Ultraviolet Disinfection Guidelines

UV disinfection is a method of water treatment, which destroys bacteria and viruses without leaving residual chemicals. Various government agencies have set guidelines for the safest and most effective disinfection standards.

History

• The Environmental Protection Agency reports the germicidal properties of sunlight were discovered in 1877. The first application of this knowledge for the disinfection of water occurred in 1910 in France and reached the United States in 1916. As of 2010, there are more than 400 UV disinfection facilities in use. Regulations and guidelines have evolved and expanded along with the process of UV disinfection.

Dosage

• Various agencies have guidelines concerning UV dosage. The U.S. Department of Health, Education, and Welfare have set the minimum amount of UV radiation required for disinfection as16 mWs/cm² (milliwatt seconds per square centimeter). The American National Standards Institutes has set the minimum at 38 mWs/cm².

Monitoring

• Water must be treated consistently with the correct dosage of UV radiation. According to the Washington State Office of Drinking Water, guidelines state process failures cannot occur any more than once a month and treatment results should be consistently monitored and recorded every 15 minutes. Any failures to meet dosage guidelines must be reported within 24 hours.