In order to obtain Cryptosporidium and Giardia inactivation credit using ultraviolet (UV) disinfection, the US Environmental Protection Agency's pending Long Term 2 Enhanced Surface Water Treatment Rule will require that UV
disinfection systems undergo validation testing. Validation testing provides UV system
performance data demonstrating that a UV reactor will deliver the required dose under design
conditions and that the monitoring systems reliably indicate dose delivery over the range of
potential operating conditions.
A Calgon 36-in; UV reactor was selected to provide disinfection at the Rossdale Water
Treatment Plant (WTP) in Edmonton, Alberta. Nine Sentinel; reactors were designed to fit in the
existing filter gallery, one after each filter. Each reactor has three 10
kW medium pressure UV lamps. Due to the very restricted space, there was need for the reactors
to be mounted in a unique vertical arrangement with limited straight piping upstream and
downstream of the reactors.
The reactors were designed to achieve 3-log Cryptosporidium reduction under the Tier 2
guidelines of the June 2003 Draft of the US Environmental Protection Agency's Ultraviolet Disinfection Guidance Manual
(UVDGM) at maximum design flow of the filters, 92% UV transmittance and a 70% end of lamp
life/fouling factor. Because the unique piping at the Rossdale WTP was anticipated to create an undesirable flow
distribution into the installed reactors, Calgon Carbon Corporation conducted a Computational
Fluid Dynamics (CFD) analysis of the proposed reactors to simulate their performance in all the
various piping configurations at the plant. The CFD analysis was performed with CFX software
(ANSYS, Inc.) and evaluated the influence that the various piping scenarios had on flow
dynamics and the resulting reactor performance. Because performance was threatened, possible
flow correction solutions were also studied. The effects of different flow-correcting baffle
arrangements and their locations were assessed to maximize dose delivery. Includes reference, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 11/01/2005 |
