Controlling Legionella pneumophila in Water Systems at Reduced Hot Water Temperatures with Copper and Silver Ionization
ELAINE CLOUTMAN-GREEN, VERA L BARBOSA, DIEGO JIMENEZ, DANIEL WONG, HELEN DUNN, BRIAN NEEDHAM, LENA CIRIC, JOHN C HARTLEYELSEVIER, AMERICAN JOURNAL OF INFECTION CONTROL, JANUARY 2019 IntroductionThis study was conducted at a newly built healthcare facility in the United Kingdom. There, the Department of Health recommends maintaining hot water temperatures above 131o F (55o C) to control Legionella in water supply systems. The goal of this study was to determine the efficacy of copper-silver ionization to control Legionella at deliberately reduced hot water temperatures in a newly-constructed healthcare facility. ResultsThe results of routine monthly sampling (1,598 total) from 2011 to 2017 demonstrated effective (100%) Legionella control with an average hot water temperature of 107.6°F (42°C). The facility experienced a 33% reduction in energy usage and a 24% reduction in carbon emissions. ConclusionThis study showed that the spread of Legionella could be controlled at reduced hot water temperatures, but interventions were required to maintain adequate levels of copper and silver. Full report
Use of Copper-Silver Ionization for the Control of Legionella in Alkaline Environments at Healthcare Facilities
DAVID M. DZIEWULSKI, ERIN INGLES, NECULAI CODRU, JOHN STREPELIS, DIANNA SCHOONMAKER-BOPPELSEVIER, AMERICAN JOURNAL OF INFECTION CONTROL, JULY 2015 IntroductionThis study examined two healthcare facilities using copper-silver ionization to control Legionella in alkaline water conditions. One facility was an acute care facility with a pH range of 8.7-9.9. The other was a long-term care facility with a pH range of 8.9-9.7. Both had previously used disinfection methods without success, including superheat-and-flush, hyperchlorination, and chlorine dioxide. ResultsAcute care facilityThe acute care facility reported six cases of Legionnaires’ disease before installing the copper-silver ionization system. After installation, the Legionella positivity rate (percentage of test sites within the building positive for Legionella) was reduced to 0%. Long-term care facilityThe long-term care facility reported two Legionnaires’ cases before installing the copper-silver ionization system. During the early stages of treatment, instabilities in both copper and silver concentrations occurred and were attributed to electrode scaling. This was followed by an increase in Legionella. Once ion concentrations were stabilized, the Legionella positivity rate was reduced to 0%. ConclusionCopper-silver ionization successfully controlled Legionella under alkaline water conditions but required frequent monitoring and system adjustments to maintain efficacy. The study found that alkaline water conditions reduce copper ion concentrations, however, the facilities were able to achieve non-detect as silver ions were less impacted and appeared to be the main ion controlling Legionella. Full study
