Photo-Fenton Treatment of Olive Mill Wastewater Applying a Combined Fenton/Flocculation Pretreatment

Abstract

In this work, a pretreatment involving a combination of acidification, the Fenton method, and flocculation with polyelectrolytes was successfully applied to remove the suspended solids of Olive mill wastewater (OMW). This pretreatment strongly augmented the reaction rate in the following photo-Fenton treatment under solar irradiation in a Compound Parabolic Collector pilot-plant at Plataforma Solar de Almería. The content in phenolic substances could be degraded down to zero, while DOC was degraded down to about 25% of the initial value. In the work we describe different aspects concerning the process parameters of the pretreatment and the photo-Fenton treatment. Furthermore, decrease in phytotoxicity in the course of the treatment was monitored by germination tests with barley (hordeum vulgare L.). The results indicate that acute phytotoxicity can be substantially reduced by the application of the above mentioned pretreatment, enabling OMW to be used for ferti-irrigation in agriculture.