Utility Week

UTILITY WEEK | NOVEMBER 2021 | 35 continued overleaf hybrid innovation festival in October 2021 will continue to explore both mainstream and off-piste approaches to CSOs. "We are continually investing in alterna- tive options and technologies, recognising the benefits of being open with our data," MacLean says. Similarly, according to Thames Water's head of environmental engagement, Yvette de Garis, the company serving 15 million customers across London and the Thames Valley is trialing a new generation of sewer- level monitors to reduce pollutions from blockages and is on course for 100% cover- age by 2023. Monitors tracking flow rates in sewers and designed to send alerts when blockages are detected have thus far been installed in Henley, South Oxfordshire, and West Ham and Harlesden in London, with larger trials afoot should they prove successful. Fast facts: Yorkshire Water • 80m. The number of data points provided by current network monitoring. • 96%. CSO monitoring coverage and reporting registered in 2020. It is aiming for 100% by 2023. • £137m. The amount to be invested by 2025 in storm overflow improvements. Use of AI and 'machine learning' Wessex Water's Knight adds that the firm is using innovative technology to reduce the number of alarms and, like Northumbrian, strengthen its early-warning capabilities. "We have carried out an open data trial into AI and machine learning analytics at storm overflow sites in Bath," she says. "The trial utilised diurnal sewage depths from EDMs and upstream rainfall data and, using machine learning algorithms, established 'normal operating parameters' for the sew- age for those conditions. "The system then alarms only when actual depths are outside these parameters – for instance, a downstream blockage or obstruction would cause the actual depth to be higher than the expected upper normal operating parameter, whereas an upstream blockage would be indicated by levels lower than the lower normal operating parameter." If a storm overflow is discharging in rain- fall, when it would be expected to discharge, no alarm will be generated in Wessex's con- trol room. She continues: "Consequently, we have been able to identify blockages before they have caused any premature discharges and Public pressure is increasingly making it untenable to dump untreated raw sewage into waterways

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