Modeling and Optimization of Coagulation-Flocculation Process to Remove High Phosphate Concentration in Wastewater from a Metal-Mechanic Industry

In this work, the performance of an empirical coagulation-flocculation plant to treat wastewater from a metal-mechanic industry located in an industrial park of Queretaro city, Mexico, is studied. Wastewater samples were obtained from the homogenization tank and treated with the employed industrial reactants through an experimental jar test to obtain statistical data. Then, a response surface methodology with ANOVA analysis was used to model the process, and the epsilon-constraints methodology was used to optimize the coagulation-flocculation process in terms of economic and environmental impact. The results showed an improvement of phosphates removal, but a minimal increment of 1.01% of operational costs regarding to the current operating conditions. Additionally, the results offered a certain reference value for practical application of the coagulation-flocculation process using calcium hydroxide, aluminum salts, and polyacrylamide/urea for the main removal of phosphates in real effluents.