UV DISINFECTION OF WASTE-WATER - PROBABILISTIC APPROACH TO DESIGN

In the design of an ultraviolet (UV) disinfection system for a wastewa ter treatment plant (WWTP), the number of lamps necessary to meet the permit requirements must be determined. Factors influencing the requir ed number of lamps include the wastewater characteristics, the variabi lity in the wastewater characteristics, and the permit requirements. I n this paper, a probabilistic approach is described for designing a di sinfection facility and is contrasted with the conventional, nonprobab ilistic approach. The approaches are illustrated using data collected from both collimated beam and pilot-scale UV disinfection studies cond ucted at a major Northern California WWTP. The advantages and disadvan tages of each approach are discussed along with criteria for selecting a suitable approach for a particular WWTP.