A Multi-Criteria Sustainability Assessment of an Avocado Waste Biorefinery Using the SASWROIM Framework

The increasing complexity of integrated biorefineries requires sustainability assessment approaches capable of supporting engineering decision-making beyond conventional economic evaluation. This study applies the Safety and Sustainability Weighted Return on Investment Metric (SASWROIM) to evaluate the redesign of a Hass avocado seed biorefinery by integrating inherent safety, thermodynamic, technical, environmental, and economic performance into a single decision-support metric. The redesigned configuration achieved a conventional ROI of 47.67%, compared with 37.58% for the baseline, while the Total Inherent Safety Index (ISI) decreased from 25 to 20 and the Potential Environmental Impact (PEI) output rate decreased from 23.2 to 20.0 PEI/h. Thermodynamic performance was represented by Specific Exergy Destruction (SED), which decreased from 196.31 to 65.83 MJ/kg of feed, corresponding to a 66.5% reduction in exergy destruction intensity. In contrast, the Wastewater Production Ratio (WPR) increased from 39.8% to 86.35%, identifying water management as the principal technical limitation of the redesigned configuration. Under equal weighting, the combined normalized contributions resulted in a SASWROIM of 59.59%, exceeding the conventional ROI of 47.67% and indicating a net positive sustainability adjustment under the nominal assessment conditions. Sensitivity analyses showed that SASWROIM remained positive across the explored weighting, normalization-target, and scenario-based uncertainty conditions; however, technical-priority weighting and unfavorable combined uncertainty scenarios reduced the metric below the conventional ROI, indicating that the sustainability benefit is conditional on water-management performance and process variability. Overall, the results show that the redesign improved economic, inherent safety, exergy-destruction intensity, and environmental performance while introducing a significant trade-off in water management, highlighting SASWROIM as a transparent framework for identifying multidimensional sustainability priorities during conceptual biorefinery design.