Waterguide - UV disinfection
What is UV disinfection?
An environmentally friendly and easy-to-use method is to expose water to ultraviolet light (UVC). The UV exposure is approved according to the German Drinking Water Ordinance (Section 11, Part II on disinfection procedures) – it reliably kills bacteria and viruses.
What is UV light?
UV light is an invisible light with a wavelength of 200 – 400 nm. Light is an electro-magnetic wave whose energy is specified by the wavelength. The shorter the wavelength, the higher the energy. UV light is divided into UVA, UVB and UVC based on its wavelength. Only UVC is used for disinfection as it has the shortest wavelength (frequency of 200 – 280 nm) and the highest amount of energy. The maximum efficiency is achieved at a wavelength of 254 nm, as this is where the absorption curve of nucleic acid and the irradiance of the UV low pressure lamp reach a common maximum potential.
What happens during the UV light exposure?
The exposure triggers photochemical reactions in the nucleus of the micro-organism, which disrupts the genetic information. This prevents any further cell division and the micro-organisms die. UV disinfection does not leave behind any chemical by-products in the water, is completely harmless and affects neither the smell nor taste. The micro-organisms that are exposed with the UV light do not build up any resistance.
The figure shows the absorption of the DNA and its maximum absorption potential at 254 nm.