Among the multiple uses of tannins. the production of coagulant agents is considered one of the most interesting one. The synthesis of tannin-derived coagulants is studied through a factorial design in order to evaluate the possible combinations between two types of tannin extracts (Acacia mearnsii de Wild and Schinopsis balansae) under three commercially-available products (Clarotan, Weibull Black and Quebracho colorado) and three types of amine compounds (ammonium chloride, glycidyltrimethylammonium chloride and diethanolamine). After several reproducibility verifications, the optimum product was found to be the one from Clarotan and diethanolamine, which was very effective if tested with surface river water, dye or surfactant-polluted wastewater. Real surface water was clarified with low coagulant dosages (ca. 10 mg L-1), while dye concentration was reduced from 100 to 8 mg L-1 and surfactant concentration decreased from 50 to 7.5 mg L-1 with coagulant dosage of ca. 150 mg L-1. (C) 2010 Elsevier B.V. All rights reserved.