bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterizing the effects of water distribution system topology modifications on its dynamic behaviour through connectivity metrics
Authors: Marsili Valentina , Alvisi Stefano , Maietta Filomena , Capponi Caterina , Meniconi Silvia , Brunone Bruno , Franchini Marco
Published: March 2024

Water distribution networks (WDNs) are complex combinations of nodes and links and their structure has an impact on their behaviour, considering both quantitative (i.e. related to pipe flows and nodal pressures) and qualitative (i.e. related to water age and quality) aspects. The complexity of WDNs has been the basis of several studies that have resorted to the graph theory to relate connectivity properties to system behaviour (e.g. its reliability and water age/quality), evaluated under the assumption of steady-state conditions. Within this framework, in recent years the tendency toward reducing network interconnection through the closure of isolation valves has emerged, mainly to (i) facilitate its monitoring and management, and (ii) increase flow velocity and reduce water age. However, changes in the topology of a network can affect not only aspects evaluated under the assumption of steady-state conditions, but also its dynamic behaviour. Based on these considerations, the present study investigates whether some metrics derived from graph theory, already applied in the context of networks’ steady-state analyses, can also provide useful indications for assessing the effects of changes in the topological structure, which could be consequences of branching operations, on the dynamic response of a network subjected to users’ activity. The analyses highlight that connectivity metrics can reflect the pressure dynamic behaviour of the hydraulic systems and support in their macroscopic understanding during design and management operations. Thus, their application can be effectively extended from the steady-state to the dynamic framework.
Local control schemes for real-time optimization of variable speed pumps
Authors: Salomons Elad , Housh Mashor , Shamir Uri
Published: March 2024

In this work, we have developed local control schemes for the optimal operation of a pumping station that includes multiple variable speed pumps. The pumping station must maintain a target pressure for a closed supply network that usually does not contain storage facilities. The control loop includes repeatedly reading the control feedback (pressure) from the control system and then adjusting the operation of the pumps in the station as needed: changing the pumps' speed and on\off status. Firstly, we formulated a control algorithm that simulates the current practice. Next, an optimization algorithm was developed to achieve minimum energy operation considering the efficiency curves of the pumps. The algorithm utilizes the pumps' characteristics curves for ensuring hydraulic feasibility while sustaining the required pressure setpoint. The optimization problem incorporates bound constraints on the speeds, time gap constraints to prevent frequent pump changes, and physical constraints that quantify the operation point in the flow-head domain and the flow-efficiency domain. We considered two operation strategies. The first is the "free strategy" in which each pump can operate with a different speed inside a predetermined speed range, while in the "equal strategy" all active pumps must share the same speed. The methodology was demonstrated using a realistic case study. Our preliminary results indicate potential energy reduction compared to the current practice.
Is water quality based stormwater management actually feasible? A SWMM based study of the trade-offs of various stormwater management approaches
Authors: Suits Kristjan , Vassiljev Anatoli , Annus Ivars , Kändler Nils
Published: March 2024

Extreme weather events caused by climate change are becoming more frequent all across the world, particularly in the Northern Hemisphere, where these events manifest themselves as more severe or long-lasting rainfalls. Because the typical response, infrastructure refurbishment, is costly and time consuming, it is necessary to develop and implement alternative, more resource efficient, stormwater management methods. The methods must benefit both the urbanites as well as the natural environment, but they must be grounded on a comparative examination of alternatives. The purpose of this paper is to evaluate the trade-offs between several stormwater control strategies in the context of climate change, such as no intervention, water quality-based intervention, water quantity-based intervention, and a combined approach. Each of the aforementioned approaches is considered to have intrinsic advantages and disadvantages that should be examined and quantified. Analysis of these trade-offs is critical because it provides some insight into the feasibility of implementing various stormwater management strategies for protecting the environment. The SWMM software was used to analyse the various scenarios, and the model was built using data from multiple national databases as well as data sets provided by the Municipality of Viimsi in Estonia. This study confirmed that water quality protection can be prioritized even in densely populated areas without jeopardizing citizens’ well-being or causing unnecessary floods. This can be accomplished even with simple rule-based control if the necessary hardware, such as sensors and flow devices for digitalizing and combining inter-linking stormwater infrastructure are installed on-site. Through the SWMM simulations it was determined that digitalization of the stormwater solutions allows for a 30-92% reduction in flow, and consequently a 50-90% reduction in pollution load entering the Baltic Sea.
Comparison between the Top-down and Bottom-up approach for the diffuse-dispersive phenomenon analysis
Authors: Piazza Stefania , Blokker E. J. Mirjam , Sambito Mariacrocetta , Freni Gabriele
Published: March 2024

In order to detect deliberate or accidental contamination in drinking water distribution systems (DWDS), typically water quality sensors need to be installed in this system, and the data need to be analysed in order to feed alert systems and prevent the harm of contamination. This requires numerical (hydraulic and water quality) models that are as realistic as possible to support monitoring systems. Currently, water quality models used in the literature adopt an advective approach and simplified reaction kinetics, such as EPANET, which neglect diffusion-dispersion phenomena that are relevant in the presence of laminar and transient flow regimes. Another important aspect providing relevant uncertainty is related to the simplified estimation of sub-daily water demands that are commonly estimated from highly aggregated consumption data.The present study aims to analyse diffusion-dispersive phenomena in a realistic DWDS model, which shows turbulent, transitional and laminar flows, and compare this to how such a DWDS would typically be modelled with a coarse estimate of demands. We are therefore considering two different demand allocation approaches (Top-down and Bottom-up).In this paper the EPANET advective model and the diffusive-dispersive model, developed in a previous study, were used to better understand what the effect using the latter approach has within the DWDS as a function of two different types of demand allocation. To do this, the models results were compared to numerical tests that were performed on the real network of Zandvoort (the Netherlands) using a conservative tracer. For the 4 locations considered, it was noted that the diffusive-dispersive model responds well when using the bottom-up approach compared to the top-down approach. We found that in order to predict the tracer pattern, the Top-Down approach of demand allocation does not work well, even when an optimized diffusive-dispersive model is used. The bottom-up approach of demand allocation leads to far better results in predicting the tracer patterns, and with the diffusive-dispersive model the prediction improves even more. This means that in order to model water quality in a DWDS the first step should be to improve water demand models for this DWDS. This leads to an improved representation of flow regimes, and will most likely include laminar flows.
Analysis of online pressure for resilience phase characterisation of leakages/burst events
Authors: Hoseini Ghafari Sotudeh , Francés-Chust Jorge , Piller Olivier , Ayala-Cabrera David
Published: March 2024

While operating a water distribution network (WDN), it is essential to prepare the system to face with intentional (e.g., cyber-physical attack) or unintentional (e.g., pipe leakage/burst) adverse events or other drivers such as the effects of climate change. Increasing the network’s preparedness to deal with anomalous events is an effective manner to improve the system’s resilience, reducing the negative impacts of events. In this paper, leakage/burst events, and ordinary network operation, are captured by both sensors and expert knowledge in a WDN in Spain. Event-driven and data-driven approaches are used to characterise the system behaviour, in particular when it is operating under the effects of an anomalous event, based on the resilience phases (i.e., absorptive, adaptive, restorative) for the collected dataset. The relationship of clustering pressure head time series based on their potential state in a particular resilience phase, in three random cases of short-term leakage events, was explored. This paper focuses on capturing the behaviour of the system, through the exploration of the hydraulic parameters of WDNs (in particular the pressure head) before, during, and after a leakage event, by means of a spatial-temporal analysis. It was observed that the network behaviour could be categorised into 1) ordinary operation and 2) during the event, which would allow to characterise the system behaviour when influenced by leakage/burst event and also explore its adaptability to resilience phases. The results show that it is possible to extract relevant patterns (i.e., feature maps) and generate an anomaly indicator from the pressure head heatmaps that facilitate the characterisation of anomalous events for WDNs.
W-NET4.0 – Integrated Platform for Small and Medium Sized Water Supply Utilities
Authors: Deuerlein Jochen Werner , Bernard Thomas , Gonuguntla Naga Mamatha , Thomas Jorge , Canzler Armin , Keifenheim Heiko , Wiese Susanne , Hoeche Ruediger , Rapp Joachim , Parra Salomé
Published: March 2024

More than 5,800 companies ensure the supply of drinking water in Germany. The vast majority of these are small and medium-sized water supply companies. So far, they are using information and automation technology to a very limited extent, measurement data is usually not collected systematically. In addition, the companies often have neither a sufficiently well-maintained database of the water network nor geoinformation systems (GIS), simulation software or data analysis tools that can be used to plan and optimise interventions in the drinking water system (e.g. expansion of the network). Large water suppliers are often better equipped technically, but the data is often not used in an efficient manner.The objective of the W-Net 4.0 research project (www.wnet40.de) was to develop a modular and scalable platform that combines GIS, simulation software and data analysis tools and meets high IT security standards. Combined with novel service concepts, value-added networks and training concepts, also small and medium-sized water utilities will be enabled to use these technologies. The high degree of usability and accessibility of the platform supports the daily work of planning engineers, and network operators. The paper includes a detailed description of the platform and use cases. It also emphasizes the training program tailored for small and medium sized utilities.
Pumping Station Design with an Analysis of Variability of Demand and Considering Techno-Economic and Environmental Criteria through the AHP Method
Authors: Briceño-León Christian Xavier , Iglesias-Rey Pedro Luis , Martínez-Solano Francisco Javier , Creaco Enrico
Published: March 2024

Pumping stations costs including, capital and operational costs are some of the highest costs in urban water distribution system. A proper pumping station design could be defined as the solution with the minimum life cycle cost and satisfying extreme scenarios in water distribution system. These costs are associated with investment, operational and maintenance costs. However, there are some important aspects to consider un a pumping station design, such as the feasibility of infrastructure construction, the size of the infrastructure, and the complexity of operation in the pumping station. These aspects are associated with technical criteria. In a classical pumping station design, the number of pumps is determined in arbitrary form according to the criteria of the engineer, and the pump model is selected according to the maximum requirements of flow and pressure of the network. In summary, these variables in a pumping station design are not usually analyzed deeply.  In addition, global warming acceleration in the last decades has gained momentum to be considered in engineering problems to mitigate the environmental impact. Hence, it is imperative to consider environmental aspects, such as greenhouse emission, energetic efficiency of the pump in modern pumping systems of water distribution networks. Finally, the most suitable solution is determined only by analyzing economic aspects. Therefore, this work proposed a methodology to design pumping stations in urban water networks considering technical, environmental, and economic criteria and link them together through the Analytic Hierarchy Process (AHP) method. The propose of this method is to determine the importance priority of these aspects to assess the possible solutions and determine the most suitable solution in the pumping station design. In addition, this work considers the variability of demand pattern. This work analyses several scenarios of demand patterns from the minimum possible demand to the maximum possible demand in a water distribution network and the respective probabilities of occurrence of scenario. It allows that the pumping station design be more robust. This methodology has been applied in different case studies to analyze how affects to determine the most suitable solution when the characteristics of the network change.
NRW Estimation and Localization in Water Distribution Networks via Hydraulic Model Calibration using 24/7 Monitoring Data
Authors: Wu Zheng Yi , Chew Alvin Wei Ze , Kalfarisi Rony , Xue Meng , Pok Jocelyn , Jianping Cai , Lai Kah Cheong , Hew Sock Fang , Wong Jia Jie
Published: March 2024

Operations of water distribution networks (WDNs) are monitored daily via installed data loggers, where the collated hydraulic data can be leveraged to improve the system’s operations over time, and to minimize total economic losses due to non-revenue water (NRW). In collaboration with Public Utility Board (PUB), Singapore’s National Water Agency, a practically novel model calibration approach using 24/7 monitoring flow and pressure data has been developed to facilitate PUB’s Smart Water Grid (SWG). The approach is developed as a generic integrated solution process to conduct a series of systematic analyses for daily WDN model calibration, namely: (1) estimating the system’s daily NRW contributions; (2) performing flow calibration that involves net demand consumption calibration, adjusting pumps operational configurations and localizing NRW sources when the system’s daily estimated NRW volume exceeds its assumed background volume; (3) performing energy calibration by rectifying possible drifting in monitored pressure head data and calibrating other physical properties which include, but not limited to, pipe roughness and valve settings, especially during peak-demand hours. The effectiveness of our proposed approach is subsequently tested on three WDN zones in Singapore, having a total pipe length of >100km, that comprises of atypical water usage patterns. The results of model calibration for one of three zones is presented in this paper. The key outcomes derived from the study are: (a) localized a reported leakage event by PUB to less than 100m; (b) calibrated the system’s flow balance, to less than 1% average mean absolute percentage error (MAPE), by first identifying and addressing the system’s billing data uncertainties, followed by localizing anomaly events that account for the total NRW volume estimated; and (c) calibrated the system’s pipe roughness values to improve the total energy balance by achieving an average daily MAPE of 4.0%.
Modelling of Air Pocket Entrapment during Pipe Filling in Intermittent Water Supply Systems
Authors: Ferreira Joao , Ferras David , Covas Didia , Kapelan Zoran
Published: March 2024

Intermittent water supply (IWS) operations frequently involve water filling and emptying cycles that are strongly influenced by air-water interaction. Storm Water Management Model (SWMM) software has been recently proposed to simulate pipe filling events in IWS systems. As the tool is conceived to simulate both free surface and pressurized flows, it also has the potential to analyse the air entrapment. However, there is no numerical model capable of accurately and efficiently simulating the air behaviour during these events, nor of predicting the locations of air pockets created during the pipe filling process.An experimental pipe rig was assembled to better understand the pipe filling process in terms of pressure variation, the propagation of the filling wave and the air entrapment locations under different initial conditions. The pipe rig has a classic reservoir-pipe-valve configuration. Different behaviours are observed in this experimental setup during the pipe filling tests. An entrapped air pocket is created at the high point for lower flow rates, which is not dragged when the pipe is full. This air pocket can go from a similarly free surface flow inside the pipe to a complete water filled flow, depending on the flow rate. For low flow rates, a high head loss is introduced due to a hydraulic jump inside the pipe. For higher flow rates, the air is dragged, no air is entrapped and only the local head losses from the change of direction at the high point are observable.Following the collected experimental data, SWMM is used to assess to which extent it can predict entrapped air pockets location and their volume. Different filling processes can occur and an air model should be included to simulate the tests carried out in the pipe rig. The results obtained show that SWMM is capable of predicting air pocket locations but not the air pocket volumes. Further research is necessary to improve SWMM in this context.
A decision-making approach to assess and prioritise intervention solutions in water distribution systems
Authors: Cabral Marta , Loureiro Dália , Covas Dídia
Published: March 2024

The present paper aims at proposing and demonstrating the application of a decision-making approach for the identification, assessment, comparison and prioritisation of different intervention solutions. Infrastructural, financial, performance and economic perspectives are considered in the study. The proposed approach is composed of three main modules: 1) Analysis planning and database construction; 2) Infrastructure, asset or component diagnosis and prioritisation; and 3) Study of intervention solutions for priority assets or components. Three assessment levels – macro, meso and micro – are proposed, and the decision-making approach is adapted to each level. A water distribution system located in Portugal is used to demonstrate the proposed approach. This case study comprises five water subsystems, including different assets, such as water storage tanks, pumping and booster stations and water distribution pipes. Five intervention solutions are defined by identifying the main problems associated with the priority subsystem and the respective causes. The intervention solutions are compared considering the financial metrics and performance indicators, such as standardised energy consumption, energy in excess per unit of the authorised consumption, infrastructure value index and non-revenue water. New metrics regarding the assets’ physical condition are also incorporated in the assessment system. Results have shown the influence of considering different assessment criteria and performance indicators in the solutions' prioritisation, highlighting that the solution with the lowest capital cost does not always correspond to the solution with the highest overall performance.
Flow dynamics in a pipe containing uneven roughness elements
Authors: Kaur Katrin , Vassiljev Anatoli , Annus Ivar , Truu Murel , Kändler Nils
Published: March 2024

The objective of this study is to improve the methodology for modelling aged pressurised urban networks, such as water distribution system (WDS) pipelines, with substantial and uneven wall roughness. Due to the complexity of the inner surface geometry of old rough pipes, WDS models are unable to predict the real velocities, which are requisite for estimating contamination propagation rates in the system. In order to analyse the impact of inner surface geometry a specifically designed experimental apparatus was built to investigate the flow dynamics in a pipe containing flow-obstructing elements. A transparent pipe was fitted with 3D-printed elements, in two different configurations, at the location of the measurement section and the velocity fields were captured using the particle image velocimetry technique at different flowrates. The experimental results revealed that in the case of one roughness element, the impact to the flow dynamics is local and can be expressed through minor losses, and in the case of multiple elements, the effective diameter of the pipe is reduced and a jet-type flow will develop.
GIS-integrated pluvial flood risk assessment methodology for urban areas
Authors: Truu Murel , Annus Ivar , Kändler Nils
Published: March 2024

To different extents, most urban areas in Europe are exposed to pluvial flood hazards.  The local communities, as well as city governments have to find measures either to cope with the consequences or look for solutions to prevent the possible damage of the floods. Moreover, in most cases cities cannot be transformed to be flood resilient with single isolated interventions, but need an adaptive approach for flood-conscious governance and management. For this, cities require up-to-date information on the flood risk, to make data-based decisions on how to avoid disastrous events, plan for flood resilient high-quality living environment, and where relevant, design and implement transformative interventions. The conventional definition of disaster risk combines the likelihood of potential hazard, exposure magnitude, and the level of vulnerability. However, when considering the multifaceted challenge of assessing the susceptibility and damage potential of urban pluvial flooding, this three-dimensional risk assessment methodology is not yet widely implemented. Additionally, a standardized risk management framework proposes an iterative risk assessment procedure, which could be well-suited for an adaptive governance approach. However, until now, the pluvial flood risk assessment has not been fitted to this framework. In the paper, we present a tiered pluvial flood risk assessment methodology, which can be applied to any urban area. The proposed solution couples the disaster risk function with the standardized iterative risk assessment procedure. This allows cities in various entry-level preparedness to improve their understanding of the city-wide pluvial flood susceptibility and identify the flood-prone urban watersheds in which more specific risk analyses are required. The methodology includes coupling a digital twin of an urban drainage system (UDS) and a geographical information system (GIS). By integrating the pluvial flood risk assessment procedure in the city GIS the cities can automatically determine the potential hazard and coping capacity of exposed areas, and analyse the concurrent vulnerabilities. The methodology has been tested in a small, but densely populated urban area in Estonia, Rakvere town.
TEmporal Scale SIgmoid Curve (TESIC): A tool to characterize short-term demand variability at water supply systems
Authors: Díaz García Sarai , Ruiz Gómez Emilio , González Pérez Javier
Published: March 2024

Water demand is the main random factor that conditions flow variability across water supply systems. Water demand measurements or pseudomeasurements (i.e. estimations based on historical data) are associated with a time interval (sampling rate), which affects the variability of water demands. Considering a long time interval implies losing information about water consumption within that temporal window. The variance (i.e. quantification of variability) computed from demand records is thus only “apparent”, because the variability within the time interval is averaged and lost (i.e. “missed”). The relationship between missed and apparent variability can be assessed through the so-called TEmporal scale SIgmoid Curve (TESIC), which is here presented as a tool to characterize short-term demand variability. TESIC is used in this work to compute demand uncertainty for a given time resolution level and to estimate peak demands for different temporal resolutions in a realistic water supply case study. These applications show that TESIC provides a conceptual framework to explain and quantify the temporal resolution effect in hydraulic modelling applications.
An Experimental Study On Early Leak Localization In Drinking Water Networks using pressure measurements
Authors: Deleuze Yannick , Nova-Rincón Arley , Batany Yves-Marie , Abril Teodulo , Chenu Damien , Roux Nicolas
Published: March 2024

Leaks represent a major issue impacting the management and efficiency of  Drinking Water Networks (DWN) in cities worldwide. According to the Development Bank of Latin America, by 2018 the losses in DWN range from 40 to 60% in the region. In Europe, the OECD reports a wider range with few losses in cities like Amsterdam (4%) up to 37% in Naples. With this context, some regional policies have emerged like the 2020 european drinking directive “Right2Water”, that aims to encourage major suppliers (more than 50000 users), to develop tools to measure and reduce leakages by 2025. Considering this situation, we introduce here a systematic approach for leak management that combines field data, hydraulic models (HM) and machine learning.Model-based and data driven methods have been of great interest for leak location methodologies in DWN. This research will design energy-efficient and cost-efficient leak localization hotspots in the DWN. The approach is intended for sectorized DWN, equipped with a SCADA system and where a calibrated hydraulic model (e.g. EPANET) is available. This latter serves to evaluate the sensitivity of the system to leaks and identify potential points for pressure measurements in order to optimise the number of installed sensors. Given a detected leak in the network, a multiclass classifier using pressure data is developed to reduce the inspected pipe length for the leak location. The leakage localization method is implemented combining multiple individual classifiers using ensemble learning methods and a reduced number of decision variables. The methodology is tested on a real case study from a Colombian site. The method faces challenges in (a) collecting correctly labelled real leak data, and (b) modelling and calibrating hydraulic models. Those challenges are being addressed. The outcome shows that the length of pipes inspected can be reduced by one third with high performance in accuracy with few sensors required (low capital expenditures) and low computational effort (low energy and low operational expenditures).
Water Distribution Network operation optimization: an industrial perspective
Authors: Lauricella Marco , Lenders Felix , Biskoping Matthias
Published: March 2024

A significant portion of the operating costs associated with drinking water distribution networks is related to energy usage, which is mostly employed to drive pumps. One strategy to improve energy efficiency and to reduce energy cost is to operate water pumps in an optimal manner that allows a reduction in energy consumption. This produces also environmental benefits, since decreasing energy consumption contributes to the reduction of the associated greenhouse gas emissions, helping utility providers to reduce their carbon footprint and to reach sustainability goals. However, numerical optimization of water distribution network operation is a difficult problem to solve, given the combination of non-linear hydraulic dynamics and the presence of discrete decision variables, corresponding to pumps and valves having on/off or open/closed characteristics. In this work, we address such problem from an industrial perspective, reformulating the mathematical program that is at the core of such operation optimization solutions using complementarity constraints to transform the resulting mixed integer nonlinear program into a nonlinear program having only continuous variables. This allow us to obtain a tractable optimization problem, that could be solved in a short amount of time even for large-scale water networks, making it compatible with industrial implementation and real-time optimization.
On the use of SINDy for WDN
Authors: Castro-Gama Mario
Published: March 2024

With the growing interest of water utilities on digitalization, running multiple scenarios can become cumbersome with limited budget and short data collections. The total number of hydraulic simulations required (usually using commercial software), becomes a burden for near real-time operation. In order to circumvent the computational burden (limitation), since a couple of decades, several Machine Learning techniques have been used to create a meta-model or surrogates of a Water Distribution Networks (WDN) based on a subset of data available through SCADA. Among the many possible surrogates a Sparse Identification of Non-linear Dynamics (SINDy) method is presented. The method is applied to two datasets: i) to obtain a surrogate of a benchmark network and ii) real data of water consumption of different District Metered Areas (DMA) of a real water utility. The method is: i) computationally inexpensive, ii) less data demanding for calibration than other modern methods, iii) parsimonious, and iv) could be used to infer physical relations among data.
Advances in Premise Plumbing Modeling
Authors: Buchberger Steven , Platten William , Murray Regan , Lee Juneseok , Janke Robert , Haxton Terra , Grayman Walter M. , Burkhardt Jonathan
Published: March 2024

In summer 2019, a new task committee on Premise Plumbing Modeling (PPM) was approved under the auspices of the Water Distribution Systems Analysis Committee of ASCE EWRI.  The primary purpose of the PPM task committee is to advance the science of the new field of premise plumbing modeling.  In particular, the PPM committee intends to identify areas where methods and models developed over the past several decades to manage municipal water distribution systems can also be applied to solve vexing problems that arise in the premise plumbing systems of contemporary buildings. The ultimate goal of the PPM committee is to identify and develop water systems management tools for use by practicing engineers, as well as the larger water distribution research community, in support of the safe design and operation of indoor water distribution systems.   Initially, three general areas were identified where current modeling approaches could be applied to premise plumbing: [1] hydraulic design and performance, [2] building water quality and age, and [3] water safety and security.  Using these three core areas as a backdrop, this presentation will describe key accomplishments of the PPM task committee including: creation of a monthly webinar series reaching an international audience, distribution of a quarterly newsletter to the professional community, presentation of technical sessions at annual EWRI national Congress, preparation of a state-of-the-art journal paper, publication of a textbook style final report to archive the main topics covered in the PPM webinar series.  Finally, this talk will conclude with a glimpse of the challenging problems posed by modern premise plumbing systems and the unique opportunities waiting for researchers working in the field of water distribution network analysis.
Survey Exploring Customer Complaint Management and Smart Water Technology Adoption Across U.S. Water Systems
Authors: DiCarlo Morgan , Berglund Emily Zechman , Kaza Nikhil , Grieshop Andrew , Shealy Luke , Behr Adam
Published: March 2024

High profile water quality events, including the Flint Lead in Water Crisis, have contributed to a decline in customer trust in their water utilities. For example, a recent study indicates as many as 60 million Americans do not drink tap water because they perceive risks in the cleanliness of water and do not trust water providers [1]. One way that utilities can build trust with customers is through improved management of customer complaints. Utilities can store, track, visualize, and share customer complaints to improve service and improve the way that customers interact with information about water quality.  Smart water technologies, including Advanced Metering Infrastructure (AMI), data portals, and personal device applications (apps) can be utilized to better communicate with customers.  Advanced data analytics can improve the insight that is gained about the source of water quality problems. We surveyed utilities about their perspectives on trust and customer complaint management. This research explores the development, implementation, and results of a survey instrument distributed to water service providers across the United States. Survey questions explore the existing tools that utilities use to collect customer complaints, the adoption of smart technology by utilities, and characteristics of customer complaints. This research will assess capabilities to detect issues from customer complaints trends and the level of smart technology integration in United States water systems. We employ cross sectional analytical techniques to assess differences in complaint reporting and management system by utility size, urbanization, and socioeconomics of their service area. This research will develop new insight about the types of tools that utilities need and are willing to adopt to receive, analyse, and report customer complaints.
Estimation of the spatial distribution of substances in Anaerobic Digestion Tanks with CFD
Authors: Dabiri Soroush , Kumar Prashant , Rauch Wolfgang
Published: March 2024

Anaerobic digestion (AD) is used in wastewater treatment plants (WWTPs) to decompose organic matter. Highly efficient AD tanks are able to mix biochemical substances within the tank, and – in order to assess such spatial distribution of substances - a proper modelling method is necessary. Computational fluid dynamics (CFD) is a simulation tool for modelling fluid flows in WWTPs, but there is a lack of studies on CFD modelling of hydrodynamics together with an integrated modelling of bio-kinetics due to the complexity of biochemical reactions in AD processes. The current study aims at estimating the distribution of biochemical components within an AD tank. For doing this, an integrated modelling of hydrodynamics and bio-kinetics is conducted, in order to assess mixing quality. The novelty of the work is the derivation of a new AD-related solver in an open source CFD platform. As the first step, the hydrodynamics of the fluid flow in our WWTP are estimated through iterative solution of fluid flow equations, and subsequently, by fixing the obtained velocity vector field, bio-kinetic equations are applied to the flow field. The bio-kinetics in our solver are based on ADM1, the state of the art transient model for AD process. The validation of our developed solver is done by comparing the results to a fully-mixed digester in an experimental setup. Then, the results of our hydrodynamic modelling are shown as the velocity profile and streamlines. Subsequently, regarding bio-kinetics, the concentrations of substances are estimated and plotted during the simulation time. In order to evaluate the distribution of the organic material within the tank, the uniformity index for the substances is analysed.
Performance evaluation of buried uPVC pipes by numerical simulation of soil-pipe interaction
Authors: Latifi Milad , Beig Zali Ramiz , Farmani Raziyeh , Javadi Akbar , Zulfiquar Suhayl
Published: March 2024

Pipelines are the most important and valuable assets in a water distribution network. Design, commissioning and maintenance of the pipes costs a huge amount of money and effort for water supply companies. Understanding the behaviour of buried pipelines is a major concern for engineers. In this paper, soil-pipe interaction has been investigated under various conditions using the numerical simulation of in-situ pipes. A finite element model has been developed to numerically simulate the interaction of soil with pipes. More than 180 scenarios have been designed to cover the different conditions. Three segments of uPVC pipes with diameters between 160-450 mm were modelled. To cover a range of soils, three different soil types were modelled. The value of Young’s modulus was decreased in various scenarios to consider the effects of age on the mechanical properties of pipes material. Four different external loads (corresponding to light to heavy vehicles) were exerted on top of the road pavement. Also, a large external load was applied to study the pipes failure under heavy loads. A variety of internal fluid pressures from 0 to 6 bars was applied inside the pipelines and the ultimate internal pressure which would cause failure in the pipe was determined. The model domain was discretized for finite element calculations. Finer mesh sizes were selected around the pipe. An appropriate mesh size was determined by mesh sensitivity analysis. The Mohr-Coulomb failure criterion was chosen to simulate the soil behaviour. Also, an elastoplastic stress-strain relationship was considered for the uPVC material. Von-Mises stress was selected as the failure criterion. Running the finite element model, the distribution of stresses and strains in the soil and the pipe were computed. In the absence of external load, the values of axial and hoop stresses were compared with the theoretical values. The comparison of the results showed a high correlation between the computed and theoretical values. In both absence and presence of external loads, the values of shear stresses are relatively small and negligible in comparison with axial and hoop stresses. As a result, the minimum and maximum principal stresses are close to the axial and hoop stresses, respectively. This implies that, only measuring the axial and hoop stresses can provide the principal stresses with a reasonable accuracy. Both internal and external pressures in which the pipe fails are significantly higher than the usual loads on roads and water distribution networks. It justifies the fact that most of the pipe failures occur not due to exceeding the yield stress, but due to fatigue in elastic region. The results of numerical modelling of soil-pipe interaction help engineers to study the pipe performance under different conditions.
Development of a graph dynamic sectorization tool using QGIS/PostgreSQL to plan and operate water distribution networks
Authors: Torret Requena Xavier , Grau Torrent Sergi , Pérez Magrané Ramon , Amat Miralles Enric
Published: March 2024

This paper presents a definition of the different  types of sectorization used by water distribution companies, as well as a methodology for their identification and application in the dynamic zoning of water distribution networks. The graph model of large water supply networks is made up of thousands or hundreds of thousands of nodes and pipelines, as well as valves, tanks, pumps and pressure groups. Its generation from the data contained in a GIS does not report difficulty with the currently existing tools, the GISWATER module of QGIS is an example of this. Problems arise when these models have to be operated from a high number of conditions and scenarios. To facilitate the operability of the system, one of the strategies is to simplify its operation through topological analysis. One of the proposals is clustering where the nodes belonging to a cluster have more and better connections with the internal nodes than with the external ones. Our work analyzes water distribution networks from five different points of view, which it represents five sector classes according to the parameter analyzed. As result, one of them, the District Metering Area (DMA) delimited by headers (flowmeters) and stoppers (other flowmeters or closed valves), is extensively covered in the literature. The other four, less common in the literature, have a definition equivalent to that of the DMA but based on other class of headers and stoppers. Therefore, if we are looking to operate the network from the point of view of pressure, we can use the dynamic sectorization algorithm by configuring Tanks, Head pumps, flow pumps, PSV, PBV or PRV as headers. Moreover, to operate and analyze the network from the point of view where water comes from, we can use again the dynamic algorithm by configuring the inlets of the system as headers (Tanks and Reservoirs). On the other hand, if the goal is to be focused on water quality, the algorithm can be configured using clorinathors, reclorinathors, water treatment equipment or water sources as headers. Finally, special attention deserves the minimum sector which represents the minimum structural unit of the network, defined by the region covered by network where there are shutoff-valves on their borders. In order to operate water networks as optimized as possible, the status of shut-off valves is dynamic. The opening and closing of valves allows a continuous reconfiguration of the network and the classes or types of sectors defined. As result, to analyze the network graph using this approach enables the water operator to analyze the best status as possible as well as it is amazing scenario to analyze resilience of network using stochastics methods.
Hydraulic and Co-located Pipe Criticalities in the Rehabilitation of Water Distribution Mains
Authors: Sitzenfrei Robert , Minaei Amin , Hajibabaei Mohsen , Creaco Enrico
Published: March 2024

Infrastructures in urban areas can have spatial and also functional correlation. Water distribution networks (WDNs) along with other infrastructures therefore constitute a complex and interlinked multi-utility system in cities. This brings up the risk of cascading failures to the different networks’ elements; for example, a pipe failure could interrupt traffic in a main street, eventually leading to a road network failure. On the other hand, WDNs should be hydraulically robust so that the potable water is supplied to the customers with high reliability. Traditionally, there is a single perspective design approach for WDN rehabilitation and upgrade activities such as pipe replacement, duplicating, and lining, which does not consider the interlinked system in a city. This study aims to assess this issue in terms of an integrated asset management perspective with a multi-utility approach. For this purpose, beyond minimizing costs, two reliability indices will be defined to represent the reliability of a WDN against the hydraulic and multi-utility cascading failures. The hydraulic reliability represents the robustness of the network against the water pressure deficit, and cascading reliability represents the extent to which WDN elements are decoupled from other assets elements. Then, the rehabilitation problem is solved with the contribution of a nature-inspired optimization algorithm, the Non-Dominated Sorting Genetic Algorithm (NSGA-II), through a dynamic approach. In every decision of pipe rehabilitation action, the priority could be given to either the first or second reliability index. These two cases will be assessed and compared to examine the hydraulic and co-location pipe criticality roles in the decision-making for the upgrade of aged water distribution mains on a simplified real network located in the southwest Iran.
Disinfection by Products Estimation in a Water Distribution Network
Authors: Vinardell Magre Laura , Jubany Güell Irene , Pérez Magrané Ramon
Published: March 2024

Even though disinfection is necessary to ensure water safety for human consumption, some disinfectants produce disinfection by-products (DBPs) that may be dangerous for human health. Current European legislation obligates water distributors to limit some DBPs concentration to final consumers. Then, water companies must control these compounds and are obligated to periodically monitor their network. DBPs modeling can be very useful for estimating online DBPs concentration throughout the network, increasing DBPs control and knowledge, but avoiding DBPs analytics time and resources consumption [1]. Trihalomethanes (THM), the first DBPs discovered, have long been the most studied and modeled. Previous studies have mostly used linear relations between variables and THM concentration, but also computational modelling, mechanistic and data driven models [2, 3]. Even though, there are still challenges to beat: most studies use a small database and laboratory-scale for model building, forgetting the impact of network pipelines and season. In addition, significant variables for DBPs’ formation such as retention time are most of the time neglected due to its difficulty to measure. Finally, THMs are not the only DBPs generated from disinfection or even the most toxic: other DBPs must be studied, and their formation pathways along the network investigated. In this study, data from a full-scale distribution network was used: online sensors and sampling campaigns. To include hydraulic conditions as retention time, EPANET software and R programming are used to simulate the network. Different models, mechanistic and data driven, have been used to estimate the chlorine decay and DBP formation within the network. Results of the calibration and validation of these models and the conclusions obtained are presented.
Modelling consumers in intermittent water supplies: a comparative review of EPANET - based methods
Authors: Abdelazeem Omar , Meyer David Donald James
Published: March 2024

Intermittent Water Supply (IWS) networks, which pressurize for less than 24 hours/day, affect 1 billion people worldwide and are associated with increased water contamination and inequitable distribution.  Due to these downsides, various methods to model consumers and understand their behaviour were proposed. We found more than 8 different methods of modelling IWS consumers, but we know of no comparative analyses of these methods nor their efficacy. This study comparatively reviews methods of modelling IWS consumers implemented in EPANET, due to their prevalence, reproducibility, and accessibility. Methods of modelling IWS consumers were found to fall into three groups based on their assumed consumer withdrawal behaviour: unrestricted, flow-restricted, and volume-restricted methods. We applied each method to three reference networks and compared the methods’ performance after subjecting each reference network to common IWS improvement strategies, including changing the supply duration and/or source pressure. Flow-restricted methods assume consumers withdraw their demands at a constant rate, leading to unrealistic predictions when subjected to unexpected changes in supply conditions. Volume-restricted methods assume consumers withdraw at the highest, hydraulically feasible rate until their storage tanks fill. This assumption highlights pronounced inequality between consumers, as consumers advantaged by source proximity and/or elevation receive their demands faster and earlier. Our results demonstrate that the simulated behaviour of IWS depends substantially on the type of consumer model employed. Presented examples demonstrate that consumer model selection can change the simulation-predicted optimal strategies for coping with and improving IWS. IWS modelling methods should reflect the consumer behaviour in the modelled network and the model’s intended use.