Decolorization of azo dye by ozonation

Abstract

Decolourization and Chemical Oxygen Demand (COD) removal of azo dye solution in different ozonation time and biodegradation processes were evaluated to apply for wastewater treatment containing azo dye. Reactive Red 120, Remazol Brilliant Blue R, Reactive Green 19 and Reactive Black 5 have been selected amongst azo dyes in performing ozonation process. Laboratory scale ozonation process are developed. Ozonation is effective for decolourization of reactive azo dye even with lower ozone dose. Ozonation time 5 minutes, 10 minutes and 20 minutes are done to evaluate the performance of ozonation and biological treatment on different azo dyes. Contrarily, significant decreased in COD concentration was only observed within higher range of ozone doses. Higher COD removal at high ozone dose was due to complete oxidation of azo dye. COD removals are increases as the increase of ozonation time and ozone dose. Biodegradation processes will decrease the COD value compare after the ozonation process. Decolorization of the dye was completed after 20 minutes of reaction.