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It is no secret that the germicidal waveband of UV ‘C’ can be used to kill a range of pathogenic micro-organisms by disrupting their DNA chain. But it is only recently that UV disinfection in the form of second generation designs has been able to satisfy even the most sceptical.
From the reduction of Sick Building Syndrome through to the prevention of lethal outbreaks of Legionella, E.coli, MRSA and Tuberculosis to name a few, second generation designs offer peace-of-mind. The technological advances ensure UV is exactly what it purports to be – a low maintenance, cost-effective and reliable means to protect employees and the general public from harmful contaminants in either a building’s water or air supply.
Integral to the acceptance of the technology with a number of industries using UV as an effective barrier against everyday bugs in the water, is the fully patented cleaning mechanism referred to as either a Tioxispring or Tioxisleeve, depending on the type of UV disinfection unit.
In order for UV ‘C’ light to kill the micro-organisms present, the quartz sleeves encasing the lamps have to remain free from fouling, otherwise the light cannot penetrate through the sleeve to kill the bugs.
Unfortunately, the majority of conventional UV units use a simple cleaning mechanism in the form of a sleeve that sweeps back and forwards. As a result, debris is smeared across the length of the tube, creating a shielding effect of the UV ‘C’ light.
This is a huge shame given the ability of UV to provide the ultimate barrier against disease, especially since UV is much more effective at killing certain bugs when compared to chemical disinfection or filtration.
This is exactly why the new generation of UV disinfection units, whether it is for disinfecting air or water, are fitted with unique integral cleaning systems that provide continuous and efficient results. This maintains the UV lamps in optimum functionality, requiring minimal maintenance with only the annual need for replacement. In the case of the water disinfectors, the unique Tioxispring cleaning mechanism provides the new disinfectors with distinct advantages over other UV systems, as it allows for the unit to be much more effective even in hard water conditions, which have traditionally caused problems for UV technologies.
The Tioxispring’s unique catalytic oxidation process (shown in figure 1) uses cleaning heads that revolve around the lamps and react with fouling materials to keep the tubes clean without the need to use additional chemicals.
Of particular interest to engineers involved in specifying products to disinfect either a company’s water or air supply, is the reduction in the amount of energy that new UV units use in comparison to traditional ones. The development is simple and effective – low pressure amalgam lamps that require less power with a longer life-span are used instead of traditional medium pressure lamps. Coupled with a highly turbulent flow and efficient lamp cleaning mechanism, the new designs require significantly less power to operate.
In addition, it has also been discovered that the cool operation of the lower pressure lamps ensures that they do not suffer from rapid fouling, unlike medium pressure alternatives. The result is improved energy efficiency and a guaranteed kill rate.
As with the introduction of any technology, the environment into which it is being used has to be carefully considered. It is simply not a case of one size fits all – the type and nature of micro-organisms have to be taken into account, as well as an audit of the existing technologies the company is using.
New style UV units used to disinfect water are available in a variety of sizes depending on the nature of the body of water to be disinfected. Typical applications include disinfecting water supply for swimming pools, as well as water used in food production and pharmaceutical manufacturing processes. However, with increasingly stringent health and safety regulations, companies are using UV as a means to disinfect a variety of water sources.
Take for example Legionella - as a form of disinfection, UV can be used to combat outbreaks in a variety of locations. Thereby, disinfection units can be fitted onto existing water tanks alongside a small pump that continuously re-circulates the water. This ensures that any micro-organisms (including Legionella) are exposed to UV at appropriate wavelengths to disrupt their DNA, rendering them harmless. Here, the UV units are fitted with the Tioixispring cleaning mechanism which is activated by the water pressure created by the pump (see figure 2).
UV is such an effective form of disinfection that it can even be used to disinfect water used in both indoor and outdoor water features. Stagnant water within the basin of a fountain, coupled with increased temperature of the shallow water during the summer months can provide the optimum environment for Legionella to develop. The spray from the fountain can be easily breathed in by passers by and those looking at the feature. If Legionella is present, it can undoubtedly cause a significant health threat since it is contracted by the inhalation of water droplets. By passing the water through a UV disinfection unit prior to the water droplets being expelled, all traces of Legionella are killed.
Of course, it’s not just the water supply that is of concern. Second generation UV air disinfectors are used to offer protection against micro-organisms for large sites through ducted air conditioning systems. Retrofitted into existing ductwork at appropriate intervals, UV offers protection for a variety of buildings where the air is re-circulated. It is used in office environments where there are potential problems from the spread of Legionella or even against general viruses that contribute to worker related illnesses and an increasing amount of time off work, commonly referred to as Sick Building Syndrome.
The majority of new UV units can be easily installed in new ductwork or retrofitted into existing systems with either round or square profiles ranging from 600mm to 2000mm. There is minimal disruption to the ventilation system, since it is only shut down for a short time whilst being pushed into place. They are quiet in operation and are proving to be effective at destroying not only the micro-organisms present in the air, but those living on the walls inside the ductwork.
