This Diploma thesis deals with minimum night flows issue. Basic findings about minimum night flows were summarized in the introductory part of thesis. Findings like the minimum night flow components, affecting parameters and used methodologies for assessment of minimal night flows. In the practical part of this thesis was this knowledge applied to real water distribution system in the municipality Hrádek u Sušice. The part of this thesis was also determinate the measurement accuracy of used water meter, which was formerly installed at the outlet in the Hrádek water tank. Measurement errors was determinate for the flow values, that are close to the real measured minimum night flow data in the water distribution system in municipality Hrádek u Sušice.

Das Auftreten von Braunwasser in Trinkwasserverteilungsnetzen ist eine Beeinträchtigung der Trinkwasserqualität, die durch mobilisierte partikuläre Ablagerungen verursacht wird. Die Partikel gelangen durch verschiedene Prozesse, wie z. B. der Korrosion metallischer Leitungen und den Eintrag am Wasserwerk, kontinuierlich in sehr geringen Massenströmen in das Rohrnetz. Durch die Akkumulation der Partikel an Rohroberflächen können sich Ablagerungsmengen bilden, die bei ansteigenden Strömungsgeschwindigkeiten resuspendiert werden und zu unerwünschten Braunwassererscheinungen führen. Die vorliegende Arbeit behandelt die experimentelle Untersuchung des Transportes von Partikeln, die für Trinkwassernetze typisch sind, in Rohrströmungen. Es werden Einflussfaktoren identifiziert, die für den Partikeltransport von Bedeutung sind. Ein neu entwickeltes dynamisches Modell beschreibt den Transport von Partikeln und die Ablagerungsbildung in Rohrströmungen und vermaschten Rohrnetzen. Das Modell wurde in einer Anwendersoftware implementiert und an einem Trinkwasserverteilungsnetz für das Nachvollziehen der beobachteten Ablagerungsbildung eingesetzt. Im Vergleich zu bestehenden dynamischen Modellen werden partikelbezogene Prozesse unter Berücksichtigung der für trinkwasserbürtige Partikel und Ablagerungen typischen Eigenschaften mathematisch genauer beschrieben. Stationäre und dynamische Ereignisse bezüglich Wasserqualität und Ablagerungsbildung können jetzt durch die Berücksichtung zahlreicher zeitabhängiger Einflussfaktoren nachvollzogen werden. / The occurrence of discoloured water in drinking water distribution systems is a disturbance of the water quality, which is induced by mobilised particulate deposits. Different processes result in the continuous entry of small mass flow rates of particles into the piping, for instance the corrosion of metallic pipes as well as the entry at the water works outlet. By the accumulation of these particles, significant amounts of deposits can be formed and at higher flow rates be resuspended, which leads to unwanted events with discoloured water. This study examines the experimental investigation of the transport of particles, which are typical for drinking water distribution systems, in pipe flow. Influencing factors are identified, which are of importance for the particle transport. With a newly developed model, the transport of particles and the deposit formation in pipe flow and in piping is described. The model is implemented into a software application and deployed at a drinking water distribution system to understand the observed deposit formation. In comparison with existent dynamic water quality models, particle-related processes are described mathematically in more details, under consideration of characteristics typical for particles and deposits in drinking water distribution systems. Hence, observed steady-state and dynamic events can be followed using several influencing time-dependent factors.

A water distribution system (WDS) is based in a network of interconnected hydraulic components to transport the water directly to the customers. Water must be treated in a Water Treatment Plant (WTP) to provide safe drinking water to consumers, free from pathogenic and other undesirable organisms. The disinfection is an important aspect in achieving safe drinking water and preventing the spread of waterborne diseases. Chlorine is the most commonly used disinfectant in conventional water treatment processes because of its low cost, its capacity to deactivate bacteria, and because it ensures residual concentrations in WDS to prevent microbiological contamination. Chlorine residual concentration is affected by a phenomenon known as chlorine decay, which means that chlorine reacts with other components along the system and its concentration decrease. Chlorine is measured at the output of the WTP and also in several considered points within the WDS to control the water quality in the system. Simulation and modeling methods help to predict in an effective way the chlorine concentration in the WDS. The purpose of the thesis is to assess chlorine concentration in some strategic points within the WDS by using the historical measured data of some water quality parameters that influence chlorine decay. Recent investigations of the water quality have shown the need of the use of non-linear modeling for chlorine decay prediction. Chlorine decay in a pipeline is a complex phenomenon so it requires techniques that can provide reliable and efficient representation of the complexity of this behavior. Statistical models based on Artificial Neural Networks (ANN) have been found appropriated for the investigation and solution of problems related with non-linearity in the chlorine decay prediction offering advantages over more conventional modeling techniques. In this sense, this thesis uses a specific neural network application to solve the problem of forecasting the residual chlorine

A model for the prediction of color release from a pilot distribution system was created in 2003 by Imran. This model allows prediction of the release of color from aged cast iron and galvanized steel pipes as a function of water quality and hydraulic residence time. Color was used as a surrogate measurement for iron, which exhibited a strong linear correlation. An anomaly of this model was an absence of a term to account for pH, due to the influent water being well stabilized. A new study was completed to evaluate the effectiveness of corrosion inhibitors against traditional adjustment. Two control lines were supplied with nearly same water qualities, one at pH close to pHs and one at pH well above pHs. The resulting data showed that effluent iron values were typically greater in the line with lower pH. The non-linear color model by Imran shows good agreement when the LSI was largely positive, but underpredicted the color release from the lower LSI line. A modification to the Larson Ratio proposed by Imran was able to give a reasonable agreement to the data at lower LSI values. LSI showed no definite relation to iron release, although a visual trend of higher LSI mitigating iron release can be seen. An iron flux model was also developed on the same pilot system by Mutoti. This model was based on a steady state mass balance of iron in a pipe. The constants for the model were empirically derived from experiments at different hydraulic conditions with a constant water quality. Experiments were assumed to reach steady state at 3 pipe volumes due to the near constant effluent turbidity achieved at this point. The model proposes that the iron flux under laminar flow conditions is constant, while the iron flux is linearly related to the Reynolds Number under turbulent conditions. This model incorporates the color release models developed by Imran to calculate flux values from different water qualities. A limited number of experiments were performed in the current study using desalinated and ground water sources at Reynolds Numbers ranging from 50 to 200. The results of these limited experiments showed that the iron flux for cast iron pipe was approximately one-half of the predicted values from Mutoti. This discrepancy may be caused by the more extensive flushing of the pipes performed on the current experiments which allowed attainment of a true steady state. Model changes were proposed to distinguish between near stagnant flow and the upper laminar region, with the upper laminar region showing a slight linear increase. Predictions using the galvanized flux model were not accurate due to an inferior color release model that was developed for galvanized pipes. The model exhibits a high dependence on sulfate concentrations, but concentrations of sulfates in the current experiments were low. This led to low predicted flux values when the actual data showed otherwise. A new galvanized model was developed from a combination of data from the original and current experiments. The predicted flux values using the new model showed great improvement over the old model, but the new model database was limited and the resulting model was not able to be independently tested.

Water contamination is a major source of diseasearound the world. Therefore, the reliable monitoring of harmfulcontamination in water distribution networks requires considerableeffort and attention. It is a vital necessity to possess a reliablemonitoring system in order to detect harmful contamination inwater distribution networks. To measure the potential contamination,a new sensor called an ’electric tongue’ was developedin Link¨opings University. It was created for the purpose ofmeasuring various features of the water reliably. This projecthas developed a supervised machine learning algorithm that usesan artificial neural network for the detection of anomalies in thesystem. The algorithm can detect anomalies with an accuracy ofaround 99.98% based on the data that was available. This wasachieved through a binary classifier, which reconstructs a vectorand compares it to the expected outcome. Despite the limitationsof the problem and the system’s capabilities, binary classificationis a potential solution to this problem. / Vatten kontaminering är en huvudsaklig anledning till sjukdom runtom i världen. Därför är det en avgörande nödvändighet att ha ett tillförlitligt övervakningssystem för att upptäcka skadliga föroreningar i vattendistributionsnät. För att mäta den potentiella föroreningen skapades en ny sensor, den så kallade ”Electric Tongue” vid Linköpings universitet Den skapades i syfte att mäta olika egenskaper i vattnet på ett tillförlitligt sätt. Genom att använda ett artificiellt neuralt nätverk utvecklades en supervised machine learning algoritm för att upptäcka anomalier i systemet. Algoritmen kan upptäcka anomalier med 99.98% säkerhet som baseras på befintliga data. Detta uppnåddes genom att rekonstruera en vektor och jämföra det med det förväntade resultatet genom att använda en binär klassificerare. Trots att det finns begränsningar som orsakats både av problemet men också systemets förmågor, så är binär klassificering en potentiell lösning till detta problem. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

Drinking water is one of our most important re- sources, so the ability to reliably monitor harmful contaminations in our water distribution network is vital. In order to minimize false alarms for water monitoring, while keeping a high sensitivity, a machine learning approach was evaluated in this project. Measurement data captured with a new kind of sensor, an electronic tongue, was provided by Linköping university. The solution was an artificial neural network, in the structure of an Autoencoder, which could learn the dynamic behaviour of natural deviations and with a false alarm rate of approximately one false alarm per week. This was done by evaluating the data and assembling an input structure to account for daily cyclic phenomena, which then was used to train the neural network. The solution could detect anomalies as small as 1.5% by comparing the input with the reconstructed vector, and raise an alarm. In conclusion, an Autoencoder is a viable method for detecting anomalies in water quality. / Drickvatten är en av våra mest värdefulla tillgångar, det är därför mycket viktigt att det finns sätt att pålitligt övervaka om dricksvattennätet blivit förorenat. För att kunna minimera antalet falsklarm och samtidigt ha hög känslighet mot dessa föroreningar undersöktes och implementerades en lösning med maskininlärningsalgoritmer. Mätdata tillhandahölls av Linköpings universitet och kom från en ny sensor kallad elektronisk tunga. Lösningen var ett artificiellt neuralt nätverk i form av en Autoencoder, som kunde lära sig det dynamiska beteende som ofarliga avvikelser utgjorde. Detta gav en lösning som i medel gav ett falsklarm per sju dagar. Detta gjordes genom att utvärdera rådata och konstruera en struktur på indata som tar hänsyn till dygnsbunda naturliga fenomen. Denna struktur användes sedan för att träna det neurala nätverket. Lösningen kunde upptäcka fel ner till 1.5% genom att jämföra indata med den rekonstruerade vektorn, och på så sätt ge ett alarm. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm

[ES] La sectorización de las redes ha demostrado ser una metodología estratégica en la reducción de los volúmenes incontrolados fugados, considerado uno de los principales problemas a los que tienen que enfrentarse diariamente los gestores de los sistemas de distribución de agua. Su principal objetivo es facilitar la monitorización de las redes, dividiéndolas en subsistemas, sobre los que se puede realizar un mejor y más fácil control de las anomalías en el consumo y presión. Uno de los inconvenientes que presenta esta técnica recae en su diseño. No existe una solución única, sino que atiende a diversos criterios para realizarlo. De manera generalizada, este diseño se basa en la experiencia del propio diseñador, siguiendo criterios puramente prácticos y con procesos manuales de prueba y error, cuyo grado de dificultad está vinculado al tamaño y complejidad de la propia red. Esta tesis plantea una metodología sistemática para el diseño de la sectorización de una red de distribución de agua, según criterios energéticos, con el fin de facilitar la delimitación de cada uno de los sectores de la red. Como resultado, se obtiene una organización de la red en sectores buscando una optimización energética de la misma, de tal modo que posteriores técnicas de mejora, como es el caso de la gestión de presiones, se vean favorecidas. La sectorización ha resultado ser una técnica eficaz en la búsqueda de fugas. Sin embargo, como supone una pérdida de capacidad hidráulica y una merma en la calidad del agua, esta tesis se cuestiona el planteamiento de una técnica no intrusiva alternativa que logre los mismos resultados. Así, se propone el desarrollo de una metodología que localice las fugas centrada en la interdependencia de todos los elementos y en el empleo de sensores de caudal y presión. El trabajo pone de manifiesto que es posible sectorizar la red de tal manera que se consigan mayores beneficios para la misma. Ahora bien, también es posible el empleo de otras técnicas que no requieran el cierre de tuberías pero que desprendan soluciones similares. El empleo de una técnica u otra dependerá de cada caso, de los objetivos establecidos y de la política de trabajo de cada gestor. / [CA] La sectorització de les xarxes ha demostrat ser una metodologia estratègica en la reducció dels volums incontrolats perduts, considerat un dels principals problemes als quals han d'enfrontar-se diàriament els gestors dels sistemes de distribució d'aigua. El seu principal objectiu és facilitar la monitorització de les xarxes, dividint-les en subsistemes, sobre els quals es pot realitzar un millor i més fàcil control de les anomalies en el consum i pressió. Un dels inconvenients que presenta aquesta tècnica recau en el seu disseny. No existeix una solució única, sinó que atén diversos criteris per a realitzar-ho. De manera generalitzada, aquest disseny es basa en l'experiència del propi dissenyador, seguint criteris purament pràctics i amb processos manuals de prova i error, el grau de dificultat del qual està vinculat a la grandària i complexitat de la pròpia xarxa. Aquesta tesi planteja una metodologia sistemàtica per al disseny de la sectorització d'una xarxa de distribució d'aigua, segons criteris energètics, amb la finalitat de facilitar la delimitació de cadascun dels sectors de la xarxa. Com a resultat, s'obté una organització de la xarxa en sectors buscant una optimització energètica d'aquesta, de tal manera que posteriors tècniques de millora, com és el cas de la gestió de pressions, es vegen afavorides. La sectorització ha resultat ser una tècnica eficaç en la cerca de fuites d'aigua. No obstant això, com suposa una pèrdua de capacitat hidràulica i una disminució en la qualitat de l'aigua, aquesta tesi es qüestiona el plantejament d'una tècnica no intrusiva alternativa que aconseguisca els mateixos resultats. Així, es proposa el desenvolupament d'una metodologia que localitze les fuites d'aigua centrada en la interdependència de tots els elements i en l'ús de sensors de cabal i pressió. El treball posa de manifest que és possible sectoritzar la xarxa de tal manera que s'aconseguisquen majors beneficis per a aquesta. Ara bé, també és possible l'ús d'altres tècniques que no requerisquen el tancament de canonades però que desprenguen solucions similars. L'ús d'una tècnica o una altra dependrà de cada cas, dels objectius establits i de la política de treball de cada gestor. / [EN] The sectorization of networks has proven to be a strategic methodology in the reduction of uncontrolled leakage volumes, considered one of the main problems that water distribution system managers must face on a daily basis. Its main objective is to facilitate the monitoring of the networks, dividing them into subsystems, on which a better and easier control of anomalies in consumption and pressure can be performed. One of the drawbacks of this technique lies in its design. There is no single solution, but it is based on different criteria. In general, this design is based on the designer's own experience, following purely practical criteria and with manual trial and error processes, whose degree of difficulty is linked to the size and complexity of the network itself. This thesis proposes a systematic methodology for the design of the sectorization of a water distribution network, according to energy criteria, in order to facilitate the delimitation of each of the sectors of the network. As a result, an organization of the network in sectors is obtained, looking for an energetic optimization of the same, in such a way that later improvement techniques, such as pressure management, are favoured. Sectorization has proven to be an effective technique in the search for leaks. However, as it implies a loss of hydraulic capacity and a decrease in water quality, this thesis questions the approach of an alternative non-intrusive technique that achieves the same results. Thus, it is proposed the development of a methodology to locate the leaks focused on the interdependence of all the elements and the use of flow and pressure sensors. The present work shows that it is possible to sectorize the network in such a way as to achieve greater benefits for the network. However, it is also possible to use other techniques that do not require pipe closure but provide similar solutions. The use of one technique or another will depend on each case, on the established objectives and on the working policy of each manager. / Salguero Barceló, FJ. (2021). La sectorización basada en criterios energéticos como herramienta para la gestión hídrica de redes de distribución de agua [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/178235

[ES] El objetivo general de la presente Tesis es investigar metodologías que permitan obtener en tiempo real los parámetros de operación de redes hidráulicas a presión que minimicen el consumo y/o el coste energético, garantizando el cumplimiento de las condiciones de funcionamiento necesarias para una adecuada calidad del servicio. Al tratarse del ámbito de la operación diaria de la red, una de las condiciones indispensables que deben reunir los métodos de optimización es una respuesta lo suficientemente rápida como para que no solo se pueda disponer de las soluciones más convenientes en el momento de ejecutar las consignas de operación, sino que además se habilite un procedimiento flexible que permita dar respuesta a posibles cambios en las predicciones o eventos que puedan producirse. Se ha abordado de manera aislada la optimización energética de los subsistemas de transporte de agua y la de los subsistemas de distribución debido a las distintas características que se pueden observar en ellos. En la parte relativa a los subsistemas de distribución, particularizada al caso de un sistema de riego con bombeo directo a red, se han explorado los métodos metaheurísticos de optimización, realizando varias aportaciones originales orientadas a la mejora en la eficiencia computacional de los mismos, debido a la necesidad de obtener una respuesta rápida compatible con la toma de decisiones en tiempo real. En cuanto a los subsistemas de transporte, se ha explorado la aplicabilidad del método determinista de optimización por programación lineal, a la vista de las importantes ventajas que presenta respecto al resto de métodos generales de optimización. Asimismo, en el contexto de los subsistemas de transporte, se ha trabajado en la definición de una heurística basada en el cálculo del coste energético y/o económico del agua entregada en los puntos de consumo y almacenada en los depósitos intermedios, que ha permitido formular un algoritmo voraz para la optimización energética en cada instante de tiempo. Este método ha conseguido igualar el desempeño alcanzado mediante la programación lineal y se espera que ofrezca unas mejores capacidades en sistemas con un comportamiento marcadamente no lineal, así como también una mejor adaptación a problemas de optimización con la participación de energías renovables. / [CA] L'objectiu general de la present Tesi és la investigació de metodologies que permeten obtindre en temps real els paràmetres d'operació de xarxes hidràuliques a pressió que minimitzen el consum i/o el cost energètic, garantint el compliment de les condicions de funcionament necessàries per a una adequada qualitat del servei. En tractar-se de l'àmbit de l'operació diària de la xarxa, una de les condicions indispensables que han de reunir els mètodes d'optimització és una resposta prou ràpida com perquè no sols es puga disposar de les solucions més convenients en el moment d'executar les consignes d'operació, sinó que a més s'habilite un procediment flexible que permeta donar resposta a possibles canvis en les prediccions o esdeveniments que puguen produir-se. S'ha abordat de manera aïllada l'optimització energètica dels subsistemes de transport d'aigua i la dels subsistemes de distribució (reg per injecció directa) a causa de les diferents característiques que es poden observar en ells. En el treball amb els subsistemes de distribució s'han explorat les possibilitats que ofereixen els mètodes meta-heurístics d'optimització, realitzant diverses aportacions originals orientades a la millora en l'eficiència computacional dels mateixos a causa de la necessitat d'obtindre una resposta més ràpida que siga compatible amb la presa de decisions en temps real. Quant als subsistemes de transport, s'ha explorat l'aplicabilitat del mètode determinista d'optimització per programació lineal a la vista dels importants avantatges que presenta respecte a la resta de mètodes generals d'optimització. Així mateix, en el context dels subsistemes de transport, s'ha treballat en la definició d'una bona heurística basada en el càlcul del cost energètic i/o econòmic de l'aigua entregada en els punts de consum i en els dipòsits intermedis, que ha permés formular un mètode voraç per a l'optimització energètica en cada instant de temps. Aquest mètode ha aconseguit igualar l'acompliment aconseguit mitjançant la programació lineal i s'espera que oferisca unes millors capacitats en sistemes amb un comportament més marcadament no lineal, així com també una millor adaptació a problemes d'optimització amb participació d'energies renovables. / [EN] The general objective of this Thesis is the research of methodologies to obtain in real time the operating parameters of pressurized hydraulic networks that minimize energy consumption and/or cost, ensuring compliance with the operating conditions necessary for an appropriate quality of service. Since this is the field of daily network operation, one of the indispensable conditions that optimization methods must meet is a response fast enough so that not only the most convenient solutions are available at the time of executing the operating instructions, but also a flexible procedure is provided to allow a response to possible changes in the predictions or events that may occur. The energy optimization of the water transport subsystems and that of the distribution subsystems (direct injection irrigation) have been approached separately due to the different characteristics that can be observed in them. In the work with distribution subsystems, the possibilities offered by metaheuristic optimization methods have been explored, making several original contributions aimed at improving their computational efficiency due to the need to obtain a faster response that is compatible with real-time decision making. Regarding transport subsystems, the applicability of the deterministic method of optimization by linear programming has been explored in view of the important advantages it presents with respect to the rest of the general optimization methods. Also, in the context of transport subsystems, there has been a work on the definition of a good heuristic based on the calculation of the energy and/or economic cost of the water delivered at the consumption points and intermediate reservoirs, which has allowed to formulate a greedy method for energy optimization at each time instant. This method has been able to match the performance achieved by linear programming and is expected to offer better capabilities in systems with a more marked non-linear behaviour, as well as a better adaptation to optimization problems involving renewable energies. / Alonso Campos, JC. (2021). Desarrollo e implementación de algoritmos para la optimización energética en tiempo real de redes hidráulicas a presión [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/180389

The innovation of electrical utilities in creating smart electrical grids has superseded that of water utilities in analogous efforts. While many water utilities are now using smart water technologies, they lack the virtual command center that allows for two-way communication for more effective forecasting, load balancing, preventive methods, emergency and master planning, and level of service delivery while ensuring environmental justice and enhancing the responsible use of resources. In this dissertation, I propose the idea of the Integrated Water Distribution System (IWDS) to overcome this challenge. IWDS coordinates management of water supply and demand in a way that benefits both the water utility and the customer. IWDS also allows for greater control over monitoring, operation and maintenance, security, asset management, artificial intelligence, and delivery of water in order to maximize economic, environmental, and social welfare. To provide a way forward for IWDS and bring water services onto a technological level equal to that of other infrastructure systems, I call for greater coordination and integration of smart water technology and data, including environmental justice evaluations, and improved customer engagement. As a demand side management (DSM) tool and smart water technology component of IWDS, smart irrigation controllers (SICs) have the potential to ensure water utilities are resilient to growth and can manage peak day demands. SICs, which interface with soil moisture, evapotranspiration, or weather sensors, have been promoted as a demand-side management tool for this purpose. I review the body of research on residential smart irrigation controllers and their effectiveness. I find that smart irrigation controllers consistently reduce water demand by 15% among general users and more than 40% among indulgent users. A hydraulic model simulation using EPANET demonstrates the effectiveness of residential SICs in shifting and shaving peak demands associated with outdoor irrigation. The pressurized irrigation system for Highland, Utah, USA, is modeled with irrigation demands on a baseline scenario compared to an intervention scenario. By employing the intervention, the water system experiences many positive impacts. Without the peak shifting and shaving adjustments, costly additional capital facility improvements would be needed to maintain the same level of service. The model indicates that the SICs, if providing a 30% conservation effect (intervention scenario with SIC conservation), would shave the peak demand allowing for greater optimization and efficiency. This is the first hydraulic model analysis to demonstrate the DSM effectiveness of SICs.

Sector Wide Approach (SWAP) can be defined as collaboration between governments, development partners and civil society. It promotes coordination of various donor funded programmes to align with a common sector vision. In the case of South Africa, a water sector SWAP was introduced in 2000. Funds were directed to municipalities that were providing water known as Water Services Authorities (WSAs). This study examines the impact of the SWAP on tangible water delivery issues in Ukhahlamba District Municipality, Eastern Cape. The literature reviewed focuses on rural development in South Africa, and abroad. The quantitative aspect of the research considered various sources including primary data from municipal records of water services provision. Interviews were held with community members, municipal and provincial government officials. Analysis of information from these sources indicates some aspects of water delivery were positive and some negative. Recommendations for improvement and further research are made in the last chapter. / Development Studies / M.A. (Development Studies)