Kinetics of Detoxification and Mineralization of Mono Azo Dyes in a Up-flow Anaerobic Fixed Film Reactors

S. Sandhya, K. Swaminathan and S. N. Kaul

Abstract
The study investigates the anaerobic treatability of azo dyes, namely, Remazol Red (RR), Remazol Blue (RB) and Golden Yellow (GY) in a three identical bench scale up-flow anaerobic fixed film reactors (UFAFF) R1, R2 and R3 followed by a semi-continuous aerobic activated sludge system. The effect of hydraulic retention time (HRT) on decolorization and degradation have been compared for three azo dyes. The kinetic studies have shown that the reactors can be operated at 2.59 – 8.3 kg m–3 d–1 COD for RR with removal of 65.72 – 76.00 % COD, 4.60 – 6.84 kg m–3 d–1 COD for RB with 74– 87.11 % COD removal, 1.89 – 9.72 kg m–3 d–1 COD for GY with 56 – 79.6 % COD removal. HRT, as varied from 0.150 – 0.452 days for all the dyes and decolorization and degradation, are decreasing in fraction of HRT. COD removal for all the three azo dyes showed that a correlation coefficients of loadings are 0.9891, 0.7154and 0.8652 for RR, RB, GY, respectively. But decolorization of azo dyes do not followed any correlation with loading.

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Keywords
Azo dye, decolorization, COD removal, loading rate, hydraulic retention time (HRT)