Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
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."
This discussion has been archived. No new comments can be posted.

Capturing Carbon With Garbage Heaps

Comments Filter:
  • Yeah (Score:4, Insightful)

    by Anonymous Coward on Sunday September 19, 2010 @08:23AM (#33626470)
    but how can you have huge federal bureaucracies and sell carbon credits and implement strange new taxes if everybody uses the simple and elegant solution? Clearly this proposal has a fatal flaw.
    • Re: (Score:3, Funny)

      by gilleain ( 1310105 )

      but how can you have huge federal bureaucracies and sell carbon credits and implement strange new taxes if everybody uses the simple and elegant solution? Clearly this proposal has a fatal flaw.

      I know what you mean, but this has surely the first time that a big pile of plant matter has been referred to as "elegant"...

    • Re: (Score:3, Informative)

      Actually the federal government already gives away tons of money to farmers to farm stuff then keep it inside a giant silo instead of selling it.
    • by Anonymous Coward

      I'm surprised that most people have missed this in the first thread. The #1 primary fatal flaw, is that the 'waste' being plowed under isn't waste at all. Farmers plow it under instead of removing it because it's the cheapest and best fertilizer that you don't need money to buy. The remaining plant matter that gets plowed under is exactly the material that the next crop of the same plant needs to grow.

      It blows me away that they figured this out in the middle ages and we've forgotten it. This is one of the p

    • A) Cap and trade is proven to have worked regarding acid rain.

      B) Who said there is a silver bullet solution and only one option can be tried?

      C) You don't deserve that karma, your statement was trite and counterproductive.
  • Actually (Score:3, Informative)

    by iONiUM ( 530420 ) on Sunday September 19, 2010 @08:24AM (#33626474) Journal

    I read TFA and his answer is two fold: 1. stop burning waste or plowing it from forests/farms and instead pile it (as the summary says), and 2. plant more trees and plants.

    It's a pretty interesting idea, but it seems like it would be really hard to get traction because people won't believe it work. To be fair, while the theory seems pretty sound to me, it still seems like it wouldn't work. Why this is, I cannot say. Perhaps because it seems too easy.

    • Re: (Score:3, Interesting)

      by Kilrah_il ( 1692978 )

      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 e

      • by mellon ( 7048 )

        What bothers me about this idea, actually, is all the non-carbon nutrients it takes out of the ecosystem. There's a reason why we have compost piles, you know--we use the output from them to fertilize our gardens, so we can grow more stuff. That's not to say it's a bad idea, but I think it would be necessary to think a little harder about it--what plant waste contains minimal nutrients, and can be safely sequestered? What plant waste is better recycled? Clearly, anything that's currently being burne

    • If it was tested successfully and had no unexpected consequences, I think most people would rejoice. Politicians would get to solve global warming without raising taxes or implementing any unpopular measures. This is what every successful politician wakes up hoping to do (the distorted view you see sometimes on Slashdot notwithstanding).

      The problem is those unexpected consequences. I've been hearing about crop residue sequestration for nearly a decade, but the problem has always been in the sequestration pr

    • by denzacar ( 181829 ) on Sunday September 19, 2010 @10:12AM (#33627014) Journal

      Besides the fact that the entire idea boils down to "plant a shitload of trees and then bury them" it is a rather uninformed... well... brain-fart. Literally.
      http://en.wikipedia.org/wiki/Compost_pile#Industrial_systems [wikipedia.org]

      Mechanical sorting of mixed waste streams combined with anaerobic digestion or in-vessel composting, is called mechanical biological treatment, increasingly used in developed countries due to regulations controlling the amount of organic matter allowed in landfills.
      Treating biodegradable waste before it enters a landfill reduces global warming from fugitive methane; untreated waste breaks down anaerobically in a landfill, producing landfill gas that contains methane, a potent greenhouse gas.

      And the "treatment" basically boils down to inducing either pre-emptive anaerobic or aerobic process - which produces either methane or CO2.
      Also, being all enthusiastic about the "After all, this is how all that coal and oil formed in the first place", author of the Washington Post story has obviously forgotten that natural gas (i.e. methane) is found in abundance wherever there is oil.

      In the end, this could never come even close to being productive. Nor cheap.
      HUGE amounts of (agriculturally usable) space to plant the trees/plants would be needed. We're talking about enough trees/plants to suck up all the CO2 produced by every power-plant.
      Plants would need to be something that grows year-round, sucks up a lot of CO2, doesn't need fertilizer or nutrient rich soil and preferably grows vertically to take up less space. Hemp would probably be ideal, combined with pines or some other evergreen for the colder months.
      Acres and acres would have to be planted for every single power-plant.
      Plus, we are back to "carbon-credits" here as it would be physically impossible to plant all that shrubbery around the powerplants.

      Then, more space would be needed to build the treatment plants that would suck out the carbon.
      Also, energy and money to run it as it would probably not be breaking even monetarily. Would it be breaking even carbon-vise is a whole new ballgame.

      Then, the now nearly inert waste would need to be transported to the landfills buried/piled there - i.e. more energy, more CO2 released, more money.

      More you go into it, the more does the whole "as big as the plant itself, costing $700 mil." [scientificamerican.com] deal sound attractive.
      Although, personally, I find the idea of burying the gas underground to be even dumber than the "piling garbage idea".

    • Re:Actually (Score:5, Interesting)

      by Will.Woodhull ( 1038600 ) <wwoodhull@gmail.com> 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.

      • The problem isn't 'carbon in the biosphere', we're basically stuck with the same amount of carbon one way or another. It's not like we're 'making' carbon or getting rid of it in a relatively closed system like 'planet earth'. The problem (if it is a problem) is too much carbon dioxide -in the atmosphere-. The solution to that could easily be sequestration in agricultural compost heaps.

        I was thinking about this recently, but with a twist. Why not bundle-up the heaped material in compressed cubes the size of

        • by brusk ( 135896 )
          Wouldn't those ecologically boring areas become exciting because there's suddenly a new food source for microorganisms there?
      • . 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.

        I don't think that's necessarily true. Take our major garbage dumps, the ones that have been around a long time. It was always presumed that the things would biodegrade spontaneously over time. We now know that isn't true ... at the bottom of a large dump the cold and lack of oxygen inhibit aerobic bacterial growth. Make these sequestration piles big enough, and only the outer layers will be bioactive. The rest be well-preserved.

    • I've always been a big fan of recycling but recently I've realized that recycling newspaper is probably wrong - it drives down the cost of wood pulp at a time when we ought to be providing economic incentives for people to plant more trees. We're better off sequestering its carbon - down some old coal mines or the equivalent - yes I know there are issues with methane and land fills but I see those as being things that one can spend some money on researching technological solutions for not just a reason for

      • I'm not sure that providing an incentive to plant and cut down trees is better than reducing the incentive to cut down the trees that already exist.

        Tax large-scale treecutting, and use the proceeds to plant trees.

    • To be fair, while the theory seems pretty sound to me, it still seems like it wouldn't work. Why this is, I cannot say.

      Because he didn't provide any hard numbers, even back-of-the-envelope calculations, or quote an authority other than himself who thinks this is a good idea?

      Note that's not to say it's a bad idea. It just means that it's just an interesting idea, but not worth getting excited about until someone has actually looked into it.

  • It's probably close to a decade ago, that I had had this specific idea. Also, burying all sorts of "energy" waste, such as difficult-to-recycle cardboard, paper, wooden and polymer products. But I guess my idea was way ahead of time, hence I'm not filthy rich.

    Actually, even now, nobody gets filthy rich from capturing carbon.

    • Re: (Score:2, Informative)

      by bdleonard ( 931507 )
      Somebody from De Beers will be calling you shortly to correct your last statement.
      • by Teancum ( 67324 )

        There is plenty of money that can be made from extracting carbon, just not capturing it in spent forms that require an energy input.... well besides agriculture. But even most forms of agriculture merely use Carbon as a temporary holding element until the energy can be released again.

    • Re: (Score:3, Interesting)

      by hairyfeet ( 841228 )

      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

      • Would it be a more productive use of that nuclear energy than displacing fossil fuel for existing electricity generation?

        • Re: (Score:3, Insightful)

          by hairyfeet ( 841228 )

          I believe so, because even if one were to replace every plant with nuclear you'll still have the carbon from other sources such as manufacture and cars, which one can capture using carbon filtering systems which capture sources of carbon like smog and can then compress it and ready it for disposal.

          Also this would answer what to do with all the carbon we have created up to this point, and instead of just digging a hole or filling Al Gore's pockets we could actually do something useful for the whole of mankin

      • Look, our planet has the same amount of carbon as it did when it satrted (basically). It's a closed system. The problem isn't 'too much carbon', it's 'too much carbon int he air'. Carbon is what makes soil fertile, it's the basis of our ecosystem. We just have a nasty habit of burning it.

        There's no point in shooting carbon off into space, once you have it in a form that's ready to pack into a railgun, you've already taken it our of the atmosphere and the important part of the job is done.

        What we should do i

    • by ceoyoyo ( 59147 )

      I've been telling people for years if they want to help the environment, to stop recycling paper. It makes some people angry. It makes other people think.

      • I've been telling people for years if they want to help the environment, to stop recycling paper.

        Yep, that would go some way towards capturing carbon, if the wood pulp for the paper is produced from tree farms (that is, continually replenished wood stock).

        • by ceoyoyo ( 59147 )

          It doesn't have to be a tree farm, just a managed forest. For example, in my country (Canada) the forested are has increased for at least the last few decades because whenever any forest is cut, more new trees are planted than were taken. I think the situation is similar in most modern foresting countries.

  • Paper is easier. (Score:3, Insightful)

    by maeka ( 518272 ) on Sunday September 19, 2010 @08:32AM (#33626498) Journal

    It seems to me it would just be easier to stop recycling paper, and create tax incentives for the consumption of more paper. ;)

  • 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.

  • Methane (Score:5, Informative)

    by Anonymous Coward on Sunday September 19, 2010 @08:39AM (#33626524)

    One word methane. It results from anarobic decomposition and is a far more potent greenhouse gas than CO2.

  • by Pharmboy ( 216950 ) on Sunday September 19, 2010 @08:46AM (#33626556) Journal

    One of the examples was to bury agricultural waste instead of plowing it into the ground. The obvious problem is that the "waste" is what becomes the soil in a few years, putting back minerals, nitrogen and other elements that the plant needs to grow. Without putting this "waste" back into the ground, the only way to get the same full, lush plants that are soaking up all this carbon is to use man made fertilizers, which are a big enough problem with ground water that we don't need to adopt a new agriculture method that requires even MORE of them.

    If we could separate out all the carbon from our garbage and bury it in the way he talks about, great, there will be coal in a few millennia. But generally speaking, this sounds incredibly unworkable and naive.

    • Re: (Score:2, Funny)

      by gabebear ( 251933 )
      bah... you evidently keep beating me by seconds... You have an ID that is only 2 less than mine.

      by Pharmboy (216950) on Sunday September 19, @08:46AM (#33626556)

      by gabebear (251933) on Sunday September 19, @08:46AM (#33626558)

    • 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
      • I'm afraid it's naive. Every gram of plant material removed from the fields represents a gram of soil and water, removed from the local ecosystem. The field does not care where it is restored from, whether manure, river silt, or petrolum based fertilizers. But if the material is not replenished, the field will lose topsoil and productivity. Topsoil also isn't that thick: 50 foot thick topsoil is considered rare and extremely valuable. The layer in many "farm belts" is quite thin from over-use.

        So just cartin

        • 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 oxyge

          • > As for 50ft topsoil....merely to have written this suggests your connection with farming is extremely tenuous.

            Absolutely, that statement baffled me too. I've dug many pits down to over 5 meters and I've never seen topsoil more than 2 meters deep. In those cases it wasn't even proper topsoil, more like loose turf which collects on low lying land due to erosion and percolation. The average is roughly 0.5 meters in my area and it is renowned for the quality of the agricultural land.

        • by ceoyoyo ( 59147 )

          Wow. Way to not even read his post.

          GP claimed that there are negligible useful materials aside from carbon stored in many plant parts. Whether that's true or not, your reply didn't even address it.

          By planting appropriate nitrogen fixing plants you could probably wind up with a net improvement in soil fertility while still removing carbon.

        • Where in the world is there 50 foot of topsoil? a few inches is more the usual, I thought.

    • You hit it right on the nose. In their efforts to solve what they see as a problem with one element (carbon) this process would also strip the other nutrients from the soil like nitrogen and potassium (potash). Do this long enough and all you are left with is sand and clay. Incapable of growing crops in any normal sense and would be about as successful as making a desert fertile without the use of supplements.

      If folks doubt that this can happen they should do some research on how cotton agriculture so sever

  • Plowing under? (Score:3, Insightful)

    by gabebear ( 251933 ) on Sunday September 19, 2010 @08:46AM (#33626558) Homepage Journal
    How much gas and money would be used by NOT plowing under leftover stuff in the field? Plowing under organic-mater enriches the soil and the collection and transportation of all this stuff would take a lot of energy.
    • Around here (California) when they made a law that tree prunings needed to be ground up and plowed under instead of burned, most farmers just spread the wood chips on top of their fields, and didn't plow them under until the next time the field needed to be plowed. So the gas expended would be the amount needed for a quick drive across the orchard (not much) plus whatever it takes to grind it all up.
  • 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.

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

    by hey! ( 33014 )

    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

  • Wrong science (Score:5, Insightful)

    by Anonymous Coward on Sunday September 19, 2010 @09:14AM (#33626674)

    Price says, "Without access to oxygen, bacteria cannot break down plant material."

    Price, who obviously knows nothing about biology, is forgetting about the vast majority of all species on the planet: anaerobic microbes. They are quite good at turning organic material into carbon dioxide and methane. This happens in all animal guts, including yours, as well as anaerobic digesters, soils, underwater sediments, bogs, etc. His garbage heap "solution" sounds, to me, like an anaerobic digester. It would transform the waste into carbon dioxide and methane. Methane, by the way, has a green house gas equivalent of about ten times that of carbon dioxide. However, you can capture the methane and burn it to generate electricity. But, there's nothing novel about this; we've been doing it with our agricultural waste for decades. Especially in Europe where, for example, Germany has 4,500 cooperative facilities solely for the purpose of anaerobic breakdown of agricultural waste and capturing the methane produced, to be used as green energy.

    • Re: (Score:3, Insightful)

      by khallow ( 566160 )
      It depends on the plant material. But cellulose (the primary component of wood and stems) is mostly carbon. It doesn't have enough oxygen and hydrogen to convert the entire biomass to carbon dioxide or methane. And if the layer of refuse is rather thick, then most of it will be hot enough to inhibit microbe growth. You could also coke the plant material first (which conveniently is somewhat exothermic), getting fairly pure carbon.
  • Perhaps weeds would be able to help us out here, since they grow quickly and don't seem to require any fertilizer. Needing only water, farmers could be subsidized to plant endless crops of some particularly fast-growing (genetically tailored?) varieties that would subsequently be harvested and buried. Perhaps burial would also help to prevent these oxygen-deprived organic masses from turning into sources of methane, which as a greenhouse gas is 25 times more potent than CO2. Or, maybe the methane could be t
  • by Thorfinn.au ( 1140205 ) on Sunday September 19, 2010 @10:20AM (#33627074)
    Professor Gregory Benford has papers on it. http://www.physics.uci.edu/faculty/benford.html [uci.edu] 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.
    • The problem with ocean-dumping is that it displaces water (naturally, I haven't examind the paper to see wether that is addressed), which we've got enough problems with as it is.

      My idea (which has taken me an aggregate of about 2 minutes to think of) is to grow fast-growing trees, cut them down, bury them in old mineshafts, fill the remaining space with sea water, seal & forget.

      If you fill all the coal mines with wood, you fill the same volume of space as the coal you took out and burnt - coal probably

  • 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 (http://www.linkedin.com/pub/hugh-price/7/2a8/68a [linkedin.com]). 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.

  • by bperkins ( 12056 ) on Sunday September 19, 2010 @01:48PM (#33628636) Homepage Journal

    Aside from some of the obvious mistakes this opinion piece makes.

    > There is no need to worry about toxins leaching into the water supply. No elaborate liner or monitoring is required

    This is wrong. There are some situations where organic rich runoff can cause problems.

    The following link:
    http://toxics.usgs.gov/topics/rem_act/saco.html [usgs.gov]

    " dissolved organic carbon in the leachate plume is dissolving arsenic from arsenic-containing iron oxides in the aquifer and bedrock"

  • I thought that this article was about debugging Mac OS memory leaks by examining the disposal of allocated memory. Slashdot. You just can't tell till you read the fine print.

  • Any gardener knows that compost heaps must be turned regularly. Without access to oxygen, bacteria cannot break down plant material. The principle can be harnessed for carbon capture: All that is necessary is to pile the plants high enough, and the carbon at the bottom will stay put indefinitely. After all, this is how all that coal and oil formed in the first place.

    TFA's author is not as much an expert or authority on the matter as he imagines: he's unaware of the fact that there are anaerobic decomp proce

  • Science cannot move forward without heaps!

  • Honestly it sounds like a pretty sound idea. I am curious if there are any obvious scientific flaws here that I am missing. I hunted around a bit and noticed someone a few years ago (in the dept of atmospheric sciences at UMD college park) ran the numbers on this using trees:

    The article is readable here:

    http://www.cbmjournal.com/content/3/1/1 [cbmjournal.com]

    His numbers are $14 / ton CO2 (or $50 per ton carbon) with an estimate of a total of 10 gigatons carbon / year .

    Given the total fossil fuel emission is right now is a

I've noticed several design suggestions in your code.