AWWA WQTC62577

AWWA WQTC62577 Analyzing UV Reactor Validation Data to Verify UV Dose Delivery Using the UV Disinfection Guidance Manual
Conference Proceeding by American Water Works Association, 11/01/2005

Wright, Harold; Gaithuma, David; Bircher, Keith G.; Tramposch, Walter

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To obtain Cryptosporidium and Giardia log inactivation credit using ultraviolet (UV) disinfection, the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) will require that UV disinfectionsystems undergo validation testing. During validation, the dose delivery of a UV system is evaluated as a function of flowrate through the UV reactor, UVT of the water, and lamp power,using a test microbe. Validation is conducted in order to develop performance relationships forUV reactors as well as to develop dose monitoring strategies for on-line compliance monitoring ofUV reactors. In anticipation of the LT2ESWTR, the US Environmental Protection Agency (USEPA) is developing the UV DisinfectionGuidance Manual (UVDGM) to provide technical information on the application of ultravioletlight for the disinfection of drinking water by public water systems. The UVDGM providesguidance on recommended procedures for validating a UV reactor and data analysis, based on theLT2ESWTR validation requirements.The dose measured during validation using the test microbe is referred to as the Reduction Equivalent Dose (RED). USEPA has developed an approach for calculating a safety factor, known as the Equipment Factor (EF), which is applied to the validation RED data. The EF accounts forbias and random errors associated with validation and dose delivery monitoring. The EF is used to define the RED that is required at water treatment plants (WTP) to achieve the inactivation requirement for the target pathogen.This paper provides a comprehensive review of the UVDGM-prescribed methodology for analyzing UV reactor validation data using the UVDGM June 2003 Draft and January 2005revisions thereof. The analysis incorporates all elements of the Equipment Factor (EF) calculations and using a real world example from a large-scale UV reactor validation conducted at the UVValidation Facility in Portland, Oregon. Includes 3 references, table, figures.