Sustainable geothermal water treatment with ultrafiltration and reverse osmosis: a life cycle assessment perspective

Geothermal waters still represent an underutilised resource for freshwater production, yet in some cases their high mineralisation, variable temperature, and the presence of trace elements such as boron and arsenic pose significant operational and environmental challenges. Efficient treatment of these waters is essential to enable their safe reuse or discharge while maintaining the sustainability of geothermal operations. This study presents a Life Cycle Assessment (LCA) of a pilot-scale ultrafiltration–reverse osmosis (UF–RO) system dedicated to geothermal water treatment. Environmental impacts of construction, operation, and end-of-life phases were evaluated using SimaPro 9.5.0.0 and the ReCiPe 2016 method. The novelty of this work lies in assessing a real UF–RO configuration for geothermal feedwater, thereby identifying system-specific environmental hotspots. Results show that material-related processes, particularly membrane production and disposal, dominate total impacts (≈80–85 %), followed by pump manufacture (10–15 %) and electricity use (<5 %). Improving material circularity and membrane lifespan offers the highest reduction potential.