AWWA WQTC62433

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 UVdisinfection systems undergo validation testing. Validation testing provides UV systemperformance data demonstrating that a UV reactor will deliver the required dose under designconditions and that the monitoring systems reliably indicate dose delivery over the range ofpotential operating conditions.A Calgon 36-in; UV reactor was selected to provide disinfection at the Rossdale WaterTreatment Plant (WTP) in Edmonton, Alberta. Nine Sentinel; reactors were designed to fit in theexisting filter gallery, one after each filter. Each reactor has three 10kW medium pressure UV lamps. Due to the very restricted space, there was need for the reactorsto be mounted in a unique vertical arrangement with limited straight piping upstream anddownstream of the reactors.The reactors were designed to achieve 3-log Cryptosporidium reduction under the Tier 2guidelines 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 lamplife/fouling factor. Because the unique piping at the Rossdale WTP was anticipated to create an undesirable flowdistribution into the installed reactors, Calgon Carbon Corporation conducted a ComputationalFluid Dynamics (CFD) analysis of the proposed reactors to simulate their performance in all thevarious 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 flowdynamics and the resulting reactor performance. Because performance was threatened, possibleflow correction solutions were also studied. The effects of different flow-correcting bafflearrangements and their locations were assessed to maximize dose delivery. Includes reference, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2005

Number of Pages:

14

File Size:

1 file , 1.8 MB