Comparative analysis of manure treatment scenarios on climate change and eutrophication in the Baltic Sea

• Separation scenario shows best performance in LCA results. • Transport is a major contributor to climate and eutrophication impacts. • Spatial differentiation in LCIA is essential for baltic region studies. • Efficient nutrient allocation reduces eutrophication in the baltic sea. • Improved nutrient use efficiency can meet p reduction targets by 65 %. This study conducted a life cycle assessment (LCA) of manure management, identifying transportation as a major contributor to global warming and freshwater eutrophication impacts. Transporting substrates to the biogas plant was the main hotspot, highlighting a critical area for improvement. The findings emphasize the importance of method selection in geographically dependent assessments, especially in the Baltic Sea region. Characterization factors specific to Sweden revealed higher environmental impact values than those produced by the ReCiPe method, underscoring the need for regional differentiation in LCA. By optimizing manure management practices and enhancing nutrient distribution, impacts on both climate change and eutrophication can be significantly reduced, thereby lowering nutrient flow to the Baltic Sea. Combining these optimizations with transportation impact reductions further amplifies these environmental benefits, demonstrating that geographically tailored approaches in LCA offer essential insights for managing regional-scale effects.