The Catskill-Delaware Water Ultraviolet Disinfection Facility is a

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

(UV) water disinfection plant built in

Westchester County, New York Westchester County is a County (United States), county located in the southeastern portion of the U.S. state of New York (state), New York, bordering the Long Island Sound and the Byram River to its east and the Hudson River on its west. The c ...

, to disinfect water for the

New York City water supply system The New York City water supply system is a combination of Aqueduct (water supply), aqueducts, reservoirs, and tunnels which supplies fresh water to New York City. With three major water systems (New Croton Aqueduct, Croton, Catskill Aqueduct, Ca ...

. The compound is the largest

ultraviolet germicidal irradiation Ultraviolet germicidal irradiation (UVGI) is a disinfection technique employing ultraviolet (UV) light, particularly UV-C (180–280 nm), to kill or inactivate microorganisms. UVGI primarily inactivates microbes by damaging their genetic ma ...

plant in the world. The UV facility treats water delivered by two of the city's aqueduct systems, the Catskill Aqueduct and the Delaware Aqueduct, via the

Kensico Reservoir The Kensico Reservoir is a reservoir in the New York City water supply system. Spanning the towns of North Castle and Mount Pleasant, New York, it was formed by the Kensico Dam in 1885, which impounded waters from the Bronx and Byram rivers. ...

. (The city's third supply system, the

New Croton Aqueduct The New Croton Aqueduct is an aqueduct in the New York City water supply system, carrying the waters of the Croton Watershed from the New Croton Dam in Westchester County, New York, to the Jerome Park Reservoir in the Bronx. Built roughly ...

, has a separate treatment plant.) The plant has 56 energy-efficient UV reactors, and cost the city $1.6 billion. Mayor

Michael Bloomberg Michael Rubens Bloomberg (born February 14, 1942) is an American businessman and politician. He is the majority owner and co-founder of Bloomberg L.P., and was its CEO from 1981 to 2001 and again from 2014 to 2023. He served as the 108th mayo ...

created research groups between 2004-2006 to decide the best and most cost-effective ways to modernize the city's water filtration process, as a secondary stage following the existing chlorination and

fluoridation Water fluoridation is the controlled addition of fluoride to public water supplies to reduce tooth decay. Fluoridated water maintains fluoride levels effective for cavity prevention, achieved naturally or through supplementation. In the mou ...

facilities. The UV technology effectively controls microorganisms such as ''

giardia ''Giardia'' ( or ) is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates, causing the disease giardiasis. Their life cycle alternates be ...

'' and ''

cryptosporidium ''Cryptosporidium'', sometimes called crypto, is an apicomplexan genus of alveolates which are parasitism, parasites that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea (inte ...

'' which are resistant to chlorine treatment. The city staff determined that the cheapest alternatives to a UV system would cost over $3 billion. In response to this finding, Bloomberg decided to set up a public competitive contract auction.

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

based Trojan Technologies won the contract. The facility treats of water per day. The new facility was originally set to be in operation by the end of 2012. The facility opened on October 8, 2013.

References

{{NYCwater Environment of New York (state) Environment of New York City Water treatment facilities Ultraviolet radiation 2013 establishments in New York (state) Water infrastructure of New York City