Green Options » phytoremediation

Seven Weeds That Could Power Your Car

Tina Casey — Wed, 30 Sep 2009 16:52:51 +0000

With the attention on first generation corn ethanol fading, the next big thing on the sustainable fuel horizon is nonfood biofuel crops. Within that category, inedible weeds are taking a front-row seat due to their relatively low demands on water, pesticides, and herbicides, and their reduced need for tilling and other mechanized soil prep. Some weeds with biofuel potential can also thrive on contaminated soils, absorbing and cleaning pollutants in a process called phytoremediation.

Cattail Army Deployed to Fight Water Pollution

Tina Casey — Sat, 16 May 2009 14:18:08 +0000

The lowly cattail is emerging as the weapon of choice against water contamination, and perhaps even global warming. In addition to its use in large phytoremediation projects to absorb contamination from groundwater and wetlands, the cattail could also work in on a small, inexpensive scale, helping to reduce arsenic contamination in impoverished areas. All this and biofuel, too?

Salty Biodiesel Crops May Be Grown at the Beach

Clayton B. Cornell — Thu, 02 Aug 2007 16:52:25 +0000

Researchers want to produce biodiesel at the coast. Building on last week’s post, University of Delaware researchers are interested in developing a type of mallow, the seashore mallow, for biodiesel and ethanol production:

And unlike soybeans and corn, which require annual plantings on valuable farmland to feed the growing appetite for biofuels, the pink-flowered seashore mallow is both a perennial and a halophyte, or salt-tolerant plant, that can grow in areas where other crops can’t.

“You don’t have to divert land that is presently used for producing food and feed to the process of making biodiesel,” said Gallagher, who runs UD’s Halophyte Biotechnology Center with his wife and fellow researcher, Denise Seliskar.

Coastal intrusion of seawater is important in many parts of the world, with more than 20 countries actively studying saltwater food crops. But the idea to use some of these crops as a fuel source is a more recent development. As it happens, seashore mallow comes from the same plant family as cotton, and has an oil content similar to soybeans and cottonseed.

At least for now, first-generation biofuels (those made from food crops) seem like they’ll be sticking around for awhile, and the door is wide-open for niche biofuel feedstocks that don’t compete with our food supply. But the there’s an underlying concept here that’s even more important: finding solutions to ecological problems that preserve or enhance ecosystem services. Many of these services are taken for granted (coastal buffers being a big one - think about the last tsunami), but they carry out tasks nearly impossible to emulate economically. The existing Canadian Boreal forest, for example, is more valuable for its role in water purification and regional climate impact than the the total profit from cutting down and processing the entire forest. This is an extreme example, but it highlights the importance of things we forget about at the smaller level too. While intact natural systems should be preserved at both macro and micro levels, there is also great potential to repair or enhance them.

While the seashore mallow might be handy for a quick snack, the sturdy plant also has provided Gallagher food for thought in addressing a smorgasbord of environmental problems, ranging from global warming to the disappearance of coastal farmland…

With the threat of sea water encroaching on farmland and coastal aquifers in response to global warming, Gallagher believes the seashore mallow could help preserve the economic value of arable land transitioning to marsh land.

Seashore mallow has other desireable attributes as well:

The meal left over after oil is extracted from mallow seeds has enough protein to be used for animal feed, while the stems, which multiply each year during the life of the plant, have potential for use in cellulosic ethanol, Gallagher said. The roots of the plant, cousin to one used by ancient Romans for a confection that lent its name to the marshmallow, could be used to make industrial gum.

A crop that desalinates land, acts as a coastal buffer, increases biodiversity, and provides a sustainable fuel and animal feed source? Sounds like a winner. While seed yields need to increase before commercialization is realistic, halophytic crops could fill a vast niche:

According to Bushnell, some 250 halophytes are potential food staple crops, while thousands more might be available as fuel biomass. With two-thirds of the earth’s available fresh water used for conventional agriculture and more than 40 percent of its land mass considered desert or wasteland, the advantages of agriculture using marginal soils and abundant seawater are readily apparent, according to Bushnell.

For the full story, click here.

UD researcher sees biofuel potential in salt-tolerant plant

Photo Credit: Delaware Online

1. Pennycress

Photographer Karen Phillips describes Pennycress as a “cool little Brassica” that can grow in nickel-contaminated soil that would kill most plants. A pennycress biofuel facility is in the works for Peoria, Illinois, and upstate New Yorkers are also looking into the weed, more colorfully known by the locals as “stinkweed.”

Image: karenphillips on flickr.com.

2. Amaranthus

Also known as pigweed, Amaranthus is a highly competitive, classified noxious weed that proves how good bad can be. The pesky little devil has garnered praises from researchers at the University of New Mexico for its ideal traits as a biofuel crop including drought tolerance, high rate of photosynthesis, and resistance to disease and pests.

Image: Just chaos on flickr.com.

3. Kudzu

Biofuel could be the redemption song for kudzu, the voracious creeper known as “the plant that ate the south.”Aside from absorbing trees and bushes into an eerie green moonscape, kudzu boasts a hi-carb content that could be converted to ethanol using a yeast-based process. To offset the expense of harvesting kudzu from the steep hillsides that it favors, researchers point out that there are no costs for fertilizing, irrigating, or planting the invader, which was imported to the U.S. from Asia in the 1870’s.

Image: Alabama kudzu by Alarob on flickr.com.

4. Arundo donax (giant cane)

Able to grow almost three inches per day in the summer, giant cane (Arundo donax) could be the superhero of the biofuel world, producing multiple harvests every year on poor soil. Left unmanaged, though, it turns to the dark side. At least six states from California to Maryland have reported it as an invasive species.

Image: Shizahao on wikimedia.org (creative commons license).

5. Castor

The lovely castor plant is a noxious weed in Australia, introduced in 1803 and firmly establishing itself as a pest in every state except Tasmania. Meanwhile over in Israel, the company Kaiima Bio-Agritech believes that it has found a way to manipulate the chromosomes of biofuel crops to double their yield, with castor showing particular promise - at least in countries where it can be cultivated without overwhelming native species.

Image: pizzodisevo on flickr.com.

6. Jatropha

The jury is still out on jatropha, which achieved biofuel superstar status a couple of years ago only to see its star tarnished by charges of land grabbing, deforestation, and even biopiracy, including the replacement of food cropland for jatropha cultivation. Lesson learned: whether it’s a food or nonfood crop, biofuel cultivation has to be balanced with regional and global nutrition.

Image: prashantby on flickr.com.

7. Chinese Tallow

We have none other than Benjamin Franklin to thank for Chinese Tallow, also known as Florida Aspen or more colorfully as the Gray Popcorn tree. It grows profusely in ditches and dikes from South Carolina through the entire Gulf Coast. Though trees aren’t usually thought of as weeds, the Chinese Tallow is in a class by itself: considered a noxious invader in the U.S., it joins algae and palm oil among the top three vegetable oil crops.

Image and background information: BaylorBear78 on flickr.com.

Turning Brownfields Into Biofuels

Clayton B. Cornell — Thu, 26 Jul 2007 13:25:27 +0000

What if you could use plants to turn industrial waste sites into fertile, productive cropland? Better yet, what if you could produce biofuels in the process? By marrying bio-remediation and crop production, a group of Carnegie Mellon University graduates hopes to do just that: produce biodiesel and ethanol on reclaimed land.

"It’s a proven technology, but in an unproven environment," said Mr. Butcher, 27. "The idea of growing energy crops is not necessarily a new one; the idea of growing them on distributed sites on vacant land, in an urban context, is kind of a new idea."

Kind of. It’s happening elsewhere, in dribs and drabs. Monroeville’s Cardinal Resources plants poplar trees, which suck up toxic waste, at manufacturing sites around the country, but doesn’t convert those plants into fuels. In Los Angeles, a design team funded by the Annenberg Foundation has turned a 32-acre rail yard into a massive cornfield and garden. But that project, dubbed "Not a Cornfield," is more urban artwork than laboratory. The closest parallel can be found in Michigan, where Michigan State University researchers are turning a 2-acre dump site into land for biodiesel and ethanol crops.

Using plants, enzymes, fungi, or microorganisms to depollute contaminated areas isn’t an entirely novel concept. Phytoremediation - using plants to clean up the soil - has been practiced for centuries. Due to general increases in industrial pollution and the sheer potential of the idea, using naturally and (more recently) genetically-engineered organisms to ameliorate pollution has gained special emphasis in the last 20 years.

The CMU group is taking the next logical step in bioremediation by attempting to create a usable byproduct, in this case fuel:

GTECH [Growth Through Energy and Community Health], a nonprofit that sprang out of a master’s thesis, is hoping to bring all of the divergent threads together, stitching a strategy that will cleanse contaminated industrial land, occupy vacant urban plots and produce renewable fuels, the last of which happens to be one of the hot political topics du jour.

Test crops already have been planted. At the former LTV Steel site in Hazelwood, the GTECH crew has taken over six barren acres of fill and planted hybrid poplar trees, switchgrass and sunflowers. The first two can be reduced into cellulosic ethanol — that is, ethanol that isn’t corn- or grain-based — while sunflowers become conventional biodiesel.

Testing several types of crops is important, since each plant removes different contaminants. For example, ragweed and poplar trees sequester lead. Barley and sugar beets excel at removing salt and have commonly been used to desalinate agricultural land. Naturally occurring bacteria can be harnessed to assist in cleaning up oil spills. And sunflowers are apparently well-suited to remove arsenic and uranium from soils - just in case you had a chemical explosion or a nuclear meltdown.

It’s also important to find crops with properties conducive to making biofuels. Growing ethanol- or biodiesel-producing crops on contaminated land bypasses the food vs. fuel issue and could make more land available for cultivation.

But it isn’t clear that any of these crops will actually work for the intended purpose, especially on really polluted sites. Will it take a succession of several different crops or polyculture to fully remediate the soil? Will the plants even grow under such poor conditions? And more importantly for the project, will the biofuels meet ASTM fuel standards, considering the contaminant load they could contain?

"We’re not growing on even farmland, which is hard enough to grow on," said Ms. Koch, 33. "We’re growing on vacant properties, which are usually demolished houses that have brick and glass and cement and rebar and all kinds of terrible things. [Crop] quality is going to be a concern," especially in the first years. It’s a concern at Michigan State, too. Will the end product meet industry standards — and, should they come to pass, federal standards — for what makes usable biofuel?

Time will tell. In any case, it’s a great idea, and the group deserves a nod:

"You’re going to see a lot more land, whether it’s a brownfield or otherwise, get utilized for crops like that. I wouldn’t be surprised to someday see all the highway grass be switchgrass instead," he said. Rather than paying PennDOT workers to mow grass along the sides of highways, farmers or biofuel companies might bid for the rights to harvest the switchgrass, which sprouts perennially and grows well in poor soil and cooler climates.

CMU grads want to use blighted industrial, residential sites to produce bio-fuel crops. July 10, 2007. Post-Gazette.
Wikipedia: Phytoremediation
Wikipedia: Bioremediation

Photo Credit: Post-Gazette