UV ODOUR CONTROL SYSTEMS
UV Odour Control Systems
UV lamps can be used to generate ozone (O3), if suitable material (pure or synthetic quartz) is used for the lamp tube. Such materials do not block wavelengths below 200nm and for the standard mercury UV lamps, the wavelength responsible for ozone production is 185nm. These ozone generators are, therefore, sometimes called vacuum-ultraviolet (VUV or UVV) ozone generators.
UV lamps are a fairly inefficient ozone source, in comparison to corona discharge ozone generators, but the ozone generated by the UV lamps in conjunction with UVC radiation at 254nm, helps to achieve much better results in odour treatment applications.
VUV ozone generators, unlike corona discharge generators, do not produce harmful nitrogen by-products and work extremely well in humid air environments. There is also not normally a need for expensive off-gas mechanisms and no need for air driers or oxygen concentrators, which require extra costs and maintenance.
The Principle of Ozone Formation Using UV Lamps
It should be noted, that most VUV radiation at wavelength of 185nm, is absorbed within several millimetres from the UV lamp. Therefore, only the oxygen in very close proximity to the UV lamp, can be utilised to create oxygen radicals and generate ozone.
It should also be noted, that the UVC radiation at 254nm, which is generated by the UV lamps at the same time as 185nm VUV radiation, breaks down molecules of ozone back to oxygen and oxygen radicals. Therefore, the UV lamps may not be the best way of producing ozone, but they are an ideal engine for producing highly reactive oxygen radicals, which help to initiate further chemical reactions (oxidisation) of harmful or smelly VOCs.