Feria Díaz, Jhon JairoBermúdez Roa, SixtoEstrada Tordecilla, Ana María2015-03-112015-03-1120141909-0455http://hdl.handle.net/10567/1262Introduction. Sinú river is the main fresh water supplying source in the Córdoba province, but its turbidity levels require it to be coagulated, and this means costly chemical products. Natural coagulants such as Moringa Oleifera (M. Oleifera) represent a sustainable, cheap and safe alternative for water purification. Objective. To evaluate the M. Oleifera seeds as a coagulant and its effects on pH and on the alkalinity. materials and methods. Eight simple samplings were performed at the Sinú river, between March and Aril 2013. M. Oleifera seeds were selected, husked, dried, minced and sifted until a fine powder was obtained. This powder was, then, degreased, by the use of a Soshlet extraction equipment. The doses of the coagulant were prepared, from 2,5 mg/L to 30,0 mg/L in saline solution and were applied to each sample taken from the river. A cubic response surface model was generated in order to evaluate the turbidity removal. Results. High turbidity removal efficiency values (>90 %) were achieved with doses between 4,5 mg/L and 17,5 mg/L of natural coagulant for initial turbidities above 90,0 UNT. Nevertheless, for initial turbidities below 66,0 UNT, efficiency levels were also lower (between 70 % and 85 %).No significant pH and alkalinity alterations were found after the tests. Conclusion. M. Oleifera is an efficient, safe and economic coagulant to remove turbidity from Sinú river´s water.esCorporación Universitaria LasallistaÁrea Metropolitana del Valle de AburráMoringa oleiferaRío SinúContaminación del aguaTratamiento de aguasCoagulaciónArticle