In the treatment of water purification, one of the most important unit operations is the coagulation-flocculation, because it is responsible for turbidity removal.Aqueous extracts of Moringa oleifera seeds prepared in saline solution have demonstrated their effectiveness in coagulation of turbid waters; however, few studies have been reported to seawater as a possible substitute of saline solution.In this work, treatability tests were carried out to verify the behavior of the seeds of M. Oleifera when are prepared in different solvents, such as distilled water, saline solution (1% NaCl) and seawater.A factorial design of 3 3 was used in this study.The factors considered in the three (3) levels were initial turbidity of the treated samples, the type of solvent, and the coagulant doses.The results showed that the samples treated with extracts prepared with saline solution and seawater had the best removal efficiencies, especially when the initial turbidity of the water is greater than 150 NTU.Similarly, it was demonstrated that seawater is an excellent option as a solvent in the preparation of natural coagulants.