A brief review of palm oil liquid waste conversion into biofuel

Abstract

Palm oil is an important edible oil because of its high content of beta-carotene and vitamin E, high oil output, and solid fat content. However, its extensive commercialization has resulted in a vast amount of waste, leading to challenges for the development of an economically feasible conversion of palm oil waste into useful products. This review focuses on exploring the various conversion processes of the liquid waste produced from the palm oil processing industry. The main treatment of palm oil mill effluent (POME), which can be separated into fiber, wastewater, residual oils, and other impurities, involves a digestion process that produces biogas, while the fiber and other impurities are often converted into animal feed, soil fertilizer, fermentation media, and yeast production. Residual oil found in POME, known as sludge palm oil (SPO), contains high levels of free fatty acid (FFA). Other residual oils resulting from palm oil refining include palm fatty acid distillate (PFAD) and palm acid oil (PAO) that also have a high FFA content. The transesterification and esterification processes are utilized to convert SPO, PFAD and PAO into fuel.