http://hdl.handle.net/10256/1548 2025-07-31T10:09:00Z http://hdl.handle.net/10256/27149 Single-pass forward osmosis for efficient feed concentration: optimizing multiple modules arrangement and flow distribution Yalamanchili, Rajashree; Olives Cegarra, Pere; Galizia Amoraga, Albert; Rodríguez-Roda Layret, Ignasi; Blandin, Gaetan Forward osmosis (FO) is gaining prominence as a concentration process. However, most systematic studies remain limited to setups involving recirculating feed solution (FS) and draw solution (DS), and employing small membrane coupons or single module, thereby limiting insights into high-recovery concentration performance at the system scale. Realizing the full potential of FO for concentration purposes and maximizing osmotic energy efficiency requires a detailed understanding of module arrangements, flow dynamics, and their influence on operational scalability. This study presents pilot-scale investigation of FO modular arrangements, including series and tree configurations operated in single-pass mode under both co-current and counter-current flow orientations, combined with MATLAB-based mass transfer modeling. Experiments used Aquaporin HFFO2 hollow fiber (HF) modules and tested both low-osmotic-pressure (DI water) and high-osmotic-pressure (5 g/L saline) FS. The model showed strong agreement with experimental results and enabled detailed evaluation of spatial performance variations, enhancing evaluation of system scalability and efficiency. The full potential of countercurrent flow emerged in multi-module setups. With a 5 g/L FS, series and tree arrangements initially performed similarly, achieving FS concentration factors of 4.59 and 5.10, respectively. Simulations revealed that water permeation in the series arrangement progressively diluted the DS, increasing its volumetric flow and leading to hydraulic imbalances that limit the system's ability to handle long-term stable operation. The tree arrangement faced similar challenges under co-current flow, but counter-current operation mitigated them by ensuring balanced flow distribution across stages, sustaining stable flux (4.76 -6.71 LMH) and achieving an overall recovery of 80.40 %. To further enhance the system performance, the impact of hydraulic conditions was explored through simulations to identify operating regimes with optimal trade-offs 2025-11-15T00:00:00Z http://hdl.handle.net/10256/27106 Solucions basades en la natura, un camí sostenible per a la gestió de l'aigua i la salut global Sepúlveda Ruiz, KaTren Paola; Padilla Gallegos, Cinthia Estefania; Torrens Armengol, Antonina L'aigua és un recurs essencial per a la vida i el desenvolupament humà. Malgrat això, milions de persones arreu del món encara no tenen accés a infraestructures adequades per a la gestió i el tractament de l'aigua. Aquesta situació és particularment greu en zones vulnerables, on la manca de sistemes de sanejament contribueix a la propagació de malalties, al deteriorament ambiental i, fins i tot, a la migració forçada. A escala mundial, segons l'informe de Nacions Unides (2021), només el 56% de les aigües residuals són tractades adequadament, la qual cosa evidencia la necessitat urgent d'adoptar solucions més sostenibles 2024-09-01T00:00:00Z http://hdl.handle.net/10256/26976 Spatial approach for assessing vulnerability to urban flooding: a proposal for a multidimensional index Gómez Vaca, Ana Noemí; Popartan, Lucia Alexandra; Nuss Girona, Sergi; Rodríguez-Roda Layret, Ignasi This study introduces a methodology for evaluating vulnerability to urban flooding across different dimensions, by employing spatialdata analysis. The methodology consists of four steps: (1) selection of indicators that reflect the vulnerability of an urban area, (2)normalization of the data for each selected indicator across all dimensions, (3) assignment of weights for each indicator and dimension,and (4) mapping and classification using spatial analysis, resulting in a grid. This study proposes a comprehensive list of 36 potentialindicators for quantifying vulnerability, with each indicator falling under one of the four dimensions (social, economic, environmental,and physical) and three components of vulnerability (exposure, susceptibility, and resilience), which are part of Step 1. Additionally,the methodology is complemented by a data generation and spatial analysis technique for Step 4. The proposed methodology can serveplanners and policymakers to make objective decisions, based on vulnerability quantification through index for long-term vulnerabilityto flooding, considering each dimension separately, as well as integrating with each other, using a multidimensional and spatialrepresentation of flood risk vulnerability 2025-06-25T00:00:00Z http://hdl.handle.net/10256/26962 The hidden challenge of membrane recycling: how drying affects membrane layers? Zappulla Sabio, Bianca; Le-Clech, Pierre; Dumée, Ludovic F.; Balakrishnan, Hari Kalathil; Monclús Sales, Hèctor; Blandin, Gaetan Improper management or storage after discharge of thin film composite membranes are challenging due to potential drying, which may affect the integrity of the material, decrease the performance and impede their potential recycling for second-hand applications. The impact of drying onto the different layers of thin film composite membranes remain empirical and poorly studied. This work systematically assessed the impact of the drying phenomena on the physical changes across poly(amide) and poly(sulfone) layers by applying drying/rewetting protocols consisting of (1) soaking the membrane in a solvent, (2) drying at 60 °C and (3) rewetting with ethanol. After each step, membrane performance as well as surface characterization were assessed. Severe loss of permeabilities, up to 65 and 90 % for the poly(amide) and the poly(sulfone) layer respectively, were observed. Drying effect was demonstrated to be quickly reversible (1 min soaking in ethanol) for the poly(amide) layer even over several drying-rehydration cycles. Permeability of the poly(sulfone) layer appeared to be permanently impacted due to a possible irreversible surface shrinkage and pores collapsing showing permanent changes in the poly(sulfone) layer. These findings highlight the importance of studying membrane drying to prevent further performance loss, optimize material lifetime, ensure continuity of operation, and enable membrane recycling 2025-08-01T00:00:00Z