Processes governing trunk main asset deterioration
Microbial viability and discolouration in trunk mains – a proposed two-year consortium funded research project building on the PODDS research and innovations.
The processes that govern the generation of material layers on the boundary surfaces in water distribution systems are poorly understood. Discolouration resulting from the mobilisation of these layers causes the greatest number of water-quality-related contacts. With increased knowledge, water utilities may identify, justify and implement strategies to reduce the rate of asset deterioration caused by the development of these layers and effectively and efficiently manage associated discolouration risk.
Such strategies might be through changes in treatment processes, thus benefiting entire networks, or through distribution operation and maintenance strategies focusing on identified risk sections. With improved understanding, the incidence of discolouration events may be reduced, asset life extended and savings made on both operational and capital expenditure. Recent laboratory-based research at the University of Sheffield has shown that biofilms play a central role in discolouration material layer formation and characteristics, and hence that field-derived understanding of biofilms is essential.
This research proposes to extend the world-leading knowledge and the application of validated tools for managing discolouration developed during previous PODDS projects. The outcome will be to encompass the processes that govern the generation of material layers within distribution systems, with particular respect to integrating the role of biofilms. Industrial partner collaboration is essential to gain access to trunk mains where in-situ studies may be undertaken.
Contributions to the project will include microbiological, computing, network analysis, sensor and discolouration modelling expertise from the University of Sheffield, together with studies using the internationally recognised Pennine Water Group laboratory pipe rig.
Contacts at the University of Sheffield
Journal and conference papers
Husband, S, Boxall, J B (2012)
Misleading velocity analysis for water quality management in transmission mains. EWRI 2012, Albuquerque, 20–24 May.
Husband, S, Xin, Y, Boxall, J B (2012)
Long term asset condition and discolouration modelling in water distribution systems with Epanet MSX. EWRI 2012, Albuquerque, 20–24 May.
Husband, S, Jackson, M, Boxall, J (2011)
Trunk main discolouration trials and strategic planning. Computing and Control for the Water Industry (CCWI) 2011, Exeter, UK, 5–7 September.
Husband, S (2010)
Discolouration in water distribution systems; understanding, modelling and practical applications. Doctoral thesis, the University of Sheffield.
Husband, S, Boxall, J B (2011)
Asset deterioration and discolouration in water distribution systems. Water Research 45, pp. 113–124. DOI
Husband, S, Williams, R, Boxall, J B (2010)
Risk managed trunk main operation. Water Distribution System Analysis 2010, Tucson, Arizona, USA, 12–15 September.
Sharpe, R, Smith, C J, Biggs, C A and J B Boxall (2010)
Pilot scale laboratory investigations into the impact of steady state conditioning flow on potable water discolouration. Water Distribution System Analysis 2010, Tucson, Arizona, USA, 12–15 September.
Dienes, P, Sekar, R, Husband, S, Boxall, J B, Osborn, A M and Biggs, C A (2010)
A new coupon design for simultaneous analysis of in situ microbial biofilm formation and community structure in drinking water distribution systems. Applied Microbiology and Biotechnology 87, pp. 749–756. DOI
Husband, S, Whitehead, J, Boxall, J B (2010)
The role of trunk mains in discolouration. In press, Journal of Water Management, ICE. DOI
Husband, S, Boxall, J B (2010)
Field studies of discolouration in water distribution systems: model verification and practical implications. Journal of Environmental Engineering 136 (1), pp. 86–94. DOI
Seth, A, Husband, S, Boxall J B (2009)
Rivelin trunk main flow test. Proceedings of the 10th International Conference on Computing and Control for the Water Industry (CCWI), 1–3 September, Sheffield, UK.
Husband, S, Whitehead, J, Boxall J B (2009)
Long term trunk main monitoring yields operational dividends. Third Biennial Conference of the UK Network on Potable Water Treatment and Supply, Buxton, 1–2 June 2009.
Husband, S, Boxall, J B, Saul, A J (2008)
Laboratory studies investigating the processes leading to discolouration in water distribution networks. Water Research 42 (16), pp. 4309–4318.
Husband, P S and J B Boxall (2008)
Water distribution system asset deterioration and impact on water quality – a case study. ASCE World Environmental and Water Resources Congress, May 13–16, Ahupua'a, Hawaii, USA.
Vreeburg, J H G and J B Boxall (2007)
Discolouration in potable water distribution systems: a review. Water Research 41, pp. 519–529.
Husband, S, Boxall, J B (2007)
Repeat DMA flushing operations: discolouration comparison, modelling and management. Proceedings of the EPSRC Developments in Water Treatment and Supply, 4–5 July 2007, Bath, UK.
Boxall, J B and Prince, R A (2006)
Modelling discolouration in a Melbourne (Australia) potable water distribution system. Journal of Water Supply: Research and Technology – AQUA, IWA. 55.3, pp. 207–219.
Husband, S, Boxall, J B (2005)
Material accumulation and mobilisation in a pipe loop system. Proceedings of the EPSRC Developments in Water Treatment and Supply, 5–6 July 2005, York, UK.
Boxall, J B, Dewis, N (2005)
Identification of discolouration risk through simplified modelling. Proceedings of the ASCE, EWRI, World Water and Environmental Resources Congress, May 15–19, Anchorage, Alaska, USA.
Boxall, J B and Saul, A J (2005)
Modelling discolouration in potable water distribution systems. Journal Environmental Engineering ASCE, vol. 131, no. 5, pp. 716–725.
Boxall, J B, Saul, A J and Skipworth, P J (2004)
Modelling for hydraulic capacity. Journal of the American Water Works Association, vol. 96, no. 4, pp. 161–169.
Boxall, J B, Skipworth, P J and Saul, A J (2003)
Aggressive flushing for discolouration event mitigation in water distribution networks. Water Science and Technology – Water Supply, vol. 3, part 1/2, pp. 179–186.
Boxall, J B, Unwin, D M, Husband, P S, Saul, A J, Dewis, N and Gunstead, J D (2003)
Water quality in distribution systems: rehabilitation and maintenance strategies. Proceedings of the International CCWI conference, Advances in Water Supply Management, 15–17 September 2003, Imperial College London, UK.
Boxall, J B, Saul, A J, Gunstead, J D and Dewis, N (2003)
Regeneration of discolouration in distribution systems. Proceedings of the ASCE, EWRI, World Water and Environmental Resources Conference, 23–26 June 2003, Philadelphia, USA.
Seth, A, Bachmann, R T, Boxall, J B, Saul, A J and Edyvean, R (2003)
Characterisation of materials causing discolouration in potable water systems. Water Science and Technology, vol. 49, no. 2, pp. 27–32.
Boxall, J B, Skipworth, P J and Saul, A J (2001)
A novel approach to modelling sediment movement in distribution mains based on particle characteristics. Water Software Systems, vol. 1: Theory and Applications (Water Engineering & Management). B Ulanicki, B Coulbeck and J P Rance, Research Studies Press, Hertfordshire, UK, pp. 263–273.
PODDS V 2015 fieldwork plan
PODDS V project summary 2015. The PODDS V research project has been hugely successful in bringing together multiple aspects of research. Increased scientific knowledge from nationwide and laboratory studies has resulted in cost effective and efficient operational strategies that improve asset performance in water distribution systems with regards to safeguarding water quality.
The work and subsequent impact has been recognised academically, by water practitioners internationally and the Drinking Water Inspectorate (DWI). This has only been possible with the active participation of project members helping organise trials that consistently demonstrate the hydraulically manageable and predictable discolouration behaviour whilst facilitating identification of governing processes.
DWI Presentation, June 2015. The DWI invited the PODDS group to London to present our research. It was commented by the organisers that 29 (out of 40+ staff including clerical) was best turnout to date for this type of dissemination event.
REF 2014 the Research Excellence Framework (guide). REF is the new system for assessing UK Universities' research. PODDS was submitted as an Impact Case Study and subsequently showcased (one of only five from 514 case studies) as an excellent example of contributions by engineering research to the better provision of public services in a report prepared by Technopolis with the EPSRC, Royal Academy of Engineering and overseen by Professor John Fisher CBE FREng – 'Assessing the economic returns of engineering research and postgraduate training in the UK'.
PODDS VI proposal (July 2015). This aims to extend the work started in previous highly successful PODDS consortia projects but with improved specified data gathering for parallel bespoke computing modelling analysis to enable evidencing the causes of discolouration whilst justifying tactical and strategic operations within the regulatory framework. PODDS VI – initial proposal (March 2015) can be found here.
NTU equivalence – set of plots that demonstrate how turbidity correlates with iron and manganese based on PODDS trials over.
PODDS flow cytometry protocol. A protocol has been written (by Kat Fish and Stewart Husband) that uses sodium ascorbate for dechlorinating. Sodium ascorbate has been selected as it is basically vitamin C so is safer to handle, store, AWWA approved and not an oxygen scavenger like sodium thiosulphate.
PODDS guiding principles. Based on over a decade of industry leading international research. Includes key innovative priorities for developing efficient, cost-effective pro-active discolouration management strategies and a flowsheet methodology for identifying and prioritising trunk main conditioning.
'To chlorinate, or not to chlorinate?' pathogen proposal 2015. This proposal seeks to challenge the current practices of maintaining disinfection residual in drinking water distribution systems, by for the first time studying and modelling the impact of disinfection residual strategies on the sheltering, proliferation, release and subsequent exposure to pathogens from within the systems.
Pipe Dreams presentation and agenda, 3 July 2014. Distribution systems are not inert transport systems. They should be considered as high surface area physical, chemical and biological reactors. They are also highly variable, highly uncertain, ageing and deteriorating. The central premise of Pipe Dreams is that the layers that form at the pipe and water interface of this extremely complex, endemic, essential infrastructure are the missing link between water quality and infrastructure.
This final year event presented results of research that sought to address the need to understand this interface, such that we can supply safe water for public health, and make the best sustainable use of existing infrastructure. The day will involve presenting results and achievements, as well as propose some ideas for the future, with opportunities for discussion, feedback and interaction across industry and academia.
PODDS Welsh Water proposal, April 2014. With the ongoing success of the PODDS project, Welsh Water have asked to become members. Here can be found the 'Discolouration proposal to Dwr Cymru Welsh Water from the Pennine Water Group at the University of Sheffield'.
PODDS V proposal, April 2013. Microbial viability and discolouration in trunk mains – a proposed two year consortium funded research project building on the PODDS research and innovations.
PODDS turbidity monitoring equipment (March 2013) reports on the turbidity monitoring formats of field kit used by the PODDS team.
Click on the filmstrip below to take you to a folder containing the 'Particles, cohesive layers and discolouration risk' video clip. The PODDS presentation from the WatNet Conference, Cranfield, September 2013 can also be found here.
DCWW Abergele November 2014. This report presents data from an initial PODDS flow conditioning trial on the 5 km 8" mixed uPVC and AC trunk main feeding Abergele service reservoir. The trial was conducted following two independent hydraulic incidents that had occurred on this main during 2014 that demonstrated a discolouration risk to customers and a follow-up DWI investigation. An updated report including findings and modelling validation from a second trial in January 2015 is also attached.
NWG Elford 6" AC flow conditioning trial and investigative study.
STW 21" Cast Iron Satnall report (March 2014) including PODDS predictive modelling, three trial analyses (two six monthly repeats) and recommended operational guidelines.
STW 21" Cast Iron Satnall trial report (January 2013) including PODDS predictive modelling from January 2012.
Turbidity versus iron. Is 1 NTU a sensible flushing target for PODDS style operational trials?
PODDS Epanet model parameters can be seen here.
Steering group meetings
Second steering meeting 15 January 2014, University of Sheffield: agenda, presentation, minutes. As an 'expert' group, do we need regulatory clarification on what is 'clean'? To assist the University of Sheffield's 'Discolouration' REF submission plus guidance notes are attached.
Updates from Will Furnass (pipe rig mobilisation results and modelling) and Isabel Douterelo (microbial analysis of field based pipe coupons) are included in the presentation. Martin Jackson also gave a presentation on how PODDS parameters may be determined directly from hydraulic values.
Fifth steering meeting 13 October 2014, University of Sheffield: agenda, presentation, minutes. The meeting involved interactive PODDS modelling and live turbidity data downloaded from the latest NephNets. In addition to the PODDS work, additional presentations from Iftekhar Sunny on his PhD with Scottish Water and Kat Fish with laboratory and chlorine associated research with Dwr Cymru Welsh Water. During the meeting Isabel Douterelo presented initial results from coupon studies with Wessex Water (slides not available online).
Discolouration risk analysis tool – opens a folder with the latest version, Epanet.exe file, Epanet.dll file and two example Epanet files. These can be downloaded and saved as appropriate. Instructions for use can be found in the user manual.
Discolouration risk analysis tool user manual – methodology, operation and validation document.