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Earth Science

Capturing Carbon With Garbage Heaps 186

davide marney writes "In a Washington Post opinion piece, Hugh Price argues that using a decidedly low-tech solution to sequestering excess carbon — making piles of agricultural waste — is better than many 'green' solutions already in practice. Sometimes the easy answer is the right answer. After all, it's how coal forms, and we know that works pretty well."
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Capturing Carbon With Garbage Heaps

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  • by lxs ( 131946 ) on Sunday September 19, 2010 @08:34AM (#33626504)

    Better use the waste to make biochar []. No artificial fertilizer necessary.

  • Hmm (Score:4, Interesting)

    by DrMrLordX ( 559371 ) on Sunday September 19, 2010 @08:37AM (#33626514)

    Kinda had this thought some time ago . . . plus, locally, we have numerous "brown fields" that are so loaded down with industrial waste from the 19th and 20th century that they aren't entirely safe for humans and certainly can't grow much of anything, outside of maybe, oh I don't know, gypsum weed. Or maybe jatropha curcas, I hear that stuff is pretty hardy.

    I don't know what plants like gypsum and/or jatropha would actually pull out of soil like that, aside from water and some other nutrients, but if they could be used to leech toxins/industrial waste out of the soil, they could then be "piled high" to create a combination CO2 heap and toxic waste dump. Of course, you'd just be moving some of the nasty crap that made "brown fields" possible from one "brown field" to the next, and I would expect the NIMBYs to be rather upset about that. Still, seems like an okay idea. Let's face it, if you've got an area cordoned off to be your CO2 dump, it's not like you want anything disturbing it anyway, so may as well infuse it with horrible toxic waste that would cost a fortune to dump elsewhere.

  • by DarkKnightRadick ( 268025 ) <> on Sunday September 19, 2010 @08:41AM (#33626536) Homepage Journal

    then explain why "old school" techniques in Africa are so inefficient and ungreen (e.g. huge releasers of CO2).

  • Make charcoal (Score:4, Interesting)

    by KDN ( 3283 ) on Sunday September 19, 2010 @09:10AM (#33626658)

    One variation of this proposal that I have seen is a bit more technical. It heats the agricultural waste in a reduced oxygen atmosphere to generate syngas and charcoal. The syngas you can burn to generate power. The charcoal you bury in old mines. The advantages were that you burn less fossil fuel and the the charcoal was less smelly than rotting waste. Disadvantage is that its more complicated.

  • by Kupfernigk ( 1190345 ) on Sunday September 19, 2010 @09:13AM (#33626662)
    They are talking about using what is almost entirely carbon,hydrogen and oxygen - stalks, leaves and bark. Plants convert as much of their available nitrogen as possible into fruiting bodies or over-winter energy stores (tubers). Leaves of deciduous plants actually fulfil some of the function of our kidneys; when they turn brown and drop off, this is because all available nitrogen and minerals has been extracted, and waste products are transported to the leaves, preventing buildup. Deciduous plants are more successful than conifers partly because of this efficient mechanism for recycling biological assets.

    In organic farming it's common to plant winter crops that fix nitrogen and then plow them in in the spring, but this is completely different from plowing in straw. Until burning of stubble was banned in Europe, this was the commonest fate of straw. Plowing it in has downsides - including returning pest eggs, fungi and viruses to the soil. Removing it completely would have many of the benefits of stubble burning with none of the pollution downsides. I suspect this is neither unworkable nor naive, but it is a solution that doesn't involve lots of pork and so will be resisted by bureaucrats.

  • Yes, and... (Score:2, Interesting)

    by hey! ( 33014 ) on Sunday September 19, 2010 @09:13AM (#33626666) Homepage Journal

    sometimes making "simple" solutions actually work is more complicated than the "complex" alternative. As an engineer you run into this all the time, the manager who's so enamored of his brilliance he can't see the flaws in his idea.

    This guy is talking about creating artificial peat bogs. It actually *is* an intriguing idea, but I don't see it as "simple". It certainly isn't an "alternative" to government subsidies or regulation. Somebody is going to have to pay the farmers to do this, and to buy the land and transport the waste there, and to deal with the effects of removing so much biomass from th cropland.

    Things like grassahol subsidies are supposed to incent the development of new technologies. If those technologies ever make grassahol cheaper than oil, then the subsidies will have bootstrapped a new private grassahol market. That's a big "if", but so is research in energy technologies like fusion. What is problematic is that the farm lobby distorts the program, just as it would a farm waste sequestration program. So it's not a politically simpler solution.

    $100 million dollars to scrub 1.5% of the carbon out of the atmosphere sounds like a huge amount of money, until you consider this. A single F22 Raptor cost half again as much (150 million), and we've managed to purchase 166 of those. Most people would admit that is a lot of money, but there are still people that think buying a few more would be a good investment. When you're talking about an entire national economy like the US, 100 million to accomplish something important isn't that much.

    Now consider the damage figure for Hurricane Katrina, which stands at 81 billion. Now you can't say that any hurricane was *caused* by global warming, but severe hurricanes are more *frequent* under an AGW scenario. If the frequency of such hurricanes increases, a few billion dollars to dial that down wouldn't be that much money, much less 100 million.

  • Re:Actually (Score:3, Interesting)

    by Kilrah_il ( 1692978 ) on Sunday September 19, 2010 @09:16AM (#33626686)

    I think what bothers you (and anyone who hears this idea), is that we expect to do something to capture CO2. Here we are actually supposed to do nothing, or more precisely, prevent the plants from decomposing. This is somewhat counterintuitive.
    Although I'm no expert in the field, the reasoning in article is sound. A few weeks ago, my brother asked me a question: If we eat, how come we don't gain weight? Granted, the food is used to make energy, but energy is only the bonds between atoms/molecules. To make energy the body just breaks those bonds. So his question was what actually happens to the atoms/molecules so that we don't gain weight (assuming a balanced diet). After a few minutes' thought, Biology 101 came back to me and the answer was easy - Part of the energy-making process (Glycolysis, Citric Acid Cycle and Oxidative Phosphorylation*) involves the outputting of CO2. i.e. certain molecules come in (Glucose, Acetyl-CoA, succinate, NADH + O2) and energy + CO2 come out. Simply put, the molecules are broken down to CO2 while releasing energy.
    So, if we stop these processes, we can stop the creation of CO2. Plants consume CO2 and produce different molecules + O2. Animals and bacteria break down the plants and produce CO2. If we grow plants and don't let them be eaten/burned/decomposed, we should have a negative CO2 balance.

    * - Wikipedia is your friend.

  • by ( 1140205 ) on Sunday September 19, 2010 @10:20AM (#33627074)
    Professor Gregory Benford has papers on it. [] There are several papers here going back several years discussing geo-sequestration of carbon in a manner non returnable to the atmosphere. The proposal here does not lock the carbon away.
  • by Kupfernigk ( 1190345 ) on Sunday September 19, 2010 @10:39AM (#33627238)
    I have no idea where you get this from. Plant stems and dead leaves roughly have a composition as if they were made of CnH2nOn, i.e. approx. 1 atom of carbon to each water molecule. This is because the basic building block of plant matter is a 6-carbon sugar. If you don't understand this I am sure Wikipedia will help.

    Now, the carbon came from the atmosphere and so did the water. The basic equation here is n(H2O) + n(CO2) -> n(CH2O) + n(O2), with carbon dioxide removed from the air and replaced with oxygen. Since hay and dead leaves are pretty dry, the effective water content is likely to be equivalent to a centimeter of rain equivalent at most.

    Looking at grasses, the main structural rigidity element is silicon dioxide, which is why grass stems are abrasive.

    This means that removing plant stems and dead leaves only really removes very small amounts of nitrogen and elements other than CHO, and insignificant amounts of water. The silica arises from stone weathering, again not morally a problem.

    The problem arises, in fact, from the removal of the actual crop. It is this that contains the essential soil elements you mention - the N,P,S, the trace elements like potassium,magnesium, selenium and chromium - that have to be replenished with either fertiliser or manure. Removing the parts of the plant that are actually waste from the view of plant reproduction is not a problem. The manure produced by ruminants contains the trace elements because their diet contains plant fruiting bodies and tubers. If you tried to feed cows on straw rather than hay, you would rapidly appreciate the difference - though you wouldn't last long as a dairy farmer.

    As for 50ft topsoil....merely to have written this suggests your connection with farming is extremely tenuous. I on the other hand live in a farming district, I'm well aware of local farming practices, and we grow a lot of our own fruit and vegetables. It isn't naive to know what parts of the plant represent renewables, and what part represents non-renewables.

  • Are we in April? (Score:4, Interesting)

    by rcastro0 ( 241450 ) on Sunday September 19, 2010 @11:01AM (#33627424) Homepage

    This is April Fools' gold:
    >Without access to oxygen, bacteria cannot break down plant material. (...)
    >Instead of trying to manufacture ethanol from switchgrass, would it be more effective to burn oil and bury the switchgrass? We sometimes pay farmers not to grow crops to sustain prices; should we pay them to grow otherwise useless crops and stockpile them? (...)
    > Can leaves, bark and branches that are now discarded or burned be piled up instead? Is it more beneficial to recycle paper or to collect it? (...)
    >The writer is the director of production planning at The Post.

    LOL In the end I get it. The writer of this Washington Post article is the guy in charge of printing the paper-version of the Washington Post ( []). And he is trying to build an argument that producing paper and stockpiling it may be the solution to the environmental problems of our times! ("Help the Planet, Get the Paper Version instead of the online version!")
    Reality can be funnier than fiction.

  • Re:Actually (Score:5, Interesting)

    by Will.Woodhull ( 1038600 ) <> on Sunday September 19, 2010 @11:28AM (#33627606) Homepage Journal

    This cannot work the way TFA suggests: TFA is far too simplistic. Just piling up agricultural byproducts would only produce a large compost heap. It would remain bioactive until it either caught fire through spontaneous combustion or turned into soil. Either way, the carbon has not been sequestered; it remains in the biosphere. The cycle of repose in the large heaps is just too short to be useful.

    That said, there is an approach that would work, in those parts of the world that have snow in the winter. We could create artificial peat bogs.

    Dig pit a couple of acres in cross section and a thousand feet deep. Make it water tight and fill it to the brim with icy cold (4 degree C) fresh water-- it doesn't have to be potable and sea water might work but I only know about fresh water peat bogs, Add a compression mechanism, such as a sinkable platform the size of the pit, weighed down with some of the rock from the digging. Let it sink to the bottom of the pit. Chip the plant material down to a size that will compact easily, then slowly force the chippings under the compressor. That's it. Once operating, the main cost is that of stuffing the new chippings into the bottom of the pit.

    There will be some slow anaerobic activity but so long as the pits are small in diameter relative to their depth, the water will stay cold, stagnant, and deoxygenated. The chip injector needs to be designed to avoid stirring the waters: you want that stagnation. You want dead, cold water that will minimize bioactivity.

    A peat farm of ten pits each 2 acres by 1,000 feet deep could accept more than 4,000 acre-feet of agricultural byproduct each year for one hundred years before it fills, and then it would continue operations indefinitely. For at that point the compressor could be removed since the weight of the old peat would be enough to hold new chippings at the bottom, and the top few feet of finished peat could be removed each year for longer term storage elsewhere. Such as tilling it into desert sand dunes to stabilize them or stuffing it into depleted mine shafts, or storing blocks of the stuff in the Greenland or Antarctic iceboxes.

    Eventually most of the carbon in the peat would return to the biosphere, but this approach would help buy us time to get off our fossil fuel dependency. For that matter, peat is not only a useable substrate for developing petroleum products, it is an effective fuel all by itself. It could be that peat farms could directly replace coal and oil, once we get our needs for petrochemicals down to sustainable levels.

  • by hairyfeet ( 841228 ) <> on Sunday September 19, 2010 @11:59AM (#33627824) Journal

    Actually I'd dare say my idea would probably be listed as crazier, but considering the answers we are getting like carbon credits and stuffing it in a hole, now I'm not so sure. everybody wants a "less painful" fix? One word...Supergun. Gerald Bull had the idea decades ago to launch objects into space by use of a supergun, and with rail technology, powered by a nuclear reactor, it should be possible to get rid of carbon by compressing it into capsules and shooting it into space, where it could then be used for other projects such as to terraform Mars or even as fuel for spacecraft.

    Considering some of the wacky ideas we've been hearing, I'd say mine isn't any crazier, and by using a magnetic rail gun powered by nuclear energy it should be a carbon negative way of getting rid of all that Co2.

  • Re:Yeah (Score:3, Interesting)

    by russotto ( 537200 ) on Sunday September 19, 2010 @04:07PM (#33629626) Journal

    When it does happen, it will affect everyone without regard to their diplomas, and you can blame those who didn't bother doing something about it, which is 99.9% of the population.

    I assure you that if there is a pandemic, poor and minorities will be the hardest hit. (or so the papers will tell us, anyway).

e-credibility: the non-guaranteeable likelihood that the electronic data you're seeing is genuine rather than somebody's made-up crap. - Karl Lehenbauer