In this paper, the degradation of Acid Blue 92 (AB92) by ozonation, O-3/H2O2 and O-3/Activated carbon is investigated. It was observed that in ozonation and O-3/H2O2 processes with gained pH and in O-3/AC with reducing pH to 4, AB92 has relatively a better degradation rate. However there had been a higher removal rate by increasing H2O2 concentration and reducing initial dye concentration. Effect of experimental parameters such as pH, H2O2 concentration, initial dye concentration, activated carbon dosage and salt existence such as sodium chloride, sodium sulfate, sodium carbonate and sodium bicarbonate on the reaction were also studied. The criterion for progress of organic pollutant removal and mineralizing was alterations in chemical oxygen demand (COD) levels which were measured several times using Open Reflux method. The outcome indicated that the removal of COD in ozonation, O-3/H2O2 and O-3/AC processes were 30%, 80% and 100% respectively. However, addition of electrolyte caused a decrease in degradation rates. (C) 2012 Elsevier B.V. All rights reserved.