WATER HYGIENE AND SAFETY
Dispelling some myths around copper silver
Joris Post, director at Dutch-headquartered specialist in copper silver ionisation, ATECA, says he is passionate about the safety of water systems in hospitals and other healthcare facilities. In this article he outlines some of the key benefits of using the technology to keep such water systems free from Legionella and other potentially harmful waterborne microorganisms. As he puts it, ‘every hospital, medical centre, and nursing home, needs to be able to guarantee 100% safe water, and copper silver ionisation is the best way to get that guarantee’.
In a country dominated by water, it is anything but unlikely to have a passion for clean and healthy water. Water is, after all, a prerequisite, but what if this drinking water is contaminated with Legionella, E. coli, or Pseudomonas? In the healthcare sector, particularly this forms a serious threat; thus various scientists and technicians have attempted to come up with ways to prevent waterborne pathogens such as Legionella in water installations.
Chlorine dioxide
One of the methods used to control Legionella bacteria is via dosing with chlorine dioxide, a neutral chlorine compound. As a gas in solution, it is made from a combination of sodium chlorate and an acid. Chlorine dioxide is less corrosive than chlorine, and more effective at a high pH value. As a disinfection method, chlorine dioxide penetrates the biofilm more efficiently than chlorine – therefore it is sometimes used as a biocide in industrial water treatment applications such as cooling towers, water processing facilities, and food processing facilities. However, chlorine dioxide also has serious disadvantages.
One of the main downsides of chlorine
dioxide is the difficulty of maintaining the most suitable residual concentration. In a drinking water installation for an eight- storey building, for instance, the chances are high that the residual concentration is compromised by the time that the treated water reaches the third storey. In large hospitals and nursing homes, this is an unacceptable risk.
An increasing number of studies indicate that treatment with chlorine dioxide alone is not sufficient to prevent growth and colonisation of Legionella bacteria – non only as a result of the difficulty in maintaining the optimal residual concentration, but also due to the fact that chlorine dioxide is active for just 48 hours. That is not sufficient to successfully attack the biofilm.
A more expensive option than its seems
Legionella pneumophila is a key target organism for ATECA’s copper silver ionisation system.
30 Health Estate Journal April 2020
In addition, chlorine dioxide is corrosive to pipework. Maintenance to pipes, valves, and pumps, will have to be increased when chlorine dioxide is used, which makes this method more expensive than it may seem at first. However, in the UK chlorine dioxide remains a popular choice when it comes to the prevention of Legionella and Pseudomonas, even though copper silver ionisation is far more effective. The reason for this is quite simple; 20 years ago, copper silver ionisation had its faults, mainly because it was hard to keep the right balance between copper and silver in the water. For copper the right amount needs to be between 200 and 400 ppb, and for silver between 20 and 40 ppb. Biofilm attaches itself to the internal surfaces of pipes, forming a breeding ground for bacteria. Depending on the intensity of the contamination of Legionella, the number of ppb needs to be either higher or lower. Once the biofilm has been eroded, the ppb can be lowered to a maintenance dose. This is a process that needs to be tuned precisely, with very accurate control.
Increasing focus is now being put on handwashing and all aspects of hospital hygiene given growing antibiotic resistance, the prevalence of healthcare- acquired infections, and, most recently, spread of the coronavirus.
Twenty years ago, alloys were used. Electrodes containing copper and silver were fused together, and there was no option to work on a proportional dosing basis, or any control on how much copper and silver was released into the water. In certain cases, the result of this was that water left a green discolouration, and that the contamination remained.
Overcoming the copper ban Copper silver ionisation quickly gained an unfavourable reputation, fed by a powerful lobby for the use of several chemical products like chlorine dioxide. The fact that there was a temporary ban on the use of copper by that time, didn’t help either. The European Chemicals Agency (ECHA) had introduced the Biocidal Product Regulation, which meant businesses had to formally apply for the use of copper in drinking water. In 2014, the UK Competent Authority for biocidal
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