Review of biodiesel production by the esterification of wastewater containing fats oils and grease (FOGs)

open access articleA promising solution for the near future is the substitution of non-renewable fossil fuels with a sustain able liquid feedstock for biofuel (biodiesel) production. The cost of conventional biodiesel production is higher than that of petroleum-based diesel production since it is produced mostly from expensive high quality virgin oil. 70–80% of the overall biodiesel production cost is associated with the cost of raw mate rials. Brown grease (with free fatty acid levels > 15%) is created from rendered trap waste and is known as Fats, Oils, and Greases (FOGs). It is a potential source of biodiesel feedstocks and is available at no cost. Many researchers are interested in using low-cost high Free Fatty Acid (FFA) oils as the feedstock for bio diesel production. This paper reviews the effect of feedstock pre-treatment and process parameters on the conversion of FOGs-wastewater to biodiesel by esterification, including alcohol to oil molar ratio, reaction temperature, reaction time, catalyst amount