ABSTRACT
ABSTRACT: In the summer season the waterworks Ponikve distribute daily approximately 7000 m3 of treated lake water “Jezero” through the complex drinking water distribution system of the northern part of the island Krk, Croatia. In order to avoid problems with disinfection byproducts of both chlorine and chlorine dioxide that were present due to presence of natural organic matter in lake water, the large-scale pilot test of UV irradiation for disinfection of drinking water was started in 2000. This paper presents the results of a 9 months investigation period that includes different seasonal qualities of raw water. During the test period intensive bacteriological monitoring showed that microbial water quality standards could be held. Despite the natural organic matter (NOM) content and very high summer temperatures of water (up to 30◦C), the disinfection process was successfully conducted solely with the UV-radiation. The waterworks Ponikve continues to change chemical disinfection equipment to UV-radiation.
