Water & Wastewater Treatment Magazine
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Comment A t Northumbrian Water Group we are investing up to £6M in developing an industry-leading "source to tap" approach to further improve drinking water quality across our network and drive innovation across the UK. The investment follows a two-year period in which reports of water discolouration dropped 35% to a record low in 2015 as new processes were put in place. The improvements have been driven by research that has given a new insight into the causes of discolouration in water networks. We set ourselves, and exceeded, targets that were better than those required by regulators, to ensure the best possible service is delivered to customers. With other industry partners we took part in groundbreaking research, with a world- leading PODDS (Prediction of Discolouration in Drinking Water Systems) team from Sheffield University. This lead to the creation of a new policy, implementation of new, non-traditional, procedures and a greater understanding of the potential causes of discoloured water in the system. The research showed that the root causes of discolouration are predominantly build-ups of iron and manganese oxides interacting with the biofilms on the inside of the water pipes. The upland sources of the raw water found in the North East are a major contributor to this. Understanding this has allowed our team to introduce new processes to tackle the issue more successfully than ever before. We are amongst the first to act upon the process that has been developed on such a scale, creating improved service, future customer savings, and a potential 90% capital cost reduction against the traditional mains water cleaning process. A 31-point strategy has been developed, improving the full breadth of the system, from the water's source to the customers' taps, including an innovative Pipeline Management (PLM) approach incorporating new flushing methods. Flushing distribution mains (<8") using a modelled unidirectional flushing (UDF) approach, ensures the generation of sufficient changes in pipe wall energy to strip off as much of the material causing discolouration as possible. This is more cost effective as overall flushing frequency can be reduced, whilst also driving a prolonged reduction in contacts from customers over time. We utilised Aquadapt network energy optimiser sožware to automate PLM wherever possible, transforming this system into a true automated network control system managing both quantity and quality of the water supplied to customers. This approach was industry leading and allowed us to incorporate water quality maintenance into control room operations without compromising the supply/demand balance or energy optimisation. More than a quarter, 923km, of our major mains water system in the North East has already been identified to benefit from PLM in the period to 2020, with £6M to be spent on enabling the introduction of automated PLM to 350km of water main by 2018. This will reduce the £170 per metre cleaning cost associated with traditional methods to £17 per metre. The research has delivered a new understanding of the root causes of discolouration in water networks that will revolutionise industry procedures. We can now build on the results of the research, field tests and our own work to go on and make our customers' experience even better, whilst also significantly reducing costs in the long-term. We are on target to beat our 2020 discolouration target by 20%, two years early, delivering best ever performance in a way that is both sustainable and cost-effective. This is fantastic for our customers and also for our team, who are to be applauded for being ahead of the game in adopting these innovations. Through the introduction of these systems and procedures, we have already reduced reports from customers about water discolouration to a record low and we have been able to achieve all internal and external targets. By adopting a complete source to tap policy, with structured forward planning, we believe we can not only adapt this way of working to boost other key business areas, such as interruptions to supply and leakage, but also provide a template for other companies to make similar improvements to their systems. Taking quality water from source to tap Northumbrian Water's achievements on drinking water quality are the result of a holistic strategy that built on sound research Michael Baker Asset spoNsor MANAger NorthuMbriAN WAter group 8 | oCtober 2016 | WWt | www.wwtonline.co.uk