The use of central composite design (CCD) to optimize and model the coagulation-flocculation process using a natural coagulant: Application in jar test and semi-industrial scale

Currently, the field of water treatment represents a very important area for researchers due to developing reliable processes for the recycling and reuse of water. Plant-based coagulants used in treatment processes are costeffective and environmentally friendly. In this study, the use of bio-coagulants based on Aloe vera was proposed for the treatment of the wastewater. The response surface method based on the central composite design was applied to optimize the considered parameters in the coagulation flocculation process. All experiments were conducted in laboratory and semi-industrial scale using a raw water with an initial turbidity and total suspended solids (TSS) of 204NTU and 240 mg/L, respectively. This study was carried out in two parts: (1) optimization and modeling of the coagulation flocculation process. Two parameters were considered, which are the pH and the coagulant dosage. The results obtained show that the R2 were 97.93 % and 98.95 %, with removal percentage efficiency of 99.13 % and 94.0 % for turbidity and TSS, respectively. (2) The jar test optimization results were applied on a pilot of coagulation flocculation and sedimentation, with a flow rate of 150 L/h. The obtained result showed that the removal percentage efficiency were respectively 98.45 % and 92.29 % for turbidity and TSS.