[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2014/07/EW-07-23-14-Versatile-Duckweed.mp3|titles=EW 07-23-14 Versatile Duckweed]
Duckweed is a tiny and extremely simple flowering aquatic plant that floats on or just beneath the surface of still or slow-moving bodies of fresh water. It is an important high-protein food source for waterfowl and is even eaten by people in some places. Duckweed is extremely fast growing and is capable of doubling its population in as little as 48 hours. In warm climates, it can grow pretty much anywhere.
Duckweed has great industrial potential. It can be used to clean up wastewater because it thrives on all sorts of sewage. A shallow pond full of effluent from a secondary treatment plant is basically duckweed fertilizer. And, in fact, water treatment plants in the South Pacific, New Zealand, and Australia already use duckweed to clean wastewater.
Alternatively, duckweed makes an excellent biofuel feedstock. The plants are large enough that they can easily be separated from water, air dried and, like hay, stored. The resultant biomass can then be burned to produce both natural gas and steam. A company in New Jersey, Biomass Alternative Power, is building a duckweed power plant that is expected to go online late next year.
There is the potential for combining these two uses for duckweed into hybrid bioenergy and wastewater treatment enterprises. Duckweed entrepreneurs may be able to generate revenue by both cleaning up industrial and agricultural wastewater and by generating energy at the same plant. It could be a pretty impressive feat for a lowly water plant that thrives on the worst sort of dirty water.
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Web Links
The Ugly Duckling: Can Duckweed Find Its Way to Bioenergy Commercialization?
Photo, posted September 18, 2013, courtesy of Texx Smith via Flickr.
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Earth Wise is a production of WAMC Northeast Public Radio.