Water Purification – Chapter 4 – UV-C Light
At the heart of all our Séon water purifiers is UV-C light germicidal disinfection. This provides a significant layer of protection in the water treatment process to protect the product drinking water against harmful bacteria and virus.
At Wananchi, we use this technology in all of our systems because, quite simply, it works and works well!
What is UV-C Light?
UV (ultraviolet) light is a type of radiation that can be found in the electromagnetic spectrum and is measured in Nanometers (nm). Invisible to the human eye, UV is an effective disinfectant due to the density of its wavelength.
There are four ranges to UV light – UV-A, UV-B, UV-C and Vacuum-UV:
- UV-A – otherwise known as black light, it has the longest wavelength, ranging between 315nm to 400nm.
- UV-B – known as the medium wavelength, it ranges between 280nm and 315nm.
- UV-C – the shortest wavelength, it ranges between 200nm and 280nm.
UV-C is germicidal, meaning it can be used effectively as a disinfectant to kill microorganisms, such as bacteria and viruses.
The UV-C light works by damaging the genetic material (DNA or RNA) in bacteria and viruses, inhibiting their ability to replicate, and causing their normal cellular functions to break down.
UV-C Led Technology
Prior to LED technology, UV-C lamps have been with us for over 100 years. It was first used in late 1800’s and even used to purify Marseille water supply in early 1900’s. The first commercial lamps arrived in the 1930’s.
These first-generation lamps are essentially conventional light bulbs made from quartz tubes with a mercury vapour inside to generate the UV rays.
From an operational perspective, the old lamps had a few important limitations; they can break easily, the mercury vapour inside is extremely hazardous whilst they degrade in intensity over time with the lifespan shortening each time they are switched on and off. They also consume a significant amount of energy just like old fashioned light bulbs.
For Wananchi and its customers, deploying with mobile water purifiers with such a vulnerable but critical component, was far from ideal. In fact, the US Army commissioned for an investigation into the vulnerability of quartz UV lamps.
UVC-LED technology first became commercially viable around 2015. Pioneers for integrating this technology is Aquisense Technologies in the USA.
Light-emitting diodes (LEDs) are semiconductor devices that are made up of multiple layers of substrate materials. They can be designed so that a wavelength can be inputted and emit photons in the UV-C range that can be used to stop the replication of bacteria.
Aquisense Technologies first devices, the Pearl Aqua, were used for disinfecting water on the International Space Station. One heck of a statement of quality and reliability for a product launch.
Wananchi pioneered adoption of this technology into the mobile water purification market by integrating Pearl Aqua into its Séon UV.
The result was a lighter, lower energy, more reliable and much, much tougher water purifier.
How does it Work?
An LED produces a pre-selected wavelength from a small amount of electricity. The LED then emits UV-C photons through the water that penetrate the cells and damage the nucleic acid in the microorganism DNA.
As these cells cannot replicate, it renders the harmful microorganism inactive. As a result, UV-C LEDs allow for high-intensity radiation to kill the bacteria in seconds, and its effectiveness is measured in LOGs.
Water is passed through radiated germicidal UV-C light from the LED which irradiates 99.99% of pathogens and bacteria. The UV-C LED is housed within a water manifold designed to ensure a complete spread of light into the water that is passing through and that the water is exposed for the correct time for germicidal efficacy.
The clarity of the water after passing through is critical to ensure high effectiveness of the UV-C process by preventing bacteria and pathogens from `hiding` from the UV-C light on particulate matter. Essentially the UV-C light needs line of sight to work. At Wananchi we call this the “dark side of the moon” affect. Our Séon water purifiers ensure that water is filtered down to 0.5 micron before UV-C disinfection.
Conclusion
- Environmentally friendly – conventional UV lamps use heavy metals that are difficult to handle and cost a great deal to dispose of safely.
- Robust/Reliable – LED simply will not break and fail when exposed to shocks and vibration when operating in a harsh, mobile environment.
- Small design footprint – LEDs are much more compact compared to their mercury-vapor counterpart, meaning they can be integrated easily into new innovative designs.
- Instant-on/off – UV-C LEDs work instantly, so there is no need for a warm-up time that is a common constraint of mercury-vapor lamps.
- Low Energy – LED’s draw far less power than conventional UV lamps and can operate on low, DC voltages making them more practical and safer.
- Unlimited cycling – on/off cycles do not impact the life of the LEDs, meaning there is an unlimited scope for lamp cycling.
- Temperature independent – LEDs can emit photons from a different surface as their heat emissions. They can be designed so that if UV-C LEDs are being used in water purification, they will not transfer heat into the water.
Oliver Lawal, CEO of Aquisense – “AquiSense is proud to support Wananchi with our unique, UV-C LED technology. The reliability, robustness and low energy consumption is a perfect fit for the basis of everything that Wananchi do.”
Find out more about Aquisense Technology’s UV-C lamps Here