Henderson Marks Years of Cryptosporidium-free Water

Henderson, the second largest city in Nevada, decided to upgrade and modernize its water treatment system in 2001 to enhance water quality and meet increasing demand. It was the first surface water plant in the United States to be specifically designed for Cryptosporidium inactivation with approval from the state and the U.S. Environmental Protection Agency.

Since then, the UV disinfection plant has served the city well. "We were very proud to be the first plant in the USA to utilize this technology for Cryptosporidium inactivation," said Mike Morine, manager of Technical Services. "We saw UV as a cost-effective way of achieving this, and since its installation almost seven years ago, the Aquionics plant has helped us to exceed the USEPA's water quality regulations. It has certainly exceeded our expectations," Morine added.

Treating 15 million gallons per day (mgd), the plant consists of four medium-pressure UV chambers, each with an independently validated capacity of 5 mgd. Three chambers are in constant use, with the fourth on standby. The plant is completely automated with UV dose control, fail-safe features, and reliable, automatic cleaning for ease of maintenance.

The water, which originates from Lake Mead, is coagulated with ferric chloride then flocculated and filtered before passing through the UV chambers prior to distribution. The system inactivates at least 99 percent of Cryptosporidium oocysts, the infective stage of the organism that is resistant to chlorine.

UV disinfection is among only a few proven methods for rendering Cryptosporidium harmless, and it does so without the use of chemicals. UV light has been used successfully for disinfection of industrial process water and municipal effluent worldwide and for drinking water treatment for many years.

Aquionics, along with UV companies Hanovia Limited in the United Kingdom and Berson UV-techniek in The Netherlands, is part of the Fluid Technology Division of Halma p.l.c.

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