UV disinfection is a powerful weapon against contaminants, but integrating the technology without disrupting water flow is no small challenge. In HDR’s work on KRS1, UV disinfection is taking center stage. Recent Kentucky River sampling identified cryptosporidium concentrations, placing KRS1 into Bin 2 under the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR). This designation requires an additional 1-log of removal for cryptosporidium at KRS1. Having successfully incorporated UV disinfection in other plants, Kentucky American Water (KAW) chose it again at KRS1, deciding to integrate on a new standalone UV disinfection building into the current plant flow. Continuous water flow during construction of the new UV disinfection building is critical. KRS1, producing an average of 23 MGD, provides the majority of the water for KAW’s service area. During Construction, the plant may only be partially shut down at any given time. KRS1 must produce a minimum of 15 MGD to meet demand. To prevent a full shutdown, HDR’s design uses existing 30- and 36-inch connections to the clearwells in combination with phasing to limit and align shutdown periods with low demand seasons. Discussion topics will include: - Pros and cons of UV as a disinfection strategy to meet LT2ESWTR requirements. - KRS1 design considerations, such as maintenance of plant operations, hydraulic conditions for future plant improvements, prolonging equipment life, and providing operations and maintenance access. - Permitting and bidding strategy within a tight schedule, including coordination with KDOW, validation requirements for what will be the largest UV system in Kentucky, pre-procurement, and construction phasing.