Optimization of Coagulation-Flocculation Process for Automotive Wastewater Treatment Using Response Surface Methodology

This study was conducted to assess the optimization of the coagulation-flocculation process and to investigate the interactive effects of experimental factors in automotive wastewater treatment. Based on the coagulation-flocculation process, an automotive wastewater was treated using polyaluminium chloride as the coagulant and anionic polyacrylamide as the flocculant. Response surface methodology was applied to optimize the operating variables: coagulant dosage, flocculant dosage and pH. We found that the optimum conditions for chemical oxygen demand removal (73.7%) were, a coagulant dosage of 73.3 mg/L, a flocculant dosage of 3.46 mg/L and pH 7.45. The optimum conditions for the removal of heavy metals (Fe, Cr, Cu) were, a coagulant dosage range of 65.26-170.9 mg/L, a flocculant dosage of 5.36 mg/L, and pH 6.13 (with 78.7-99.7% of heavy metals removal). The experimental data and predicted model proved that RSM is a suitable approach for optimizing the coagulation-flocculation process in automotive wastewater treatment.