UV Disinfection of Wastewater: Probabilistic Approach to Design

Abstract

In the design of an ultraviolet (UV) disinfection system for a wastewater treatment plant (WWTP), the number of lamps necessary to meet the permit requirements must be determined. Factors influencing the required number of lamps include the wastewater characteristics, the variability in the wastewater characteristics, and the permit requirements. In this paper, a probabilistic approach is described for designing a disinfection facility and is contrasted with the conventional, nonprobabilistic approach. The approaches are illustrated using data collected from both collimated beam and pilot-scale UV disinfection studies conducted at a major Northern California WWTP. The advantages and disadvantages of each approach are discussed along with criteria for selecting a suitable approach for a particular WWTP.