Optimization of coagulation process for treatment of olive oil mill wastewater using Moringa oleifera as a natural coagulant, CCD combined with RSM for treatment optimization

Wastewater from olive oil mills (OMW) represents a major environmental problem that requires effective treatment to decrease pollution. In the present work, the treatment of olive oil mill wastewater by coagulation was studied using Moringa Oliefera as a natural coagulant. The processing is optimized using both Design of Experiments (DOE) methodology and a central composite design (CCD) combined with the response surface methodology (RSM). The optimization describes the relationship between 3 responses (turbidity, COD, and polyphenols) and 4 independent variables (Moringa Oliefera concentration, pH, agitation speed, and time). Analysis of variance ANOVA using Fisher's test indicated that the established models were significant. The study showed that the model was characterized by a good fit, justified by the very high adjusted coefficient of determination (R(2)Adj = 86.73%, R(2)Adj = 90.39% and R(2)Adj = 93.33% for the turbidity, COD, and polyphenols, respectively). Furthermore, the optimum conditions for a good purification performance of OMW using Moringa Oliefera are as follows [Mo] = Moringa Oliefera = 65 g/L, pH = 6, Agitation speed (Ss) = 35 rpm and Agitation time (St) = 25 min. Under these conditions, the turbidity, COD and polyphenol removal efficiencies are 96%, 88%, and 86% respectively. Finally, the proposed treatment process is a critical development in sustainable environmental technologies. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.