To achieve the rapid decomposition of refractory organic compounds for water purification, an effective technique for the generation of bromine oxyacids by O-3 fine bubble injection and bromide addition was developed. When O-3 bubbles are micronized in the liquid phase, the absorption of O-3 is accelerated, and OH- generation is promoted because of the increased contact probability between the dissolved O-3 and accumulated OH- at the minute gas-liquid interface. Additionally, when O-3 fine bubbles are supplied into a liquid phase containing Br-, further improvement in the oxidation potential of the liquid phase can be expected because of the increased HOBr/BrO- generation with OH center dot generation. At 298K, O-3 bubbles with an average diameter (d(bbl)) of 50 or 2000 mu m were supplied into NaBr aqueous solutions with different initial NaBr concentrations ((C-NaBr)(0)). The rate of generation of total oxygen species and the constant value of concentration of total oxygen species (Q) increased with the acceleration of the bromine oxyacid generation, induced by the decrease in d(bbl) and the increase in (C-0s*). Furthermore, the decomposition of tert-butyl alcohol (TBA) by O-3 fine bubble injection at various (C-NaBr)(0) values was carried out. Consequently, the rate constant of TBA decomposition showed a maximum value at C-0s* of 0.54 mmol/L because of the conversion of HOBr/BrO- with a high oxidation potential to BrO3- with a low oxidation potential, caused by the excess oxidation of Br-. Hence, the generation of HOBr/BrO- with O-3 fine bubble injection and bromide addition is effective for achieving enhanced decomposition of refractory organic compounds.