This will be a summary because even with my limited but ongoing knowledge of UV, this subject is massive. I will outline what UV does and doesn’t do and hopefully make it interesting while I go. I know when I looked at Wikipedia when I was new to UV, the huge page I was confronted with was a little over my head. So I’ll attempt a ‘UV for dummies’ equivalent.
UV gets rid of germs and bacteria in air, water and on surfaces and makes it safe to breathe, drink, touch etc. This is the essence of what we do at UVO3.
UV works by inactivating the DNA of cellular organisms. In short, when UV light collides with DNA it breaks down the helix that makes it. This means the bacteria can’t split in two. Because the life of a single germ is usually measured in minutes or less and it usually relies on reproduction to sustain numbers, UV can be seen to take effect very quickly. Once the germ has passed through the UV unit and is dead, more bacteria can only be introduced from other sources. This is why if we were sourcing a UV unit for a single tap, we would put it as close to the tap as possible.
UV light doesn’t kill or sterilise bacteria, it only makes it unable to reproduce. It’s basically the same thing but can only be quoted being up to 99.9999% effective. It also doesn’t get rid of what’s left after the bacteria dies, it isn’t vaporised.
UV does have this affect on all know bacteria and DNA, it’s just more effective on some against others. While some bacteria has built in defences against temperature and UV exposure, a prolonged exposure time to the UV light and filtration is how we deal with the more hardy ones. This is also why UV is harmful to humans, it does exactly the same thing to our DNA. This brilliant example of what an under-prepared UV engineer would look like by exposing himself to the beautiful blue light, shows how destructive a short amount of time in concentrated UV can be. He would also be very lucky to have his sight. Because of the eye’s sensitivity to light, high levels of UV could be enough to seriously damage the cells in them
Ok, that’s my comprehensive insight into how UV disinfection works. Hopefully it makes sense and the pictures have made it interesting. I may go into factors that affect UV in an up coming blog.