Researchers from North Carolina State University have shown that Duckweed, a tiny aquatic plant much loved by Ducks, can thrive in the effluent waste water produced by large feedlots, such as hog farming operations, and potentially, in urban sewage water, as well. This hardworking little plant not only cleans the waste water of the excess nutrients, but in the process, it produces large quantities of valuable starchy biomass. This biomas can be harvested and used to produce ethonol in the same types of facilities that are currently being used to make ethanol from corn starch.
The starch yields from Duckweed promise to be many times higher than that of corn. “Based on our laboratory studies, we can produce five to six times more starch per unit of footage, ” says Jay Cheng, a biological engineer at North Carolina State University.
That is a lot of starch, and the beauty of it is that biomass needs no fertilizer inputs in order to grow. All of its nutrient needs are contained in the waste water that it is also cleaning. Also, because Duckweed is already a very widely distributed plant, there is little risk of it becoming an invasive species.
The world’s waste water problem is massive and growing. Agricultural and urban waste water are one of the main sources of water pollution and contributors to the formation of dead zones, in lakes and in coastal waters. It destroys and degrades wildlife habitats and fisheries downstream.
Producing ethanol biofuel from corn has proven to be a failure. When one accounts for the energy inputs, including the petrochemical based fertilizers and pesticides, growing the corn uses as much or more embodied energy than the ethanol that it can produce, yields. Furthermore, corn ethanol is objectionable because it uses a very important food crop, in a hungry world, to make fuel. Corn ethanol has been supported by a very powerful lobby and has received very generous government subsidies, but even after many years it has proven to be a very bad idea, and in the process has given all biofuels a bad name.
Perhaps Duckweed can be the humble little aqautic plant that can. While it must be clearly stated that the biofuel grown from Duckweed will never be enough to replace the huge quantities of petroleum that we currently use — no biofuel and no concievable energy carrier exists on the horizen of possibilities that can do that — it may play an important part in providing a portion of that liquid fuel that our economy needs and will continue to need. What makes Duckweed especially appealing is that it produces its biomass by cleaning waste water that would otherwise leech out into our waterways, or require expensive treatment.
