Synergizing process efficiency and environmental sustainability in a pilot-scale anaerobic digestion system for volatile fatty acid recovery from waste

ABSTRACT Volatile fatty acids (VFAs) are valuable industrial inputs traditionally produced through petrochemical routes. Converting waste into VFAs offers a sustainable and environmentally responsible alternative. To identify optimal operational conditions, pilot-scale treatability studies are essential. This study evaluates the environmental performance of such a pilot anaerobic digestion system using life cycle assessment (LCA) to reveal the sustainable treatment condition. LCA modeling was conducted in GaBi software with the Ecoinvent database, applying the CML2001 method for impact assessment. The pilot plant inhibits the methanogenesis to efficiently yield VFA-rich liquid from primary sludge and food waste. System boundaries cover electricity and chemical inputs, the anaerobic digestion process, and sludge incineration, following a gate-to-gate approach. By integrating treatability results with LCA outcomes, this study identifies the most environmentally favorable operating conditions and underscores the importance of impact assessment before scaling waste-to-VFA technologies to full-scale applications. Although quantifying the financial cost of environmental burdens remains challenging, linking efficiency with environmental performance highlights the industrial significance of this work.