April 21, 2004

SUPERFREAKINCOOL (via John Resnick):

Money that grows on crops (Jen Ross, 4/15/04, The Christian Science Monitor)

He can't quite make money grow from trees, but a New Zealand scientist has devised a way to harvest gold from plants.

The idea: Use common crops to soak up contaminants in soil from gold-mining sites and return the areas to productive agriculture. The gold harvested from the process pays for the cleanup - with money left over for training in sustainable agriculture.

"We get the plants to do the hard work, and then we basically harvest the plants and extract the metal," says Christopher Anderson, an environmental geologist from Massey University in Palmerston North, New Zealand. "So we farm mercury and gold." [...]

Mercury, for example, is one of the most toxic contaminants for humans and animals, and one of the most difficult and costly to clean up. But using regular corn and canola plants, Anderson has found that this can be done at almost no cost, and with benefits to the environment and local community.

The process is called phyto- remediation. First, he treats the contaminated soil with chemicals that break the gold down into water-soluble particles. Then he introduces the crops.

"Basically a plant will take up anything that's in the soil," he says. Corn and canola have a natural ability to take up huge amounts of metal.

Of course, the crops aren't eaten because they're full of toxic metals.

Instead, Anderson harvests them for their minerals as they begin to die. He estimates he can recover 1 kilogram of gold per hectare (14 ounces an acre) and about half as much mercury through this process. Then the gold is used to pay for the cleanup and to educate locals about sustainable agriculture.

During the metal-harvesting, his team trains local people in farming techniques, so once the land is clean, they can reclaim it and use it for subsistence farming. "It's turning waste into a resource," says Anderson. "We're looking to create an alternative lifestyle for these artisanal miners to help them escape the poverty."

Can you use the corn byproduct for ethanol?

Posted by Orrin Judd at April 21, 2004 11:17 AM

No reason the ethanol can't be recovered, unless the metal extraction process destroys the carbohydrates that are fermented to get the ethanol. Of course, there may be some metal efflux to attend to also.

Posted by: M. Murcek at April 21, 2004 11:25 AM

Using the byproduct for ethanol would depend on what kind of product is left after the gold is extracted. This article seems to indicate that they are using standard corn and canola (rape), but research has shown that plants can be selected for superior metal accumulating characteristics. This is the first I have heard of recovering metals from plants. Generally plants used for phytoremediation are deposited in a hazardous waste-approved landfill after harvest.

Posted by: Jason Johnson at April 21, 2004 11:28 AM

"We're looking to create an alternative lifestyle for these artisanal miners to help them escape the poverty."

Subsistence farming is poverty.

Posted by: Raoul Ortega at April 21, 2004 11:30 AM

You understand, of course, that ethanol is a terrible fuel, more wasteful of energy than petroleum products and exists only because of huge federal subsidies to agriculture and ADM.

Posted by: David Cohen at April 21, 2004 11:41 AM

We have corn. We don't have oil.

Posted by: oj at April 21, 2004 12:19 PM

>>"We're looking to create an alternative
>>lifestyle for these artisanal miners to help
>>them escape the poverty."
>Subsistence farming is poverty.

It could still be a better deal for them than what they have now. As my church puts it, there is poverty and there is MISERY. If they're in Misery and this enables them to climb to Poverty, it is still an improvement in their lot.

Posted by: Ken at April 21, 2004 12:56 PM

I think it would be very unlikely that you could get non-contaminated ethanol out of the plants. I suspect that the extraction method involves burning the plants.

Posted by: Annoying Old Guy at April 21, 2004 1:07 PM

Although there are some industry and government studies going the other way, it seems to take more energy to turn corn into ethanol and get it into a car's tank than you get from a tank full of ethanol. At the same time, it is considerably more expensive than fossil fuels, considering the tax breaks, higher food prices and outright subsidies we pay to keep gasahol only slightly more epensive than gasoline. Finally, it takes about as much land to grow the ethanol to keep one car going for one year as it does to grow the food for seven families for one year.

Posted by: David Cohen at April 21, 2004 1:38 PM

I am assuming this costs less than just hauling
away the soil? Are there any lost opportunity
costs to waiting all that time for the process
to take place? Otherwise it's an interesting
idea. Certainly there are plenty of sites in the
Northeast and Midwest that could benefit from
this ostensibly low-intensity remediation.

Posted by: J.H. at April 21, 2004 1:41 PM


We don't import food from the Islamic world.

Posted by: oj at April 21, 2004 1:45 PM

No oil for religious morals, David.

I expect Guy's right about burning the plants. Wonder what they use to "break down" gold. Gold doesn't form compounds easily, and some of the stuff it does form compounds with is pretty nasty.

Posted by: Harry Eagar at April 21, 2004 2:19 PM


Which is why we shouldn't promote ethanol, the manufacturing of which requires us to import more petroleum than if we just put straight gas in our tank.

As it happens, there is an alternative energy source that is environmentally friendly, based on robust, well-understood technology, is price-competitive with current energy sources, would fit seamlessly into the current infrastructure and, for Senator Kerry's benefit, is very popular in France. Best of all, we're the Saudi Arabia of uranium. I'll believe we're serious about energy independence when we start building nuclear power plants.

Harry: ?

Posted by: David Cohen at April 21, 2004 2:38 PM


But isn't the point that we aren't serious though and only exorbitant costs for fossil fuels could make us so?

Posted by: oj at April 21, 2004 2:52 PM

David (and others) are right about the problems with net energy consumption involved in producing ethanol from corn. However, ethanol (or methanol) could be produced from other sources not growing on our nation's prime farmlands or produced using energy-intensive measures.

For instance, I work as a forester in Utah. My biggest concern is the unnaturaly high densities of our forests (a result of decades of fire suppression, grazing, and too little harvesting). I help manage many square miles of forests that are choked with many tons per acre of low-quality small diameter trees, trees that are not suitable for sawing into logs, and would not pay their way to a paper mill. There is practically an unlimited supply of this kind of material in the Rocky Mountain and Pacific states, as well as many eastern forests. If someone could design a small scale plant that could be erected close to the forests one might be able to produce fuel cost-effectively while reducing fire risk and improving the health of our forests.

Just because Tom Latham and other midwestern politicians think that biofuels should only produced from farm state politicians does not mean than we have to follow that track.

Posted by: jasonjohnson at April 21, 2004 2:54 PM

Just because . . . midwestern politicians think that biofuels should only produced from farm state politicians does not mean than we have to follow that track. I'd be perfectly willing to follow that track and it's gratifyingly self-sacrificing of them, I must say.

OJ: Spending lots of money on demonstration projects so that we can spend lots of money on subsidies for a technology that would require us to spend lots of money on infrastructure to set up a process that would ultimately implode, is not serious.

Posted by: David Cohen at April 21, 2004 3:02 PM


Who said anything about spending any money--I'm suggesting we collect it.

Posted by: oj at April 21, 2004 3:41 PM

Ow, my head hurts.

If you want to develop alternative fuel sources, then, yes, the best way to do it is to jack up the price of gas (by at least $2.50/gallon, and that's probably not enough) and see what develops. I'm not sure what it would be, but it won't be ethanol and it won't be fast. Unless you make it a carbon tax, it would probably be coal. In the short run, we'll all be screwed, including the government which will see its tax collections plunge and its costs explode.

Posted by: David Cohen at April 21, 2004 3:48 PM

If you want an omelette...

Posted by: oj at April 21, 2004 3:56 PM

Is the broken egg in this metaphor the economy, the government or my head? Just wondering.

Posted by: David Cohen at April 21, 2004 4:08 PM

Heard a man on the radio say we are short of oil because the oil is in alaska but the dipsticks are in washington.

"Just because Tom Latham and other midwestern politicians think that biofuels should only produced from farm state politicians does not mean than we have to follow that track."

like the old bumper sticker in Texas:

Cold? Burn a Yankee Politician

Posted by: Robert Schwartz at April 21, 2004 4:30 PM


It's the previous disastrouss experiment in social engineering--the federal highway system.

Posted by: oj at April 21, 2004 4:42 PM

David, right on. My physics adviser tells me that there is a nuclear technology (at Ft. St. Vrain, Colo.) that is absolutely foolproof. No safety issue whatsoever.

When I wrote earlier that there are no alternatives to gasoline, I was ignoring nuclear because I believe it is out of court. Shouldn't be, but is.

Question for Jason: how do you get the scrub wood out leaving the forest intact?

Out here, where Molokai has the highest electricity rates in the country, they tried using wood chips in the boilers a few years ago. A disaster on the ground and didn't work in the boilers.

Posted by: Harry Eagar at April 21, 2004 5:40 PM

Orrin, you just made my head hurt again, and I just got over a nasty little cold too, blast you anyway *sneeze*, *cough*, *honk*. Did I just hear you call the Interstate Highway System a disaster?
Never mind, that was a rhetorical question. I invite you to tell that to my mother and stepfather when they drive up I-95 this coming weekend to visit me, my sister, and my brother-in-law here in Northern VA, and to see off two of their closest friends as they move to Wyoming (presumably moving their chattels via the Interstate).

Posted by: Joe at April 21, 2004 5:42 PM

On second thought, I think I've figured it out:

Orrin wants to revive the passenger railroad industry.

Posted by: Joe at April 21, 2004 5:48 PM


Take the train and talk to someone.

Posted by: oj at April 21, 2004 6:22 PM

Update: I meant to say that farm state politicians think that all ethanol must be made from corn. Thats what I get for not rereading my post.

Harry, I would assume that mechanical means would have to be used if this is to be done cost-effectively. If there is a market then manufacturers would create the needed equipment fairly quickly. There is already a lot of equipment available for reducing fuel loads, most of these reduce the material to something less likely to burn vigorously and leaves it on-site. An example:http://extension.usu.edu/forestry/Business/Equip_BrushCutter.htm. I would expect that a scaled down grapple skidder would be the type of vehicle used to remove small diameter material uickly:http://www.timberjack.com/products/skidders/360D-Single.htm. A mechanical harvester like this one can keep a skidder pretty busy: http://www.timberjack.com/products/harvesters/770D.htm.

Right now the Forest Service and others are paying to have small trees cut, then piled and burned onsite in order to reduce fuel risks in many areas (burning is done in the winter or spring after fire season has passed). A market for such material would be very welcome.

Posted by: jason johnson at April 21, 2004 6:25 PM

I linked to the Timberjack products just as an example of the types of equipment currently out there. Looking around there site further I discovered that they already are working on biomass harvesting equipment. They claim that their equipment can harvest such materials while expending 3% of the energy content contained in the material removed. I have no idea how efficienly such materials can be converted to usable fuels. The net efficiency would consist of energy content of fuels - harvest - transportation - processing into fuel. Someone with a better idea of the physics and economics involved would have to figure out how well this compares to Iowa-grown corn - which is much more energy-intensive to grow and harvest, but a higher quality feedstock for fuel production.

The Timberjack forest energy page: http://www.timberjack.com/products/forest-energy/index.html

The Timber

Posted by: Jason Johnson at April 21, 2004 6:51 PM

Jason, does that mean the areas are almost all scrub, no big trees that need saving?

The Molokai situation was a mess from start to finish, but for the purposes of this discussion the biggest problem, I think, was erosion after what amounted to clearcutting.

(Personal note: my wife's family are tree farmers. After observing them and others over the years, I have a rule: anybody who says he is logging selectively is lying. It's all clear cut.)

Posted by: Harry Eagar at April 21, 2004 9:22 PM

Not to get to technical, but most people that do "selective" or "partial" cutting are high-grading - taking the best genetics out of the forest and leaving the slow-growing and deformed trees in the woods. You can do selective logging in a sustainable way for a number of decades (assuming your forest type is ecologically amenable), but at some point it is better to start over.

I won't get into a discussion of clearcutting here, a term foresters hate to see used as a codeword for rape and pillage of the land. For many forest types clearcuts (when done properly) are the best method of harvesting both in terms of the quality of the forest that follows and in terms of conserving the soils that sustain the forest.

Thinning and partial cutting, in general, should always be done from below (meaning the smallest, least vigorous trees come out first) up until the point that the oversory is removed and a new forest started.

The need in the west is for removal of less-desirable shade-tolerant species like fir and spruce that are growing up through stands of sun-loving trees like pines which were established in an era of either clearcutting or frequent fire. Not only are the shade tolerant trees less desirabe, they also change the way that fires behave when they burn through the forest making them more intense and more damaging.

In the southeast, where most of our 2X4s and other dimension lumber come from trees are grown intensively in plantations. Part of the management includes using herbicides to control unwanted hardwoods, and several thinnings before final harvest. I am sure the timber companies would love to put out a press release about how their "weed trees" and pre-commercial thinnings are being turned into clean, green ethanol rather than being sprayed with 2-4D.

Is your wife's families tree farm in Iowa, or back in Kentucky?

Posted by: Jason Johnson at April 22, 2004 12:48 PM

Arkansas. Her great great grandfather homesteaded a beautiful primeval forest, and it was, as you describe, selectively harvested as long as her grandfather was still vigorous.

In his old age, he leased his land to someone who was also going to selectively cut, but thy guy took everything.

What a former planning director on this island called "selective harvesting with a D-9."

Up until the 1980s, my wife's grandfather was bucking out select logs with mules. That makes it really selective, but try contracting for that these days.

Posted by: Harry Eagar at April 22, 2004 3:03 PM

By the way, jason, I guess I should say I'm not opposed to using plants for fuel. On Maui we get about 15% of our electricity from bagasse, the dried remnant of sugar cane after it's been crushed.

The practical problems of doing it with forests, though, particularly in rugged country, make me skeptical.

Posted by: Harry Eagar at April 22, 2004 3:08 PM


I would like to have seen that forest. I don't think biofuels will ever be economical in steep country (over 35% slopes). Burlington, Vermont, where I grew up has an electric plant fired by wood chips - probably a more efficient way of using low-quality wood and wastes than breaking it down and converting it to liquid fuels. However, if the government subsidizes it, as they probably will, then people will get in the business.

Horse and mule logging, by the way, are making a bit of a comeback. Many, many acres of forestland are now owned by retirees and second home owners who are not adamant about getting the absolute highest return from their harvest and are usually most interested in partial cutting. Horse logging makes sense in those situations, especially when only a few acres are being put up for bid. I for one am glad to see it, as I love to watch heavy horses work.

Posted by: Jason Johnson at April 22, 2004 5:44 PM

Me, too, though I haven't had the chance since I left Iowa.

Posted by: Harry Eagar at April 22, 2004 7:19 PM
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