Performance of anaerobic sequencing batch reactor for treatment of wastewater containing azo dye Acid Red 18

The aim of present research was to investigate the performance of anaerobic sequencing batch reactor (An-SBR) for treatment of wastewater containing azo dye Acid Red 18 with the main focus on decolorization kinetic study. Three An-SBRs were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The kinetic study showed that the AR18 decolorization in the reactor with 100 mg/L initial dye concentration followed first order kinetics with respect to the dye concentration. However, in the case of two other reactors with 500 and 1000 mg/L initial dye concentration, correlation of the dye decolorization data suggested two successive parts with two different reaction orders (zero and first order). The results of the UV-Vis analysis as well as the bio-sorption test proved that the AR18 decolorization was mainly due to the anaerobic azo bond reduction and contribution of physical absorption in AR18 decolorization was less than 10%.