SUSTAINABLE ENVIRONMENT
maintenance and control routines. Under the approved code of practice for Legionella management (ACoP L8 and Technical Guidance HSG274) , duty holders of buildings with large-scale water systems are required to carry out regular Legionella risk assessments. These assessments must be carried out by a person with the necessary training, knowledge and expertise in Legionella management. If no such person exists, a third party will need to be brought in to conduct the assessment.
What can be done to control Legionella bacteria?
Controlling levels of Legionella and other potentially dangerous pathogens, including Pseudomonas aeruginosa in buildings, such as hospitals, universities and schools, is an expensive undertaking. ESG estimates that every year, UK building owners and facilities managers are currently spending around £140 million on water treatments. These treatments are not always effective, are often energy intensive and require expensive maintenance. Evidence suggests that temperature control and chlorination continue to be the most common disinfection methods, and their inefficacy in eradicating and controlling Legionella is well documented.
It is extremely difficult, if not impossible, to maintain water temperatures of 55°C
in all the parts of an extensive pipework system. Attempting to keep large-scale hot water systems heated in this way requires a significant amount of energy, and can potentially mean a large bill for building owners. Disadvantages associated with conventional chlorination include the transport and storage of dangerous chemicals and the costly repairs associated with the failure of pipes due to corrosion.
A fresh approach to water treatment
As facilities managers realise the benefits of energy efficiency, more research in alternative treatment technology is taking place in an effort to make Legionella control more affordable for public sector buildings. One such technology is Electrolytic Disinfection (ED), which provides a number of advantages over traditional water treatment methods. Disinfectants are generated on site through the process of ED, eliminating the handling, storage and transport of hazardous chemicals. In ED, current is applied to electrodes immersed directly into the contaminated water. Deactivation of bacteria is achieved by the disinfectants formed from the electrolysis of water and the species dissolved within it. This method of disinfection also allows for water temperatures to be reduced from 60°C to 45°C in all premises other than in healthcare scenarios, with meticulous control, as suggested in HSE guidelines (ACoP L8, v4). ESG estimates that UK non-domestic buildings could
make hot water related energy savings of up to 20 per cent with ED systems. What’s more, by using a water treatment system which uses no consumables and requires little maintenance, UK building owners could collectively save millions of pounds in other related costs, as well as decrease their carbon footprint. Further reductions in CO2 emissions can also be achieved by heating the water with green technologies that become more efficient if one demands water at a lower temperature. Brunel University London researchers evaluated the use of ED in actual water systems in a project funded by ESG. In particular, PhD candidate Giovanna Cossali, supervised by a team led by Professor Tassos Karayiannis and co-supervisors Dr Edwin Routledge and Martin Ratcliffe as well as Jon Fielder of ESG, assessed the performance of ED in the hot water system of the Chiltern Multiple Sclerosis Centre in Wendover. This two-year trial is the first long-term monitoring of an electrolytic device in a building’s hot water system. During the trial, the Brunel-ESG team observed bacterial levels decrease by up to 99 per cent. This was the first time a device of this kind had been proven effective. In turn, this led to Knowledge Transfer Partnership funding being awarded by the UK Government’s Innovate UK scheme to ESG and Brunel University London for further development of the device, which is known as Protex!. It is evident from the trial at Chiltern that these alternative treatment systems, such as Protex!, have the potential to play an important role in public sector building safety. Electrolytic devices could help facilities managers make significant energy savings, reduce their carbon footprint and most importantly keep vulnerable people safe from Legionella infection. Mick Pratt, commercial director, Built Environment Services, ESG Additional technical input provided by Giovanna Cossali, PhD candidate, Brunel University
• •
For more information visit
www.esg.co.uk
PSS MAGAZINE • NOVEMBER/DECEMBER 2015
23
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40