Drinking Water Networks Research Articles

Statistical modelling of French drinking water pipe inventory at national level using demographic and geographical information

Abstract At the request of the French Ministry for Ecological and Inclusive Transition (MTES) and the French Biodiversity Agency (AFB), INRAE carried out a study focusing on the creation of a national asset knowledge base for drinking water networks, operating at Water Agency (WA) scale. Our study involved the creation of a number of statistical models. These models combine data relating to network characteristics (gathered from a sample of utilities) with geographical and demographical data collected from all municipalities in France. The SISPEA database, along with GIS data from a sample covering around half of the total French drinking water network, were used to configure multi-linear pipe models by diameter, installation period and type of material. On the basis of these models, the total length of drinking water pipes in mainland France was estimated to be 875,000 km. Networks are quite young (60% of the total length was laid after 1970), small diameter pipes are the majority (70% of the pipes have a diameter less than or equal to 100 mm) and the materials used are linked on geographic areas (pipes are mainly made of PVC in the west of France while cast iron pipes predominate in the other regions).

¿Agua que no has de beber? Acceso al agua potable e intermediarios en asentamientos informales del Conurbano Bonaerense (1983-2015)

Latinoamérica cuenta con el mayor volumen de agua dulce per cápita del mundo. Sin embargo, parte de su población no tiene acceso regular a fuentes de agua segura o es provista por servicios precarios. Aunque Argentina es uno de los países de la región con mejores porcentajes de población servida por redes de agua potable, dichas redes están desigualmente distribuidas. Entre los sectores más afectados, se encuentran quienes habitan en asentamientos informales de la Región Metropolitana de Buenos Aires, la mayor metrópolis del país. Al respecto, este estudio se pregunta: ¿de qué modos acceden dichos sectores a redes de agua potable? ¿Por qué acceden en menor medida que otros sectores? A partir de una etnografía y otras herramientas de investigación, se argumenta que: 1) acceden a redes de agua potable por vías alternativas que requieren necesariamente de la coparticipación de vecinos, y 2) que lo hacen en menor proporción, entre otras cosas, por el modo en que se relacionan con el Estado para extender las redes de agua en sus barrios. A la luz de los resultados, se discuten nociones relativas a las gestiones privadas, públicas y comunitarias del servicio, y se pone en cuestión ideas como las de gobernanza y coproducción.Ideas destacadas: artículo de investigación donde se analiza las vías por las que acceden al servicio de agua potable de red quienes residen en asentamientos informales de la periferia de la Región Metropolitana de Buenos Aires, Argentina. Al respecto se señala que, a diferencia de otros sectores sociales, quienes viven en dichos barrios deben hacerse cargo de gran parte de la extensión del servicio. A la luz de los resultados, se discuten nociones generales sobre formas de gestión privada, pública y comunitaria del agua en América Latina, y se ponen en cuestión conceptos como gobernanza y coproducción de bienes comunes.

Analysis of Performance Indicators for Sustainable Management of Community Drinking Water Networks in Cameroon

The present study on the management of community drinking water networks in Cameroon aims to analyze, using efficiency indicators, the performance of five community water supply networks in the municipalities of Ndu and Kumbo in the North West region, Bandja in the West region and Efoulan and Zoetélé in the South region. The analysis of the said networks was done using technical and financial indicators: primary yield, rate of unpaid invoices, linear distribution loss index, average annual rate renewal network and the maximum connection opening time for new subscribers. The analysis of financial performance was done through the analysis of annual revenues, leading to the conclusion that these six indicators are important for analyzing the performance of community water supply networks. The study demonstrated also the strong influence of overall water consumption, the linear water loss index and annual turnover on the overall performance of the community water supply network.

Drinking water supply as low-temperature source in the district heating system: A case study for the city of Copenhagen

This paper explores the potential for using large-scale heat pumps (HPs) to extract energy from Copenhagen’s drinking water network and deliver it to its district heating system. The system involves certain losses in terms of additional heat and power consumption for end-use water heating. The net potential for energy extraction was analysed by means of an EPANET model to simulate system-wide temperatures in a piped distribution network. The model was validated against measured data from the network. Heat transfer in service lines was computed analytically and included in the net potential for energy extraction, which was determined to be 21 MW in Copenhagen. Around 38% of the HP source demand was harnessed from the ground. With HP COPs between 2.8 and 3.2, the System COP was only 1.7, thus suggesting that the choice of drinking water as a low-temperature heat source should depend on the available alternatives. Drinking water HPs have the side-benefit of preventing high drinking water temperatures; if operated in the summer they increased the share of supplied water complying with a recommended upper temperature limit of 12 °C from 42% to 81%.

Desinfección del agua para consumo humano mediante el uso de filtro de arcilla y plata coloidal en sector urbano de Lurigancho-Chosica

La importancia de la desinfección del agua potable es esencial para prevenir brotes de enfermedades infecciosas y parasitarias. Un método comúnmente utilizado para potabilizar agua es por aplicación de filtros de arcilla, cuyo uso es común en zonas desprovistas de red de agua potable. En consideración de ello, la presente investigación tuvo como objetivo evaluar la desinfección del agua en un sector de Carapongo (Lurigancho-Chosica) con el uso del filtro de arcilla con aserrín y plata coloidal. Se elaboraron modelos de filtro de arcilla prototipo de distintos tamaños con aserrín a un 50%, después se le añadió plata coloidal. En total, se diseñaron 5 filtros de diferentes tamaños y grosores, utilizando en 3 de ellas arcilla de cerámica y en 2 arcilla natural; luego del moldeamiento de los filtros, se llevaron a altas temperaturas para que se formen membranas microporosas que cumplan la función de filtros, para aumentar el poder de filtración se impregnó solución de plata coloidal, esta última para inhibir el paso de bacterias. El experimento cumplió con el proceso de desinfección, potabilización y remoción. Los resultados de las muestras de agua analizadas se compararon con los estándares de calidad ambiental y los análisis estadísticos mostraron resultados favorables tanto en los parámetros físicos, químicos y bacteriológicos, y evidenciaron que el filtro mejoró la temperatura en 2 °C, favoreció el aumento el pH en 0.15 unidades, ayudó a disminuir de 1979.44 a 1333.55 mg/L los Solidos Disueltos Totales (disminuyendo el nivel de turbiedad del agua), y los coliformes totales y Escherichia coli (E.C); los resultados muestran que el método de tratamiento es efectivo, de bajo costo y fácil accesibilidad para viviendas.

A Series of ILP models for the optimization of water distribution networks

The design of rural drinking water schemes consists of optimization of several network components like pipes, tanks, pumps and valves. The sizing and configuration of these network configurations need to be such that the water requirements are met while at the same time being cost efficient so as to be within government norms. We developed the JalTantra system to design such water distribution networks. The Integer Linear Program (ILP) model used in JalTantra and described in our previous work solved the problem optimally, but took a significant amount of time for larger networks—an hour for a network with 100 nodes. In this current work, we describe a series of three improvements of the model. We prove that these improvements result in tighter models, i.e. the set of points of linear relaxation is strictly smaller than the linear relaxation for the initial model. We test the series of three improved models along with the initial model over eight networks of various sizes and show a distinct improvement in performance. The 100-node network now takes only 49 s to solve. These changes have been implemented in JalTantra, resulting in a system that can solve the optimization of real world rural drinking water networks in a matter of seconds. The JalTantra system is free for use, and is available at https://www.cse.iitb.ac.in/jaltantra/.

Implementation of a nationwide Waterborne disease outbreak surveillance system in France

Abstract Issue/Problem Waterborne disease outbreaks (WBDOs) remain a public health issue in developed countries, but to date the surveillance of WBDOs in France, mainly based on the voluntary reporting of clusters of acute gastrointestinal infections (AGIs) by general practitioners to health authorities, is characterized by low sensitivity. In this context an integrated and automatized approach to detect WBDO relying on the identification of clusters of medicalized AGI cases sharing a same drinking water networks (DWN) was developed, evaluated in a simulation study and tested in a pilot study by the French National Public Health Agency. Description of the problem Two national big databases support the detection process of potential WBDO: health insurance database for AGI, ministry of health database for drinking water system information. Each detected outbreak has to be investigated regarding environmental criteria during the days before the onset of the outbreak: results on bacterial water monitoring, weather (e.g. heavy rain), technical incidents in the drinking water system (e.g. chlorination breakdown, alarm malfunction). To evaluate the strength of association with drinking water, four levels are proposed based on epidemiological and environmental criteria (strong, probable, possible and undetermined). Results The WBDO surveillance system has been implemented in all french departments since start of 2019 and support by the ministry of health. A web-application, named “EpiGEH”, was also developed to support the surveillance system. A retrospective study between 2010 and 2017 has detected almost 300 to 550 potential WBDO per year while voluntary reporting identified 2 to 3 WBDO each year during the same period. Lessons Such a specific surveillance system should help health authorities to formulate recommendations regarding the management of drinking water systems and propose appropriate preventive measures, in accordance with the water safety plans. Key messages The WBDO surveillance system based from health insurance databases constitutes a daily surveillance system of drinking water quality. The WBDO surveillance system should drastically improve the detection sensitivity by a factor 100 to 200 compared to voluntary reporting.

Determinants of real water losses in the Australian drinking water sector

ABSTRACT The Sustainable Development Goals (SDG) agenda calls for safe drinking water and sanitation for all communities around the world and the use of water in a sustainable and efficient manner. Although under less scrutiny in developed countries, network water losses can be a costly resource misallocation. This paper analyses real water losses in drinking water networks in Australia by applying a panel data regression model with fixed effects to ascertain the main drivers of real water losses. The results indicate population growth and water main breaks as major drivers of water losses in Australia. Real water losses also have an impact on utilities net revenue per unit water delivered, infrastructure leakage index and operational costs. In order to reduce real water losses, water managers and regulators must pay more attention to the health of the distribution network in the face of rapid urbanisation experienced in the east coast of Australia.

Experimental Investigations and CFD Modeling of Contaminant Intrusion in a Water Network during Transient Events

Intrusion in drinking water networks (DWN) can be triggered by transient low-pressure events. This intrusion may result in the contamination of drinking water supplied to consumers, which may have major health impacts. This research aims to investigate the influence of a DWN’s operating parameters on the intrusion and progression of the contaminant in a pilot drinking water network setup. Results show that the minimum time required for the contaminant to begin entering the system was influenced by the system operating pressure. Faster initial intrusion times were observed under low operating pressure. In addition, the crack size influenced the time required for the contaminant to fully intrude the system. Similarly, the time required for the contaminant to reach certain points in the DWN was influenced by the operating pressure. These results were verified using two additional tools; a high-speed camera was used to monitor the contaminant transient progression through the DWN under different pressures; and computational fluid dynamics modeling was used to calculate the corresponding contaminant concentration. The results suggest that the ability of the system to quickly stabilize its operating pressure would reduce the probability of a contaminant intrusion into the DWN.

Pharmaceuticals in the marine environment: a review

Despite the increasing presence of pharmaceuticals in marine environments and their potential negative impacts, little research has been reported on the level and occurrence of these contaminants in the marine ecosystem. This review provides information on the occurrence (level–concentration) of pharmaceuticals in marine environments including seawater, sediments, and organisms within and (or) around this ecosystem. Also, the classification, sources, metabolism, and fate of these contaminants in the marine environment were discussed to identify knowledge gaps. We showed that antibiotics are the most commonly investigated and detected drugs in marine environments. In addition, this review suggested that focused case studies should be a priority for future research and highlighted the need for future assessments of the potential risks of pharmaceuticals to marine species. We also suggested that it is necessary to monitor the level of the most frequent and widespread pharmaceuticals like antibiotics and nonsteroidal anti-inflammatory drugs in sewage and marine outfalls. Finally, we concluded that there is a need for the development of effective treatment methods for the removal of these pollutants from wastewater before their discharge into the receiving marine environment or the main drinking water networks.

An interdependent infrastructure asset management framework for high-density cities

Infrastructure facilities, namely highways, drinking water networks, sewerage systems, gas pipelines and telecommunication networks are crucial to the daily operation and continuous development of ...

Spatio-temporal survey of opportunistic premise plumbing pathogens in the Paris drinking water distribution system.

Opportunistic premise plumbing pathogens present in drinking water are linked to a significant number of infections for health compromised patients. However, their monitoring is not required in current water potability standards and they have been poorly studied in a full-scale network. In this study, we quantified, by qPCR, three opportunistic pathogens, Mycobacterium spp., Legionella pneumophila, Pseudomonas aeruginosa throughout the Paris drinking water network over a one-year sampling campaign. While Mycobacteria spp. seemed ubiquitous whatever the distribution system and the time of the year, the occurrence of L. pneumophila and P. aeruginosa showed seasonal variations. Unlike L. pneumophila and P. aeruginosa, the concentration (copies number/L) of Mycobacterium spp. varied between sampling sites. The variation in microbial numbers did not demonstrate any correlations with temperature, pH, chlorine, conductivity, orthophosphate or nitrate levels. In conclusion, Mycobacterium spp. are common inhabitants of the Paris network while L. pneumophila and P. aeruginosa presence fluctuate over space and time. Such qPCR approach would help to better understand the behaviour of opportunistic premise plumbing pathogens.

Changes on Eubacteria 338I, Gamma-, Betaproteobacteria in Biofilms from Drinking Water Systems According to Operational Conditions

Biofilms in drinking water network are ubiquitous, hosting bacteria that must be assessed and controlled, particularly pathogens. Bacterial population can be affected by operational conditions in the network. Variables including distance, time of stabilization, velocity and high (biofilm 1) and low (biofilm 2) chlorine were assessed as modifiers of bacterial population, in a pilot-scale system during a long-term period and laminar conditions. Gram-positive bacteria and other Proteobacteria, pathogens and versatile bacteria were quantified in biofilm samples by fluorescent in situ hybridization (FISH), using respectively Eubacteria 338I, Gamma- and Betaproteobacteria probes. Denaturing Gradient Gel Electrophoresis (DGGE) analyses were also performed to determine similarity between samples. Based on results, a high heterogeneity was observed even at short length (3 m: <40% similarity). The time of stabilization changed the effect of velocity over bacterial population. After 169 days, water velocity was negatively correlated with Betaproteobacteria (r = −0.71; p = 0.11 in biofilm 1) and Eubacteria 338I (r = −0.91; p = 0.01 in biofilm 2), while at the end, Eubacteria 338I from biofilm 2 correlated positively with water velocity (r = 0.78; p = 0.06). Chlorine favored the proliferation of Gamma-, Betaproteobacteria, especially in biofilm 1, being Gammaproteobacteria counts one order higher than in biofilm 2. Chlorine proved to be the most influential operational condition on the bacterial population, because it benefited the group characterized by pathogenicity. Due to the scarce information about mature biofilms at low flux conditions, this study contributes to the understanding on Eubacteria 338I, Gamma- and Betaproteobacteria populations, thus to water distribution system management in rural operation.

Water supply system in Titab village and Telaga village, Busungbiu district, Buleleng regency

The rate of population growth in Titab and Telaga Village, Busungbiu District, Buleleng Regency in 2007-2010 reaches 0.75%, which affects the level of water demand needed for daily needs. One of the efforts to meet the needs of raw water for drinking water, among others, by the development of a potable water supply system infrastructure. Based on the facts, it is necessary to design Water Supply System (SPAM) in Titab and Telaga Village with Titab Reservoir spring with 350 l/dt of debit which is expected to give standard of quantity, quality, continuity of service for Titab and Telaga Village which is 5 km from the dam. In order to maximize the service to the community in Titab and Telaga Village, it is necessary to know the use of drinking water for each household. The next analysis is the calculation of projected drinking water needs over the next 20 years. Planning and calculation of water distribution using WaterCad i8 Software. From the result of projection analysis, the drinking water requirement in Titab and Telaga Village based on the fact of household drinking water usage in 2037 is 5,568 lt/sec. While the effort to maximize water supply network services is by projecting drinking water needs in Titab and Telaga Village based on the fact of household drinking water usage. With the help of WaterNet Software, it will simplify the distribution network planning of drinking water in order to produce integrated drinking water network system to meet the needs of clean water in Titab and Telaga Village.

Effect of chlorine and chloramine disinfection and the presence of phosphorous and nitrogen on biofilm growth in dead zones on PVC pipes in drinking water systems

In drinking water systems, 'dead zones' may have higher biofilm counts than areas of higher flow rates, as there are limited/no shear stresses removing biofilms from the pipe material, and disinfectant concentrations are significantly lower due to no/low supply of disinfected water from the reservoir. Biofilms affect the quality of drinking water and may lead to severe health issues for downstream consumers. Biofilms can be controlled by disinfection, two common disinfectants being chlorine and monochloramine. The growth of biofilms is also affected by the presence of nutrients, as nutrients act as a food source to bacteria in the biofilms. To compare the growth of biofilms in 'dead zones' under different disinfectant (chlorine and chloramine) conditions, PVC coupons were placed in stagnant distilled disinfected waters inoculated with 10% pond water (environmental source), and the biofilm growth was monitored on the coupons using visual analyses. Chloramine has a better disinfectant inhibiting potential than chlorine. To compare the influence of nutrients on biofilms in 'dead zones', coupons were placed in distilled water inoculated with pond water from the same environmental source, and nitrogen and phosphorous concentrations were monitored. It was found that for 'dead zones' in drinking water networks, chloramine has a better biofilm inhibiting and inactivation potential, and the presence of nitrates in water influence biofilm growth, and to a lesser extent so does phosphorous.

Microbiome of drinking water: A full-scale spatio-temporal study to monitor water quality in the Paris distribution system

The microbiological water quality of drinking water distribution system (DWDS) is of primary importance for human health. High-throughput sequencing has gained more and more attention in the last decade to describe this microbial diversity in water networks. However, there are few studies describing this approach on large drinking water distribution systems and for extended periods of time. To fill this gap and observe the potential subtle variation in microbiota of a water network through time and space, we aimed to apply high-throughput sequencing of the 16S rRNA gene approach to characterize bacterial communities of the Paris’ DWDS over a one-year period. In this study, the Paris network, composed of four different DWDSs, was sampled at 31 sites, each month for one year. The sampling campaign was one of the largest described so far (n = 368) and the importance of key spatio-temporal and physico-chemical parameters was investigated. Overall, 1321 taxa were identified within the Paris network, although only fifteen of them were found in high relative abundance (>1%) in all samples. Two genera, Phreatobacter and Hyphomicrobium were dominant. The whole bacterial diversity was not significantly affected between the four DWDSs (spatial parameter) and by physico-chemical parameters. However, the bacterial diversity was slightly modified over the one-year period (temporal parameter) as we were able to observe DWDS microbiome perturbations, presumably linked to a preceding flood event. Comparison of high-throughput sequencing of the 16S rRNA gene amplicons vs. cultivation-based techniques showed that only 1.8% of bacterial diversity was recovered through cultivation. High throughput sequencing has made it possible to monitor DWDS more accurately than conventional methods by describing the whole diversity and detecting slight fluctuations in bacterial communities. This method would be further used to supervise drinking water networks, to follow any perturbations due to internals events (such as treatments) or external events (such as flooding).

Technical note: Problem-specific variators in a genetic algorithm for the optimization of drinking water networks

Abstract. Genetic algorithms can be a powerful tool for the automated design of optimal drinking water distribution networks. Fast convergence of such algorithms is a crucial factor for successful practical implementation at the drinking water utility level. In this technical note, we therefore investigate the performance of a suite of genetic variators that was tailored to the optimization of a least-cost network design. Different combinations of the variators are tested in terms of convergence rate and the robustness of the results during optimization of the real-world drinking water distribution network of Sittard, the Netherlands. The variator configurations that reproducibly reach the furthest convergence after 105 function evaluations are reported. In the future these may aid in dealing with the computational challenges of optimizing real-world networks.

A Dynamic Approach for Faster Performance Measurements on Hydraulic Turbomachinery Model Testing

During the design and optimization of hydraulic turbomachines, the experimental evaluation of hydraulic performances beyond the best efficiency point and for off-design conditions remains essential to validate the simulation process and to finalize the development. In this context, an alternative faster method to measure the efficiency of hydraulic turbomachines using a dynamic approach has been investigated. The so-called “sliding-gate” dynamic measurement method has been adapted and implemented on the hydraulic test rig of the HES-SO Valais//Wallis, Sion, Switzerland. This alternative approach, particularly gainful for small-hydro for which the investment devoted to development is limited, has been successfully assessed on two cases for drinking water networks energy recovery. A 2.65 kW double-regulated laboratory prototype of a tubular axial micro-turbine with two independent variable speed counter-rotating runners and a 11 kW multi-stage centrifugal pump-as-turbine (PAT) with variable speed have been selected. The hydraulic efficiency results obtained by dynamic measurements are compared to the ones obtained by the classical steady point-by-point method. This dynamic method, suitable not only for hydraulic machinery, allows: (i) reducing significantly (up to 10×) the time necessary to draw the complete efficiency characteristics of a hydraulic machine; (ii) rapidly detecting the hydrodynamic instabilities within the operating range of the machine.

Chemical characterization and relative toxicity assessment of disinfection byproduct mixtures in a large drinking water supply network

In order to reduce the formation of disinfection by-products (DBPs) during potabilization of water it is necessary to explore the potential of the source water and the applied treatment to generate these chemicals. This is actually more challenging in large drinking water networks that use different source waters to satisfy drinking water demand. In this regard, this work investigated the formation of DBPs in water matrices that are commonly supplied to the city of Barcelona and its metropolitan area. The regulated trihalomethanes and haloacetic acids were the most abundant DBP classes in these waters, followed by haloacetamides and haloacetonitriles or trihalogenated acetaldehydes (THALs). On the contrary, the formation potential of iodo-DBPs was minor. Mixing of drinking water treatment plant finished waters with desalinated water decreased the overall DBP formation potential of the water but resulted in the increased formation of brominated DBPs after long chlorine contact time. The formation of most DBPs was enhanced at high water temperatures (except for Br-THALs) and increasing residence times. Potential cytotoxicity and genotoxicity of the DBP mixtures were mainly attributed to the presence of nitrogen-containing DBPs and HAAs.

System reliability upper bound assessment for health-aware control of complex systems

When a system is composed of a large number of components, the computation of its exact reliability turns computationally costly and depending on the number of components it has such computation could be infeasible. This paper investigates the possibility of using a system reliability approximation. Specifically, an upper bound of the system reliability will be computed in order to overcome the computational problem of determining the exact system reliability and its integration into a health-aware control strategy. A comparison between the exact and the approximated approaches is presented on a drinking water network system.