DETERMINATION OF ASSIMILABLE ORGANIC-CARBON (AOC) IN OZONATED WATER WITH ACINETOBACTER-CALCOACETICUS

The effect of ozone application in drinking water on the production of assimilable organic carbon (AOC) was evaluated. The typical procedure to determine AOC is suggested by van der Kooij, which is the method o f bacterial growth measurement by colony-forming units using the strai n P17 and/or NOX. The bacterial indicator species used for this study is Acinetobacter calcoaceticus which was isolated and identified while ozonating Nakdong river water. This strain could never be isolated fr om the raw water, but this strain was the predominant isolate in the o zonated water. Within a short incubation time, this organism was found to replicate well on acetate and oxalate as the sole carbon sources. The yield coefficients of this organism for acetate and oxalate are th e same order of magnitude as the value of P17 and NOX. With full-scale experiments, A. calcoaceticus concentration was found to increase aft er ozonation, but did not decrease upon chlorination. In laboratory-sc ale experiments with Yongsan river water, aldehyes were found to be pr oduced in proportion to the ozone dose. The raw water contains low con centrations of aldehydes, but has a high AOC concentration. A correlat ion between aldehyde production and AOC production was observed in the tested water with ozonation.