Real-life Water Distribution System Research Articles

Optimizing Water Quality Treatment Levels for Water Distribution Systems under Mixing Uncertainty at Junctions

A real-life water distribution system (WDS) contains uncertainty in numerous stages. This makes the optimal management and design of a WDS a complex problem. Water quality has also become a significant factor in the design and management of a WDS. Our objective was to incorporate water quality uncertainty in the WDS design problem. The mixing level was assumed to be uncertain and used to design the WDS such that the design was immune to the level of mixing. This method aimed to yield designs that satisfied the nodal concentration constraints irrespective of the mixing level in the junctions. Two optimization methodologies, robust optimization and info-gap decision theory combined with a cuckoo search optimization algorithm, were proposed to solve this problem. An illustrative example 4×4 grid network was used to understand nonuniform mixing and explain the design methodology using both methodologies. Then these methodologies were applied to solve a similar treatment plant problem on a modified Fossolo network. The results also exhibited a significant variation in cost between complete mixing and nonuniform mixing. The WDS designs obtained from both methods were evaluated through Monte Carlo simulations.

Self-Adaptive Cuckoo Search Algorithm for Optimal Design of Water Distribution Systems

Self-adaptive cuckoo search algorithm is used to optimize the design of water distribution system problems. It is proposed to dynamically adjust the two sensitive parameters of the algorithm, (i) step size control parameter ‘α’ and (ii) discovering probability parameter ‘Pa’ which largely govern the exploration and exploitation search strategies of the algorithm. These parameters are essential for enhancing the performance of the algorithm and normally the values of these parameters needs careful selection according to the type of problem. Single objective self-adaptive cuckoo search algorithm (SACSA) and multi-objective self-adaptive cuckoo search algorithm (SAMOSCA) are proposed in this study. Robustness and efficiency of these algorithms in single (minimization of cost) and multi-objective scenarios (minimization of cost and maximization of resilience) is validated using standard water distribution benchmark problems i.e. Two loop and Hanoi network. These are later applied to solve a medium size real-life water distribution system located at Pamapur, Telangana, India. A simulation-optimization based program combining the water distribution network simulation software EPANET 2.2 and MATLAB is used for computation. The proposed methodology has provided better results in terms of computational efficiency as well as found better solutions when compared to the previously reported results in both single and multi-objective scenarios. In the case of multi-objective problems, it has been observed that SAMOCSA has been able to find new points in pareto front when compared to the best-known pareto front reported in the literature. Self-adaptive cuckoo search algorithm has been found to be an attractive alternative in both exploration and exploitation of larger search spaces for finding better optimal solutions.

Research on Hydraulic Safety Assessment of Water Distribution Systems

There are two key issues in the safety assessment of the water distribution system (WDS). One is how to evaluate the safety levels of water supply for customers, while the other is how to describe the importance of a pipe for the global or local WDS. The water demand guarantee rate (DGR) and the water demand failure rate (DFR) are proposed. The mathematical expectations of the DGR and DFR describe the average customer’s water safety levels for the first issue. Moreover, the unit influence of pipe failure (UIPF) is put forward for the second issue. It describes the importance of the pipe for the global or local system. Several cases show how to calculate the above values with the pressure-driven model. It is also shown how to find key pipelines in the WDS. The results show that the method can provide an effective reference for real-life WDS management.

Fire and drinking water capacity enhancement in water distribution networks

Abstract The purpose of the present study is to introduce a newly developed capacity increment (also pressure sensitivity reduction) technique in the case of drinking water distribution systems (WDS). The main novelty of this method is based on a correlation between two parameters of the water distribution network – one characterises its robustness in a topology-specific way, the other can be calculated with only one hydraulic simulation. With the help of connection the topology optimisation – the identification of the optimal place for installing a new pipe – can be determined within a short processing time, and without the implementation of a stochastic optimiser algorithm. The first part of the paper presents problems caused by high pressure sensitivity and introduces the mathematical background of the method, besides which it discusses the details of the algorithm. After that, the second part presents the results gained by the implementation of the method in two case studies: real-life water distribution systems of a small and a medium-sized town. For the small town, verification is possible by comparing the result of our method with the total hydraulic evaluation of the WDS.

Adaptive water demand forecasting for near real-time management of smart water distribution systems

This paper presents a novel methodology to perform adaptive Water Demand Forecasting (WDF) for up to 24 h ahead with the aim to support near real-time operational management of smart Water Distribution Systems (WDSs). The novel WDF methodology is exclusively based on the analysis of water demand time series (i.e., demand signals) and makes use of Evolutionary Artificial Neural Networks (EANNs). It is implemented in a fully automated, data-driven and self-learning Demand Forecasting System (DFS) that is readily transferable to practice. The main characteristics of the DFS are: (a) continuous adaptability to ever changing water demand patterns and (b) generic and seamless applicability to different demand signals. The DFS enables applying two alternative WDF approaches. In the first approach, multiple EANN models are used in parallel to separately forecast demands for different hours of the day. In the second approach, a single EANN model with a fixed forecast horizon (i.e., 1 h) is used in a recursive fashion to forecast demands. Both approaches have been tested and verified on a real-life WDS in the United Kingdom (UK). The results obtained illustrate that, regardless of the WDF approach used, the novel methodology allows accurate forecasts to be generated thereby demonstrating the potential to yield substantial improvements to the state-of-the-art in near real-time WDS management. The results obtained also demonstrate that the multiple-EANN-models approach slightly outperforms the single-EANN-model approach in terms of WDF accuracy. The single-EANN-model approach, however, still enables achieving good WDF performance and may be a preferred option in engineering practice as it is easier to setup/implement.

Use of Metamodels in Real-Time Operation of Water Distribution Systems

This paper presents a methodology for real-time pump scheduling in water distribution system. The methodology uses an optimizer linked to other two modules: one to predict the hydraulic behavior of the system and another to forecast the demands. A metamodel is used instead of a traditional hydraulic simulator to speed up relevant computations, i.e. evaluations of large number of candidate pump schedules generated during the optimization process. The methodology presented is applied to a real-life water distribution system in Brazil. The results obtained show that the use of metamodel can generate low cost pump schedules in a computationally fast manner.

A Surrogate Measure for Multi-Component Failure Based Reliability Analysis of Water Distribution Systems

Abstract Multi-component failure based reliability analysis of a real-life water distribution system (WDS) is extremely time consuming and computationally demanding. Reliability surrogate measures are novel techniques to lessen the associated computational burden in estimating the reliability of a WDS. Results of this study reveal that flow entropy of a WDS has stronger correlation with higher states of reliability rather than lower states. Consequently, statistical flow entropy is a better surrogate measure for multi-component failure based reliability of a WDS.

A deterministic approach for optimization of booster disinfection placement and operation for a water distribution system in Beijing

Previous studies on booster disinfection optimization were commonly based on ‘blank networks’, neglecting the impact of existing disinfection facilities, which could result in misleading solutions. To overcome this limitation, a method, which incorporates the existing disinfection facilities, is developed and demonstrated in this study. A particle backtracking algorithm, which traces the upstream pathways of the disinfection insufficiency nodes, is employed to narrow down the potential positions for booster stations. Deterministic optimization results are then efficiently yielded by the introduction of a ‘coverage matrix’. The proposed method is applied to a real life water distribution system in Beijing, China. Results show the methodology effectiveness in optimizing booster disinfection placement and operation for real life water distribution systems. For the explored case study, results suggest that adding a booster disinfection station at 0.1% of the nodes of the system can satisfy chlorine residual at about 97.5% of all nodes.

Calibration of Hydraulic Model in Rea-Life Water Distribution System

The most uncertain input parameters that often considered for calibration in water distribution system hydraulic model are pipe roughness coefficients and nodal demands. Both pipe roughness coefficients and nodal demands are considered to be calibrated in the calibration process, which works alternately. The calibration model was formulated as a constrained optimization problem. The entire head losses under different loading conditions are introduced in the objective function to guide the calibration direction, which can make consistent calibration effects on different loading conditions. The calibration model uses real-coded genetic algorithm along with a general network solver (EPANET 2.0) to adjust pipe roughness coefficients and nodal demands multipliers until the preset criteria are meet. The approach was applied in the calibration of a real-life water distribution system hydraulic model in China, which takes three loading conditions (max, min and average hour) into consider. The results show that the approach works well in achieving good calibration results, which match field observation in a reasonable level and meet engineering requirements.

Calibration of Nodal Demand in Water Distribution Systems

This paper presents an optimization methodology to calibrate the nodal demand in the model of water supply distribution systems. The matrix analysis has been carried out to get the sensitive coefficients matrix for the model of water distribution systems. Singular value decomposition is applied to calculate search director of optimization by solving the sensitive coefficients matrix, which is more efficient than the finite-difference method. Two cases are used to show the performance of this algorithm. The first case is a hypothetical water distribution network showing the calculation of the optimization vector. The second case is the application of real-life water distribution system in Hangzhou, China, which shows the determination of the cutoff singular value and the search step size in one-dimensional search. The calibrated model has been also validated using the measured data. The results have shown that the proposed algorithm is reliable and effective in real-time system.

Wall decay of chlorine in water distribution system

Research Article| August 01 2009 Wall decay of chlorine in water distribution system G. R. Munavalli; G. R. Munavalli 1Department of Civil Engineering, Walchand College of Engineering, Sangli 416415, India E-mail: gurumunavalli@yahoo.co.in Search for other works by this author on: This Site PubMed Google Scholar M. S. Mohan Kumar; M. S. Mohan Kumar 2Department of Civil Engineering, Indian Institute of Science, Bangaluru 560004, India Search for other works by this author on: This Site PubMed Google Scholar M. A. Kulkarni M. A. Kulkarni 3Department of Civil Engineering, Walchand College of Engineering, Sangli 416416, India Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2009) 58 (5): 316–326. https://doi.org/10.2166/aqua.2009.048 Article history Received: May 20 2008 Accepted: January 30 2009 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation G. R. Munavalli, M. S. Mohan Kumar, M. A. Kulkarni; Wall decay of chlorine in water distribution system. Journal of Water Supply: Research and Technology-Aqua 1 August 2009; 58 (5): 316–326. doi: https://doi.org/10.2166/aqua.2009.048 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Chlorination is a widely practised method of disinfection in India. The chlorine consumption in a distribution pipe is due to bulk and wall reactions. The chlorine decay due to wall reactions is particularly significant in old distribution systems with unlined metallic pipes. The estimation of the wall reaction parameter is difficult and is a product of calibration. The approaches adopted for the estimation are pipe column studies and calibration of the chlorine transport model for the water distribution system model. In the present study both these approaches are carried out for a real-life water distribution system. The relative decay of chlorine in cast iron and PVC pipes of different diameters were determined using laboratory experiments. The pipe column studies showed that the chlorine decay rates were significantly higher in CI pipes than in PVC pipes and vary inversely with initial chlorine concentration. The field data on pressure and chlorine residuals was collected for the hydraulic and water quality calibration of the system. The hydraulic calibration of the system was carried out successfully using network flow and a pressure simulation model. Global and zoned wall reaction parameters were estimated using an inverse model applied onto the distribution system. The estimated zoned parameters are marginally better in simulating the chlorine residuals. The wall reaction parameters are found to be inversely proportional to the pipe diameter. The calibration of distribution system for hydraulic flow conditions and water quality is essential for better operation, maintenance and control. calibration, distribution system, residual chlorine, wall reaction parameter, water quality This content is only available as a PDF. © IWA Publishing 2009 You do not currently have access to this content.

Modelling of demand and losses in real-life water distribution systems

Despite the rapid development of modelling methods in the water industry, some problems of water distribution network modelling are still unresolved, such as how to represent adequately real demand and losses. Both are dependent upon service pressure, yet the relationship is not fully known. The paper discusses various proposals and shows how the modelling procedure could be improved – if that relationship were known. A case from practice is included for illustration. It describes how a real emergency was analysed on the model with the help of the local staff and using past experience. A few suggestions for further work are included at the end of the paper.