The wastes generated in the production of juice from citric fruits can become a great environmental problem if they are not managed correctly. Over the last years the European laws have become more restrictive about the pollution levels from industries. The environmental problem is directly related to the high organic matter content present in the leachates from solid wastes, which is measured as chemical organic demand. One way to avoid this is to extract the liquid content from these solid wastes, pressing them, and afterwards treating the pressed liquid, which is very rich in sucrose, by reverse osmosis as a preconcentration system. After that, a concentrated stream will be obtained to be treated later in an evaporation system to achieve citrus molasses (65 degreesBrix) and a permeate one with a very low sucrose content to be reused in the production process. The aim of this work is to study the performance of this preconcentration using model solutions of sucrose (10, 20 and 30 degreesBrix) as feed stream at different pressures, temperatures and feed flows. Also, an empirical function was found that fits the obtained results.