A Decision Support Tool for Water Supply System Decentralization via Distribution Network Sectorization

[EN] Many water supply systems, conceived to operate in centralized manner, face difficulties to adapt to dynamic changes, such as population growth, city extension, and industrial development. Decentralization of these systems may be an effective solution. Known techniques for distribution network sectorization design can help to achieve such a goal, but this has not been recognized in the literature. None of those known techniques considers the conversion of a centralized system to a decentralized one. In this paper, two new distinct yet complementary methodologies for water supply system decentralization by distribution network sectorization are proposed and implemented in a software decision support tool freely available on internet. The first methodology identifies the main flow paths from water sources to some strategic nodes and considers the nodes in these paths as new potential sources for dividing the rest of the network. The second methodology sectorizes the network according to the contribution of sources to the consumption at nodes, based on mass balance equations for the transport of a hypothetical conservative constituent in a steady state. Both methods were applied to two real network models. The results obtained were better, for decentralizing the supply, compared to those obtained by other methodologies proposed in the literature.The main author of this paper wishes to thank the National Studentship Program of Peru for financing his doctoral studies at the Polytechnic University of Valencia, Spain.Vegas Niño, OT.; Martínez Alzamora, F.; Tzatchkov, VG. (2021). A Decision Support Tool for Water Supply System Decentralization via Distribution Network Sectorization. Processes. 9(4):1-15. https://doi.org/10.3390/pr9040642S1159

Modelación de redes de agua potable basado en el proceso de neyman-scott

Uno de los parámetros más difíciles de estimar al modelar las redes de distribución de agua potable es el del consumo doméstico. Se ha demostrado que este sigue un proceso estocástico posible de caracterizar a través de pulsos rectangulares, con ciertas intensidad, duración y frecuencia de arribo, por medio de esquemas estocásticos como el modelo de pulsos rectangulares de Neyman-Scott (Neyman-Scott Rectangular Pulses Model, NSRPM. El esquema NSRPM se basa en la solución de un problema de optimización no lineal que involucra momentos teóricos de las series sintéticas (equiprobables) y los momentos observados (mediciones de campo). Se ha publicado la metodología, así como trabajos orientados a la generación de la demanda en los domicilios, sin embargo no su validación en una red de distribución real, con la conjunción y agregación de las demandas de los domicilios, y su comparación con los métodos tradicionales. En el presente artículo se comparan resultados obtenidos empleando series sintéticas con carácter estocástico, producto del esquema NSRPM aplicado a la determinación de presiones y caudales, con los obtenidos por el método tradicional que utiliza curva de variación horaria de la demanda, y con mediciones de presión y caudal hechas en el sector Humaya, en Culiacán, Sinaloa, México.Residential water demand is one of the most difficult parameters to determine when modelling drinking water distribution networks. It has been proven to be a stochastic process which can be characterised as a series of rectangular pulses having set intensity, duration and frequency. Such parameters can be determined using stochastic models such as the Neyman-Scott rectangular pulse model (NSRPM). NSRPM is based on resolving a non-linear optimisation problem involving theoretical moments of the synthetic demand series (equiprobable) and of the observed moments (field measurements) statistically establishing the measured demand series. NSRPM has been applied to generating local residential demand. However, this model has not been validated for a real distribution network with residential demand aggregation, or compared to traditional methods (which is dealt with here). This paper compares the results of synthetic stochastic demand series (calculated using NSRPM applied to determining pressure and flow rate) to results obtained using traditional simulation methods using the curve of hourly variation in demand and to actual pressure and flow rate measurements. The Humaya sector of Culiacan, Sinaloa, Mexico, was used as study area

Modelación de la variación del consumo de agua potable con métodos estocásticos

A pesar de su importancia, en la práctica, la variación de la demanda de agua potable se estima de manera muy aproximada de mediciones continuas del gasto en la tubería que abastece a una zona; por su lado, la curva de variación de la demanda medida se asume válida para cualquier otra tubería de la red, independientemente del número de usuarios al que da servicio. El presente artículo describe una metodología para obtener la variación diaria estocástica de la demanda instantánea de agua potable, aplicable a una sola casa o cualquier número de casas con base en los parámetros estadísticos del consumo de agua en casas individuales, nivel de fugas dado y la variación del gasto medida en la tubería de abastecimiento, considerando casos de suministro continuo e intermitente. La metodología propuesta ofrece una base racional para la determinación de la variación de la demanda a cualquier nivel de agregación, que puede combinarse con la correspondiente manera tradicional o sustituirla. Los resultados se compararon con mediciones de campo en una ciudad mexicana donde el suministro de agua potable es continuo. La variación de los gastos en las tuberías con suministro intermitente o con servicio continuo, pero con cisternas y tinacos en los domicilios, es muy diferente de aquella en tuberías con suministro continuo sin cisternas y tinacos. El coeficiente de demanda máxima horaria es más alto en suministro intermitente que en suministro continuo, pero más bajo en redes que tienen servicio continuo, y cisternas o tinacos en los domicilios

Neyman-Scott-based water distribution network modelling

Residential water demand is one of the most difficult parameters to determine when modelling drinking water distribution networks. It has been proven to be a stochastic process which can be characterised as a series of rectangular pulses having set intensity, duration and frequency. Such parameters can be determined using stochastic models such as the Neyman-Scott rectangular pulse model (NSRPM). NSRPM is based on resolving a non-linear optimisation problem involving theoretical moments of the synthetic demand series (equiprobable) and of the observed moments (field measurements) statistically establishing the measured demand series. NSRPM has been applied to generating local residential demand. However, this model has not been validated for a real distribution network with residential demand aggregation, or compared to traditional methods (which is dealt with here). This paper compares the results of synthetic stochastic demand series (calculated using NSRPM applied to determining pressure and flow rate) to results obtained using traditional simulation methods using the curve of hourly variation in demand and to actual pressure and flow rate measurements. The Humaya sector of Culiacan, Sinaloa, Mexico, was used as study area

Implementation of graph theory based algorithms in water distribution network sectorization projects.

Water distribution network sectorization projects currently underway in many Mexican cities consist of dividing the city distribution network into smaller sub-networks, or sectors, with one or at most two water inlets per sector. To design the sectors, water distribution network models are used, which review whether the proposed sectorization can adequately function hydraulically. For large network sectorization projects, however, additional algorithmic capabilities are needed, such as connectivity analisys, zone of influence and the contribution of each source on consumption. This paper discusses efficient algorithms of this type based on graph theory, implemented in a computer system

Economic and energy criteria for district meter areas design of water distribution networks

Water Network Partitioning (WNP) improves water network management, simplifying the computation of water budgets and, consequently, allowing the identification and reduction of water losses. It is achieved by inserting flow meters and gate valves into a network which has been previously clustered into subsystems. Generally, the procedures are subdivided into two main steps: the clustering and partitioning phases. At first, network nodes are assigned to each cluster and then the appropriate pipes are selected, in which flow meters or gate valves are to be inserted. In this paper, an improved multilevel-recursive bisection algorithm was used to achieve network clustering. To better allocate the hydraulic devices, the partitioning phase was carried out through the minimization of a novel, multi-objective function, taking simultaneous account of energy and economic aspects. The aim is to define a solution that occupies a minimum possible number of flow meters, simplifying the water budget computation, preserving the hydraulic performances, and minimizing the capital and the operational costs. The procedure was tested on an extensive and real Mexican network, providing different optimal solutions and a smart Decision Support System (DSS) (based on visual diagrams and innovative energy, robustness, and balancing metrics

CCWI2017: F17 'Assessment of alternatives for energy efficiency improvement using a hydraulic simulation model'

Many water utilities that provide water, drainage and sanitation services in Mexico encounter several problems performing these duties. They face insufficient funds, frequent changes of administrative and qualified technical personnel, as well as distribution-network aging. This situation, along with high water losses in transmission pipelines and distribution networks, illegal service connections, and intermittent water supply have led to a large portion of the water utilities having to deal with a low willingness from the users to pay for the service provided. Pumping and water treatment make up most of the high electricity costs generated from the provision of water supply services. This paper presents the results of an energy efficiency study, using a hydraulic simulation model as a starting point in which various energy-consumption optimization scenarios were considered. Priority was placed on existing infrastructure use, the assessment of alternatives for pumping equipment operation, the addition of complimentary equipment with its corresponding capital and running costs as well as its repercussions on the service provided to end-users and finally their impact on the total running costs for the water utility. To carry out an adequate interpretation of the hydraulic model, it was necessary to perform a detailed analysis of existing pumping equipment, primarily its electromechanical parameters in such a way that upon integrating them into the model, the proposed alternatives carry the certainty of success. In general form, the analyzed sources of supply produce an average of 437 L/s, with an energy consumption of 920 kW/h. Based on the hydraulic simulation, it is possible to take 5 pumping sites out of operation from the Pump Stations G.O. 1 and 2 which implies a reduction of 121.7 kW/h and as such, considering the rate at the moment of this study which is $1.025 kW/h, yields an annual savings of$55,000.00 USD, representing a 24% decrease in the total energy consumed by the distribution network