An ultraviolet (UV) sterilizer uses ultraviolet germicidal irradiation (UVGI) as a sterilization method to break down microorganisms including pathogens, viruses and molds. The ultraviolet rays work to destroy microorganisms' DNA, thus disrupting their ability to reproduce and effectively killing them. Of the three types of UV — UV-A, UV-B and UV-C — UV-C light is the one used in UV sterilizers. UV-C contains germicidal UV within its spectrum, measured at a wavelength of 254 nanometers (nm). UV-C is shortwave ultraviolet radiation, compared to longwave UV-A and UV-B, and is the type of UV capable of causing the breakdown of the molecular bonds in microorganisms' DNA.
Ultraviolet rays used in sterilization are delivered by way of germicidal lamps that emit UV at the proper wavelength. To be effective, the lamps must be placed in line of sight relative to the area being treated. This ensures the microorganisms' full exposure to the UV light. The main types of germicidal lamps used in UV sterilizers are low-pressure UV lamps, medium-pressure UV lamps and amalgam lamps, and they each have varying efficiency, power and performance.
UV sterilizers have a variety of applications in various industries. Some of their uses include air sterilization, water sterilization, and the sterilization of aquariums and ponds. UV sterilizer usage is also common in food and beverage production, medical sanitation and other sterile work facilities, such as laboratories.
In air sterilization, a fan forces air past UV sterilizer lamps to sterilize the air before it is taken through a filtration system to remove dead microorganisms. In water sterilization, water flows past a UV sterilizer and is taken through a filtration system to expel dead microorganisms. This method is increasingly being used to replace chlorination as a method of water purification.
In ponds and aquariums, a UV sterilizer is used to prohibit the growth of algae. This provides clearer water and prevents the spread of disease by eliminating any pathogens that may be present. The water is allowed to flow through tubing that contains the UV sterilizer before being taken through a filtration system.
In food and beverage production, the U.S. Food and Drug Administration (FDA) requires fruit and vegetable juice producers to use UVGI in the sterilization of fresh juices. This is done to ensure that no harmful pathogens contaminate the juice during the production process. UVGI is also used to treat drinking water. UV sterilizers are also used in laboratories to sterilize equipment and to maintain good hygiene practices.