In recent decades, ultraviolet (UV) disinfection has become an appealing technology in the global water treatment industry due to declines in UV equipment costs and increased concerns about chemical disinfection. Although UV disinfection typically employs a conventional mercury vapor lamp, a relatively new technology is poised to make that lamp a thing of the past: the UV-C light-emitting diode (LED). The UV-C LED operates in the so-called C range of the UV spectrum, with a wavelength from 100 to 280 nanometers. In this range, UV light has germicidal properties, making it ideal for water disinfection.
Shedding Light on the Benefits of UV-C LEDs
LEDs, which are semiconductor-based light sources, have been commercially available since the 1960s, but it wasn’t until 2012 that UV-C LEDs became widely available for water disinfection. UV-C LEDs have a much different material structure than the more familiar visible light LEDs and are much harder to fabricate in mass quantities.
Compared to mercury vapor lamps, UV-C LEDs offer a number of advantages, including lower power requirements, which make them safer to use. Another key benefit is that UV-C LEDs can be made in extremely small sizes, enabling the manufacture of portable disinfection systems – possibly compact enough to fit inside a residential water pipe or faucet, which would render these fixtures virtually self-disinfecting.
Additionally, UV-C LEDs have instant on/off capabilities while mercury vapor lamps can require up to ten minutes to warm up to the necessary level of disinfection intensity. In order to avoid these long warm-up periods, mercury vapor lamp-based disinfection systems are often left on continuously, which leads to more frequent lamp replacement. UV-C LEDs also do not utilize mercury, an environmentally hazardous substance with high disposal costs.
Drawbacks of UV-C LEDs
Despite their numerous benefits, UV-C LEDs have several disadvantages, such as their higher initial cost relative to mercury vapor lamps. Thermal management is another major problem area for UV-C LEDs. Since only about 5% of their power is converted into light, the remaining 95% becomes heat that must be quickly removed from the circuit board before the heat-sensitive LED die fails. Relatively costly materials, including nanoceramics and aluminum nitride, must be used on the circuit board to provide the necessary thermal conductivity, and even some of these materials have performance limitations (such as brittleness).
Who's Who Among UV-C LED Manufacturers
A number of producers are involved in supplying UV-C LEDs for water disinfection systems. These include:
In particular, in February 2017 METAWATER announced the development of the world’s first UV-C LED disinfection system capable of a treatment capacity of 2,000 cubic meters per day and a lifespan of 45,000 hours – approximately three times longer than a mercury vapor lamp system. METAWATER intends to build on this achievement by developing UV-C LED disinfection systems that can treat 30,000 cubic meters of water per day, the amount of water used by a community of 100,000 people.
Where to Find Out More
Need more information? For historical demand data and forecasts by product, market, and geographic region, see Global Water Disinfection Equipment, an industry study published by The Freedonia Group. The study also covers market environment factors, industry structure, company market share, and top companies.
About the Author
Joseph Iorillo is a researcher and writer at The Freedonia Group, where he contributes to studies on a wide array of topics, including consumer and industrial goods, chemicals, and packaging.