Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | JANUARY 2016 | 19 Project focus Water and energy Sewage heat system warms Scottish college Project focus A n innovative system installed at Galashiels in southern Scotland is using heat from sewage to power the heating in a student campus building. The SHARC heat recovery system intercepts wastewater from a main sewer near the Borders College campus and uses heat pumps to amplify its thermal energy so it can be used to supply the campus with warmth. Opened in December, the ● First UK heat-from-sewage system opens at Scottish college campus ● Installation at Galashiels supplies 95% of building's heating needs ● Green investment backs renewable energy potential ● The installation uses a plate heat exchanger to transfer heat from the wastewater stream to the clean water stream, augmenting the temperature by powering a heat pump ● It will produce 1.9 GwH of thermal energy annually, replacing natural gas and saving 150 tonnes of carbon per year ● Heat from sewage has a high coefficient of performance (COP) for powering the heat pumps because sewage stays at a relatively constant level of 12-20 0 C all year round • Innovations with SHARC to facilitate similar installations across Scotland. Wastewater in sewers typically has a temperature of 12-20 degrees, depending on its location in the network and the extent to which surface water is mixed with the sewage. By running this flow across a plate heat exchanger and then using this latent heat to power a heat pump, the SHARC unit can heat clean water pipes, which are kept entirely separate from the dirty flow, to the level required for a building's hot water system. While some electricity is still used to power the heat pumps, the system has a high coefficient of performance (COP) because of the relatively reliable warmth of the sewage. It is expected to deliver 1.9 GwH of thermal energy a year, displacing natural gas and saving 150 tonnes of carbon. The roots of the project date back 18 months when Borders College was looking to replace its heating system and was keen to investigate low-carbon alternatives to gas. A"er initially expressing interest in a biomass system, the college was introduced by Scottish Water to SHARC, who were already in touch with the utility. The campus was an ideal location for the project because of its size, good insulation and stable future energy needs, while it soon became clear that the proposed new system could offer the college the savings and carbon reductions it was looking for. SHARC - which last summer received £4M in funding from the Green Investment Bank and Equitix to invest in its renewable energy projects – was able to meet the capital costs of installation provides 95% of the heating needs of the campus, which is home to 4,500 students. The project, the first of its kind in the UK, uses technology developed six years ago by SHARC Energy Systems' Canadian parent company, International Waste Water Heat Exchange (IWHES). Scottish Water has been a partner in the project because the installation uses its sewer infrastructure, and is working James BrOCkeTT eDIToR WATeR & WASTeWATeR TReATMeNT Russ Burton, SHARC Energy Systems (le ) and Energy Minister Fergus Ewing (right) in the new energy Centre at Borders College

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