Water & Wastewater Treatment Magazine
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The Talk: opinion substantial benefits. Advances in data capture and analysis and the insights that are revealed, combined with an ability to utilise and integrate technologies, will enable asset optimisation and hence leverage cost efficiencies whilst giving greater assurance on compliance and service. Similarly water companies that can move towards more proactive maintenance approaches and operate performance and condition-based maintenance programmes will transition from paying a cost of asset failure to a lower cost based on optimum asset intervention. Behavioural change will also be required, and should not be underestimated or overlooked, as water companies and their partners embark on these operational and delivery realignments. In terms of asset management and operation the sector is not short of data. The deployment of analytics tools can transform asset data into actionable information for smart decision making; for example the application of tools that allow asset performance data to be combined with external data, such as weather and rainfall information. Such tools enable the identification of SPONSORED BY ABB DAN BANKS, WATER FRAMEWORK MANAGER – DRIVES AND CONTROLS, ABB LIMITED The pressure is on to control leaks The use of variable speed drives to control and reduce water pressure could play a significant role in the fight against leakage, writes Dan Banks L eaks are a perennial problem for water companies. Despite considerable countrywide investment and modernisation, the UK's water distribution networks continue to lose around 3,300 mega litres of water per day. That amounts to 15 to 25 percent of its annual production of potable water every year. Few other industries would or could tolerate such a loss. The public has an image of burst pipes as those roadside events that get mentioned on the traffic news but, being so visible, these are cleared up quickly operating condition trends that facilitate the development of new system operating procedures and interventions to mitigate pollution risk. More sophisticated analysis of asset performance data will enable water companies to get a better understanding of which are their most critical assets, and when intervention is required to keep those assets delivering optimum performance. An early example of how these capital maintenance programmes might look is Yorkshire Water's Workstream 69 (WS9). In collaboration with Yorkshire Water (YW) Black & Veatch has developed a Lean Reliability Centred Maintenance (LRCM) programme covering the water company's process safety critical assets. Central to WS69 is Failure Modes Effects and Criticality Analysis (FMECA), which is being used to produce a condition-based maintenance programme. In collaboration with YW's Operations and Maintenance (O&M) teams failure mode responses have been developed for each asset category. Mobile technology is used to capture live asset survey findings and Piping & Instrumentation Diagram updates, and upload these to a dynamic asset database, and so are not the big problem. Difficult to find and largely unreported, smaller background leaks are the major culprits. A big cause of these is elevated supply pressures, which ožen don't mix well with ageing pipes. While pressure is high, water is forced out into any existing leaks. New leaks can be generated at any points of strain such as joints in the pipework. Leakage can be reduced significantly by a little reduction of pressure - a mere 20 percent reduction in pressure could reduce leakage by up to 50 percent. This is readily achieved using variable speed drives (VSDs). The ability of VSDs to control the speed of motors and thus pumps means that mains pressure can be easily controlled. If the system uses a VSD, flows can be adjusted to ensure that pressure levels are adequate. As modern VSDs are easy to operate and making adjustments is not difficult, settings can be approximately adjusted at installation and then fine-tuned over time. For example, a system with 5 bar in the day could be automatically reduced to 3 bar at night using the inbuilt control. Cutting pressure also means reducing pumping energy costs, while controlling leaks also avoids spending money twice to process and pump extra water. improving data accuracy for the FMECA study. Mobile devices also allow O&M teams to access the condition-based maintenance programme in the field, providing information needed to complete their tasks and instant feedback of asset/ process performance. This system ensures asset condition and performance is under constant review and allows maintenance teams to assess probability of failure and take informed, proactive action. The systems and processes are facilitating evidence-based decision making for operational improvements and risk-based investment planning, and helping to remove unnecessary planned maintenance from O&M programmes, reducing spares holdings and reducing reactive maintenance by 30 percent. Water companies are not a homogenous group and, as we head towards PR19, they are at different points along the journey to make asset management and capital maintenance the viable tools they should be for delivering successful outcomes during the 2020 – 2025 price review period. Some have already begun to embed the necessary practices and data analytics tools; others so far appear to be less quick to adapt to what is likely to become the new normal. It's clear that the water industry needs to improve leakage rates, but as the old saying goes, you cannot control what you cannot measure. This is where metering comes in. Using data from night time flow measurements enables water companies to accurately spot any unexpected continual increases in water consumption, which might suggest a burst or an undetected leak. Traditional mechanical meters do not offer the accuracy needed and cannot cope with the low flows seen at night. By contrast, electromagnetic flowmeters offer improved accuracy over a far superior range of flows. In fact, modern meters could even detect a toilet flushing. With energy costs only going up and environmental concerns rising, highly controllable VSDs and accurate measurement of flow rates is the route to keeping on top of leaks. 12 | JUNE 2018 | WWT | www.wwtonline.co.uk "Difficult-to-find small background leaks are the major culprits, and a big cause of these is el- evated supply pressures, which don't mix well with ageing pipes."