Power Savings with Increased Disinfection Confidence: Design and Operation of UV Systems Based on a Modified Wastewater Validation Protocol

UV systems for secondary wastewater applications are currently designed and operated using a variety of techniques, ranging from mathematically-derived intensity and flow distribution models to biodosimetry based validation testing. Although several UV manufacturers have validated wastewater UV systems and UV system design specifications have begun to incorporate biodosimetry-based sizing requirements, not all validation protocols are equal. As a result, comparing UV system designs proposed by various manufacturers is not an easy task and can be host to a high level of uncertainty since engineers evaluating such designs are not typically comparing apples to apples.This paper provides a methodology for the development of site-specific disinfection requirements based on the UV dose-response of the targeted indicator microbe for the design of a theoretical UV facility for the disinfection of secondary wastewater effluent. The validated performance models generated for the ITT WEDECO TAK55M HP UV disinfection system are reviewed and a detailed procedure of how the models are used for the design and operation of a UV system to comply with the design specifications. In addition, the impact of RED bias on UV system design and the potential power savings associated with UV system designs based on a multiple challenge microorganism-based validation approach are addressed.