Source-separating sanitation systems (SSSS) involve the separate collection and treatment of distinct wastewater fractions, enabling the recycling of nitrogen and phosphorus from urban wastewater and human excreta as valuable resources. SSSS offer a sustainable solution for resource recovery. However, expanding these systems in the European context requires addressing significant challenges and leveraging critical opportunities. While existing research has examined the potential benefits of SSSS, a comprehensive understanding of the barriers and enablers for their widespread adoption from relevant stakeholders’ perspective remains limited. This paper addresses this research gap by categorizing and ranking key challenges and opportunities for expanding source-separating sanitation systems in the European Union, using a political, economic, social, technological, environmental, and legal (PESTEL) analysis framework. Data were collected through expert surveys (n=43) designed to assess the intensity of challenges and opportunities within PESTEL categories on a 10-point scale. The analytical hierarchical process (AHP) methodology was applied to rank these factors based on expert judgments. The results highlight that the most significant challenges include an inconsistent regulatory framework, a lack of cross-sectoral cooperation and a shared vision, and high investment requirements. Opportunities, on the other hand, include tax incentives as the most impactful measure, followed by a paradigm shift toward circularity and legislative support for nutrient reuse. These findings offer actionable insights for policymakers to address systemic barriers, promote innovation, and foster cross-sectoral collaboration to advance resource recovery in the sanitation sector.
