Duckweed is the tiny flower that turns pig poop into fuel, producing more starch, and thus ethanol, per acre than corn:
More than a decade ago, Cheng and fellow NC State forestry professor Anne-Marie Stomp wondered whether fast-growing duckweed, commonly seen in shallow ponds, might remediate animal waste. Excrement from the billions of animals raised every year in America’s factory farms has fouled watersheds, especially in the South, and fed oxygen-gobbling algae blooms responsible for rapidly-spreading coastal dead zones.Duckweed, they discovered, has an appetite for animal waste, quickly converting it to leafy starch that can then be converted into ethanol. The current source for most U.S. ethanol is industrial-scale corn farming, which requires large amounts of toxic pesticides and dead zone-feeding, fuel-intensive fertilizers. When the costs are added up, corn-based ethanol may prove little cleaner than gasoline.
Duckweed could help solve both problems at once.
“We did small-scale tests in the laboratory to convert duckweed starch to ethanol using the same technologies as the fuel industry currently uses in corn,” said Cheng. “With the same technology, we can easily convert it.”
Duckweed consumes nitrogen, phosphorous, calcium and iron, making it a potential source of remediation not only for the lagoons in which farm waste accumulates, but any type of wastewater.Because duckweed is found in all but the coldest climates, there’s little chance of it causing problems as an invasive species, said Cheng. The researchers have moved from the laboratory to a pilot-scale operation on a commercial farm.