Utilization of locally sourced waste fats for biodiesel production: Experimental characterization and environmental life cycle assessment

Abstract

This study presents the production, chemical characterization, and life cycle assessment (LCA) of biodiesel derived from various local waste feedstocks using experimental setup. Biodiesel was produced via transesterification in a 50-L batch reactor using oils sourced from a five-star restaurant (A), three-star café (B), rancid palm oil (C), and chicken feather oil (D). Fourier Transform Infrared Spectroscopy (FTIR) was used for identification of functional groups, while gas chromatography-mass spectrometry (GC-MS) analyzed fatty acid methyl ester (FAME) composition, revealing key variations such as Hexadecanoic acid (C16:0) and Octadecenoic acid (C18:1). Type A biodiesel exhibited the highest saturation, while Types B and C contained more unsaturated FAMEs, influencing their heating values. Conversion efficiencies were significantly influenced by the acid values of the feedstocks, with a maximum yield of 85 % achieved for a sample with an acid value of 3.5 mgKOH/g and a heating value of 35.8 MJ/kg. LCA performed using Simapro V9.5.0.2 demonstrated that biodiesels from Types A, B, C, and D reduced carbon footprints by 70 %, 64 %, 63 %, and 65 %, respectively, compared to fossil diesel. Feedstocks with lower free fatty acid (FFA) levels resulted in lower environmental impacts, while extensively reused cooking oils with higher FFA values contributed to increased carbon footprints. This study underscores the potential for scalable biodiesel production from waste resources, aligning with global and regional sustainability goals.