Phase four
Discolouration risk performance

Introduction

The PODDS model, developed by the Pennine Water Group at the University of Sheffield has been shown capable of predicting the discolouration response of distribution networks to changes in hydraulic conditions. Results highlighting the capabilities of the full model are presented in figure 1 (below). The model is based on the novel application of cohesive transport theory and its development has led to a step change in philosophy and perception relating to discolouration.

The PODDS research projects have developed the model into a tool suitable to be readily utilised by the water industry with a high degree of confidence in the parameter dataset required to achieve accurate model simulations. Critically the work has highlighted differential rates of material accumulation (layer regeneration or asset deterioration) within water distribution networks based on water quality factors and how hydraulic regimes are operated. Additional confirmation of these findings and how this information may be best utilised, including the application to larger diameter trunk mains now remains to be resolved.

The fourth phase of this project is therefore a way for the collaborators to lead the industry in developing and producing justifiable guidelines for planning operational and maintenance strategies to manage discolouration, particularly in strategic trunk mains.

Project approach

1. Controlled laboratory testing

Initial trails have been conducted in a pipe loop facility (non-temperature controlled) confirming that material layers can be accumulated and subsequent discolouration generated in a laboratory based pipe loop. Issues remain over the practical applicability of these results as the system operated at 20°C and hence the biological processes involved may be considered non-representative.

Trials utilising a new temperature controlled pipe test loop facility at the University of Sheffield are now underway. This is an internationally unique facility, with the capability of fully recreating operational pressures and flows and time vary patterns within a controlled environment. The rig is comprised of 79mm internal diameter MDPE pipe, representative of pipe currently installed in the UK. The rig comprises over 600m of pipe, which can be run either as a complete length or as three independent systems.

The control of a laboratory facility will be used to systematically investigate and quantify the relative impact of different potentially influencing factors and mechanisms on material accumulation rates. Only by testing influencing processes in isolation can a true appreciation of their significance be derived.

Questions that it is proposed to investigate include:

Hydraulics

• Is there a steady state self cleaning velocity?

• What are the effects of daily flow patterns? Does this change if a stagnation period is present?

• Is there an ultimate layer strength for plastic pipes?

Source water effects

• What is the effect of changing concentrations of iron, manganese and aluminium (the dominant metals species found consistently in flushing samples)?

• What is the effect of pH, alkalinity, DO?

Infrastructure

• What would be the influence of introducing a length of cast iron pipe into the system?

The laboratory based studies will run throughout the programme, with details of further study to be refined on an ongoing basis through the steering group and with reference to the field results.

2. Field regeneration trials

Field sites utilised during PODDS project trials will continue to be tested in the same manner at determined intervals. This will provide quantification of regeneration processes within live water distribution systems, capturing the complex interaction of processes and variables at each site. This data will provide:

• Confidence in the repeatability of regeneration processes in sites where conditions do not change.

• Verification of the effects quantified through idealised laboratory trials by comparison between the different sites and with respect to changes to these sites.

3. Trunk mains

Due to the criticality and political sensitivity of trunk mains, work relating to trunk mains will be subject to change and adaptation to suit individual company policies and strategies. However, due to significant level of interest and need for practical tools relating to discolouration in trunk mains as expressed by the PODDS Water Company Consortium, the PODDS approach will continued to be developed for prediction of trunk main response to changing hydraulic conditions.

Critically trials are planned to assess the regeneration of cohesive material layers responsible for discolouration incidents when mobilised. With this information strategic fiscal planning can be justified for capital or operational investment. Trials will be conducted on a site by site basis as opportunities arise within the companies of the consortia.

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.

Project base

• University of Sheffield

• Department of Civil Engineering

• Pennine Water Group

Project collaborators

All of the project sponsors below provided operational experience, field sites and assistance.

• Northumbrian Water

• Seven Trent Water

• United Utilities

• Wessex Water

• Yorkshire Water

PODDS IV proposal.

With the increasing uptake and use of the PODDS tool as part of operational planning strategies within consortium water companies, an updated users guide to the PODDS Model and Epanet Manual (2009) is included here.

Following a proposed year's extension to the project to facilitate collection of regeneration data, revised project objectives were submitted.

PODDS IV extension Gantt chart.

Customer contacts – cluster analysis. Access database template to derive customer contacts associated with trunk mains. File supplied by Dominic Cook, Yorkshire Water as detailed in the eighth steering group meeting minutes.

PODDS IV interim report (July 2012) and revised objectives. A supporting document with consortium member uptake statements is also available here.

PODDS IV report (April 2013) including papers on the VCDM and influence of hydraulic regimes on bacterial community structure.

PODDS V proposal (April 2013). Microbial viability and discolouration in trunk mains – a proposed year consortium funded research project building on the PODDS research and innovations. A supporting document with consortium member comments is also available here. In addition further comments regarding the inclusion of Scottish Water are available here.

PODDS turbidity monitoring equipment (March 2013) reports on the turbidity monitoring formats of field kit used by the PODDS team.

Documents

STW 21" Cast Iron Satnall trial report (January 2013) including PODDS predictive modelling from January 2012.

WW Odcombe to Compton Durville May/June 2012. Data collected from the Odcombe to Compton Durville trunk main indicate that there exists a discolouration risk that correlates with operator experience. Monitoring of turbidity is shown to be useful, but may also be misleading as monitoring suggests significant settling of material. Report includes PODDS modelling.

Conference: New Developments in IT and Water Conference, Amsterdam, 4–6 November 2012. Modelling both the continual erosion and regeneration of discolouration material in drinking water distribution systems and presentation, W R Furnass, R C Collins, P S Husband, R L Sharpe, S R Mounce, J B Boxall.

Conference: SWIG – Sensors in Water Industry Group, Nottingham, 21–22 September 2011. Know the flow: managing discolouration risk, S Husband, H Vicente and J Boxall.

Conference: Computer and Control for the Water Industry (CCWI) Exeter, 5–7 September 2011. Trunk main discolouration trials and strategic planning and presentation, S Husband, M Jackson and J Boxall.

Conference: Developments in Water Treatment and Supply Cheltenham, 7–8 June 2011. Managing Trunk Main Discolouration by Managing Flow and presentation, S Husband, H Vicente and J Boxall.

PODDS IV planned schedule (high-level Gantt).

STW 45" CLCI Bamford trunk main monitoring turbidity results, September 2010. Video clips from inside 45" CLCI, 1908 and 46" Bitumen lined steel, 1938 trunk mains exiting Bamford WTW. Believe the clips show the entire circumference of pipe.

NWL Evaluation of the HydraClam water quality monitor. Internal report circulated May 2009.

PODDS Variable Condition Discolouration Model (VCDM) – mathematical formulation and description.

STW Meridan to Highters Heath, 7 km 1200 mm trunk main flushing and PODDS modelling report.

STW Satnall trunk main – report commissioned to fulfil DWI objectives for maintenance strategies.

UU fifth repeat flushing results, Frodsham.

UU fourth repeat flushing results, Frodsham.

UU fourth repeat flushing results, Rainhill.

Portable ATI 15/76 turbidity monitor trials report including operational temperature sensitivity analysis.

Turbidity versus iron – is 1 NTU a sensible flushing target for PODDS style operational trials?

Steering group meetings

Inaugural meeting 21 May 2010, University of Sheffield: presentation, minutes.

Second meeting 24 August 2010, University of Sheffield: agenda, presentation, minutes.

Third meeting 23 November 2010, University of Sheffield: agenda, presentation, minutes.

Fourth meeting 1 March 2011, University of Sheffield: agenda, presentation, minutes.

Fifth meeting 15 June 2011, University of Sheffield: agenda, presentation, minutes (minutes include PODDS IV status review that evaluates feasibility of project objectives within remaining time frame).

Sixth meeting 29 September 2011, University of Sheffield: agenda, presentation (including slides from John Coulson, Wessex Water Danesborough trunk main model calibration), minutes.

Seventh meeting 12 January 2012, University of Sheffield: agenda, presentation (including slides from STW Highters Heath flow trials and PODDS modelling, Paul Brown slides from Warton flow trials, John Coulson on PODDS planning for a Wessex water scheme and ATI turbidity equipment), minutes.

Eighth meeting 24 April 2012, University of Sheffield: agenda, presentation, Dominic Cook presentation on customer contacts, minutes.

Ninth meeting 19 July 2012, University of Sheffield: agenda, presentation, minutes. John Coulson presented two modelling videos on possible sedimentation in Watsed: the original model calibration and transfer flows.

Tenth meeting 23 October 2012, University of Sheffield: agenda, presentation, minutes. Will Furnass presented information on the progress of the VCDM with slides forming part of his presentation at the upcoming New Developments in IT and Water Conference, Amsterdam 4–6 November 2012.

MJ presented information from turbidity monitoring and trials at Compton Durville that indicate material dropping out and uncharacterised behaviour of material layers seeding downstream networks. Paul Brown presented at the Potable Water Treatment and Supply Conference: Maintaining the Flow, Cranfield (Developments in Water Treatment and Supply Fifth Conference of the UK Network on Potable Water and Supply), 11 September, 2012. His presentation can be found here (note as .pdf animations do not work). Presentation by Isabel Douterelo on microbial flushing trials is also included here.

Eleventh meeting 23 January 2012, University of Sheffield: agenda, presentation, minutes. Will Furnass presented information on the progress of the VCDM with slides forming part of his presentation.

Risk tool

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.

Publications

I Douterelo, R L Sharpe and J Boxall (2013)
Influence of hydraulic regimes on bacterial community structure and composition in an experimental drinking water distribution system. Water Research, 47, issue 2, 1 February 2013, pp. 503–516. DOI

W R Furnass, R P Collins, P S Husband, R. L. Sharpe, S R Mounce and J B Boxall (2012)
Modelling both the continual erosion and regeneration of discolouration material in drinking water distribution systems. IWA New Developments in IT and Water Conference, Amsterdam, 4–6 November 2012.

S Husband and J B Boxall (2012)
Misleading velocity analysis for water quality management in transmission mains. EWRI 2012, Albuquerque 20–24 May.

S Husband, Y Xin and J B Boxall (2012)
Long term asset condition and discolouration modelling in water distribution systems with Epanet MSX. EWRI 2012, Albuquerque 20–24 May.

S Husband, M Jackson and J Boxall (2011)
Trunk main discolouration trials and strategic planning. Computing and Control for the Water Industry (CCWI) 2011, Exeter, 5–7 September.

S Husband (2010)
Discolouration in water distribution systems; understanding, modelling and practical applications. Doctoral thesis, University of Sheffield.

S Husband and J B Boxall (2011)
Asset deterioration and discolouration in water distribution systems. Water Research 45, pp. 113–124. DOI

S Husband, R Williams and J B Boxall (2010)
Risk managed trunk main operation. Water Distribution System Analysis 2010, Tucson, Arizona, USA, 12–15 September.

R Sharpe, C J Smith, C A Biggs 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.

P Dienes, R Sekar, S Husband, J B Boxall, A M Osborn and C A Biggs (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

S Husband, J Whitehead and J B Boxall (2010)
The role of trunk mains in discolouration. Journal of Water Management, ICE. DOI

S Husband and J B Boxall (2010)
Field studies of discolouration in water distribution systems: model verification and practical implications. Journal of Environmental Engineering 136 (1): pp. 86–94. DOI

A Seth, S Husband and J B Boxall (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.

S Husband, J Whitehead and J B Boxall (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.

S Husband, J B Boxall and A J Saul (2008)
Laboratory studies investigating the processes leading to discolouration in water distribution networks. Water Research 42 (16): pp. 4309–4318.

P S Husband 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.

J H G Vreeburg, and J B Boxall (2007)
Discolouration in potable water distribution systems: a review. Water Research 41, pp. 519–529.

S Husband and J B Boxall (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.

J B Boxall and R A Prince (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.

S Husband and J B Boxall (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.

J B Boxall and N Dewis (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.

J B Boxall and A J Saul (2005)
Modelling discolouration in potable water distribution systems. Journal Environmental Engineering ASCE, vol. 131, no. 5, pp. 716–725.

J B Boxall, A J Saul and P J Skipworth (2004)
Modelling for hydraulic capacity. Journal of the American Water Works Association, vol. 96, no. 4, pp. 161–169.

J B Boxall, P J Skipworth and A J Saul (2003)
Aggressive flushing for discolouration event mitigation in water distribution networks. Water Science and Technology – Water Supply, vol. 3, part 1 of 2 pp. 179– 186.

J B Boxall, D M Unwin, P S Husband, A J Saul, N Dewis and J D Gunstead (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.

J B Boxall, A J Saul, J D, Gunstead and N Dewis (2003)
Regeneration of discolouration in distribution systems. Proceedings of ASCE, EWRI, World Water and Environmental Resources Conference, 23–26 June 2003, Philadelphia, USA.

A Seth, R T Bachmann, J B Boxall, A J Saul and R Edyvean (2003)
Characterisation of materials causing discolouration in potable water systems. Water Science and Technology, vol. 49, no. 2, pp. 27–32.

J B Boxall, P J Skipworth and A J Saul (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.