When ozone gas is transfered into water, the dissolved ozone reacts with the organic and inorganic
compound, including any pathogens.The initial reaction of ozone with chromophores group of dyes in
wastewater, ozone can react with organic compounds at double bond of carbon, nitrogen (C = C, N = N) and
aromatic rings. The cause is a product of destroy of the bonds. The begining of the first two hour reaction, the
decolorization was potentially less and the color was still remained because the complexity of the
intermediate molecules occurred of various types. At the result, the ozone generator could not produce enough
ozone to react with the polluted water.
Ozone can decompose to oxygen by split to radical such as hydroxyl radical (OH ), OH3, OH4 and super
oxide (O2 -). The radical that occurs is very strong oxidant to react with various substances. From past
research, the researchers demonstrated that the rate of decomposition of ozone is correlated with temperature,
pH and concentration of organic and inorganic compound [4]. The next step of this study will study the
factors that affect on the capability of ozone for treatment of wastewater and two types of reactive dyes tested
(Nova cron super black G and Terasil red ww 3BS). The factors studied were pH and the COD removal
efficiency of the decolrization.