Slashdot Mirror
Biodiesel From Sewage Sludge
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."
They say that fryer oil based bio diesel smells vaguely of fries. This slightly concerns me.. as sewage based bio diesel would smell like...
I've never taken my wife seriously when she's said my poo smells so bad I could use it to fuel my truck for the life of the vehicle.
Chewbacon
The Bible is like Wikipedia: written by a bunch of people and verifiable by questionable sources.
Emission production as you state it is only a problem on a local level where the emissions are most concentrated (dense cities). Even electric cars will have emissions (either in production or at whatever plant is making the electricity for it). It's the part about digging up materials which have been locked underground for millions of years and then releasing those emissions into the atmosphere that is the global problem. If all of the energy and consumables your vehicle used during it's entire lifetime (including manufacture) were harvested from plants or otherwise scraped off of the surface of the biosphere instead of from within the ground you would essentially be close to net-neutral impact on the planet as far as emissions are concerned (not that there is no impact, it would just be ridiculously low impact).
Biodiesel (as usable in my VW Jetta) is only a little less efficient than petrol / oil based diesel. Mileage is about 5mpg lower or so, but you have to make sure the biodiesel is clean of other contaminants which can be a bit laborious depending on the original source. Of course most people I am aware of will typically use an 85/15 blend for better performance (15% regular diesel).
As far as emissions go, I don't think it's too much different but I don't know much about that. I guess it would entirely depend on how "clean" and viable the input is.
In any case, if we can turn something which truly does not have a better use other than to be cleaned (at great expense) and sent back into the biome into a usable fuel at less expense I fully support research into it. It seems to be much smarter than ethanol where suddenly the price of fuel becomes linked to the price of food. We honestly don't currently have a better use for human sewage anyways considering it is not considered fit for fertilizer either. Besides, if this comes to America just think of how much fatty acids are already present in the McSewage, or how we could just re-introduce Olean oil if we needed to increase production (how's that for a disgusting thought?).
- Toast
To expand on this, in new TDI's from Audi/VW at certain intervals raw diesel is injected into the cylinders post burn to heat up the particulate filter and burn off collected carbon. Because of this the raw diesel fuel mixes a little with the oil. For petroleum based fuels this is not a problem as the synthetic oil is designed to allow this to happen. Unfortunately biodiesel is a really great engine cleanser. The problem is that when biodiesel above 5-10% mixes with the synthetic oil the oil is diluted and loses its ability to adhere to the cylinder wall and prevent friction. I think most people understand the basic concept of running an engine without oil. My understanding is that a person could run up to 20% biodiesel if they are willing to make very frequent oil changes, say every 5k miles. But at ~$60 a change it may seem pricey for you.
There is or can be built a machine that can simulate any physical object. -Church-Turing principle
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).
xkcd is not in the sudoers file. This incident will be reported.
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.
Hectice, baby, Mercator says hello to you
Please do. Western people use their own manure to pollute the seas and then spend money on chemicals to give the soil what the manure should have given it. If you use a compost toilet, you save the environment in a lot of ways and also a lot of money (like the money spent on sewage treatment). There's a nice book about it. You can download it for free at http://humanurehandbook.com/ (link on the left of the page).
Nae king! Nae laird! Nae yurrupiean pressedent! We willna be fooled again!
The issue I see is that newer VW TDIs (with the common rail system) is not designed to run on anything higher than B5 (95 Diesel/5 Bio). With my 2012 Jetta, if I use anything higher, they can void my warranty, and they are able to tell. Which sucks cause the station right near me that does Diesel does anywhere from B1 to B11, no notice as to what it is at that time. The problem here is the point in which biodiesel combusts, as compared to straight diesel. To be "clean burning", which VW Diesels are, they do a direct injection of diesel into the exhaust system to burn off the soot and other impurities that are/were common with diesel engines. Biodiesel doesnt ignite the same, leaving the impurities/soot, causing it to clog part of the exhaust system up, requiring expensive replacements.
This is to say, annoying, at the least. Now, I've heard of people having good luck with mod kits adding a second (heated) tank to use with filtered waste vegetable oil, with a cutover switch in the cabin. Start on diesel, switch over to WVO, then switch back later, but those were with pre-2010 VW Diesels.
OMG... I have a sig?
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!
Problem with this is heavy metals. Lots of heavy metals that would be processed out of industrial waste just goes down the drain in household sewage. They used to spread sewerage solids on corn fields in Michigan when I was growing up, but they had to stop because the metals were ending up in the corn in levels too high for human consumption. For years those fields were only usable to grow animal feed, until finally the metals were leeched out of the soil (and probably into the water table).
"Think about how stupid the average person is. Now, realise that half of them are dumber than that." - George Carlin