AWWA WQTC64087

Quantitative measurements of the light output from low pressure (LP), medium pressure (MP) and the pulsed ultraviolet (UV) lamps were made using calibrated spectrometry, chemical actinometry and biodosimetry approaches to compare their relative efficiency in producing germicidal UV energy. Furthermore, disinfection capabilities of these lamps were compared using phage T4 and T7. The spectrometry and chemical actinometry showed good agreement in measurement of pulsed UV fluence. The log inactivation of T7 and T4 phage using the three different lamp types was compared based on UV fluence calculated using ferrioxalate actinometry. The LP lamp had the lowest inactivation with UV fluence, but was similar to the MP lamp. The pulsed UV lamps resulted in significantly higher inactivation than the mercury lamps on a per-fluence basis. These results suggest that the pulsed UV lamp has the potential to compete with mercury lamps in UV treatment system disinfection efficiency. Includes 16 references, tables, figures.