AWWA JAW10367

This article presents the results of a study conducted to establish test protocols to be used to ensure adequate ultraviolet (UV) light disinfection under adverse conditions, particularly in the presence of turbidity and color in water. A test protocol was devised for fail-safe light sensors by using a color or turbidity agent in the feed solution to reduce the UV dosage to established minimum limits, in order to determine whether the fail-safe device was properly calibrated and functional. Three commercial UV devices were tested with this method. Results indicate that only one of the three devices was UV meter sensitive, correctly calibrated, and likely to deliver a welldisinfected product under all conditions of operation. Includes 16 references, tables, figures.