UV Disinfection System Design for the City of Thornton

UV Disinfection System Design for the City of Thornton

Location: Thornton, Colo.

Client: City of Thornton

Completion Date: 2003

Burns & McDonnell provided design and construction phase services for the addition of ultraviolet (UV) disinfection systems at two water treatment facilities in the City of Thornton. The Wes Brown (formerly Columbine) Water Treatment Plant was a 28-million-gallons-per-day (MGD) conventional facility that was later expanded to 50-MGD.  The Thornton Water Treatment Plant is a 20-MGD conventional facility. The UV disinfection acts as a second barrier at these facilities to provide additional microbiological protection.   

The UV manufacturer was selected based on evaluated proposals after an extensive evaluation of available UV technologies. Since each plant utilizes different water sources, the designs at each facility differ considerably. At the Wes Brown plant, three medium-pressure UV chambers rated at 15-MGD were installed in the existing filter gallery with a design UV transmittance (UVT) of 85 percent. To ensure performance of the UV chambers, off-site validation testing was conducted in accordance with the Draft USEPA UV Disinfection Guidance Manual. The UV equipment was brought online in the fall of 2003.

After completion of the recent plant expansion, each chamber is now capable of disinfecting 20-MGD of filtered water due to the increase in transmittance to greater than 90 percent. The Thornton plant design included a new UV disinfection facility between the existing filter gallery and the clearwell. Two UV reactors were installed, with each reactor validated to the full 20-MGD capacity at a design UVT. 

  •  Ultraviolet (UV) disinfection