The batik industry generates large amounts of highly colored wastewater. Azo dyes in wastewater can cause environmental pollution. In this study, synthetic containing 32 mg/L Reactive Black 5 (RB5) and Orange 16 (RO16) was treated by ozonation a 2 L batch reactor. color unit reduced from 4240 to 70 after 10 min below 50 15 (7.3 g O3/m3, 4 L/min). first-order decay constant for determined be 1.1...