WET News

Project sPecs • Replace existing blowers Dorking STW with new state-of-the-art technology • Secure significant energy savings • Reduce maintenance requirements techKnow • The Sanitaire TurboMAX turbo blower is direct-driven and utilises air bearings that are completely contactless • The blowers are equipped with best-in-class permanent magnet synchronous motors, offering 95% efficiency • The blowers' air bearings are mechanical and self-controlled in operation, so no complex control systems or battery back-ups are required the VerDIct "As an energy intensive industry, we are constantly on the lookout for new ways to improve our operations and reduce costs. Working with Xylem for the installation of the replacement blowers, has enabled us to achieve what we set out to do and restored our confidence in the site's treatment process" Jack Whitby, Thames Water Inefficiencies blown away at turbo speed • With ageing technology and equipment causing ongoing maintenance issues at a key site, Thames Water new state-of-the-art kit was needed. I n wastewater applications such as sewage treatment works (STW), aeration sys- tems can typically account for between 40 and 80% of a plant's total energy consumption. Where equipment is old and technology dated, other factors such as downtime and ongoing maintenance issues are a fur- ther concern. With this in mind, Thames Water worked with Xylem to replace existing blowers at one of its key sites with new state-of- the-art technology. Dorking STW is a plant in Dorking, Surrey, serving a popu- lation equivalent (PE) of approx- imately 11,500 people. The existing equipment installed on site was highly unreliable and inefficient utilis- ing a conventional activated sludge process with fine bubble diffused aeration fed by three 55kW bi-lobe positive displace- ment blowers. For Thames Water, the goal was simple – to replace the existing system with modern technology. As a result, the business aimed to secure significant energy savings and reduced maintenance requirements, which would in turn provide the operating team with confidence in the system's ability to deliver the biological secondary treat- ment process. The solution from Xylem was to replace the existing blowers with new Sanitaire TurboMAX turbo blowers. Offering improved compression effi- ciency over a traditional positive displacement blower, the Tur- boMAX is also direct-driven and utilises air bearings that are completely contactless, result- ing in zero mechanical losses. Furthermore, the blowers are equipped with best-in-class per- manent magnet synchronous motors, offering 95% efficiency. With no gears or belts, the blow- ers are driven direct from the motor, resulting in low mainte- nance requirements. The system is also incredibly easy to main- tain, thanks to the completely oil-free blowers, and air bear- ings that are entirely mechani- cal and self-controlled in opera- tion, so there are no complex control systems or battery back- ups required – unlike other turbo blowers that may require this. In addition, the blowers fea- ture integral variable frequency drives and integrated control panels which offer simple plug- and-play operation to help sim- plify the installation, alongside increased control on a day-to- day basis. Michael Hancock, applica- tions engineer at Xylem, said: "The Sanitaire range of blowers is extensive, which means we were ideally placed to offer the perfect equipment to meet Thames Water's requirements. Thanks to an optimised motor size and the best possible effi- ciency ratings, the blowers have clearly demonstrated their worth and have proved to offer an excellent return on capital expenditure for Thames Water too." In fact, the new installation has resulted in a 23kW energy saving per blower – when compared to the old system – which equates to an annual sav- ing of approximately £37,600 together with reduced mainte- nance costs and decreased sound levels. Jack Whitby, project integra- tor at Thames Water, said: "As an energy intensive industry, we are constantly on the lookout for new ways to improve our opera- tions and reduce costs. Working with Xylem for the installation of the replacement blowers, has enabled us to achieve what we set out to do and restored our confidence in the site's treat- ment process." AUGUST 2017 wet news 7 The sewage treatment plant serves around 11,500 people in the Dorking area ONSITE ASSeT MAnAGeMenT neeD to Know 1 Dorking STW serves a population equivalent of around 11,500 people 2 Aeration systems can typically account for between 40 and 80% of a plant's total energy consumption 3 The new installation has resulted in a 23kW energy saving per blower 4 An annual saving of about £37,600 has been achieved together with reduced maintenance costs and decreased sound levels The new installation has resulted in a 23kW energy saving per blower With no gears or belts, the blowers are driven direct from the motor

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