Aeration as a factor in textile dye bioremoval by Aspergillus niger

Abstract

Experiments were done to study the bioremoval/ biosorption of dis-azo dye byAspergillus niger strain 20 in two concentrations using 5 liter bioreactor at five aeration rates. The experimental results are compared for various operating conditions. The dye used was direct brown and the inlet air flow rate was: 1/8, ¼, ½, 1, 2 v/v/min. The aeration rate of ½ v/v/min yielded 9.2 g fungal biomass and removed 72 % of the dye. Increasing of the aeration rate to 2 v/v/min increased the removal to 77%, whereas the biomass was decreased markedly at the end of the incubation time. The results also indicate that the fungal biomass obtained at the three other air flow rates was more or less the same after 3 days of incubation. The obtained results indicate that air flow rates 1/8, ¼ and ½ v/v/min gave better dye bioremoval as compared with the high aeration rate (1, 2 v/v/min) and can be recommended for dis-azo dye bioremediation. Isotherm experiments were conducted to determine the sorbents-desorption behavior of examined dye from aqueous solutions using Langmiur and Freundlich equations. Key words: Textile dyes, removing, dis-azo, batch reactor, modeling, bioremediation.