Water Supply Pipe Network Research Articles

A Study on the Development of a Water Supply Pipe Network Optimal Operation Program through Minimum Hydraulic Gradient Evaluation

A Study on the Development of a Water Supply Pipe Network Optimal Operation Program through Minimum Hydraulic Gradient Evaluation

Selection of Water Transmission Method and Analysis of Pipe Network Zoning in Municipal Water Supply and Drainage Design

With the acceleration of urbanization, the demand for water supply and drainage pipe networks has increased significantly. In the planning of urban construction, it is necessary to optimize the design of the water supply and drainage system pipe network to effectively save energy while providing residents with more accessible water resources. Therefore, the municipal water supply and drainage system and the water transmission methods should be designed according to the geographical conditions of the city. In this paper, we mainly analyze the design of municipal water supply and drainage systems and the selection of water transmission methods. Besides, the optimization of the water supply and drainage network zoning process and pipe network maintenance is also discussed, so as to provide a reference for municipal water supply and drainage work.

Study on the Influence of Urban Water Supply Pipeline Leakage on the Scouring Failure Law of Cohesive Soil Subgrade

Urban water supply pipelines serve as vital lifelines for urban operations. However, the occurrence of underground pipeline leakage, caused by various factors, results in significant water loss and gives rise to safety hazards such as pavement collapse due to the erosive action of leaking water on the overlying soil. To conduct a more comprehensive investigation into the erosion characteristics of the leaking jet on the soil, this study employed a custom-built soil-test system to investigate the erosive effects of leakage from the water supply pipe network on the clay roadbed above. The study considered water flow rate, leakage port size, and leakage angle as influential factors. The experimental results demonstrated that reducing the water flow rate significantly enhances the soil’s erosion resistance. There is a positive correlation between the caliber of pipe leakage, pipe diameter, and the erosion rate of the soil cavity. Under identical conditions, the erosion rate of the specimen increased consistently with an increase in the leakage port angle. The study also investigated and summarized the curve depicting the formation of soil cavities. The aforementioned findings offer valuable insights for the implementation of reinforcement measures using fine-grained cohesive soil backfill in urban water supply pipelines.

A method for water supply network DMA partitioning planning based on improved spectral clustering

Abstract Recently, the scale and complexity of water distribution networks (WDNs) have been increasing with the acceleration of urbanization process. It has become a hot research focus to use district metering area (DMA) for more efficient management and control of WDNs. This article proposes a multistage DMA planning method based on improved weighted spectral clustering and genetic algorithm, aiming to address issues such as high investment cost and large differences in the water network demand distribution. First, the actual case pipe network is transformed into an undirected weighted graph based on graph theory, and a similarity matrix is formed by combining the physical properties and hydraulic characteristics of the water network. Then, based on the similarity matrix, the weighted spectral clustering algorithm is used to preliminarily divide the WDN, and the performance of the water supply pipe network formed with different division quantities and different weighting schemes is discussed. Finally, the genetic algorithm is used to optimize the arrangement of valves and flow meters on boundary pipes to generate the final configuration of DMA. The results show that the proposed method has a significant improvement in pipe network topology, hydraulic performance index, and economy compared with the traditional DMA method.

A Feasibility Study on Applying the Concept of Removing Odd Nodes to Design of Water Supply Pipe Network

Objectives : In this study, the concept of the Eulerian path, which has already been proposed as a solution to the problem of head loss and residual chlorine reduction caused by complexity of nodes and pipelines, and the non-Euerian path proposed in this study were compared and their feasibility were examined.Methods : The concepts of ‘removal of odd nodes’, ‘removal of 3-intersection nodes’, and ‘removal of zero demand nodes’ were applied to the virtual water supply networks, and the number of cases were analyzed and evaluated from the viewpoint of configuration complexity and hydraulic efficiency. For Euler graph and non-Euler graph water supply networks, each total pipe length, number of removal pipes, pressure head and flow rate were simulated with EPANET2 program.Results and Discussion : As a result of simplifying and designing new output networks for virtual Euler and non-Euler graph, it was revealed that the concept of ‘removing a 3-intersection nodes’ could be the most efficient by removing more pipes. However, in terms of configuring the output network as an Euler graph, the concept of ‘removing odd nodes’ can be considered more reasonable.Conclusion : It is difficult to configuring watersupply network as a perfect Euler graph. Therefore, the application of the concept of removing odd nodes suggested in this study can promote efficient simplification of the network. In addition, it can be thought that the application of this concept can expect efficiency in terms of hydraulics and water quality.

Analysis of water supply system characteristics and water hammer protection measures in hilly towns

The terrain of hilly areas is undulating. The water supply system of small towns in this area is characterized by small scale of water consumption, large variation of water quantity, complex operation of pipe network, frequent start and stop of pumps, poor integrity of pipe network and low safety and reliability. Therefore, the layout and operation management of water supply pipe network caused many problems, and the water hammer protection of pipe network can not be ignored. Taking K town in typical hilly area as the object, the characteristics of water supply are investigated and analyzed, and the water hammer and protection measures are analyzed, in order to provide reference for the safe and stable operation of water supply network in small towns in hilly area.

Development and Application of An Integrated Urban Water Cycle System by Combining Water Cycle Elements

Smart city in water resources area attempts are being made by establishing an integrated urban water cycle model for a stable water supply and efficient water management in the city. Accordingly, the need for simulation and integrated management of water consumption in cities is increasing. If it is possible to predict and respond in advance to consumers' water consumption, more efficient urban water resource management will be possible based on river intake. Therefore, in this study, an integrated urban water cycle model was constructed that links river intake, water purification plants, retention tanks, water distribution, sewage pipe networks, sewage treatment plants, and river discharge of treated water. It was developed using C++, and was built by linking the modules of the water intake pump station, retention tank, water purification plant, sewage treatment plant, water supply pipe network, and the sewage pipe network. Among them, the water intake pumping station and retention tank were developed independently, and the other modules were linked with commercial software such as WaterFlow, MassFlow, EPANET, and SWMM. The model measures data such as water quality factors and flow rates for each module, displays the operation status, and enables linkage for each module, even when the measurement time interval is different. In addition, warnings and error messages were generated when a problem occurred during the operation of each module. To verify the applicability of the developed integrated model, the change in the water level of the retention tank was calculated by simulating consumer water consumption. As a result, it was confirmed that the water level change in the retention tank was proper, which meant that the operation changed from the intake pumping station. The developed model is expected to be used as an integrated urban water cycle model in the future.

Hyperparameter Sensitivity Analysis of Deep Learning-Based Pipe Burst Detection Model for Multiregional Water Supply Networks

In a deep learning model, the effect of the model may vary depending on the setting of the hyperparameters. Despite the importance of such hyperparameter determination, most previous studies related to burst detection models of the water supply pipe network used hyperparameters applied in other fields as-is or made a trial-and-error setting based on experience, which is a limitation. In this paper, a study was conducted on the deep learning hyperparameter determination of a deep neural network (DNN)-based real-time detection model of pipe burst accidents. The pipe burst model predicted water pressure by using operation data in units of 1 min, and the data period applied for the model training was less than 1 month (1, 2, and 3 weeks) in order to consider frequent changes in the system. A sensitivity analysis was first performed on the type of activation function and the period of the learning data, which may have different effects depending on the characteristics of the target problem. The number of hidden layers related to the network structure and the number of neurons in each hidden layer were set as hyperparameters for additional sensitivity analysis. The sensitivity analysis results were derived and compared using four quantified prediction error indicators. In addition, the model running time was analyzed to evaluate the practical applicability of the development model. From the results, it was confirmed that excellent effects could be expected if using a rectifier function as the activation function, 144 nodes in the hidden layer, which is eight times the number of nodes in the input layer, and four hidden layers. Additionally, by analyzing the appropriate period of training data required for model pressure prediction through prediction error and driving time, it was confirmed that it was most appropriate to use the data of two weeks. By applying the hyperparameter values determined through detailed sensitivity analysis and by applying the data of one week including actual burst accidents to the built-up pressure prediction model, the accident detection and predictive performance of the model were verified. The rational determination of the period of input factors for the optimal hyperparameter setting and model building, as in this study, is very necessary and very important as it can serve to ensure the continuity of the operation effects of the deep learning model.

Does intermittent supply result in hydraulic transients? Mixed evidence from two systems

Abstract Pressure transients can cause severe damage in continuous water supply pipe networks, but little is known about pressure transients in intermittent networks. Published examples of high-frequency pressure monitoring in intermittent networks are lacking. Intermittent supply can be caused by poor network condition and is associated with delivering less water, less frequently, and with poorer quality than continuous supply. Given the frequency with which intermittent systems drain, fill, and change supply regimes, pressure transients have been hypothesized to be common and to be one mechanism by which intermittent supply further degrades network condition. We present supply start-up data from two very different intermittent systems: a low-pressure, intermittent network in Delhi, India, and a higher-pressure intermittent network in Arraiján, Panama. Across monitoring locations at both sites, we did not detect substantial pressure transients due to pipe filling. In Arraiján, pump start-ups, pump shutdowns, and pipe bursts were associated with potentially problematic transients. We conclude that pipe filling in intermittent supply does not always result in concerning pressure transients. The largest risks to pipe conditions we observed were due to pumping changes in close succession; hence, we recommend that utilities operating intermittent (and continuous) systems leave adequate dissipation time between changes in pump operation.

A Feasibility Study on Application of Eulerian Path Concept to Design of Water Supply Pipe Network

Objectives : This study attempted to investigated the advantages that can be obtained by applying the concept of ‘Eulerian path’ called ‘one-touch drawing’ to the block type water supply network which actually has been operating in Korea.Methods : This study applied the ‘Eulerian path’ concept to an actual water supply network, and suggested simple C language program for searching adjacency matrix. Five Eulerian path based design scenarios were derived using the C language program. The pressure and residual chlorine distribution pattern of five design scenarios and the existing small block network were simulated using EPANET and compared each other. Also, by comparing all scenarios construction costs, the economic feasibility related to initial investment cost was reviewed.Results and Discussion : Five Eulerian path scenarios with two or more closed pipe loops were suggested using the C language program checking out adjacency matrix. One of them(scenario 5) consists of 7 closed pipes that can supply water to all nodes even if the number of pipes is reduced by about 10, and an increase in residual chlorine concentration of about 0.01 mg/L can be predicted at each node. In addition, it is expected that the initial investment cost of Scenario 5 can be reduced by about 23%, compared to the initial investment cost of the existing small block.Conclusion : Therefore, by applying the concept of an Eulerian path to the design of a water supply pipe network, it is possible to economically eliminate meaningless pipes while maintaining the redundancy of water supply.

Development of LSN-based pipe repair rate models utilising data from the 2011 Christchurch earthquakes

The Canterbury Earthquake Sequence (CES) adversely impacted built, economic and social environments. This included widespread physical damage to the water supply pipe network in Christchurch, resulting in long service disruptions. The transient and permanent ground deformations generated by the earthquakes in the CES caused a range of pipe damage, particularly in the MW 6.2 22 February 2011 and the relatively less damaging MW 6.0 13 June 2011 event. Damage to the pipes in both events was largely attributed to liquefaction and lateral spreading effects. Pipes made of ductile material (e.g. PVC, HDPE) sustained lesser damage (and therefore lower repair rates) compared to the pipes made of non-ductile material (e.g. AC, CI). In all cases, the repair rates (number of repairs per kilometre) typically increased with increasing liquefaction severity. Utilising the pipe repair dataset and Liquefaction Severity Number (LSN) maps generated from extensive geotechnical investigation following the CES events, new repair rate prediction models for water pipes subjected to liquefaction effects have been derived and are presented in this paper. Repair data from both earthquakes has been analysed independently and in combination, providing two sets of repair rate functions and different levels of uncertainty. Repair rate functions were first derived from pipes grouped by combination of diameter (i.e. ϕ < 75 mm or ϕ ≥ 75 mm) and material type (i.e. ductile or non-ductile). The models were then refined by adding correction factors for those material types and diameters with sufficient sample length. Correction factors were derived for AC, CI, PVC pipes of diameter ≥75 mm and for MDPE and HDPE80 pipes of diameter <75 mm. Galvanised Iron (GI) pipes performed poorly during the earthquakes, resulting in very high repair rates compared to the other non-ductile pipes of diameter <75 mm damaged in the network; this warranted a separate repair rate model to be developed for this pipe type. The proposed models can be used in risk assessment of water pipe networks; i.e. to estimate the number of pipe repairs from potential liquefaction damage from future earthquakes.

Buckling behaviour of internal stiffened thin-walled stainless steel liners under external constraints

As a trenchless repair technology for water-supply pipe networks, the thin-walled stainless-steel lining method has been widely used in China in recent years. However, because of the nature of the pressure pipeline, the inner lining often bears the negative pressure of the system, resulting in its instability. Through full-scale testing, numerical simulation, and theoretical analysis, the mechanical properties and buckling and post-buckling behaviours of the lining under stiffening were studied, and the influence of various parameters on the critical buckling pressure of the lining system was analysed. The results indicated that structural stiffening can effectively improve the buckling instability resistance of the system. With an increase in the stiffness of the stiffening part, the lining demonstrated a change from global to local buckling. Through comparative tests, the reinforcement coefficients of the host pipe were obtained, and a design model was established to predict the critical buckling instability of the inner lining, which was consistent with the actual FEM results.

Potential Water and Energy Savings for Reducing Urban Water Supply Loss in China

The high water loss rate of the urban water supply system owing to the old and failing water supply pipe network may cause serious water leakage and consequently unnecessary energy waste. Taking water-scarce China as an example, we evaluated urban water loss and the accompanying electricity waste from the water supply network for 266 Chinese cities in 2015 and further designed different water loss control scenarios to assess the potential water and energy benefits in 2035. Results indicated that the quantity of water loss equaled the domestic water demand of 134.0 million urban residents, and the related electricity waste could meet the electricity demand of 4.4 million urban residents for a year. The potential water and energy savings in 2035 can reach up to 4.8–9.7 billion cubic meters and 1.7–3.3 TW·h in different scenarios, respectively. Cities with water scarcity show higher water loss rate, more electricity waste, and greater potential of water and energy savings compared with the others. For water-receiving cities along the South to North Water Transfer Project, the ratio of their total urban water loss to their total water transferred was as high as 70.9% in 2015, and potential water saving can be accounted for 0.2–44.1% of their total water transferred in 2035. We suggested that differentiated local water loss control can be an effective supplement to local water supply and water stress alleviation, as well as energy conservation.

Antibiotic enhances the spread of antibiotic resistance among chlorine-resistant bacteria in drinking water distribution system

The extensive use of antibiotics leads to the occurrences of antibiotic resistance genes (ARGs) in aquatic environment. As an emerging environmental pollutant, its pollution in aquatic environment has aroused widespread concern. However, the residues of antibiotics and antibiotic resistance genes in drinking water distribution system were barely reported up to now. Here, we studied the correlation and coordination between chlorine resistance mechanism and antibiotic resistance mechanism of chlorine-resistant bacteria. Antibiotics induce the resistance of chlorine-resistant bacteria (CRB) to NaClO, so that low-dose disinfectants can not inactivate CRB. We put forward a strategy to control the growth of CRB by controlling the concentration of biodegradable dissolved organic carbon (BDOC) in the front section of the water network. Moreover, We screened two strains of chlorine-resistant bacteria with different antibiotic resistance after mixed culture, the results showed that antibiotic resistance could spread horizontally among different kinds of bacteria. Then, the non-pathogenic bacteria can be used as a carrier, causing the pathogen to become resistant to antibiotic, and ultimately pose harm to human health. Generally, the antibiotic, antibiotic resistant genes, and the chlorine disinfectants added in water treatment plants will interact with bacteria in the water supply pipe network, which causes pollution to drinking water.

Development and Verification of a Pipe Network Scale Model

The main function of a water supply and storm sewer pipe network is to properly maintain planned flow rates, water pressure, and water depth within pipes. This can be simulated with a numerical analysis model. In general, model experiments are required to verify and correct the accuracy of numerical analysis models, but due to the nature of complex facilities, scale model experiments and related studies are very limited. Therefore, this study aimed to develop a kit capable of general-purpose scale model experiments for water and sewage networks, and verified the applicability of the developed model through simple experiments. A set of model experimental parts, including manhole parts, pipe connections, and venturi meters for pipe network implementation and measurement, was manufactured with a three-dimensional printer (Stratasys F170). The angle, height difference, and slope of the pipe could be adjusted. A pipe connection cap was developed to implement all commercial circular pipes with a diameter of 300 mm to 1,200 mm based on 1/50 scale. A transparent acrylic pipe was used. EPANET analysis indicated that the scale model experiment of the water supply network, with 13 manholes, 18 pipelines, and 5 venturi meters had a flow error of about 13% in the total pipeline and about 8% in the venturi meter measurement value. In addition, a scale model of the storm sewer pipe network was developed to determine the change in water depth according to the connection angle of the pipe. Results of simulations in FLUENT showed a similar trend in water depth change.

Water supply network modeling and pipe burst analysis based on WaterGEMS

In recent years, the water supply task of urban water supply pipe network is more and more heavy, and leakage accidents of pipe network often occur, among which the most serious leakage accident is pipe burst accident. To solve this problem, this study uses WaterGEMS software to establish the topological structure of water supply pipe network, adopts the water supply pipe network model and computer technology to carry out dynamic analysis on pipe burst accident of pipe network, and uses golden section method to predict the water leakage caused by pipe burst accident state.

Prediction of Global Efficiency and Economic Viability of Replacing PRVs with Hydraulically Regulated Pump-as-Turbines at Instrumented Sites within Water Distribution Networks

AbstractPressure management in water supply pipe networks using conventional pressure reducing valves (PRVs) results in the dissipated energy being lost. In pursuit of more energy efficient solutio...

Leak Identification Based on CS-ResNet Under Different Leakage Apertures for Water-Supply Pipeline

Considering the problem of difficulty in transmission and storage due to a large amount of data in the water-supply network monitoring system based on a wireless sensor network (WSN), we propose a sparse representation of the water-supply network monitoring data by using compressed sensing (CS) method. At the same time, aiming at the problem of low leakage identification accuracy caused by information loss under compressed sensing, we propose a leak identification method for a water-supply pipe network based on compressed sensing and deep residual neural network (ResNet). Firstly, under the condition that the observation matrix ensures the integrity of signal information, the compressed sensing theory is used to compress and observe leakage signals to obtain observation data, to reduce the redundant information and volume of the data. At the same time, the observation data is preprocessed to realize the transformation of a one-dimensional signal to a two-dimensional matrix. Then the residual neural network is trained by using the two-dimensional data to realize the automatic, efficient, and accurate leak identification under different leakage apertures. Experimental results show that the proposed method can obtain relatively high accuracy and greatly reduce the training time of ResNet by using compressed data. When the Compression rate (CR) is 70% and the observation matrix is a Gaussian random matrix, the average accuracy is 96.67% and the training time is only 50% compared to uncompressed data. The research work provides a new intelligent leak identification under different leak apertures using WSN and has important application prospects in saving water resources.

Leakage Reduction of Water Distribution Network System Based on the Observation Data of Water Leakage and Pressure of Actual Water Distribution Network System

As the main way of urban water use, water supply system is an important urban infrastructure. It plays an important role in guaranteeing people’s life and economic construction. In recent years, it has an overall and guiding influence on the city. The monitoring and leak detection of water supply network system has become one of the most important problems in the water supply network system. The purpose of this paper is to explore the leakage reduction of the water distribution network system under the observation data of water leakage and pressure based on the actual water distribution network system. This paper analyzes the different pipe diameter of pressure change on the influence of water leakage, and the effect of different decompression interval to reduce water leakage results show that the leakage and pipeline pressure changes exponentially, it changes with reduced pressure pipe installation of pipe diameter and valve for high same diameter of pipeline, decompression and leakage effect is more effective, for the decompression range of basically the same pipeline, pipe diameter, the greater the effect is more obvious. In this paper, we study a kind of based on the pressure signal and traffic signal of the existing urban water supply pipe network leakage recognition and positioning method, and carries on the simulation of urban pipeline leakage simulation test platform through test analysis, probes into the key technology of this method and improvement, to improve the accuracy and positioning precision of the method to detect leaks. The research results show that the simplest method can be realized and the best effect can be achieved through the summary analysis of existing studies. When the leakage coefficient is set as 1, the water leakage is about 600%, and the pressure value of the leakage node and the pressure monitoring point for 24h is shown. It is obvious that when the lowest pressure is 10h, the pressure value is 300%. Through the analysis and improvement of this method, it can realize the timely identification and positioning of leakage events, reduce economic losses, and guarantee people’s normal life.

Aerobic methanotrophs in an urban water cycle system: Community structure and network interaction pattern

Aerobic methane-oxidizing bacteria (MOB) play an important role in reducing methane emissions in nature. Most current researches focus on the natural habitats (e.g., lakes, reservoirs, wetlands, paddy fields, etc.). However, methanotrophs and the methane-oxidizing process remain essentially unclear in artificial habitat, such as the urban water cycle systems. Here, high-throughput sequencing and qPCR were used to analyze the community structure and abundance of MOB. Six different systems were selected from Yunyang City, Chongqing, China, including the raw water system (RW), the water supply pipe network system (SP), the wastewater pipe network system (WP), the hospital wastewater treatment system (HP), the municipal wastewater treatment plant system (WT) and the downstream river system (ST) of a wastewater treatment plant. Results clearly showed that the MOB community structure and network interaction patterns of the urban water cycle system were different from those of natural water bodies. Type I MOB was the dominant clade in HP. Methylocysis in Type II was the most abundant genus among the whole urban water cycle system, indicating that this genus had a high adaptability to the environment. Temperature, dissolved oxygen, pH and concentration significantly affected the MOB communities in the urban water cycle system. The network of MOB in WT was the most complicated, and there were competitive relationships among species in WP. The structure of the network in HP was unstable, and therefore, it was vulnerable to environmental disturbances. Methylocystis (Type II) and Methylomonas (Type I) were the most important keystone species in the entire urban water cycle system. Overall, these findings broaden the understanding of the distribution and interaction patterns of MOB communities in an urban water cycle system and provide valuable clues for ecosystem restoration and environmental management.