(575i) Lumped Kinetic Models for Olive Mill Wastewaters Catalytic Ozonation

The activity of ozone through high electronic density pollutant molecules degradation at normal conditions of pressure and temperature is well known. However, when total mineralization of the wastewater is required, single ozonation leads to unsatisfactory results due to the formation of refractory compounds. Nevertheless the presence of an active catalyst truly improves ozonation performance in what concerns the wastewater remediation that is possible to be achieved. In this context, catalytic ozonation is a promising technology for liquid pollutants abatement. The real industrial effluents are often characterized by the presence of a complex mixture of compounds and in addition the degradation processes lead to the formation of innumerous intermediates along the wastewater treatment. Therefore, it becomes practically impossible to identify and follow the concentration of the various species in solution during the treatment processes. As a consequence, the use of lumped models is required in order to describe the evolution of the reactional mixture. In this context, lumped parameters like Total Organic Carbon ? TOC involving all the organic compounds in solution are used, instead of individual concentrations. On the other hand, the various pollutant compounds are grouped according to their higher or lower ability to be oxidized leading to different models, which are not frequently used in the ozonation field. Olive oil extraction industries are spread all over Mediterranic countries, the world main producers. The mills operate only a few months each year, nevertheless the production consumes large amounts of water generating a high volume of liquid pollutants. The application of biological treatments to the depuration of these wastewaters it is not efficient due to the seasonability and high organic load which includes biorefractory substances as phenolic compounds. Several ceramic catalysts were tested to improved the mineralization achieved in the treatment by ozone of a simulated OMW consisting in a mixture of phenolic substances and, among them, the laboratorial catalyst Mn-Ce-O (70/30) was the most active. In this context, the scope of this work addresses the discussion of different mathematical models and their applicability to describe the non-catalytic and catalytic ozonation based on the results of a mixture of phenolic acids presents in Olive Mill Wastewaters (OMW) over a Mn-Ce-O catalyst. The main goal is to achieve kinetic equations suitable to be applied in the project of industrial ozonation reactors. The First-Order Kinetic Model (FOKM), Modified First Order Kinetic Model (MFOKM), Lumped Kinetic Model (LKM), and Generalized Kinetic Model (GKM), which have been extensively used in Catalytic Wet Oxidation processes, were used in our work to assess catalytic ozonation in the presence of the Mn-Ce-O (70/30) catalyst. The FOKM failed in the prediction of the laboratorial values and both MFOKM and LKM, described by identical mathematical expressions, led to the same inadequate fitting. Finally, the GKM allowed a good description of the catalytic system. This model was then further applied to achieve kinetic expressions for the catalytic and non-catalytic systems required for industrial reactors design.