 1","pages":"87-92"},"PeriodicalIF":0.0,"publicationDate":"2012-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5194/DWES-5-87-2012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71220891","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}
L. D. Sánchez, L. M. Marin, J. Visscher, L. Rietveld
This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF) in a multi-stage filtration (MSF) plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF) and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%). Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.
{"title":"Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration","authors":"L. D. Sánchez, L. M. Marin, J. Visscher, L. Rietveld","doi":"10.5194/DWES-5-73-2012","DOIUrl":"https://doi.org/10.5194/DWES-5-73-2012","url":null,"abstract":"This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF) in a multi-stage filtration (MSF) plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It strongly reduces the load of particulate material before the water enters in the slow sand filters (SSF) and therewith avoids short filter runs and prevents early interruption in SSF operations. The removal efficiency of turbidity in the CF-UGF with coagulant was between 85 and 96%, whereas the average efficiency without coagulant dosing was 46% (range: 21–76%). Operating with coagulant also improves the removal efficiency for total coliforms, E-coli and HPC. No reduction was observed in the microbial activity of the SSF, no obstruction of the SSF bed was demonstrated and SSF runs were maintained between 50 and 70 days for a maximum head loss of 0.70 m. The most important advantage is the flexibility of the system to operate with and without coagulant according to the influent turbidity. It was only necessary for 20% of the time to operate with the coagulant. The CF-UGF unit represented 7% of total construction costs and the O&M cost for the use of coagulant represented only 0.3%.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"5 1","pages":"73-85"},"PeriodicalIF":0.0,"publicationDate":"2012-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5194/DWES-5-73-2012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221229","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. Nejjari, R. Pérez, V. Puig, J. Quevedo, R. Sarrate, M. Cugueró, G. Sanz, J. M. Mirats
Abstract. This paper proposes a model based detection and localisation method to deal with abnormal quality levels based on the chlorine measurements and chlorine sensitivity analysis in a water distribution network. A fault isolation algorithm which correlates on line the residuals (generated by comparing the available chlorine measurements with their estimations using a model) with the fault sensitivity matrix is used. The proposed methodology has been applied to a District Metered Area (DMA) in the Barcelona network.
{"title":"Abnormal quality detection and isolation in water distribution networks using simulation models","authors":"F. Nejjari, R. Pérez, V. Puig, J. Quevedo, R. Sarrate, M. Cugueró, G. Sanz, J. M. Mirats","doi":"10.5194/DWES-5-67-2012","DOIUrl":"https://doi.org/10.5194/DWES-5-67-2012","url":null,"abstract":"Abstract. This paper proposes a model based detection and localisation method to deal with abnormal quality levels based on the chlorine measurements and chlorine sensitivity analysis in a water distribution network. A fault isolation algorithm which correlates on line the residuals (generated by comparing the available chlorine measurements with their estimations using a model) with the fault sensitivity matrix is used. The proposed methodology has been applied to a District Metered Area (DMA) in the Barcelona network.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"5 1","pages":"67-72"},"PeriodicalIF":0.0,"publicationDate":"2012-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5194/DWES-5-67-2012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221315","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}
Abstract. Leaks in water systems are presently a frequent and increasing event that involves cost increase and poor service, not compliant to quality standards and modern management criteria. The most recent data available in Italy, resumed into the report issued by Control Committee for Water Resources Use (CONVIRI), shows leakages with an average value of 37%. It is therefore important, for maintenance perspective, to investigate occurrence and evolution of water leaks and the analytical link between leaks Qp and network pressure P, for a reliable calibration of water networks quali-quantitative simulation models. The present work reports the first results of an experimental campaign started at Laboratory of Hydraulics of Department of Hydraulics, Geotechnical and Environmental Engineering of University of Naples Federico II in order to analyze the features of Qp(P) relation, which are compared with other results issued in literature.
{"title":"Leakages and pressure relation: an experimental research","authors":"F. Paola, M. Giugni","doi":"10.5194/DWES-5-59-2012","DOIUrl":"https://doi.org/10.5194/DWES-5-59-2012","url":null,"abstract":"Abstract. Leaks in water systems are presently a frequent and increasing event that involves cost increase and poor service, not compliant to quality standards and modern management criteria. The most recent data available in Italy, resumed into the report issued by Control Committee for Water Resources Use (CONVIRI), shows leakages with an average value of 37%. It is therefore important, for maintenance perspective, to investigate occurrence and evolution of water leaks and the analytical link between leaks Qp and network pressure P, for a reliable calibration of water networks quali-quantitative simulation models. The present work reports the first results of an experimental campaign started at Laboratory of Hydraulics of Department of Hydraulics, Geotechnical and Environmental Engineering of University of Naples Federico II in order to analyze the features of Qp(P) relation, which are compared with other results issued in literature.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"5 1","pages":"59-65"},"PeriodicalIF":0.0,"publicationDate":"2012-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5194/DWES-5-59-2012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221103","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}
Abstract. Sporadic detection of live (viable) Escherichia coli in drinking water and biofilm with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. The aim of this study was to determine spatial distribution of different viability forms of E. coli in a drinking water distribution system which complies with European Drinking Water Directive (98/83/EC). For two years coupons (two week old) and pre-concentrated (100 times with ultrafilters) water samples were collected after treatment plants and from four sites in the distribution network at several distances. The samples were analyzed for total, viable (able to divide as DVC-FISH positive) and cultivable E. coli. The results showed that low numbers of E. coli enters the distribution sytem from the treatment plants and tend to accumulate in the biofilm of water distribution system. Almost all of the samples contained metabolically active E. coli in the range of 1 to 50 cells per litre or cm2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli significantly increased into the network irrespective of the season. The study has shown that DVC-FISH method in combination with water pre-concentration and biofilm sampling allows to better understand the behaviour of E. coli in water distribution networks, thus, it provides new evidences for water safety control.
{"title":"Application of DVC-FISH method in tracking Escherichia coli in drinking water distribution networks","authors":"L. Mezule, S. Larsson, T. Juhna","doi":"10.5194/DWES-6-25-2013","DOIUrl":"https://doi.org/10.5194/DWES-6-25-2013","url":null,"abstract":"Abstract. Sporadic detection of live (viable) Escherichia coli in drinking water and biofilm with molecular methods but not with standard plate counts has raised concerns about the reliability of this indicator in the surveillance of drinking water safety. The aim of this study was to determine spatial distribution of different viability forms of E. coli in a drinking water distribution system which complies with European Drinking Water Directive (98/83/EC). For two years coupons (two week old) and pre-concentrated (100 times with ultrafilters) water samples were collected after treatment plants and from four sites in the distribution network at several distances. The samples were analyzed for total, viable (able to divide as DVC-FISH positive) and cultivable E. coli. The results showed that low numbers of E. coli enters the distribution sytem from the treatment plants and tend to accumulate in the biofilm of water distribution system. Almost all of the samples contained metabolically active E. coli in the range of 1 to 50 cells per litre or cm2 which represented approximately 53% of all E. coli detected. The amount of viable E. coli significantly increased into the network irrespective of the season. The study has shown that DVC-FISH method in combination with water pre-concentration and biofilm sampling allows to better understand the behaviour of E. coli in water distribution networks, thus, it provides new evidences for water safety control.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"97 1","pages":"25-31"},"PeriodicalIF":0.0,"publicationDate":"2012-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221742","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}
Abstract. To explore the possibility of fluoride toxicity, 747 water samples were collected from surface water and groundwater sources of 16 major cities of Pakistan, adopting a uniform sampling design with distribution of samples: Lahore (79), Kasur (46), Faisalabad (30), Khushab (50), Chakwal (51), Mianwali (30), Jhelum (53), Bahawalpur (60), Karachi (60), Mirpur Khas (55), Peshawar (38), Risalpur (35), Quetta (81), Ziarat (21), Loralai (21), and Mastung (37). Comparison of analytical findings with WHO Guidelines of Drinking Water for Fluoride (i.e., 1.5 ppm) has concluded that 16% of the monitored water sources have fluoride concentration beyond the permissible safe limit of 1.5 mg L−1 falling in the concentration range of 1.6–25 mg L−1. The highest fluoride contamination (22%) is detected in the Balochistan province followed by 19% in Punjab province. Comparatively higher fluoride levels of > 20% in the groundwater sources like hand pumps supported the possibility of increased groundwater contamination as excessive fluoride concentrations are expected to come from calcium-poor aquifers and in areas where fluoride-bearing minerals are common or where cation exchange of sodium for calcium occurs. Field observations have also indicated the prevalence of fluoride-associated health implications in the study areas with excessive fluoride in water sources. Findings of this study have provided bidirectional vision for the epidemiological investigations as well as to mitigate the issues in the affected vicinities of fluoride-rich areas.
摘要为探讨氟化物毒性的可能性，采用均匀抽样设计，从巴基斯坦16个主要城市的地表水和地下水中采集了747个水样，样本分布如下:拉合尔(79)、卡苏尔(46)、费萨拉巴德(30)、库沙布(50)、查克瓦尔(51)、米安瓦利(30)、杰勒姆(53)、巴哈瓦尔布尔(60)、卡拉奇(60)、米尔普尔卡尔斯(55)、白沙瓦(38)、里萨尔布尔(35)、奎达(81)、齐亚拉特(21)、洛拉莱(21)和马斯通(37)。将分析结果与世卫组织饮用水氟化物含量准则(即1.5 ppm)进行比较后得出的结论是，16%的监测水源的氟化物浓度超过了1.5 mg L - 1的允许安全限值，落在1.6-25 mg L - 1的浓度范围内。氟化物污染最严重的是俾路支省(22%)，其次是旁遮普省(19%)。在手动泵等地下水来源中，相对较高的氟含量为100 - 20%，这表明地下水污染可能会增加，因为预计过量的氟浓度将来自缺钙含水层和含氟矿物普遍存在的地区，或发生钠与钙阳离子交换的地区。实地观察还表明，在水源中氟化物含量过高的研究地区，与氟化物有关的健康问题普遍存在。本研究结果为流行病学调查提供了双向视角，也为富氟地区受影响地区的问题提供了缓解途径。
{"title":"Fluoride in the drinking water of Pakistan and the possible risk of crippling fluorosis","authors":"M. A. Tahir, H. Rasheed","doi":"10.5194/DWES-6-17-2013","DOIUrl":"https://doi.org/10.5194/DWES-6-17-2013","url":null,"abstract":"Abstract. To explore the possibility of fluoride toxicity, 747 water samples were collected from surface water and groundwater sources of 16 major cities of Pakistan, adopting a uniform sampling design with distribution of samples: Lahore (79), Kasur (46), Faisalabad (30), Khushab (50), Chakwal (51), Mianwali (30), Jhelum (53), Bahawalpur (60), Karachi (60), Mirpur Khas (55), Peshawar (38), Risalpur (35), Quetta (81), Ziarat (21), Loralai (21), and Mastung (37). Comparison of analytical findings with WHO Guidelines of Drinking Water for Fluoride (i.e., 1.5 ppm) has concluded that 16% of the monitored water sources have fluoride concentration beyond the permissible safe limit of 1.5 mg L−1 falling in the concentration range of 1.6–25 mg L−1. The highest fluoride contamination (22%) is detected in the Balochistan province followed by 19% in Punjab province. Comparatively higher fluoride levels of > 20% in the groundwater sources like hand pumps supported the possibility of increased groundwater contamination as excessive fluoride concentrations are expected to come from calcium-poor aquifers and in areas where fluoride-bearing minerals are common or where cation exchange of sodium for calcium occurs. Field observations have also indicated the prevalence of fluoride-associated health implications in the study areas with excessive fluoride in water sources. Findings of this study have provided bidirectional vision for the epidemiological investigations as well as to mitigate the issues in the affected vicinities of fluoride-rich areas.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"490 1","pages":"17-23"},"PeriodicalIF":0.0,"publicationDate":"2012-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221257","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}
Abstract. This paper extends the analysis concerning the importance in numerical models of unsteady friction and viscoelasticity to transients in plastic pipes with an external flow due to a leak. In fact recently such a benchmarking analysis has been executed for the cases of a constant diameter pipe (Duan et al., 2010), a pipe with a partially closed in-line valve (Meniconi et al., 2012a), and a pipe with cross-section changes in series (Meniconi et al., 2012b). Tests are based on laboratory experiments carried out at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy, and the use of different numerical models. The results show that it is crucial to take into account the viscoelasticity to simulate the main characteristics of the examined transients.
摘要本文扩展了非定常摩擦和粘弹性数值模型中对塑料管道外流泄漏瞬态的重要性的分析。事实上，最近已经对等径管道(Duan et al.， 2010)、带有部分关闭的直列阀的管道(Meniconi et al.， 2012a)和横截面连续变化的管道(Meniconi et al.， 2012b)进行了基准分析。测试基于在意大利佩鲁贾大学水工程实验室进行的实验室实验，并使用了不同的数值模型。结果表明，考虑粘弹性是模拟被测瞬态主要特性的关键。
{"title":"Numerical and experimental investigation of leaks in viscoelastic pressurized pipe flow","authors":"S. Meniconi, B. Brunone, M. Ferrante, C. Massari","doi":"10.5194/DWES-6-11-2013","DOIUrl":"https://doi.org/10.5194/DWES-6-11-2013","url":null,"abstract":"Abstract. This paper extends the analysis concerning the importance in numerical models of unsteady friction and viscoelasticity to transients in plastic pipes with an external flow due to a leak. In fact recently such a benchmarking analysis has been executed for the cases of a constant diameter pipe (Duan et al., 2010), a pipe with a partially closed in-line valve (Meniconi et al., 2012a), and a pipe with cross-section changes in series (Meniconi et al., 2012b). Tests are based on laboratory experiments carried out at the Water Engineering Laboratory (WEL) of the University of Perugia, Italy, and the use of different numerical models. The results show that it is crucial to take into account the viscoelasticity to simulate the main characteristics of the examined transients.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"6 1","pages":"11-16"},"PeriodicalIF":0.0,"publicationDate":"2012-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71221078","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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