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9. Managing discolouration in drinking water distribution systems by integrating understanding of material behaviour

Author

Boxall, Joby (author), Blokker, E.J.M. (author), Schaap, Peter (author), Speight, Vanessa (author), Husband, Stewart (author), Boxall, Joby (author), Blokker, E.J.M. (author), Schaap, Peter (author), Speight, Vanessa (author), and Husband, Stewart (author)

Abstract

Discoloured drinking water, caused by elevated concentrations of organic and inorganic particles, is unacceptable. It occurs due to accumulation and subsequent mobilisation of material from within drinking water distribution infrastructure. Discolouration is currently partially explained by either the theories of cohesive layers or gravitational sedimentation. It is proposed and shown here how the processes behind these two theories both occur and how to integrate them to better explain observed behaviour and inform operational interventions to reduce discolouration. Deficiencies in understanding regarding the process and factors that influence material accumulation are highlighted. Future research addressing these deficiencies will enable determination of long term sustainable management strategies balancing capital investment and operational maintenance to safeguard distribution of high quality drinking water., Sanitary Engineering

Published
2023
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17. Guidance Manual: Water Quality in Drinking Water Distribution Systems

Author

Speight, Vanessa, Quintiliani, Claudia, Schaap, Peter, Husband, Stewart, Summeren, Joost Van, Kapelan, Zoran, Creaco, Enrico, Blokker, Mirjam, Preciado, Carolina Calero, Soler, Isabel Douterelo, and Boccelli, Dominic L.

Subjects
90508 Water Quality Engineering, FOS: Civil engineering
Abstract

This Guidance Manual has been produced by the members of the Wat-Qual consortium, funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 778136. The manual provides a series of fact sheets covering the latest understanding of drinking water quality management in water distribution systems, covering the topics of:- flushing- disinfection- maintenance and repairs

Published
2020
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18. Decision-Making Tools to Manage the Microbiology of Drinking Water Distribution Systems

Author

Universitat Politècnica de València. Departamento de Matemática Aplicada - Departament de Matemàtica Aplicada, Engineering and Physical Sciences Research Council, Reino Unido, Carpitella, Silvia, Del Olmo, Gonzalo, Izquierdo Sebastián, Joaquín, Husband, Stewart, Boxall, Joby, Douterelo, Isabel, Universitat Politècnica de València. Departamento de Matemática Aplicada - Departament de Matemàtica Aplicada, Engineering and Physical Sciences Research Council, Reino Unido, Carpitella, Silvia, Del Olmo, Gonzalo, Izquierdo Sebastián, Joaquín, Husband, Stewart, Boxall, Joby, and Douterelo, Isabel

Abstract

[EN] This paper uses a two-fold multi-criteria decision-making (MCDM) approach applied for the first time to the field of microbial management of drinking water distribution systems (DWDS). Specifically, the decision-making trial and evaluation laboratory (DEMATEL) was applied removing the need for reliance on expert judgement, and analysed interdependencies among water quality parameters and microbiological characteristics of DWDS composed of different pipe materials. In addition, the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) ranked the most common bacteria identified during trials in a DWDS according to their relative abundance while managing vagueness affecting the measurements. The novel integrated approach presented and proven here for an initial real world data set provides new insights in the interdependence of environmental conditions and microbial populations. Specifically, the application shows as the bacteria having associated the most significant microbial impact may not be the most abundant. This offers the potential for integrated management strategies to promote favourable microbial conditions to help safeguard drinking water quality.

Published
2020

22. CCWI2017: F148 'Rusby Wood a Smart Network for Sustainable Discolouration Risk Reduction'

Author

Cook, Dominic and Husband, Stewart

Subjects
90599 Civil Engineering not elsewhere classified, FOS: Civil engineering
Abstract

Managing discolouration customer contacts has never been more important to UK Water Companies, with the Economic Regulator setting strict water quality customer contact targets, imposing large financial penalties if they are exceeded without providing additional funding to facilitate necessary network investment. 19% of discolouration customer contacts can be directly associated with the mobilisation of discolouration material from the trunk main distribution system, but these pipes due to their criticality of supply and size are extremely expensive to clean. This paper presents a practical example demonstrating that with the addition of relatively inexpensive automated flow control, metering and instrumentation, a water supply system can be configured to automatically re condition itself. Five trunk main sections will sequentially run a maximum flow between service reservoirs before returning to normal operating flows. This produces a safety headroom between normal operating flow and the maximum hydraulically available flow this dramatically reduces discolouration risk should an un planned high flow event occur on the network. The system is designed to ‘self check’ whereby sending and receiving reservoir levels and flow pressure and turbidity at strategic points are within set parameters before the reconditioning occurs. In addition, if abnormal flows, pressures or turbidity levels are detected at any time on one of the trunk main sections, the inlet valve on the appropriate receiving reservoir will automatically close. This prevents discoloured water from entering the reservoir allowing the operator time to repair and flush the affected main.

Published
2017
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23. CCWI2017: F86 'DISCOLOURATION RISK MANAGEMENT AND CHLORINE WALL DECAY'

Author

Iftekhar Zaman Sunny, Husband, Stewart, Moore, Graeme, Drake, Nick, Mckenzie, Kevan, and Boxall, Joseph

Subjects
polycyclic compounds, 90599 Civil Engineering not elsewhere classified, FOS: Civil engineering
Abstract

This paper explores the concept that periodic imposed excess shear stress events to manage discolouration risk in trunk mains can also impact on the chlorine wall decay by changing the properties of the accumulated pipe wall material. By implementing a series of varying magnitude shear stress events in multiple trunk main demonstrated that significant material was mobilised, thereby cleaning the mains and reducing discolouration risk. Measured chlorine data also suggests that repeated shear stress intervention also reduced the chlorine wall decay relative to a control network and the larger the intervention greater the benefit. Calibrated first order chlorine decay simulations in EPANET supported this finding. The modelling results further show that the wall decay has a dominant influence on this change even for these large diameter pipes. The significance of these findings is to evidence the additional value of regular hydraulics based cleaning interventions for large diameter mains delivering service improvement in terms of both discolouration risk and persistence of chlorine residual.

Published
2017
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30. Predictive water quality modelling and resilience flow conditioning to manage discolouration risk in operational trunk mains.

Author

Husband, Stewart and Boxall, Joby

Subjects
*MATHEMATICAL models, *WATER quality, *IRON founding, *MASS mobilization, *LOGICAL prediction, *MAINTENANCE
Abstract

This paper presents predictive discolouration modelling and subsequent field trial validation for a cast iron trunk main network. This enabled a UK water company to propose an 'operational flow conditioning' maintenance plan that reduces discolouration risk, improves network resilience and asset condition and yet does not require the trunk main to be decommissioned for invasive cleaning. This represents substantial time and cost benefits. Pre- and post-trial turbidity monitoring data are presented which identified a daily flux of material, a factor in the regeneration of material layers that have been shown to cause discolouration when mobilised. Additional data showing the occurrence of pressure transients are also presented, the latter being a possible cause of contaminant ingress and asset failure. After 6 months a second flow trial was conducted and modelled, confirming the regeneration of particulate discolouration material across the range of mobilising forces applied during the trial. It also indicated full layer development, or maximum discolouration risk, may occur in just over 2 years for this cast iron main. This highlights the need for appropriate maintenance strategies, such as periodic flow conditioning identified here, to mitigate discolouration risk and help safeguard water quality. [ABSTRACT FROM AUTHOR]

Published
2015
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31. Understanding microbial ecology to improve management of drinking water distribution systems.

Author

Douterelo, Isabel, Sharpe, Rebecca L., Husband, Stewart, Fish, Katherine E., and Boxall, Joby B.

Subjects
MICROBIAL ecology, DRINKING water, WATER distribution, WATER management, WATER utilities, BIOFILMS
Abstract

Microorganisms in drinking water distribution systems (DWDS), and in particular the microbial communities that form biofilms on infrastructure surfaces, drive critical processes impacting water quality. This paper reviews knowledge, research approaches, and monitoring methods to consolidate understanding of the microbial ecology of DWDS. The review highlights how microbial characteristics and subsequent behavior can be broadly classified as common or complex. Common behavior relates to the ubiquitous and continual development of biofilms, consistent core communities, and mediated material accumulation. In contrast, the complex aspect relates to the shape, structure, and composition of the microbiome, defined by site‐specific properties such as supplied source water, pipe material, and hydraulic regimes. It is shown how the latest microbial tools and techniques can be applied to increase our understanding of DWDS ecology and how water utilities are starting to use this knowledge. This is not because of regulatory requirements, but in recognition that they provide valuable information facilitating proactive management and operation benefits to these critical yet aging systems, protecting water quality and public health in the process. This article is categorized under: Engineering Water > Sustainable Engineering of WaterWater and Life > Nature of Freshwater Ecosystems Microbial characteristics and behaviour in drinking water distribution systems can be classified as common or complex [ABSTRACT FROM AUTHOR]

Published
2019
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32. Guidance Manual: Water Quality in Drinking Water Distribution Systems

Author

Speight, Vanessa, Quintiliani, Claudia, Bosch, Arne, Marketa Rajnochova, Schaap, Peter, Husband, Stewart, Rucka, Jan, Suchacek, Tomas, Ivetic, Damjan, Zeljko Vasilic, Jacimovic, Nenad, Summeren, Joost Van, Kapelan, Zoran, Creaco, Enrico, Blokker, Mirjam, Preciado, Carolina Calero, Soler, Isabel Douterelo, Xenochristou, Maria, Avvedimento, Stefania, Boccelli, Dominic L., Nikoloudi, Eirini, Novakova, Jana, Wagner, Martin, and Laarhoven, Karel Van

Subjects
90508 Water Quality Engineering, 6. Clean water, FOS: Civil engineering
Abstract

This Guidance Manual has been produced by the members of the Wat-Qual consortium, funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 778136. The manual provides a series of fact sheets covering the latest understanding of drinking water quality management in water distribution systems, covering the topics of:- flushing- disinfection- maintenance and repairs

33. Guidance Manual: Water Quality in Drinking Water Distribution Systems

Author

Speight, Vanessa, Quintiliani, Claudia, Bosch, Arne, Marketa Rajnochova, Schaap, Peter, Husband, Stewart, Rucka, Jan, Suchacek, Tomas, Ivetic, Damjan, Zeljko Vasilic, Jacimovic, Nenad, Summeren, Joost Van, Kapelan, Zoran, Creaco, Enrico, Blokker, Mirjam, Preciado, Carolina Calero, Soler, Isabel Douterelo, Xenochristou, Maria, Avvedimento, Stefania, Boccelli, Dominic L., Nikoloudi, Eirini, Novakova, Jana, Wagner, Martin, and Laarhoven, Karel Van

Subjects
90508 Water Quality Engineering, 6. Clean water, FOS: Civil engineering
Abstract

This Guidance Manual has been produced by the members of the Wat-Qual consortium, funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 778136. The manual provides a series of fact sheets covering the latest understanding of drinking water quality management in water distribution systems, covering the topics of:- flushing- disinfection- maintenance and repairs

36. Long-term cost-effective trunk main discolouration risk management strategy

Author

Sunny, Iftekhar Zaman, Boxall, Joby, and Husband, Stewart

Subjects
624
Abstract

Material responsible for discolouration risk has been shown to accumulate on pipe walls even after cleaning intervention, suggesting that risk cannot be eliminated with a single applied intervention and hence the long-term water quality benefits are uncertain. This recurring cleaning requirement can substantially increase total expenditure on interventions. Although different interventions exist to manage accumulated material, flow conditioning is considered to be a long-term intervention due to the use of only system hydraulic (shear stress) with minimal resources. The water quality performance of the selected intervention was tested in multiple operational trunk mains including a control main with similar physical, chemical and microbiological conditions and their discolouration risk and chlorine wall decay were measured as a water quality performance indicator. The periodic trunk main flow conditioning improved the long-term chronic material loading and chlorine wall decay of trunk mains compared to the control. Although transport of occasional acute loading to the downstream network from the flow conditioning trial was recorded, the improved downstream accumulation return period found for the flow conditioned main evidenced that chronic loading has a significant influence on discolouration risk than acute loading. Using the field observed material accumulation processes for large diameter main and long-term measured data, the Variable Condition Discolouration (VCD) model was used successfully to simulate long-term discolouration behaviour with high accuracy and the model’s accumulation functionality was validated. This fundamental way of capturing accumulation behaviour in the VCD model was used to develop a novel whole life costing (WLC) model for designing flow conditioning intervention cycle cost trading against hydraulic resilience. The WLC modelling framework derived exponential Pareto front solutions that can select best solutions between intervention expenditure and level of resilience achieved. This research enlightens for the first time how the trunk main and downstream network discolouration risk behaves in response to periodically controlled interventions and how risk can be managed proactively and strategically from treatment works to trunk main and downstream distribution zone.

Published
2018

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