Waste grease and fats could be used to produce bioproducts and biodiesel. The non-meat parts of livestock (including fats) undergo further processing (called rendering) to make them useful for other products. About 9.3 billion pounds of fats and greases (edible and inedible tallow, greases, lard, and poultry fat) are processed by the rendering industry annually. Included in that quantity are 1.3 to 1.5 billion pounds of yellow grease that is collected and recycled.
Yellow grease is generated by restaurants; it is the used fats and oils contained in cooking vats. Restaurants and other institutions also generate trap (brown) grease, which is cooking fats and oil lost down the sink drain and captured in grease traps. An estimated 3.81 billion pounds of trap grease are produced annually. Some trap grease is collected and recycled by the rendering industry, but most is collected by the septic industry or disposed of as part of municipal wastewater.
Around 42% of the fats and grease processed by the rendering industry are currently used domestically - primarily for livestock feed (about 85%), with the remainder used for human consumption (edible tallow and lard) and industrial products (soap, lubricants, fatty acids). Approximately 58% of the total fats and grease produced is exported. Prices of waste greases and fats are lower than virgin vegetable oils, such as soybean oil.