Starting in 2012, New York City will begin operation of the world’s largest UV disinfection facility and will contain fifty-six 151 million litre UV disinfection units, capable of treating up to 9 billion litres of water per day. The changes, first proposed in 2003, come into effect as the US Environmental Protection Agency urges municipalities to cut back on their use of chlorine which, when mixed with water, produces harmful by-products.
The city currently uses a combination of fluoride and chlorine to treat their water. New York is not the only city planning to use UV rays in water purification. San Francisco has just awarded a $5 million contract to begin installation of 48 UV units that would treat up to 11.5 million litres of water each day.
Source: Scientific American