Abstract:
purpose of this study was to evaluate the biodegradability of synthetic azo dyes in
anaerobic treatment system. Azo dye biodegradation study was conducted in batch
experiments in 1000 ml conical flask with 500 ml total working volume. The dye
concentrations used in the study were in the range of 100 to 600 mg/l of synthetic azoic
diazo5, Diazo Fast Red Salt (DFRS). Testes were performed at a temperature of 30oC for
four days at 50 rpm in rotary shaker. Color removal and dye degradation efficiencies
were monitored for absorbance, COD, BOD5, TN, NH4
+-N, S-2 and SO4
-2.
The results from the absorbance indicated that the color removal and dye degradation
efficiencies were 92.6, 83.8, 67.3, 41.2, 18.7 and 10.6 % for the dye concentrations of
100, 200, 300, 400, 500 and 600 mg/l, respectively. COD and BOD5 removal efficiencies
of the batch bioreactors were also ranged from 85-20 % and 86-16 % for the dye
concentrations of 100-600 mg/l, respectively.
The TN hydrolysis of the azo dye removal efficiencies were also fount to vary from 64,
48, 23.2, 14.8 and 8.3 % with the corresponding production of ammonium-nitrogen
ranging from 368-247.8 mg/l for 100, 200, 300, 400 and 500 mg/l, respectively. The
reduction of TN and production of ammonium-nitrogen significantly correlated with
absorbance values indicating the biodegradation of the azo dyes. Sulfide removal of the
batch bioreactors were also 87.2, 72.5, 58.2, 36.7 and 18.6 % for 100, 200, 300, 400 and
500 mg/l, respectively, consistent with other parameters. The result from this study
showed potential application of the system using tannery sludge biomass for the
treatment of azo dye containing textile and other similar industries effluents.
Key Words: Azo dye, biodegradation, decolorization, anaerobic batch bioreactor