Drinking Water Engineering and Science最新文献

{"title":"Water reclamation for industrial use in sub-Saharan Africa – a critical review","authors":"N. Gulamussen, A. Arsénio, N. Matsinhe, L. Rietveld","doi":"10.5194/DWES-12-45-2019","DOIUrl":"https://doi.org/10.5194/DWES-12-45-2019","url":null,"abstract":"Abstract. The increasing world population and growth of industrial\u0000development lead to growing water scarcity that, combined with deficient\u0000sanitation services, represents serious challenges, particularly in regions\u0000like sub-Saharan Africa. Water reclamation is a promising approach to reduce\u0000water scarcity, serving as a driving force for better sanitation services\u0000and protecting the environment by treating sewage and redistributing for the\u0000benefit of other water-dependent applications (e.g., industries). This paper aims to give an overview of the global trends on water\u0000reclamation, with a focus on industrial use, and to derive lessons for\u0000implementation of water reclamation projects in sub-Saharan Africa. Findings\u0000show that extensive experience exists in technology and management practices\u0000that can allow successful implementation of water reclamation projects in\u0000the region. Under the conditions of deficient sanitation services and low\u0000levels of technical expertise, the main challenge is to develop a framework\u0000that can facilitate the integration of social and technological\u0000methodologies and help in introducing water reclamation in water allocation\u0000planning, including the development of specific legislation for industrial\u0000water use and disposal.\u0000","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48947925","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":"Comprehensive analysis of the start-up period of a full-scale drinking water biofilter provides guidance for optimization","authors":"L. Ramsay, I. L. Breda, D. A. Søborg","doi":"10.5194/DWES-11-87-2018","DOIUrl":"https://doi.org/10.5194/DWES-11-87-2018","url":null,"abstract":"Abstract. The use of biofilters to produce drinking water from anaerobic\u0000groundwater is widespread in some European countries. A major disadvantage of\u0000biofilters is the long start-up period required for virgin filter medium to\u0000become fully functional. Although individual aspects of biofilter start-up\u0000have previously been investigated, no comprehensive study in full scale using\u0000inherent inoculation has previously been documented. A thorough investigation\u0000of a full-scale drinking water biofilter was carried out over 10 weeks of\u0000start-up. The many spatial and temporal changes taking place during start-up\u0000were documented using a holistic approach. In addition to collection of many\u0000samples over time (frequency) and space (filter depth), this study entailed\u0000the use of multiple sample media (water, backwash water and filter media) and\u0000multiple types of analyses (physical, chemical and microbiological). The\u0000decrease in filter effluent concentrations of individual substances to\u0000compliance levels followed a specific order that was shown to coincide with\u0000the spatiotemporal development of bacteria on the filter media. Due to the\u0000abiotic nature of the iron removal process, iron disappears at the earliest\u0000in the start-up period followed by substances that require growth of\u0000microorganisms. Ammonium disappears next, with nitrite appearing briefly near\u0000the end of ammonium removal, followed by manganese. The thorough overall\u0000picture obtained by these efforts provides guidance for optimization and\u0000monitoring of the start-up. Guidance for optimization includes shortening the\u0000start-up by focusing on kick-starting the ammonium removal; limiting the\u0000monitoring burden (at-line measurements of ammonium in finished water\u0000supplemented with manual manganese measurements when ammonium removal is\u0000complete); and improving filter design by isolating the removal processes in\u0000separate, smaller filters.\u0000","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48795336","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":"Mass imbalances in EPANET water-quality simulations.","authors":"Michael J Davis, Robert Janke, Thomas N Taxon","doi":"10.5194/dwes-11-25-2018","DOIUrl":"https://doi.org/10.5194/dwes-11-25-2018","url":null,"abstract":"EPANET is widely employed to simulate water quality in water distribution systems. However, in general, the time-driven simulation approach used to determine concentrations of water-quality constituents provides accurate results only for short water-quality time steps. Overly long time steps can yield errors in concentration estimates and can result in situations in which constituent mass is not conserved. The use of a time step that is sufficiently short to avoid these problems may not always be feasible. The absence of EPANET errors or warnings does not ensure conservation of mass. This paper provides examples illustrating mass imbalances and explains how such imbalances can occur because of fundamental limitations in the water-quality routing algorithm used in EPANET. In general, these limitations cannot be overcome by the use of improved water-quality modeling practices. This paper also presents a preliminary event-driven approach that conserves mass with a water-quality time step that is as long as the hydraulic time step. Results obtained using the current approach converge, or tend to converge, toward those obtained using the preliminary event-driven approach as the water-quality time step decreases. Improving the water-quality routing algorithm used in EPANET could eliminate mass imbalances and related errors in estimated concentrations. The results presented in this paper should be of value to those who perform water-quality simulations using EPANET or use the results of such simulations, including utility managers and engineers.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"11 1","pages":"25-47"},"PeriodicalIF":0.0,"publicationDate":"2018-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6093308/pdf/nihms1500983.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36406833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimum coagulant forecasting by modeling jar test experiments using ANNs","authors":"S. Haghiri, Amin Daghighi, Sina Moharramzadeh","doi":"10.5194/DWES-11-1-2018","DOIUrl":"https://doi.org/10.5194/DWES-11-1-2018","url":null,"abstract":"Abstract. Currently, the proper utilization of water treatment plants and\u0000optimizing their use is of particular importance. Coagulation and\u0000flocculation in water treatment are the common ways through which the use of\u0000coagulants leads to instability of particles and the formation of larger and\u0000heavier particles, resulting in improvement of sedimentation and filtration\u0000processes. Determination of the optimum dose of such a coagulant is of\u0000particular significance. A high dose, in addition to adding costs, can cause\u0000the sediment to remain in the filtrate, a dangerous condition according to\u0000the standards, while a sub-adequate dose of coagulants can result in the\u0000reducing the required quality and acceptable performance of the coagulation\u0000process. Although jar tests are used for testing coagulants, such experiments\u0000face many constraints with respect to evaluating the results produced by\u0000sudden changes in input water because of their significant costs, long time\u0000requirements, and complex relationships among the many factors (turbidity,\u0000temperature, pH, alkalinity, etc.) that can influence the efficiency of\u0000coagulant and test results. Modeling can be used to overcome these\u0000limitations; in this research study, an artificial neural network (ANN)\u0000multi-layer perceptron (MLP) with one hidden layer has been used for modeling\u0000the jar test to determine the dosage level of used coagulant in water\u0000treatment processes. The data contained in this research have been obtained\u0000from the drinking water treatment plant located in Ardabil province in\u0000Iran. To evaluate the performance of the model, the mean squared\u0000error (MSE) and correlation coefficient ( R2 ) parameters have been used. The\u0000obtained values are within an acceptable range that demonstrates the high\u0000accuracy of the models with respect to the estimation of water-quality\u0000characteristics and the optimal dosages of coagulants; so using these models\u0000will allow operators to not only reduce costs and time taken to perform\u0000experimental jar tests but also to predict a proper dosage for coagulant\u0000amounts and to project the quality of the output water under real conditions.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"11 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2018-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45645360","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":"The effect of a loss of model structural detail due to network skeletonization on contamination warning system design: case studies.","authors":"Michael J Davis, Robert Janke","doi":"10.5194/dwes-2017-39","DOIUrl":"10.5194/dwes-2017-39","url":null,"abstract":"<p><p>The effect of limitations in the structural detail available in a network model on contamination warning system (CWS) design was examined in case studies using the original and skeletonized network models for two water distribution systems (WDSs). The skeletonized models were used as proxies for incomplete network models. CWS designs were developed by optimizing sensor placements for worst-case and mean-case contamination events. Designs developed using the skeletonized network models were transplanted into the original network model for evaluation. CWS performance was defined as the number of people who ingest more than some quantity of a contaminant in tap water before the CWS detects the presence of contamination. Lack of structural detail in a network model can result in CWS designs that (1) provide considerably less protection against worst-case contamination events than that obtained when a more complete network model is available and (2) yield substantial underestimates of the consequences associated with a contamination event. Nevertheless, CWSs developed using skeletonized network models can provide useful reductions in consequences for contaminants whose effects are not localized near the injection location. Mean-case designs can yield worst-case performances similar to those for worst-case designs when there is uncertainty in the network model. Improvements in network models for WDSs have the potential to yield significant improvements in CWS designs as well as more realistic evaluations of those designs. Although such improvements would be expected to yield improved CWS performance, the expected improvements in CWS performance have not been quantified previously. The results presented here should be useful to those responsible for the design or implementation of CWSs, particularly managers and engineers in water utilities, and encourage the development of improved network models.</p>","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"0 ","pages":"1-25"},"PeriodicalIF":0.0,"publicationDate":"2018-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896566/pdf/nihms942967.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36012338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photocatalytic degradation of dyes in water by analytical reagent grades ZnO, TiO 2 and SnO 2 : a comparative study","authors":"D. Shinde, P. Tambade, M. Chaskar, Kisan M. Gadave","doi":"10.5194/DWES-10-109-2017","DOIUrl":"https://doi.org/10.5194/DWES-10-109-2017","url":null,"abstract":"Abstract. In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO2, and SnO2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO2, and SnO2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO2 and SnO2 as well as that of Degussa P-25 (TiO2). The photocatalytic dye decolourisation rates with ZnO were 1.14–1.35, 1.70–3.1, and 4–8.5 times higher than those of the Degussa P-25, TiO2, and SnO2, respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"10 1","pages":"109-117"},"PeriodicalIF":0.0,"publicationDate":"2017-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44814552","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":"Use of an external organic carbon source in the removal of nitrates in bio-sand filters (BSFs)","authors":"C. Mutsvangwa, Evans Matope","doi":"10.5194/DWES-10-119-2017","DOIUrl":"https://doi.org/10.5194/DWES-10-119-2017","url":null,"abstract":"Abstract. Bio-sand filters (BSFs) are point-of-use (POU) potable water filtration systems commonly used in low-income communities at household level. The principle of operation is similar to that of a slow sand filter and the major difference is that they are operated intermittently at the POU. It is one of the emerging low-cost technologies which makes use of readily and locally available construction materials but is poor in the removal of nitrates. In order to enhance the removal of nitrates through denitrification, a modified BSF with ethanol as an external carbon source at C  /  N ratios of 1.1 and 1.8 was investigated. In the absence of an external carbon source, the nitrate removal efficiency was 32 %, whilst removal efficiencies at C   /   N ratios of 1.1 and 1.8 were 44 and 53 % respectively. The inflow rate reduced significantly from an initial flow rate of 0.04 to 0.01 m3 h−1. The reduction in the inflow rate was mainly due to the growth of the biological layer on the filter media. The study showed that the use of an external carbon source like ethanol in bio-sand filtration enhances the removal of nitrates in potable water.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"10 1","pages":"119-127"},"PeriodicalIF":0.0,"publicationDate":"2017-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43192275","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":"Modeling particle transport and discoloration risk in drinking water distribution networks","authors":"J. Summeren, M. Blokker","doi":"10.5194/DWES-10-99-2017","DOIUrl":"https://doi.org/10.5194/DWES-10-99-2017","url":null,"abstract":"Discoloration of drinking water is a worldwide phenomenon caused by accumulation and subsequent remobilization of particulate matter in distribution systems (DWDSs). It contributes to a substantial fraction of customer complaints to water utilities. Accurate discoloration risk predictions could improve system operation by allowing for more effective programs on cleaning and prevention actions and field measurements, but are challenged by incomplete understanding on the origins and properties of particles and a complex and not fully understood interplay of processes in distribution networks. In this paper, we assess and describe relevant hydraulic processes that govern particle transport in turbulent pipe flow, including gravitational settling, bed-load transport, and particle entrainment into suspension. We assess which transport mechanisms are dominant for a range of bulk flow velocities, particle diameters, and particle mass densities, which includes common conditions for DWDS in The Netherlands, U.K., and Australia. Our analysis shows that the theoretically predicted particle settling velocity and threshold shear stresses for incipient particle motion are in the same range, but more variable than, previous estimates from lab experiments, field measurements, and modeling. The presented material will be used in the future development of a numerical modeling tool to determine and predict the spatial distribution of particulate material and discoloration risk in DWDSs. Our approach is aimed at understanding specific causalities and processes, which can complement data-driven approaches.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"10 1","pages":"99-107"},"PeriodicalIF":0.0,"publicationDate":"2017-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48548145","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":"Limitations of demand- and pressure-driven modeling for large deficient networks","authors":"M. Braun, O. Piller, J. Deuerlein, I. Mortazavi","doi":"10.5194/DWES-10-93-2017","DOIUrl":"https://doi.org/10.5194/DWES-10-93-2017","url":null,"abstract":"Abstract. The calculation of hydraulic state variables for a network is an important task in managing the distribution of potable water. Over the years the mathematical modeling process has been improved by numerous researchers for utilization in new computer applications and the more realistic modeling of water distribution networks. But, in spite of these continuous advances, there are still a number of physical phenomena that may not be tackled correctly by current models. This paper will take a closer look at the two modeling paradigms given by demand- and pressure-driven modeling. The basic equations are introduced and parallels are drawn with the optimization formulations from electrical engineering. These formulations guarantee the existence and uniqueness of the solution. One of the central questions of the French and German research project ResiWater is the investigation of the network resilience in the case of extreme events or disasters. Under such extraordinary conditions where models are pushed beyond their limits, we talk about deficient network models. Examples of deficient networks are given by highly regulated flow, leakage or pipe bursts and cases where pressure falls below the vapor pressure of water. These examples will be presented and analyzed on the solvability and physical correctness of the solution with respect to demand- and pressure-driven models.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"10 1","pages":"93-98"},"PeriodicalIF":0.0,"publicationDate":"2017-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45620236","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":"Identifying (subsurface) anthropogenic heat sources that influence temperature in the drinking water distribution system","authors":"C. Agudelo-Vera, M. Blokker, H. Kater, Rob Lafort","doi":"10.5194/DWES-10-83-2017","DOIUrl":"https://doi.org/10.5194/DWES-10-83-2017","url":null,"abstract":"The water temperature in the drinking water distribution system and at the customers’ taps approaches the surrounding soil temperature at ca. 1 meter depth. Water temperature is an important determinant of water quality, since it influences physical, chemical and biological processes, such as absorption of chemicals, microbial growth and chlorine decay. In the Netherlands drinking water is distributed without additional residual disinfectant and the temperature of drinking water at the customers’ tap is not allowed to exceed 25 oC. Routine water quality samples at the tap in urban areas have shown locations with relatively high soil temperatures compared to the expected modelled soil temperatures, which indicate so called ‘underground hot-spots’. In the last decades, the urban sub-surface is getting more occupied with various types of sub-surface infrastructures and some of these can be heat sources. A few recent studies tackle the anthropogenic sources and their influence on the underground, at coarse spatial scales. Little is known about the urban shallow underground heat profile on small spatial scales, of the order of 10 m × 10 m. Our research focuses on developing a method to identify and to localise potential underground hot-spots at −1.0 m at a small spatial scale. In this article we describe a method to find anthropogenic heat sources that influence temperature in the drinking water distribution system through a combination of mapping urban anthropogenic heat sources, modelling the soil temperature and extensive measurements in Rotterdam.","PeriodicalId":53581,"journal":{"name":"Drinking Water Engineering and Science","volume":"10 1","pages":"83-91"},"PeriodicalIF":0.0,"publicationDate":"2017-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42124207","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}