Water & Wastewater Treatment

22 | APRIL 2014 | WWT | www.wwtonline.co.uk Pump Into Action with SLD Turn to the rental experts 0870 392 9649 www.sldpumpspower.co.uk info@sldpumpspower.co.uk Pump Into Action with SLD • Diesel Pumps • Electric Submersible Pumps • Hydraulic Pumps • Specialist Generators • Heaters / Boilers www.wwtonline.co.uk | WWT | APRIL 2014 | 23 Lontra's Blade Com- pressor installed at Severn Trent's Worcester wastewater treatment works T he underlying principle behind the technology at the heart of wastewater treatment (WwT) has remained unchanged for nearly a cen- tury, but Severn Trent Water (STW) spot- ted the potential of Lontra's new Blade Compressor, a viable alternative to the traditional blowers and compressors that are used to pump air into wastewater to feed the micro-organisms that clean it. The utility decided to undertake a site trial and performed exhaustive tests that have proven, beyond doubt, that the Blade Compressor is a game-changer for water and wastewater utility businesses globally, delivering a step-change reduc- tion in electricity usage, maintenance costs and CO2 emissions. The activated sludge process, invented in Manchester in 1914 and used at full-scale for the first time in the world at STW's Worcester treatment works in 1916, remains at the heart of the WwT process worldwide to this day. Severn Trent's wastewater treatment works operate around the clock, handling more than 2.5Bn litres of wastewater every day. The activated sludge process relies on the injection of air into tanks contain- ing wastewater to encourage the large scale growth of natural bacteria that break down the impurities it contains. Depending on the type of wastewater be- ing treated, the resulting liquid from this aeration process can usually be returned to the environment, although in some cases further treatment processes may be required. Severn Trent site trial Innovative blower set to slash energy costs Industry estimates suggest that 1% of all of the UK's electricity is consumed by compressors used for the aeration of wastewater at the nation's utility businesses. Given the cost of electricity consumption – and the associated CO2 emissions – STW has been investigating alternative solutions with lower energy costs, improved operational efficiency and reduced environmental impact. The first step for Severn Trent was to work out how just how important the Lontra technology could be to its business and so the company worked for over a year with Lontra on a study evaluating its entire wastewater estate. The knowledge gained from this study allowed Lontra to take a fresh look at the challenges faced in wastewater treatment and to design a solution specifically optimised to the needs of the industry as whole. The results were so encouraging that Severn Trent agreed to part-fund a full-scale trial alongside the Carbon Trust, the organisation that assists businesses, governments and the public sector to accelerate the move to a sustainable low carbon economy. Where better to validate the Lontra Blade Compressor's performance and reliability against existing machines, in a real-time production environment, than back at Worcester wastewater treatment works, where the world's first large-scale wastewater aeration system, powered by conventional compressors, burst into life almost a Project focus ● Potential energy savings of £1.8M per year ● Reduction in CO 2 emissions of 3% ● Reduced maintenance costs Steve LindSey ChIef exeCuTIve And CO-fOundeR LOnTRA ● traditional compres- sors or 'blowers', used to inject air into wastewater, use large quantities of electricity ● Severn trent spends around £9M a year on electricity to run 300 blow- ers at its treatment works, more than half of the entire cost of Wwt • Drivers century ago? Mark Jones, Severn Trent's waste- water research & development man- ager said, "To make the test as repre- sentative as possible, only the existing blower and motor were replaced, with the Lontra Blade Compressor fitted into an existing enclosure and running from an existing variable speed drive. This ensured that only the gains in the blower technology - and not those from optimising the supporting systems and drives - were captured." In addition, the conventional blower that the Blade Compressor was to be compared against had been re- placed just six months before the trial commenced, ensuring that the Lontra solution would not have an unfair advantage by being tested against an ageing or worn alternative.

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