The term WASTE FUEL can be summarized as the use of MANURE as a fuel source. MANURE is a type of organic matter that is produced by animals, such as cows, horses, and pigs, and is often used as fertilizer for crops. It can also be used as a fuel source, as it contains combustible materials that can be burned to produce energy. This type of fuel is considered to be renewable and sustainable, as it is a natural resource that can be replenished over time.