Industrial wastewater treatment: Case study on copper removal from colloidal liquid using coagulation

In this study, two coagulants based on aluminum and ferric, as well as three poly-acrylamide flocculants with different charges were used to compare the intensity and how each parameter affects. Using the Plackett-Burman method, aluminum sulfate coagulant and anionic flocculant showed the greatest effect. Among the operational influencing factors, the speed of the mixer in the fast mode had the greatest effect. In the optimal conditions, the amount of coagulant (17.5 ppm), flocculant (1 ppm), and the speed of the mixer in fast mode (75 rpm) were reported, and the optimal sedimentation velocity was equal to 0.95 cm/min. The percentage of turbidity, total suspended solids, Total Dissolved Solid, Chemical Oxygen Demand, and Biological Oxygen Demand are respectively equal to 100 (with an approximation of 0.01), 100 (with an approximation of 0.01), 53, 92 and 86 % was obtained. All these results were obtained at a confidence level of 0.95 % with a confidence factor of 0.99 %, which means that the experimental data are in very good agreement with the modeling. In general, the combination of the screening method (Plackett-Burman) and response surface method (Box-Benkhen) is applicable to optimize the chemical coagulation process for the management and treatment of wastewater for reuse.