The end-of-life management of reverse osmosis (RO) membranes is an increasingly important environmental and economic challenge in the water treatment sector. These membranes, primarily used in desalination and water reuse processes, have a limited lifespan of 3 to 5 years and are commonly discarded in landfills despite retaining part of their functionality. In this context, the Osmo4Lives project, led by the LEQUIA research group at the University of Girona, proposes a cascade recycling strategy to extend membrane lifespan through chemical conversion treatments, adapting them for less demanding applications such as nanofiltration (NF) and ultrafiltration (UF). The main objective of this study was to evaluate the technical feasibility of RO membrane cascade recycling through physicochemical characterization and analysis of their response to chemical conversion and fouling. To achieve this, several experiments were developed: first, commercial and converted membranes were characterized in terms of water permeability and salt rejection. Then, controlled sodium hypochlorite treatments were applied to reduce the selectivity of the polyamide layer. In addition, fouling experiments were carried out using a synthetic solution rich in organic compounds to simulate real conditions, and Chemical Oxygen Demand (COD) was measured to assess the quality of the permeate. The results demonstrate that converted membranes can reach performance levels similar to commercial ones, both in permeability and rejection. Furthermore, a consistent fouling response was observed, with flow stabilization and a slight improvement in organic matter retention. These findings confirm that membrane recycling is a feasible and promising strategy, with the potential to support more sustainable water resource management within the framework of the circular economy

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