Ultra-Violet Light (UV)
Ultraviolet (U.V.) disinfection is a chemical-free process used to directly attack microbes and viruses in water. Even difficult to kill parasites like Cryptosporidia or Giardia are greatly reduced in this process. Essentially a specific 254 nanometer wavelength will scramble the organisms DNA such that they will not reproduce. Systems are rated at so many gallons per minute which is a function of contact time and bulb energy. The fluid needs to have sufficient UV transmission, and clarity is a must for transmission. However, low UV transmission can be present with a clear fluid. A 5 micron pre-filter is a standard design component. Equipment efficiency is expressed as log reduction or % removal such as 99.99%, which is 4 log reduction. Usually bulbs have a useful life of one year. Even though the light is on, it does not mean it is as effective as claimed. Check with manufacturer.