A senior member of the Health Protection Agency said the organisation did not support the use of products containing silver stabilised hydrogen peroxide to disinfect hot and cold water systems colonised by legionella or showing high readings for the bacteria.
Dr Susanne Surman-Lee, director of the HPA’s Regional Food, Water and Environmental Microbiology Services in London, told those attending H&V News’ Combating Legionella conference: “We don’t suggest you use silver stabilised hydrogen peroxide particularly in situations where we know we have colonised buildings, which is where we are tending to advise.
“Our experience is that it doesn’t work in those situations. Where you have high levels of legionella you cannot take the risk of using a biocide which is not going to be effective.
“There is no peer-reviewed data which shows situations where you can effectively use hydrogen peroxide. I’m sure there are some, but the research needs to be done and needs to be put into independent peer-reviewed literature so that it can be evaluated and a proper trial comparing it
to traditional biocides can be carried out.”
Rob Wilson from the Meadowhead Consultancy, which specialises in the use of silver stabilised hydrogen peroxide, said the chemical had proved popular with health trusts, councils and social landlords due to its ease of application.
He said a research paper was being prepared by a principal engineer at a hospital he has been working with.
He said: “We do have a hospital in Scotland where the chemical has been dosed on line for the past three years and we have taken a situation where there was very high legionella to a situation where you can barely find a TVC (Total Viable bacteria Count) in the water.
“Slowly we are accumulating a lot of good data on its use. The trend will be that eventually silver will be eliminated from these products and we will be using stabilised hydrogen peroxide.
“The future of disinfection must lie with eco-friendly and safe-to-use products. I perceive hydrogen peroxide as that chemical, but we have to learn how to use it properly.”
Simon French, managing director of Water Hygiene Training and a member of the Heating and Ventilating Contractors’ Association’s
Services and Facilities Group, said: “It is down to the manufacturers’ to provide a product which is fit for use. We need industry to sort this issue out and give guidance to water treatment companies about the circumstances in which it should be used.”
Dr Paul McDermott, specialist inspector at the Health and Safety Executive, said: “This is a relatively new technology so we don’t really have an awful lot of experiential data in terms of its efficacy.
“There are some concerns about its application in certain settings, particularly in some healthcare settings.
“If its efficacy can be demonstrated and it doesn’t have any other adverse effects, then the Health and Safety Executive would not have any oroblem with its use.”