One day the people of the world may say, "In America, the roads are paved with pig manure."
Processed pig manure is a cheap and sustainable petroleum-free way of paving roads, according to a group of scientists, who say their tests are showing promising results.
The most commonly used substance for paving roads in America now is asphalt, which is made from petroleum pitch and rock, typically sand or gravel.
But Ellie Fini of North Carolina Agricultural and Technical State University says that pig waste is oil-rich and abundant in the United States, and can serve as a petroleum substitute.
The world produces 43 billion gallons of pig manure every year — and that number could climb further if more industrializing nations increase their consumption of meat.
Fini and her team process the manure into a black petroleum-like substance for a low cost of 56 cents per gallon. Once they mix it with rock, they have a natural, renewable asphalt.
They have even set up a company called Bio-Adhesive Alliance to market the substance.
Here is a video from the National Science Foundation describing the team's work.