When Is POME a Residue? Definitional Boundaries, Carbon Accounting and Policy Integrity in Sustainable Aviation Fuel

This qualitative literature review examines the definitional controversy surrounding palm oil mill effluent (POME) and its recovered oil as sustainable aviation fuel (SAF) feedstocks. Drawing on 52 cited peer-reviewed journal articles from 2020–2026 and official ICAO and certification documents, it distinguishes unavoidable wastewater, genuinely recovered residual lipids and deliberately diverted primary palm oil. The review interprets the CORSIA POME-HEFA default core lifecycle value of 18.1 g CO₂e/MJ, derived from two modelling estimates, without conflating its assigned indirect land-use change treatment with measured system-wide climate effects. Five thematic findings concern classification boundaries, model-dependent emissions, wastewater methane interactions, plausible recovered-oil supplies and an auditable chain of custody. An origin-and-function framework is proposed to preserve legitimate feedstock eligibility while preventing inappropriate relabelling, duplicate emissions claims and undocumented changes in oil flows. The discussion differentiates official fuel lifecycle accounting from supplementary assessment of methane management and displaced product markets. It recommends mill-level mass balances, independent verification, measured conversion inputs and an adaptive Indonesian policy roadmap. Definitional precision is necessary for regulatory credibility, but cannot substitute for reliable environmental performance or certified fuel production