WATER HYGIENE AND SAFETY
‘Outstanding disinfection without toxic chemicals’
Hagbard Eriksen, managing director at Danish Clean Water (DCW), says he is ‘committed to developing more environmentally-friendly ways of controlling waterborne bacteria’. Here he explores the threat presented by Legionella and Pseudomonas in hospital water systems, and describes ‘a cost-effective disinfection system’ that DCW says ‘achieves outstanding, sustained results without the use of toxic chemicals’.
Whether inhaled in the tiny aerosolised drops of water from a rarely used hosepipe or a badly maintained hot tub, or even an air-handling system that vents onto the street – as occurred during one of the UK’s worst outbreaks in Barrow-in- Furness in Cumbria in 2002 – Legionella ‘horror stories’ still appear in the press with unsettling regularity. One of the biggest stories to be reported recently dealt with the £300,000 fine imposed on Royal United Hospitals Bath NHS Foundation Trust for failing to control the risk to patients from exposure to Legionella bacteria in its water system following the death of a cancer patient. The incident highlights the huge responsibility that hospitals have when it comes to maintaining a safe water system, and the moral, legal, and financial implications if they fail.
In this article, I will take a broad look at the ways that hospitals and the government address the issue of Legionella, and explore what I believe to be the most effective system for controlling Legionella in water systems – a system that steps away from traditional treatments, and takes a holistic approach to the business in hand. It provides a solution that helps hospitals to comply with the guidelines of HTM 04-01 without using or producing toxic chemicals that, ironically, could do as much damage to people and the planet as the bacteria they were brought in to destroy – all at a fraction of the price that hospitals are used to paying.
Legionella pneumophila and Pseudomonas aeruginosa The bacterium Legionella pneumophila has two forms of infection – pneumonic and non-pneumonic. Pontiac fever, the non-pneumonic form, usually lasts for a couple of days, and is not serious, often going undiagnosed. However, in its pneumonic form – Legionnaires’ disease – symptoms are more severe, and outcomes far less positive. It spreads through water particles in the air, for example when showering in water
ORP Heating supply HEAT Return
EXCHANGER TANK
Neuthox injection
Circulation pump Hot water system
DCW unit F
Cold water supply
Brine tank Salt solution
Neuthox tank Disinfectant fluid
Figure 1: A diagram showing how a DCW system will typically be installed.
that holds the bacteria. Its optimum temperature for growth is 37˚C, or ‘body core temperature’, which is why it makes such an efficient attack on the human body once it gets into our system.
Each year around 300 to 500 cases of Legionnaires’ disease are reported in Britain, with many contracted abroad. For a healthy person, the flu-like symptoms are treated with antibiotics, and after a few weeks everything is usually back to normal, but for the hospital population, the outcome can be very different. Older people, or those with an underlying health problem – particularly if they are immunosuppressed or have chronic respiratory or renal illnesses, have much greater morbidity and mortality rates, with around one in 10 cases proving fatal. Legionella is just one ingredient in the bacterial ‘soup’ that may be lurking in water systems. Pseudomonas aeruginosa is another pathogen that flourishes in these conditions, causing rashes, chest infections, and even possibly septicaemia. Like Legionella, it doesn’t affect healthy people as badly as the immunosuppressed, but is a worry for the medical profession, as hospital patients are vulnerable, and the bacteria is resistant to many different types of drugs, making it difficult to treat.
Made up of various microorganisms, biofilm is ‘a microbial community’ – and an ideal breeding ground for bacteria.
The role of biofilm Legionella and Pseudomonas are common in natural water sources such as rivers and lakes, and may be found in
February 2019 Health Estate Journal 43
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