Advancing Social Life Cycle Assessment in wastewater treatment: a review of practices and alignment with ISO 14075

This study presents the first systematic review of Social Life Cycle Assessment (S-LCA) applications in wastewater treatment, explicitly benchmarking methodological practices against the requirements of the International Organization for Standardization (ISO) 14075:2024 standard. We provide guidance for advancing S-LCA towards product-oriented, ISO-consistent applications. Following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, peer-reviewed studies were identified and analyzed according to their methodological choices, stakeholder coverage, and impact assessment approaches. Results show that Workers and the Local community were the most frequently assessed stakeholder categories, whereas Children and Value chain actors were largely neglected. The majority of studies relied on reference scale assessments and often employed organizational instead of product-based indicators, leading to partial or no alignment with ISO 14075. Findings highlight the early stage of S-LCA practice in wastewater treatment and point to the need for future research to advance product-oriented indicators, robust functional units, and broader stakeholder coverage in line with ISO 14075.