Aggressive flushing for discolouration event mitigation in water distribution networks

2003 ◽  
Vol 3 (1-2) ◽  
pp. 179-186 ◽  
Author(s):  
J.B. Boxall ◽  
P.J. Skipworth ◽  
A.J. Saul
Keyword(s):  
Exponential Decay ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Distribution Networks ◽  
Customer Complaint ◽  
Key Factor ◽  
The Uk ◽  
Factor Governing ◽  
Pipe Materials

Discolouration is one of the biggest causes of customer complaint associated with potable water. The flushing of systems has been widely identified as an appropriate pro-active means of removing material from distribution networks and hence controlling discolouration. Such flushing involves creating aggressive hydraulic forces within the network such that the materials that contribute to discolouration are mobilised and removed. Understanding of the causes and mechanisms leading to discolouration are poor. Previous work has been presented on the characterisation of material and particles collected at hydrants during flushing trials in the UK. From this data it was hypothesised that the materials causing discolouration originated from cohesive layers on pipe walls, and that once disturbed the material is maintained as a permanent suspension even under the most quiescent of networks conditions. The work presented in this paper attempts to validate the hypothesis that the discolouration materials originate from cohesive layers, and investigate the nature and variability of such layers within live distribution systems. The study involved the aggressive flushing of a long discrete length of cast iron pipe with known discolouration problems. The results showed a progressive generation of material over the length of the pipe, confirming that the material originated from a uniformly distributed cohesive source. This was followed by a sequence of flushing operations for the systematic cleaning of a complex network area, encompassing a mixture of pipe materials and ages. All measured turbidity traces showed exponential decay with time. Such exponential decay may be predicted by a model based on a change in layer strength with degree of erosion. Hydraulic forces appear to be a key factor governing the availability and mobilisation of material. Iron is the dominant material mobilised from all the pipes. There is no direct trend between the amount or the composition of the material mobilised from the different pipes.

scholarly journals Sectorization for Water Distribution Systems with Multiple Sources: A Performance Indices Comparison

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 131
Author(s):  
Jezabel D. Bianchotti ◽  
Melina Denardi ◽  
Mario Castro-Gama ◽  
Gabriel D. Puccini
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Performance Criteria ◽  
Performance Indices ◽  
Multiple Sources ◽  
Multiobjective Problems ◽  
Open Questions ◽  
Minimum Number ◽  
And Performance

Sectorization is an effective technique for reducing the complexities of analyzing and managing of water systems. The resulting sectors, called district metering areas (DMAs), are expected to meet some requirements and performance criteria such as minimum number of intervention, pressure uniformity, similarity of demands, water quality and number of districts. An efficient methodology to achieve all these requirements together and the proper choice of a criteria governing the sectorization is one of the open questions about optimal DMAs design. This question is addressed in this research by highlighting the advantages of three different criteria when applied to real-word water distribution networks (WDNs). To this, here it is presented a two-stage approach for optimal design of DMAs. The first stage, the clustering of the system, is based on a Louvain-type greedy algorithm for the generalized modularity maximization. The second stage, the physical dividing of the system, is stated as a two-objective optimization problem that utilises the SMOSA version of simulated annealing for multiobjective problems. One objective is the number of isolation valves whereas for the second objective three different performance indices (PIs) are analyzed and compared: (a) standard deviation, (b) Gini coefficient and (c) loss of resilience. The methodology is applied to two real case studies where the first two PIs are optimized to address similar demands among DMAs. The results demonstrate that the proposed method is effective for sectorization into independent DMAs with similar demands. Surprisingly, it found that for the real studied systems, loss of resilience achieves better performance for each district in terms of pressure uniformity and demand similarity than the other two specific performance criteria.

scholarly journals MUWS (Microbiology in Urban Water Systems) – an interdisciplinary approach to study microbial communities in urban water systems

2010 ◽  
Vol 3 (2) ◽  
pp. 91-99 ◽  
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  
Keyword(s):  
Microbial Ecology ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Urban Water ◽  
Infrastructure Systems ◽  
Urban Water Systems ◽  
Sewer Networks

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems and sewer networks are both large, highly interconnected, dynamic, subject to time and varying inputs and demands, and difficult to control. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance within urban water infrastructure systems is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we ultimately aim to link microbial community abundance, diversity and function to physical and engineering variables so that novel insights into the performance and management of both water distribution systems and sewer networks can be explored. By presenting the details and principals behind the molecular microbiological techniques that we use, this paper demonstrates the potential of an integrated approach to better understand how urban water system function, and so meet future challenges.

scholarly journals Optimal placement of valves in a water distribution network with CLP(FD)

2011 ◽  
Vol 11 (4-5) ◽  
pp. 731-747 ◽  
Author(s):  
MASSIMILIANO CATTAFI ◽  
MARCO GAVANELLI ◽  
MADDALENA NONATO ◽  
STEFANO ALVISI ◽  
MARCO FRANCHINI
Keyword(s):  
Logic Programming ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Network ◽  
Real Life ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Constraint Logic Programming ◽  
Optimal Placement ◽  
Isolation System

AbstractThis paper presents a new application of logic programming to a real-life problem in hydraulic engineering. The work is developed as a collaboration of computer scientists and hydraulic engineers, and applies Constraint Logic Programming to solve a hard combinatorial problem. This application deals with one aspect of the design of a water distribution network, i.e., the valve isolation system design. We take the formulation of the problem by Giustolisi and Savić (2008 Optimal design of isolation valve system for water distribution networks. InProceedings of the 10th Annual Water Distribution Systems Analysis Conference WDSA2008, J. Van Zyl, A. Ilemobade, and H. Jacobs, Eds.) and show how, thanks to constraint propagation, we can get better solutions than the best solution known in the literature for the Apulian distribution network. We believe that the area of the so-calledhydroinformaticscan benefit from the techniques developed in Constraint Logic Programming and possibly from other areas of logic programming, such as Answer Set Programming.

scholarly journals Graph Neural Network for Integrated Water Network Partitioning and Dynamic District Metered Areas

2021 ◽  
Author(s):  
KEZHEN RONG ◽  
Minglei Fu ◽  
JIAWEI CHEN ◽  
LEJIN ZHENG ◽  
JIANFENG ZHENG ◽  
...  
Keyword(s):  
Neural Network ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Pollution Monitoring ◽  
Practical Case ◽  
Network Partitioning ◽  
Water Network ◽  
Search Range ◽  
Water Network Partitioning

Abstract Water distribution systems (WDSs) are used to transmit and distribute water resources in cities. Water distribution networks (WDNs) are partitioned into district metered areas (DMAs) by water network partitioning (WNP), which can be used for leak control, pollution monitoring, and pressure optimization in WDS management. In order to overcome the limitations of optimal search range and the decrease of recovery ability caused by two-step WNP and fixed DMAs in previous studies, this study developed a new method combining a graph neural network to realize integrated WNP and dynamic DMAs to optimize WDS management and respond to emergencies. The proposed method was tested in a practical case study; the results showed that good hydraulic performance of the WDN was maintained and that dynamic DMAs demonstrated excellent stability in emergency situations, which proves the effectiveness of the method in WNP.

scholarly journals Management of Water Distribution Systems in PDA Condition with Isolation Valves

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 672 ◽  
Author(s):  
Attilio Fiorini Morosini ◽  
Olga Caruso ◽  
Paolo Veltri
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Optimal Number ◽  
System Control ◽  
Pipe Failure ◽  
Reliable System ◽  
Network Nodes ◽  
Pipe Burst

The correct management of Water Distribution Networks (WDNs) allows to obtain a reliable system. When a pipe failure occurs in a network and it is necessary to isolate a zone, it is possible that some nodes do not guarantee service for the users due to inadequate heads. In these conditions a Pressure Driven Analysis (PDA) is the correct approach to evaluate network behavior. This analysis is more appropriate than the Demand Driven Analysis (DDA) because it is known that the effective delivered flow at each node is influenced by the pressure value. In this case, it is important to identify a subset of isolation valves to limit disrupting services in the network. For a real network, additional valves must be added to existing ones. In this paper a new methodological analysis is proposed: it defines an objective function (OF) to provide a measure of the system correct functioning. The network analysis using the OF helps to choose the optimal number of additional valves to obtain an adequate system control. In emergency conditions, the OF takes into account the new network topology obtained excluding the zone where the broken pipe is located. OF values depend on the demand deficit caused by the head decrement in the network nodes for each pipe burst considered. The results obtained for a case study confirm the efficiency of the methodology.

scholarly journals Legionella pneumophila and Protozoan Hosts: Implications for the Control of Hospital and Potable Water Systems

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 286 ◽  
Author(s):  
Muhammad Atif Nisar ◽  
Kirstin E. Ross ◽  
Melissa H. Brown ◽  
Richard Bentham ◽  
Harriet Whiley
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Systems ◽  
Water Disinfection ◽  
Health Concern ◽  
Waterborne Pathogen ◽  
Microbial Biofilms ◽  
Pontiac Fever

Legionella pneumophila is an opportunistic waterborne pathogen of public health concern. It is the causative agent of Legionnaires’ disease (LD) and Pontiac fever and is ubiquitous in manufactured water systems, where protozoan hosts and complex microbial communities provide protection from disinfection procedures. This review collates the literature describing interactions between L. pneumophila and protozoan hosts in hospital and municipal potable water distribution systems. The effectiveness of currently available water disinfection protocols to control L. pneumophila and its protozoan hosts is explored. The studies identified in this systematic literature review demonstrated the failure of common disinfection procedures to achieve long term elimination of L. pneumophila and protozoan hosts from potable water. It has been demonstrated that protozoan hosts facilitate the intracellular replication and packaging of viable L. pneumophila in infectious vesicles; whereas, cyst-forming protozoans provide protection from prolonged environmental stress. Disinfection procedures and protozoan hosts also facilitate biogenesis of viable but non-culturable (VBNC) L. pneumophila which have been shown to be highly resistant to many water disinfection protocols. In conclusion, a better understanding of L. pneumophila-protozoan interactions and the structure of complex microbial biofilms is required for the improved management of L. pneumophila and the prevention of LD.

Fungi from Potable Water: Interaction with Chlorine and Engineering Effects

1988 ◽  
Vol 20 (11-12) ◽  
pp. 153-159 ◽  
Author(s):  
William D. Rosenzweig ◽  
Wesley O. Pipes
Keyword(s):  
Water Samples ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Fungal Spores ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Storage Tanks ◽  
Water Interaction ◽  
Low Concentrations

In recent years various types of imperfect fungi have been isolated from water systems. Fungal spores and mycelia can be inactivated by low concentrations of chlorine in the laboratory but survive in some habitats in water distribution systems. This report describes a field study which provides evidence that some types of fungi are able to grow in water distribution systems. Replicate samples from private residences were used to demonstrate that fungal densities are sometimes much greater than the levels which could be explained by adventitious spores. The microbiological content of water samples from fire hydrants was often significantly different from that of water samples from nearby private residences. The treated water input to distribution systems was found to be significantly lower in fungus content than water from private residences. Elevated storage tanks open to the atmosphere appear to be significant sources of fungal input to some systems.

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