I saw an emergency filter idea I figured some of you might be interested in

Discussion in 'Wilderness & Survival Skills' started by De Plano, Oct 16, 2015.

  1. De Plano

    De Plano

    399
    Jun 28, 2012
  2. Preacher Man

    Preacher Man Moderator Moderator

    Jan 28, 2005
    That is quite interesting. Thank you for sharing.
     
  3. SAK Guy

    SAK Guy

    Jul 2, 2013
    +1 Thank you!
     
  4. De Plano

    De Plano

    399
    Jun 28, 2012
    My pleasure.

    It would have been nice if they mentioned the results of the variety of trees tested.

    I also picture a conversation going on in the department at MIT. "How much is this study going to cost?"

    "Well, we have the testing equipment already. If we reuse the materials we can it should cost about $1.00, give or take $.50."

    "Uhh, well, we are going to need you to pad that number"
     
    Last edited: Oct 17, 2015
  5. Chignecto Woodsman

    Chignecto Woodsman

    746
    Aug 2, 2014
    Interesting. I wonder if it filters out the other stuff we need to filter out in the woods.
     
  6. gadgetgeek

    gadgetgeek

    May 19, 2007
    if its going to filter out e.coli, it will get the parasites without much trouble. I would wonder about viruses, but those are not as often a concern, and once the water is clear, a little UV solves that. One thing I've never seen regarding these is any sort of flow rate numbers. I would be thinking that you could create a bowl or cup shape in the field and use that, but generating the head pressure would be difficult, and if its strictly capillary action it would be very slow I'd think. And since you are cutting wood, making some charcoal shouldn't be a much harder step.
     
  7. De Plano

    De Plano

    399
    Jun 28, 2012
    I thought about the flow as well. Any wood that gave you better flow would provide less filtration. I figure if you had enough tubing to make it worth it you would probably have better options (solar still or others).

    The charcoal is a good idea, strange they did not think of that with the study.
     
  8. gadgetgeek

    gadgetgeek

    May 19, 2007
    I think that was just not a focus of the study. I recall from farther back that the idea was researching low cost filter materials, charcoal is good in some ways, poor in others, and has greater value as a fuel in a lot of places. Oddly due to the nature of trees, I don't think that flow rate would affect the filtration, as ideally the water is going cell to cell, as the wood would still be "living" but I'm totally guessing now.
     
  9. Chignecto Woodsman

    Chignecto Woodsman

    746
    Aug 2, 2014
    This article suggests it was more of a preliminary study and that actual polluted water sources may be more difficult to achieve the same results:
    http://www.popularmechanics.com/sci...-can-become-a-backyard-water-filter-16540288/

    We're just talking a half-inch to inch piece of branch? That would be pretty simple to carry the tubing and clamp.

    As for viruses:
    "Xylem filtration won’t fix this by itself, not least because it can’t presently filter waterborne viruses such as hepatitis, rotavirus adenoviruses and so on. But it could have a big impact by removing bacterial and protozoan pathogens such as E coli, salmonella typhi, vibrio cholera and giardia."
    http://www.technologyreview.com/view/520706/how-to-build-a-plant-xylem-water-filter/

    Flow rate was also a concern, although they used white pine in this study.
     
  10. Thomas Linton

    Thomas Linton

    Jun 16, 2003
    Here is the more-detailed MIT article
    http://news.mit.edu/2014/need-a-water-filter-peel-a-tree-branch-0226

    Commentary:
    MIT said 99.9%. That's "LOG 3"

    Sawyer has a filer that does 99.999%

    2 log reduction = 99%
    3 log reduction = 99.9%
    4 log reduction = 99.99%
    5 log reduction = 99.999%
    6 log reduction = 99.9999%

    EPA standards
    99.9999% of Bacteria (LOG 6)

    99.9% of Protozoa (cysts) (LOG 3)

    99.99% of Viruses (LOG 4)
     
    Last edited: Oct 18, 2015
  11. De Plano

    De Plano

    399
    Jun 28, 2012
    Thanks for providing some more information. The article I posted was pretty lacking
     
  12. Thomas Linton

    Thomas Linton

    Jun 16, 2003
    Everything is obvious -- after someone else (like you) discovers it.
     

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