Wastewater samples were collected from FSBR1 and GSBR1 for toxicity assessment at three different cycle stages, namely WW feed at the feeding phase (corresponding to the simulated dye-laden textile wastewater prior to treatment), WW anaer at the end of the anaerobic reaction, and WWfinal at the end of aeration (i.e., at the end of the treatment cycle). A sample corresponding to the feed solution without dye was used as control (WWcontrol).