We will construct an ultraviolet disinfection facility to destroy disease-causing organisms in our upstate watershed
Although the Delaware and Catskill Water Supplies are not filtered, the EPA still requires us to treat the water with chlorine as an additional layer of protection. The chlorine kills tiny organisms and prevents the spread of waterborne diseases. But one pathogen, known as Cryptosporidium, has always been able to evade this treatment. This microscopic parasite is encased by a shell that enables it to survive outside of a body-and resist chlorine-based disinfectants. When it is ingested by humans or animals, it can lodge in an intestine and cause cryptosporidiosis, a diarrheal disease.

We will open the world's largest ultraviolet disinfection facility in 2012. The plant will use ultraviolet light to destroy the pathogens' abilities to reproduce. Because this is a physical process rather than a chemical one, there are no harmful impacts on humans or aquatic life. This plant will also enable us to scale back the use of chlorine pumped into the water, limiting the amount of disinfection by-products that are created.

The ultraviolet disinfection plant will be located at a 153-acre property in the towns of Mount Pleasant and Greenburgh in Westchester County. It will have the capacity to treat 2,020 mgd from the Catskill and Delaware systems.

Progress (as of 4/22/08):
DEP began construction on the UV Disinfection Plan on January 31 and anticipates completion in 2012. Once completed, this facility will disinfect against Cryptosporidium, which is resistant to chlorination.