Duckweed grown on waste water from industrial pig (hog) units in the USA, produces five to six time more starch per acre than corn, and is now being touted as a ethanol feedstock of the future by researchers at North Carolina State University. The duckweed system, says Dr. Jay Cheng and Dr. Anne-Marie Stomp from NCS, consists of shallow ponds that can be built on land unsuitable for conventional crops, and is so efficient it generates water clean enough for re-use. The technology can utilize any nutrient-rich wastewater, from livestock production to municipal wastewater.

"We can kill two birds – biofuel production and wastewater treatment – with one stone – duckweed," Cheng says. Large-scale hog farms manage their animal waste by storing it in large "lagoons" for biological treatment. Duckweed utilizes the nutrients in the wastewater for growth, thus capturing these nutrients and preventing their release into the environment. In other words, Cheng says, "Duckweed could be an environmentally friendly, economically viable feedstock for ethanol."

"There's a bias in agriculture that all the crops that could be discovered have been discovered," Stomp says, "but duckweed could be the first of the new, 21st century crops. In the spirit of George Washington Carver, who turned peanuts into a major crop, Jay and I are on a mission to turn duckweed into a new industrial crop, providing an innovative approach to alternative fuel production."

Cheng and Stomp are currently establishing a pilot-scale project to further investigate the best way to establish a large-scale system for growing duckweed on animal wastewater, and then harvesting and drying the duckweed.