Don't use food to make ethanol, use garbage
Let's check out another method which promises to deliver cheap ethanol from something that's not edible. According to Mercedes Ballesteros, a scientist working for the Unidad de Biomasa del Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (Ciemat), ethanol can be obtained from urban solid waste (aka, home garbage).
First of all, all non-organic and/or pollutant waste must be separated from the organic part (in some European cities there are special containers to classify trash for this purpose). This organic fraction is then chemically treated with diluted acid to convert cellulose into glucose which is then fermented to obtain ethanol. Her estimates are that 10 to 12 kg of domestic waste can produce 1 liter of ethanol using this method (about 93 pounds of waste for a gallon). The most efficient process? No, but we're at least getting something from, basically, nothing.
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[Source: Público]
Reader Comments (Page 1 of 1)
Domenick 8:56AM (10/12/2007)
I wonder how much water gets used in this process.
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Fabio 9:04AM (10/12/2007)
Organic garbage might not be edible, however it can be transformed in "compost" and thefefore be used as an organic fertilizer, both fixing the CO2 in the ground (rather than releasing it in the atmosphere) and doing without chemical (often, petrolchemical) fertilizers.
In other words, you can't eat garbage, but it can be used to make edible things.
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GoodCheer 9:52AM (10/12/2007)
I mostly agree with Fabio. For anybody with more than a postage stamp of a back yard, a small compost pile is a great way to a) reduce the amount you send to the local landfill / incinerator and b) get some wonderful rich fertilizer for anything you grow.
I should be pointed out however that this process will not fix the carbon with any degree of permanence: While it will be taken up by plants, those plants will eventually die and decompose, at which point the carbon will be released by the bacteria doing the decomposing. To fix the carbon on geologic timescales basically entails making coal.
While you might feel that 'eventually' is better than 'right now', it is not a distinction that will make much of a dent in long-term problems like climate change or altering the chemistry of the atmosphere and oceans.
... but composting is still probably a better approach than this.
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jcwinnie 11:46AM (10/12/2007)
"A drunkard's dream, if I ever did see one." The Band - "Up on Cripple Creek"
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bioburner 4:30PM (10/12/2007)
Why make ethenol when you can make diesel fuel and natural gas. THERMAL DEPOLYMERIZATION is a simple process that converts organic materials in to oil and gas. Unconverted organic materials are essientaly compost and can be used to fertilize plants. The beauty of this technology is that it even breaks down plastics and converts them in to oil. You don't have to seperate your trash for this process to work. You can also use farm waste,
animal offal, sewage sludge, grass clippings and used tires.
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Azrael4h 8:07AM (10/15/2007)
I think the point of this is to show that not only do we have a viable source for an alternate fuel, without affecting our food availability or prices; but that we can kill two birds with one rifle shot as it is. Oil dependency and massive amounts of trash. In the case of efficiency, I'm not really sure it matters as the US has plenty of organic wastes to convert. We're still likely tossing millions of gallons of ethanol out daily, with millions if not billions more doing nothing.
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