Production of Biodiesel from Food Waste

Abstract

Food waste generated faces serious environmental problem. It pollutes surrounding land, air and water. There is an urgent need of its sustainable disposal technique. In this study, an innovative initiative has been taken to chemically characterize the food waste and identify the possible reuse and disposal techniques. Food waste samples are collected from kitchen of girls hostel of National Institute of Technology, Rourkela. Collected food waste samples were dried by various methods i.e., oven drying (55 ºC, 75 ºC, 105 ºC), freeze drying (-4 ºC) and sun drying. It is observed that oven drying method at 105 °C is the optimum temperature for maximum dewatering of food waste. The dried samples were further used for lipid extraction using solvents. Lipid profile analysis of the food waste samples were performed using a combination of different times (20, 40, 60, 80 and 100 min) of contact with varying solvent to food waste volumes (1:4, 1:2, 1:1, 2:1, 3:1 and 4:1). Gas chromatography- mass spectrometry (GC-MS) and gas chromatography- flame ionization detector (GC-FID) analyses have been performed to identify and quantify the presence of organic compounds in lipid from food waste. The results obtained from lipid profile analysis suggest that the kitchen food waste can be an innovative raw material for biodiesel production. The extracted lipid was transesterified for biodiesel production. During transesterification, effect of temperature, reaction time and methanol: lipid ratio was performed to study its effect on biodiesel production. Conversion of lipid to biodiesel increases with temperature upto the boiling point of methanol then it decreases. The produced biodiesel was analyzed in GC-FID for FAME analysis and compared with international standards. Chemical characterization (Ca, Mg, Cu, Zn, Cr, Fe, Ni) have also been performed of residue left after lipid extracted from food waste to identify its other possible reuse techniques. Calcium (20.36 mg/kg, iron (30.84 mg/kg), magnesium (3.00 mg/kg) and chromium (1.28 mg/kg) dominate the metallic species. The residue thus can be further reused by pharmaceutical industries after extracting these metals and also as soil and plant nutrients.