Improving the simultaneous removal efficiency of COD and color in a combined HABMR-CFASR system based MPDW. Part 1: Optimization of operational parameters for HABMR by using response surface methodology

► The HABMR-CFASR system was used to remedy mixed printing and dyeing wastewater (MPDW). ► The optimizing operational parameters of HRT, pH and SLR were determined by response surface methodology (RSM). ► The experiment revealed the effluent COD and color decreased by 9.97% and 10.12% compared to the usual operating conditions.