The issue of effective legionella bacterium treatment is currently the focus of a consultation launched by the Health and Safety Executive (HSE) at the beginning of June on the control of legionella bacteria in water systems – and an innovative UV technology looks set to play an increasingly role in its treatment.

The consultation, which runs until 23^rd August, has set out proposals from HSE to publish an updated Approved Code of Practice on Legionnaire’s disease and once again emphasises that the disease is potentially fatal and everyone is susceptible to the infection. This month a hospital in Australia has cancelled all admissions in response to a legionnaires’ outbreak that has killed one person and left another in intensive care - the bacteria has been found in the hot water system at Brisbane Hospital. 

The disease was first identified at a reunion of the American Legion in Philadelphia in 1976 when 221 fell ill with pneumonia and 34 died from a hitherto unidentified bacterium which was traced to the hotel’s air conditioning system. The innovative NeoTech UV technology from Bluewater Bio which delivers significantly enhanced operational performance, together with major cost benefits, now looks set to bring a step-change in legionella treatment compared with existing technologies.

The consultation comes at the time of year when an increase in temperature is often associated with outbreaks of the illness – in the future more variations as a result of climate change could see a greater incidence in the disease.

The organism occurs through inhaling droplets of water vapour infected with the bacterium, which thrives at 20-45 C while surviving in cooler waters. While other techniques are better suited for dealing with residuals in a water system such as sludge and scale, UV light kills pathogens that are directly exposed to it, making it particularly suitable in warm water environments like industrial cooling towers, swimming pools and spas, air conditioning systems, hot water systems and hospitals.

An increasing level of interest is now being shown in the NeoTech UV technology which offers 5-10 times the disinfection performance of a conventional unit in terms of its size and energy use, needing 2-10% of the energy used while lowering lamp costs by 50-90%.

Some 300 NeoTech units are already in use in industrial and municipal facilities across the USA which sees between 8,000-18,000 cases of the illness per year – and where NeoTech is now leading the way in making UV a universal application of choice.

The higher UV reflection makes it harder for the Legionella pneumophila organism to avoid treatment - due to NeoTech’s unique chamber coating which reflects over 99% of UV light compared with less than 30% in conventional devices. A vast improvement compared to conventional stainless steel, the exponential increase in UV enables a much higher UV dose by a factor of 10 to 50 times compared to conventional UV systems with polished stainless steel reflectors. For users who must comply with the HSE guidance, the technology also provides the key benefit of a system which requires little maintenance, typically once per year, which is fully monitored to ensure the correct dose of UV.

Another key benefit is the smaller footprint and compact size of the unit compared with existing technologies - NeoTech is ultra-compact in design and requires little space. 

The technology now looks set to make increasing inroads in both the UK and European markets. In the EU, over 4,000 cases a year have been noted since 2002, where peak infection months in Europe are between June and September.

In England & Wales, 7,693 cases were identified in 1981-2011, with 925 fatalities, a third coming from travel. Five major outbreaks saw 487 falling ill with 31 fatalities, the two largest being from air conditioning systems, two via industrial coolers and the fifth at a hot tub. The worst outbreak was at Stafford District Hospital in 1985 when 175 people were infected and 28 died due to contamination in the air conditioning’s cooling tower.

Often, the cause is never found, but the European Centre for Disease Prevention and Control’s Surveillance Report for 2011 found that in 201 sites, 77% of outbreaks were from water systems, 7% from pools and 1% from cooling towers.

In the UK, the HSE guidance emphasises the need to periodically clean water systems and ensure that legionella levels are continually minimised. Traditionally, water has been disinfected with chlorine – however, shortcomings in the technology mean other approaches such as ultra violet light treatment are being incorporated into systems where residence time is dealt with by minimising the potential for pathogen reoccurrence. The HSE guidance also requires risk assessment to specify the particular means of controlling the risk from exposure to legionella bacteria if prevention is not practicable.

Legionella is just one of many pathogens increasingly prevalent in water systems, ranging from cryptosporidium to giardella and antibiotic resistant bacteria, all of which are thriving as air and water temperatures rise. The need to ensure water purity as it enters drinking water systems, circulates through the built environment and when it is discharged as treated effluent means UV looks set to play an increasingly key role in the holistic management of pathogens across the water cycle.

As part of the ACOP, the HSE are now planning to produce three-part technical guidance for evaporative cooling systems, hot and cold water systems and other risk systems. Following on from the consultation, HSE will prepare a final draft for approval by the HSE Board – the ACOP is due for publication by December 2013.

Click here to access the HSE consultation CD258 – Consultation on Legionnaires' disease: The control of legionella bacteria in water systems

Click here for more information on the NeoTech UV technology