Abstract
Waste oils are generated in massive amounts and can be used for biodiesel, biogas, and biopolymers production due to their high lipid content. In this study, the potential applications of pig-cooked waste oil (PCW) and vegetable-cooked waste oil (VCW) were evaluated by proximate and ultimate analyses. The elemental composition was also determined by using an elemental analyzer followed by acid-catalyzed transesterification for the conversion of PCW and VCW to biodiesel. In both waste oils, carbon (57% and 77%) was highest which resulted in high heating values of 27 and 40.79 MJ kg(-1) for PCW and VCW, respectively. The lipid content of both waste oils ranged from 81 to 84% with the highest C16/C18 (30-78%). The major fatty acids were palmitic (8-26%), elaidic (20-23%), and oleic (18-37%) acids, and their derived biodiesel properties complied with international standards. Fourier transform infrared spectroscopy (FTIR) represented the presence of lipid-specific linkages such as hydroxyl, carbonyl, and ester groups. Thermogravimetric analysis (TGA) confirmed the presence of high volatile matter (99%) and low ash content, indicating their organic nature. VCW showed high biomethane potential (775 mL/g VS), while the high saturated fatty acids (48%) in PCW indicated its suitability for biopolymers production. This study demonstrated that the utilization of PWC and VCW for eco-friendly applications would address the issues of environmental pollution and waste management.