Water & Wastewater Treatment Magazine
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Flood intentions At a time when building flood resilience is a national priority, innovative technologies can help keep sewer flooding under control By Robin Hackett www.wwtonline.co.uk | WWT | OCTOBER 2018 | 27 Innovation Zone Innovations to help you...protect against floods T he rise in extreme rain- fall events, in addition to challenges around sewer capacity, leaves the water and sewerage companies with a sizeable task in preventing sewer flooding. Ofwat's 14 common per- formance commitments for PR19 include both reducing the number of internal sewer flooding incidents per year (Goal 7) and protecting against floods (Goal 10), a risk-based resilience metric for wastewa- ter measuring the potential for sewer flooding in a storm. Here, we've picked out a selection of solutions that can help keep things in check. GOAL 10 FLOOD RESILIENCE StormHarvester (StormHarvester) StormHarvester's forecast control system allows optimisation of large drainage networks at a fraction of the cost of large capital infrastructural upgrades. Essentially, it controls water and wastewater levels within drainage networks based on rainfall forecasts by the operation of valves, pump sets and floodgates. The system, which is being trialled by some of the UK's leading water companies, uses machine learning to analyse live and historic short-term radar rainfall forecasts and site information to predict future network performance at specific pumping stations and CSOs within the network. Once predictions of future network performance are made, the system can control pump sets to optimise network performance and reduce flooding and pollution. StormHarvester can reduce CSO spillages as well as energy usage and enables more accurate predictions on likely flooding and pollution incidents while identifying pump failures and network blockages in real time. StormHarvester can also be used with the rainwater tanks used for flood prevention in new commercial, industrial and residential developments. The active attenuation system determines levels in the tanks and, using the forecast control system, can empty as much water as is required to create capacity for heavy rainfall events; at other times, it maximises the amount of water that is retained to allow it to be recycled for various uses such as flushing toilets, washing floors and washing vehicles. SMART Sewer (Environmental Monitoring Solutions Ltd) SMART Sewer is used to detect the development of sewer blockages before they lead to flooding events, using wireless-communication- enabled level monitors, an AI-based analysis engine and a web-hosted dashboard. Based on level data from key points within the wastewater network, a Fuzzy Logic algorithm is used to assess the presence of any developing blockages. The system, which can differentiate between rainfall events and blockage formation, is designed to be low power, low maintenance and low cost and is intended primarily for use in known risk areas of the network. SMART Sewer can also be used for the optimisation of sewer cleaning programmes, and is an example of the growing presence of smart technology in wastewater networks. BDT (Radio Data Net- works Limited) The BDT is a wireless sewer- level alarm device designed for simplicity, reliability, durability and adaptability, eliminating the need for so ware and programming in the field. The technology moves away from the convention of measuring sewer level using ultrasonic level transducer and GSM for communications, which – due to battery constraints – had only been able to provide measurements at 15-minute intervals and upload the data daily. As an ultra-low power dielectric contact probe, the BDT can both measure levels and transmit the data every 2.5 seconds while still offering a 10-year battery life. As such, it can provide warnings over high levels in real-time so that, in addition to offering a sewer blockage alarm system, it can also be used for real-time control projects. The BDT is capable of communicating to local gateways that can convert the high/low level readings into relay contacts for interface to existing telemetry/SCADA. BDT data has been successfully collected via satellites, permitting monitoring even in areas devoid of cellular coverage or power.