Evaluating the Effectiveness of Electrochemical Disinfection of Hot Water System

Session 3, Paper 3, CIBSE ASHRAE Technical Symposium. Dublin, Ireland, 3-4 April 2014

Standard methods to prevent the growth of Legionella and Pseudomonas in the hot water systems of non-domestic buildings include pasteurisation and chlorination. Despite their effectiveness, they often fail to penetrate biofilm and they have some drawbacks. The generation of toxic by-products is the main disadvantage of chlorination, whilst temperature control is associated with high running costs, considerable CO2 emissions and increased risk of scalding. Research has been undertaken at Brunel University to evaluate an alternative approach involving continuous electrochemical disinfection. Long-term testing of the method within the hot water system of a new health-care building is being carried out. Monthly monitoring showed a decrease in the density of Pseudomonas and the total number of microorganism since the installation of the electrolytic device.