APPLICATION of the Proposed UVDGM Requirements TO AN EXISTING UV DISINFECTION INSTALLATION

The Clayton County (Ga.) Water Authority (CCWA) has installed ultraviolet (UV) disinfection systems at three water treatment plants. The CCWA's projects were designed, constructed, and tested in advance of publication of the proposed Ultraviolet Disinfection Guidance Manual (UVDGM) by the US Environmental Protection Agency (USEPA) in June 2003. Onsite validation testing was successfully completed at the three facilities early in 2003. Following the publication of the proposed UVDGM, the UV system configuration and validation results for the CCWA's Freeman Road plant were analyzed under the UVDGM framework. A comparison to the Tier 1 requirements indicated that not all criteria were met, making a Tier 2 analysis necessary. From the Tier 2 analysis, the UV safety factors and dose requirement were reduced by approximately 12% compared with the proposed Tier 1 dose requirement. These analyses showed that the CCWA systems are surpassing all potentially applicable USEPA requirements, and the CCWA is providing enhanced public health protection as intended at project inception. As a result of these analyses, significant comments, focused on simplifying the proposed UVDGM and enhancing its ease of use, were submitted to the USEPA.