Any nonylphenol compounds found in water have to be removed since they are endocrine disruptors. In this study, natural water from the river Ebro fortified with nonylphenol compounds (4n-nonylphenol and technical nonylphenol) is used as a sample in order to simulate a real situation in drinking water treatment plants. The aim is to compare conventional disinfection with advanced oxidation processes (O3, O3/H2O2, O3/TiO2 and O3/H2O2/TiO2) used for the removal of nonylphenol compounds present in natural water. Furthermore, a study is carried out of the by-products (THMs) generated as a consequence of the presence of natural organic matter. Preoxidation by chlorine completely oxidizes 4n-nonylphenol and technical nonylphenol. It can be seen that the best of the advanced oxidation processes is the O3/H2O2, achieving an average oxidation of 55%, although the differences among the processes were not very significant. Furthermore, the use of post-chlorination guarantees the total removal of nonylphenol compounds.
