OPERATING ONE OF WORLD'S LARGEST UV DISINFECTION SYSTEMS CHALLENGES AND SUCCESSES

In 1997 JEA decided to convert from disinfection with chlorine to disinfection by UV irradiation. One of the UV systems has the capacity to treat up to 157.5 mgd during wet weather conditions with an average capacity of 52.5 mgd. This medium-pressure system was selected because of its compact size and the self-cleaning feature. Space was limited, as all the UV equipment had to be installed into the former chlorine contact basin. Headloss considerations were carefully evaluated, as the discharge from the treatment plant was to flow by gravity during dry weather conditions. The design of the UV system also had to be coordinated with the design and installation of a wet weather effluent pump station.Effective disinfection during construction presented challenges for plant operating staff as well. Following the commissioning of the UV system, JEA has monitored the equipment operation and maintenance costs. Cost data collected after the first several months of operation indicated that the power consumption of the new system was higher than indicated by the information provided during the selection on the UV equipment. JEA conducted studies to identify the causes of the increased power requirements. The paper will discuss the issues faced during the design of the UV disinfection system; operation of the existing disinfection system during construction of the new system and results of the economic comparison of the operation costs of the chlorine and UV disinfection systems. Since start-up, the plant has experienced a number of challenges and successes.