Biofuel From Water, With the Help of Duckweed

(MoneyWatch)  Find a reference to duckweed dated earlier than last year, and you're likely to be seeing complaints about the tiny aquatic plant. Like invasive water hyacinth and other floating plant species, duckweed is capable of quickly carpeting ponds and slow-moving water streams.

Now it's being pushed as yet another biofuel savior. From North Carolina State University:

[R]esearch shows that growing duckweed on hog wastewater can produce five to six times more starch per acre than corn, according to researcher Dr. Jay Cheng. This means that ethanol production using duckweed could be "faster and cheaper than from corn," says fellow researcher Dr. Anne-Marie Stomp ... The duckweed system 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.

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."

At this point, taking pot shots at corn is a well-established sport among environmentalists and researchers (at least those not funded by the corn industry). But the NCSU release does itself a disservice by not mentioning the real competitor: open pond algae cultivation. Companies like Sapphire Energy are already eyeing marginal water for algae production, and are more established in the space, if such a thing can be said in an industry where nobody has a product yet.

Amusingly, the NCSU release, while hyping the revolutionary nature of the work, also failed to mention that Rutgers University already announced last year that it would be sequencing duckweed's genes with the Department of Energy, with an eye to making biofuels. But for the biofuel industry, the growing focus on duckweed is probably a good thing; in the future, what was a watery pest may provide a viable way to work yet another part of the planet's surface.