Dosage optimization of Moringa oleifera seed and traditional chemical coagulants solutions for concrete plant wastewater treatment

The purpose of this study was to determine the ideal ranges for the application of aluminum sulfate, ferric chloride and Moringa oleifera (MO) extract, all in the form of solutions, for the treatment of concrete plant wastewater. This optimization was performed using the response surface methodology. A rotational central composite design was used based on three independent variables and five levels, which yielded a total of 20 assays. Applying a desirability function, were identified the optimum ranges of the coagulant concentrations. The ideal ranges were experimentally analyzed and the results compared to the predicted values by the model. The optimum concentrations of the coagulants MO, aluminum sulfate (Al2(SO4)3) and ferric chloride (FeCl3) were 9.4 mL L−1, 7.2 mL L−1 and 3.6 mL L−1, respectively, with a 99.9% reduction in the turbidity. Reuse of the treated wastewater outside the concrete plant requires the correction of pH, alkalinity and hardness.