Special Issue "Urban Water Networks Modelling and Monitoring"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Urban Water Management".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 11777

Special Issue Editors

Prof. Dr. Gabriele Freni
E-Mail Website
Guest Editor
School of Engineering and Architecture, University of Enna “Kore”, Cittadella Universitaria, 94100 Enna, Italy
Interests: integrated urban water systems; wastewater treatment plant management and optimization; advanced water treatment; oily and salty water treatment; energy management in integrated water systems
Special Issues, Collections and Topics in MDPI journals
Dr. Mariacrocetta Sambito
E-Mail Website
Guest Editor
Department of Engineering, University of Palermo, Viale delle Scienze, Ed. 8, 90100 Palermo, Italy
Interests: urban water systems; sensor network design; urban water quality; optimization techniques; advanced numerical modelling; water and energy balance in water services; life cost assessment to CFP evaluation in water service
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Innovation in information and communication technologies has produced a large impact in the production of goods and in service provision. Urban water research and practice received a boost thanks to the availability of new and advanced numerical models, the increase of computing resources (especially distributed in clouds), and the availability of cheap and reliable sensors that can be deployed through the system to trace its evolution. This Special Issue welcomes research papers dealing with new technologies and models to monitor and manage urban water distribution networks and drainage systems. Papers about new monitoring strategies and technologies both including water quantity and quality aspects are also welcome, as well as scientific reports regarding the application of optimization techniques to improve system management, report leakages, investigate water quality, and reduce energy consumption. Well-documented and internationally relevant case studies and practical field test reports could be a valuable addition to this Special Issue that aims to catch the interest of researchers in the water and IT sector as well as of water managers and practitioners.

Prof. Dr. Gabriele Freni
Dr. Mariacrocetta Sambito
Guest Editors

Manuscript Submission Information

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Keywords

  • water distribution networks
  • urban drainage systems
  • numerical modelling
  • optimization
  • water quality
  • illicit intrusion
  • decision making
  • maintenance schedule
  • energy saving
  • online sensors
  • asset management
  • leakage management

Published Papers (11 papers)

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Research

Article
A Digital Twin of a Water Distribution System by Using Graph Convolutional Networks for Pump Speed-Based State Estimation
Water 2022, 14(4), 514; https://doi.org/10.3390/w14040514 - 09 Feb 2022
Cited by 1 | Viewed by 966
Abstract
Water distribution system monitoring is currently carried out using advanced real-time control technologies to achieve a higher operational efficiency. Data analysis techniques can be implemented for condition estimation, which are crucial tools for managing, developing, and operating water networks using the monitored flow [...] Read more.
Water distribution system monitoring is currently carried out using advanced real-time control technologies to achieve a higher operational efficiency. Data analysis techniques can be implemented for condition estimation, which are crucial tools for managing, developing, and operating water networks using the monitored flow rate and pressure data at some network pipes and nodes. This work proposes a state estimation methodology that enables one to infer the hydraulic state of the operating speed of pumping systems from these pressure and flow measurements. The presented approach suggests using graph convolutional neural network theory linked to hydraulic models for generating a digital twin of the water system. It is validated on two benchmark hydraulic networks: the Patios-Villa del Rosario, Colombia, and the C-Town networks. The results show that the proposed model effectively predicts the state estimation in the two hydraulic networks used. The results of the evaluation metrics indicate low values of mean squared error and mean absolute error and high values of the coefficient of determination, reflecting high predictive ability and that the prediction results adequately represent the real data. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Rehabilitation in Intermittent Water Distribution Networks for Optimal Operation
Water 2022, 14(1), 88; https://doi.org/10.3390/w14010088 - 04 Jan 2022
Viewed by 412
Abstract
Equitable distribution of water is a growing source of worry, and concerns water systems’ managers as water-stressed areas steadily increase and situations of water scarcity are becoming more frequent. The problem goes beyond just the water sector and globally affects many countries’ economies [...] Read more.
Equitable distribution of water is a growing source of worry, and concerns water systems’ managers as water-stressed areas steadily increase and situations of water scarcity are becoming more frequent. The problem goes beyond just the water sector and globally affects many countries’ economies since water resources have multiple uses (i.e., power generation, irrigation, etc.). One of the various strategies to overcome periods of extreme events (e.g., water scarcity) is the adoption of intermittent operation. Intermittent operation can minimize water losses, and manages to supply the same water demand (in terms of volume) during a reduced period of time. However, despite minimizing water losses, the energy consumption necessary to cope with the increased flows and head loss, due to the reduced number of operating hours, increases. This paper explores a strategy based on rehabilitation of the system’s main pipes. It also considers optimal selection and scheduling of pumps aiming at improving the system’s hydraulic parameters (e.g., velocity and head losses) and at reducing the operating costs. Both selection and scheduling of pumps and resizing of main pipes are optimized using Particle Swarm Optimization. The obtained results show that this strategy can significantly reduce the energy consumed and can be economically feasible. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Appraising the Impact of Pressure Control on Leakage Flow in Water Distribution Networks
Water 2021, 13(19), 2617; https://doi.org/10.3390/w13192617 - 23 Sep 2021
Cited by 2 | Viewed by 562
Abstract
Water losses in Water Distribution Networks (WDNs) are inevitable. This is due to joints interconnections, ageing infrastructure and excessive pressure at lower demand. Pressure control has been showing promising results as a means of minimising water loss. Furthermore, it has been shown that [...] Read more.
Water losses in Water Distribution Networks (WDNs) are inevitable. This is due to joints interconnections, ageing infrastructure and excessive pressure at lower demand. Pressure control has been showing promising results as a means of minimising water loss. Furthermore, it has been shown that pressure information at critical nodes is often adequate to ensure effective control in the system. In this work, a greedy algorithm for the identification of critical nodes is presented. An emulator for the WDN solution is put forward and used to simulate the dynamics of the WDN. A model-free control scheme based on reinforcement learning is used to interact with the proposed emulator to determine optimal pressure reducing valve settings based on the pressure information from the critical node. Results show that flows through the pipes and nodal pressure heads can be reduced using this scheme. The reduction in flows and nodal pressure leads to reduced leakage flows from the system. Moreover, the control scheme used in this work relies on the current operation of the system, unlike traditional machine learning methods that require prior knowledge about the system. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Comparison of Online Sensors for Liquid Phase Hydrogen Sulphide Monitoring in Sewer Systems
Water 2021, 13(13), 1876; https://doi.org/10.3390/w13131876 - 05 Jul 2021
Cited by 1 | Viewed by 1471
Abstract
Hydrogen sulfide (H2S) related to wastewater in sewer systems is known for causing significant problems of corrosion and odor nuisance. Sewer systems severely affected by H2S typically rely on online H2S gas sensors for monitoring and control. [...] Read more.
Hydrogen sulfide (H2S) related to wastewater in sewer systems is known for causing significant problems of corrosion and odor nuisance. Sewer systems severely affected by H2S typically rely on online H2S gas sensors for monitoring and control. However, these H2S gas sensors only provide information about the H2S emission potential at the point being monitored, which is sometimes inadequate to design control measures. In this study, a comparison of three market-ready online sensors capable of liquid-phase H2S detection in sewer systems was assessed and compared. Two of the three sensors are based on UV/Vis spectrophotometry, while the other adapted the design and principles of a Clark-type electrochemical microsensor. The H2S measurements of the sensors were statistically compared to a standard laboratory method at first. Following that, the performance of the online sensors was evaluated under realistic sewer conditions using the Berlin Water Company (BWB) research sewer pilot plant. Test applications representing scenarios of typical H2S concentrations found in sulfide-affected sewers and during control measures were simulated. The UV/Vis spectrometers showed that the performance of the sensors was highly dependent on the calibration type and measurements used for deriving the calibration function. The electrochemical sensor showed high sensitivity by responding to alternating anaerobic/anoxic conditions simulated during nitrate dosing. All sensors were prone to measurement disturbances due to high amounts of sanitary solids in wastewater at the study site and required continuous maintenance for reliable measurements. Finally, a summary of the key attributes and limitations of the sensors compared for liquid phase H2S detection is outlined. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
A Sewer Dynamic Model for Simulating Reaction Rates of Different Compounds in Urban Sewer Pipe
Water 2021, 13(11), 1580; https://doi.org/10.3390/w13111580 - 03 Jun 2021
Cited by 1 | Viewed by 1447
Abstract
A sewer dynamic model (SDM), an innovative use of combined models, was established to describe the reactions of compounds in a pilot sewer pipe. The set of ordinary differential equations in the SDM was solved simultaneously using the fourth-order Runge–Kutta algorithm. The SDM [...] Read more.
A sewer dynamic model (SDM), an innovative use of combined models, was established to describe the reactions of compounds in a pilot sewer pipe. The set of ordinary differential equations in the SDM was solved simultaneously using the fourth-order Runge–Kutta algorithm. The SDM was validated by calculating the consistency between the simulation and observation values. After the SDM was validated, the reaction rate was analyzed. For heterotrophs in the water phase and biofilm, their growth rates were greater than the organism decay rate. For ammonia, the supply rate was greater than the consumption rate at the initial time, but the supply rate was smaller than the consumption rate from the 3rd hour. The supply rate was smaller than the consumption rate for the other six compounds. The supply rate of oxygen was smaller than the consumption rate before the 4th hour because of the microorganism activities, and, subsequently, the supply rate was greater than the consumption rate after the 4th hour because of reaeration. The results of this study provide an insight into the reaction rates of different compounds in urban sewer pipes and an urban water network modeling reference for policymaking and regulation. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
An Enhanced Multi-Objective Particle Swarm Optimization in Water Distribution Systems Design
Water 2021, 13(10), 1334; https://doi.org/10.3390/w13101334 - 11 May 2021
Cited by 1 | Viewed by 734
Abstract
The scarcity of water resources nowadays lays stress on researchers to develop strategies aiming at making the best benefit of the currently available resources. One of these strategies is ensuring that reliable and near-optimum designs of water distribution systems (WDSs) are achieved. Designing [...] Read more.
The scarcity of water resources nowadays lays stress on researchers to develop strategies aiming at making the best benefit of the currently available resources. One of these strategies is ensuring that reliable and near-optimum designs of water distribution systems (WDSs) are achieved. Designing WDSs is a discrete combinatorial NP-hard optimization problem, and its complexity increases when more objectives are added. Among the many existing evolutionary algorithms, a new hybrid fast-convergent multi-objective particle swarm optimization (MOPSO) algorithm is developed to increase the convergence and diversity rates of the resulted non-dominated solutions in terms of network capital cost and reliability using a minimized computational budget. Several strategies are introduced to the developed algorithm, which are self-adaptive PSO parameters, regeneration-on-collision, adaptive population size, and using hypervolume quality for selecting repository members. A local search method is also coupled to both the original MOPSO algorithm and the newly developed one. Both algorithms are applied to medium and large benchmark problems. The results of the new algorithm coupled with the local search are superior to that of the original algorithm in terms of different performance metrics in the medium-sized network. In contrast, the new algorithm without the local search performed better in the large network. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Decay of Free Residual Chlorine in Wells Water of Northern Brazil
Water 2021, 13(7), 992; https://doi.org/10.3390/w13070992 - 04 Apr 2021
Cited by 1 | Viewed by 828
Abstract
The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed [...] Read more.
The concentration of chlorine in water declines as it reacts with various substances, causing decay of the residual free chlorine until its total consumption. In light of the typical characteristics of the water from protected dug wells and tube wells, this study aimed to evaluate the decay kinetics of free chlorine in the water of alternative individual supply (AIS) solutions used in the city of Porto Velho in the Brazilian Amazon region. The free chlorine decay constant in the water was evaluated by “bottle tests,” applying a first-order model. According to the results, the type of well and initial chlorine concentration significantly influences the free chlorine decay speed. The water samples from the tubular wells had lower chlorine demand levels, attributed to their better water quality. The simulation of the residual chlorine decay in the different supply sources is an important tool to support safe disinfection processes. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Strategies for Improving Optimal Positioning of Quality Sensors in Urban Drainage Systems for Non-Conservative Contaminants
Water 2021, 13(7), 934; https://doi.org/10.3390/w13070934 - 29 Mar 2021
Cited by 14 | Viewed by 1059
Abstract
In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network [...] Read more.
In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network is necessary to promptly detect and contain the event of contamination. Sensor location is usually an optimization exercise that is based on probabilistic or black-box methods and their efficiency is usually dependent on the initial assumption made on possible eligibility of nodes to become a monitoring point. It is a common practice to establish an initial non-informative assumption by considering all network nodes to have equal possibilities to allocate a sensor. In the present study, such a common approach is compared with different initial strategies to pre-screen eligible nodes as a function of topological and hydraulic information, and non-formal ‘grey’ information on the most probable locations of the contamination source. Such strategies were previously compared for conservative xenobiotic contaminations and now they are compared for a more difficult identification exercise: the detection of nonconservative immanent contaminants. The strategies are applied to a Bayesian optimization approach that demonstrated to be efficient in contamination source location. The case study is the literature network of the Storm Water Management Model (SWMM) manual, Example 8. The results show that the pre-screening and ‘grey’ information are able to reduce the computational effort needed to obtain the optimal solution or, with equal computational effort, to improve location efficiency. The nature of the contamination is highly relevant, affecting monitoring efficiency, sensor location and computational efforts to reach optimality. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
An Integrated Bottom-Up Approach for Leak Detection in Water Distribution Networks Based on Assessing Parameters of Water Balance Model
Water 2021, 13(6), 867; https://doi.org/10.3390/w13060867 - 23 Mar 2021
Cited by 1 | Viewed by 838
Abstract
Loss of water due to leakage is a common phenomenon observed practically in all water distribution networks (WDNs). However, the leakage volume can be reduced significantly if the occurrence of leakage is detected within minimal time after its occurrence. Based on the discriminative [...] Read more.
Loss of water due to leakage is a common phenomenon observed practically in all water distribution networks (WDNs). However, the leakage volume can be reduced significantly if the occurrence of leakage is detected within minimal time after its occurrence. Based on the discriminative behavior of different consumption in water balance, an integrated bottom-up water balance model is presented for leak detection in WDNs. The adaptive moment estimation (Adam) algorithm is employed to assess the parameters in the model. By analyzing the current value and the rising rate of the assessed parameters, abnormal events (e.g., leak, illegal use, or metering inaccuracy) could be detected. Furthermore, a one-step-slower strategy is proposed to estimate the weighted coefficient of pressure sensors to provide approximate location information of leak. The method was applied in a benchmark WDN and an experimental WDN to evaluate its performance. The results showed that relatively small leak could be detected in near-real-time. In addition, the method was able to identify the pressure sensors near to the leak. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Incomplete Mixing Model at Cross-Junctions in Epanet by Polynomial Equations
Water 2021, 13(4), 453; https://doi.org/10.3390/w13040453 - 09 Feb 2021
Viewed by 1167
Abstract
In Water Distribution Networks (WDN), the water quality could become vulnerable due to several operational and temporal factors. Epanet is a hydraulic and water quality simulation software, widely used, to preserve the control of chemical disinfectants in WDN among other capabilities. Several researchers [...] Read more.
In Water Distribution Networks (WDN), the water quality could become vulnerable due to several operational and temporal factors. Epanet is a hydraulic and water quality simulation software, widely used, to preserve the control of chemical disinfectants in WDN among other capabilities. Several researchers have shown that the flow mixing at Cross-Junctions (CJs) is not complete as Epanet assumes for the cases of two contiguous inlets and outlets. This paper presents a methodology to obtain the outlet concentrations in CJs based on experimental scenarios and a validated Computational Fluid Dynamics (CFD) model. In this work, the results show that the Incomplete Mixing Model (IMM) based on polynomial equations, represents in a better way the experimental scenarios. Therefore, the distribution of the concentration could be in different proportions in some sectors of the network. Some comparisons were made with the complete mixing model and the Epanet-Bulk Advective Mixing (BAM), obtaining relative errors of 90% in some CJs. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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Article
Hydraulic Transient Analysis of Sewer Pipe Systems Using a Non-Oscillatory Two-Component Pressure Approach
Water 2020, 12(10), 2896; https://doi.org/10.3390/w12102896 - 16 Oct 2020
Cited by 1 | Viewed by 1171
Abstract
On the basis of the two-component pressure approach, we developed a numerical model to capture mixed transient flows in close conduit systems. To achieve this goal, an innovative Godunov finite-volume numerical scheme is proposed to suppress the spurious numerical oscillations occurring during rapid [...] Read more.
On the basis of the two-component pressure approach, we developed a numerical model to capture mixed transient flows in close conduit systems. To achieve this goal, an innovative Godunov finite-volume numerical scheme is proposed to suppress the spurious numerical oscillations occurring during rapid pipe pressurization. To dissipate the spurious numerical oscillations, we admit artificial numerical viscosity to the numerical scheme through applying a proposed Harten, Lax, and van Leer (HLL) Riemann solver for calculating the numerical fluxes at the computational cell interfaces. The proposed solver controls the magnitude of the numerical viscosity through adjusting the left and right wave velocities. A wave velocity calculator is proposed to optimally distribute the numerical viscosity over several computational cells around the computational cell in which the pressurization front is located. The proposed solver admits significant artificial numerical viscosity when the pipe pressurization is imminent and automatically reduces it in other places; in this way the numerical diffusion and data smearing is minimized. The validity of the proposed model is justified by the aid of several test cases in which the numerical results are compared with both experimental data and the results obtained from analytical methods. The results reveal that the proposed model succeeds in completely removing the spurious numerical oscillations, even when the pipe acoustic speed is over 1000 m/s. The numerical results also show that the model can successfully capture occurrence of negative pressures during the course of transient flow. Full article
(This article belongs to the Special Issue Urban Water Networks Modelling and Monitoring)
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