Treatment of a simulated textile wastewater containing the azo-dye reactive orange 16 in an anaerobic-biofilm anoxic-aerobic membrane bioreactor

This study evaluated the treatability of simulated textile wastewaters in a bench-scale experimental system, comprising an anaerobic biofilter, an anoxic reactor and an aerobic membrane bioreactor. The Reactive Orange 16 (RO16) was used as model of azo dye. The proposed system was demonstrated to be effective in the treatment of the synthetic wastewater under the operating conditions applied in the study. The results demonstrate that neither the azo dye, nor the aromatic amines formed by the anaerobic azo-bond cleavage seem to significantly affect the COD and nitrogen removal under the operating conditions applied. Although aromatic amines are considered easily degradable under aerobic conditions, the results confirms that at least the sulfonated aromatic amines formed under anaerobic conditions from the RO16 are recalcitrant to biodegradation and therefore aromatic amines are still a matter of concern for the biological treatment of textile wastewater.