Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | XXXX 20XX | 17 In Focus W ith increasing pressures from a growing population, climate change and environmental concerns, water companies are embrac- ing innovation and new technologies in a bid to future-proof their networks and ensure the quality of drinking water and wastewater. Water quality management is fraught with complex processes that require care- ful control throughout the supply system. In recent years, various high-pro le water quality incidents in the UK and US have underlined the need to manage water quality risks through strategic planning and critical investment. Engineering consultant Atkins is sup- porting a number of its clients in undertak- ing signi cant changes to their drinking water supply systems. "We specialise in water quality and ensure that it's 'front and centre' when making changes to water sup- plies, as new or alternative sources destined for drinking water production can contain contaminants from agricultural, municipal or industrial discharges," explains Hugh Thomas, chief engineer, Atkins. A comprehensive approach to water safety planning – based on the hazard analysis and critical control points (HAC- CP) technique – is crucial and establishes control points and measures throughout the supply system. "Undertaking a risk-based approach is essential as the rst part of a water safety plan," adds Thomas. "Water quality data for new sources may not be available, therefore experience and judgement is needed together with modelling and other predictive methods." According to Thomas, Atkins' experi- ence in water treatment and process safe- ty helps clients establish the best value balance of cost and risk. The company is also driving innovation to support clients' water quality strategies, including the use of digital tools to optimise performance and e‹ ciency, water quality modelling to predict future conditions, and water chemistry analytical tools to understand the risks associated with new, changing and blending diŒ erent sources. Real-world solutions Severn Trent's Birmingham Resilience Project is a high-pro le example of a major source water change. Atkins has been working closely with the company to manage water quality during this periodic change of source water to over one million customers. "We recognised the value of existing water safety plans in managing water quality risks at each key stage – source water, treatment and dis- tribution – and developed a Water Quality Management Plan as a live document to identify and mitigate risks throughout the programme," says Thomas. During the project, signi cant risks have included emerging pesticides, nitrate, customer acceptability of hard water and corrosion by-products from the distribution network. Control measures have been identi ed to manage each of these risks, with an updated water safety plan for the alternative supply.• Atkins has also worked with Wessex Water as part of a major investment into its water supply, providing increased resilience to customers. As part of the investment, improved monitoring and automated control of new trunk mains between Dorset and Wiltshire has yielded energy savings, as well as facilitating "conditioning". "Conditioning is a technique devel- oped at She‹ eld University that manages the risk of discoloured water by controlled increases in – ow and shear stress at the pipe wall. It could not be performed with- out accurate real-time – ow and turbidity data," explains Thomas. The development of the water supply grid allows water to be moved from areas with surplus water to other areas which are de cient. This improves – ows in some rivers and protects their ecology, as well as improving resilience and securing a reliable, constant supply of water. As part of the project, the Optimiser – a closed-loop control system – has been implemented to allow Wessex Water to respond more eŒ ectively to incidents and ensure supplies can be maintained in the event of water treatment plant failures. www.wwtonline.co.uk | WWT | DECEMBER 2019 | 17 Refi ning water quality management As part of our Utility of the Future campaign, Nadine Buddoo looks at why maintaining water quality is a fundamental challenge for utilities as they seek to achieve ambitious regulatory objectives and meet consumer confi dence. Wessex Water Cromhall water recycling centre.