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Biotech Earth Transportation Science Technology

Biodiesel From Sewage Sludge 88

MTorrice writes "Scientists have developed a way to convert lipids from sewage sludge into biodiesel. The low cost and high yield of the sludge process may make it economically feasible as a source of biofuel, the researchers say. Today, biofuel producers use lipids in vegetable oils to derive biodiesel, a mixture of fatty-acid-like molecules. Biodiesel is compatible with existing diesel engines, burns with less pollution than petroleum-derived diesel does, and comes from renewable resources. But current biodiesel feedstocks are expensive, limiting the fuel's widespread use. The researchers from South Korea found that sewage sludge, the semisolid material left over from wastewater treatment, can yield 2,200 times more lipids than soybeans and costs 96% less to process. To turn the sludge lipids into biodiesel, the researchers heated them with methanol."
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Biodiesel From Sewage Sludge

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  • lipids? (Score:2, Interesting)

    by Anonymous Coward on Friday August 31, 2012 @01:47AM (#41186893)

    free liposuction for biodiesel production. People could live on fat farms, where they are paid to be fat, in exchange for all of their 'lipids'. free doritos and fox news for all.

    read: soylent green won't be food, it'll be fuel.

  • That's how... (Score:4, Interesting)

    by Vintermann ( 400722 ) on Friday August 31, 2012 @02:47AM (#41187067) Homepage

    To turn the sludge lipids into biodiesel, the researchers heated them with methanol.

    Yeah, that's basically the way all biodiesel is made... But the problem with biodiesel isn't just the price of feedstock (used fryer oil is cheap enough already!), it's the price of removing stuff from the feedstock that would make the biodiesel of unacceptably low quality (free fatty acids, BCBs).

  • Re:Still.. biofuel (Score:5, Interesting)

    by ldobehardcore ( 1738858 ) <steven.dubois@gma[ ]com ['il.' in gap]> on Friday August 31, 2012 @03:21AM (#41187195)

    Regarding Emissions:

    Biodiesel is much better for the air. While it certainly does produce CO2 in nearly the same amounts per unit burned, it is unlikely to contain sulfur in measurable amounts. How much sulfur is in deep fryer oil, or sewage? Practically none, since it's poisonous. People don't eat it in more than trace amounts.

    So while Biodiesel is still not great for greenhouse emissions (unless it's balanced. Plant a tree dammit!), it's great for the breathing air of critters like us, compared to petroleum derived diesel. And if you clean it so it burns better in your engine, it's going to be much lower in particulate emissions as well.

    If sewage derived biodiesel is scalable, (and it looks like it might be), this could mean the end to all the shit we put up with going to war for petroleum.

  • Re:Still.. biofuel (Score:2, Interesting)

    by Anonymous Coward on Friday August 31, 2012 @04:14AM (#41187401)

    Biogas from waste water treatment plants (WWTPs) do contain sulfur, and the amount can vary a lot. Basically it depends on type of water treatment plant and the chemical (if it uses chemicals) used. In some cases reports have indicated more than 1000 ppm of H2S in biogas, but generally it's approximately 0-100 ppm.

    The sulphur does come from waste and some from water as well. According to Wikipedia, human body (70kg) contains approximately 140g of sulphur. It's necessary component for living cells. So sulphur as itself is not that poisonous. LD50 value for pure sulphur is ~5g/kg. H2S is more poisonous (>100ppm is immediately dangerous, and 10 ppm is recommended limit for 10 min exposure), and active reducing bacteria tend to reduce the organic sulphur into H2S in biological plants.

    And obviously the location determines the amount of sulphur in waste water, whether it's mostly municipal waste or chemical process waste water.

    I don't know how much of this sulphur would end up in the lipids, though, but generally stating that sulphur is poisonous and waste water does not contain it, is just wrong.

  • Re:LOL! (Score:4, Interesting)

    by morgauxo ( 974071 ) on Friday August 31, 2012 @09:56AM (#41189469)
    Actually for several decades now most sewage treatment plants have been separating out all of the solid particles and what can be is used for fertilizer. You can even go into some stores and buy bags of dried, treated sewage to use as spread on your lawn! My dad used to do it when I was a kid. It said so on the package but you could definitely tell exactly what it was when it got wet! I think they baked it or something like that to kill all the bacteria and make it safe first. I stayed far away from the lawn for a week or two whenever he did it but the grass loved it! It got very green very fast!

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