Performance Validation of a UV Reactor for High and Low Dose Applications

The Siemens Barrier Sunlight V-48E-A300 was validated in conformance with a recently developed test protocol that combines and updates the objectives and methods found in established UV disinfection guidance documents, including the NWRI/AwwaRF protocol (2003), the UVDGM (2006), and the USEPA-ETV protocol (2002). The UV disinfection system was tested at full-scale at a single power input, adjusted to simulate a combined fouling and lamp aging attenuation. Testing was conducted by HydroQual at the UV Validation and Research Center of New York (UV Center), located in Johnstown, NY. A unique feature of this project was the validation of the reactor in two RED regimes: using MS2 to develop MS2 RED performance data in the range 20 to 100 mJ/cm2, and using T1 coliphage to develop T1 RED performance data in the range 10 to 25 mJ/cm2. Because multiple surrogates were used to test the system, a dose algorithm was developed to combine the observed MS2 and T1 RED data and incorporate the sensitivity of each in order to differentiate their individual reaction at the specified operating conditions. The validation factor was established as a function of the interpolation uncertainty of the dose algorithm, wherein the QA goals were met and the RED bias was set to one, based on the premise that the sensitivity of the T1 is essentially equivalent to the sensitivity of the coliform groups, which are considered the targeted microbes for such applications. The commissioned system can then incorporate the sensitivity of the targeted pathogen (e.g., total or fecal coliforms, enterococcus, etc.) when calculating the RED delivered by the system. For plant design, the targeted disinfection performance can be achieved by using a number of reactors in series, such that their summed dose delivery will meet the design dose requirement, with the assumption that the commercial reactors are identical to the test reactor in all technical specifications.