[GSBN] Help us help in Haiti

Tue Jan 4 19:54:15 UTC 2011

Bruce,

This is great  when will the plasters be applied?  Any option of letting
large mixes sit and compost?

Here are two versions I¹ve used to process large quantities of raw
materials.

1) A large wooden trough with a sheet laid in and overlapping the edges
clamped to top of box, slightly tilted.  Lay a 2¹x2; or so window mesh
screen, ideally framed, on the uphill  corner.  We used a small imer mixer
to break down and suspend the clay and silt with a lot of water then poured
it off through the screen.  If any material did not break all the way down
we would add more water and pour it off a second or third time.  The screen
acted as an initial catch for the silt  most of the particles were larger
than the clay.  Fill the trough to the top.  Water gets whicked down into
the earth through the sheet and when the particles settle roll the lower
corner of the sheet back and under the top clear water and drain it off.  At
that point you will have material that is thick and ready to be mixed with
other materials and/or layers of clay and silt that can be more easily
separated.

Using this same set up you can set up multiple troughs either next to each
other and acting individually or stage to overlap at the corners or end with
spillways.

2) This is a modified system a la Nadir Kahlili:  I think he actually wrote
this up in one of his books, maybe the ceramic houses book...?  This is a
lower tech system digging large troughs in the ground and using them both as
the mixing ground and settling ponds.  Basically dig a series of troughs
with a slight slope and at the connecting wall(s) cut a channel and put in a
board or block to keep closed.  Mix the earth in  a lot of water and let sit
to let the water do part or the work of breaking down the dirt.  Remix with
feet, shovels, hoes etc and add water as needed to create a very thin
consistency.  As the particles settle open the channel and let the lightest,
longest suspended particles (hopefully your clay) flow into the second
trough.  Repeating to fill the lower troughs with clay.  The last trough can
also be the mixing plaster trough.

The channel could also be fitted with a screen.  If your silt is terribly
small consider doubling up the screening material.

Feel free to call for clarifications I¹m finding with the second babe in
arms the mama brain is not always articulate as intended.

Best to you and thank you all for the work you are doing in Haiti.

Tracy

On 1/4/11 8:09 AM, "Bruce King" <bruce at ecobuildnetwork.org> wrote:

> 
>  
> Thanks to all who have replied.  Tim Owen-Kennedy (with whom I'm working in
> Haiti) advises a good settling pond left to dry, then pull off the surface
> clay chips that curl into the distinctive pattern.  Makes sense, but takes a
> lot of time, especially in the rainy tropics.
> 
> What I've seen and heard so far essentially describes extensive settling, by
> gravity or machine, to separate the tiny silt particles from the teensy weensy
> clay particles.  I guess I could imagine two or three adjacent settling ponds
> on successfully lower grades, such that you could siphon the surface stuff
> from the first into the second, then again to the third, thus getting finer
> and finer particle sizes.
> 
> To answer Derek's questions:  we'll be dealing with hundreds of pounds at a
> time, no machinery of any sort other than human powered.  Soils around Haiti,
> as everywhere, vary, and we're not trying to quantify particle gradations.  We
> just want a robust system that anyone can use to "improve" a particular soil
> to the point where it will pass the ribbon or ball tests.
> 
> That's our challenge.  All your help and comments are very much appreciated.
> 
> Bruce King, PE
> Director of EBNet
> Ecological Building Network
> the art and science of building well
> bruce at ecobuildnetwork.org
> PO Box 6397
> San Rafael, CA 94903 USA
> (415) 987-7271
> follow us on Twitter: @EBNetwork
>  
> 
> On Jan 3, 2011, at 12:46 PM, Derek Roff wrote:
> 
>> Hi, Bruce,
>> 
>> I appreciate your humor, and your New Year's salutations.  Sign me up for the
>> Hawaii Silt Vacation Sweepstakes.
>> 
>> Can you say more about the volume and efficiency that you need in the system?
>> That would help us propose ideas that would be useful to you.  For example,
>> are you trying to process a hundred pounds of soil, a thousand, or ten
>> thousand per day?
>> 
>> What amount of "waste" soil is acceptable.  I'm guessing that your goal is to
>> get at the clay, and that the silt will be a unimportant byproduct.  Is that
>> correct?  In wondering about efficiency, I'm thinking along these lines:  If
>> the soil is naturally 20% clay and 30% silt, then the optimum system would
>> extract 2 pounds of clay from each ten pounds of soil.  What if you could
>> only extract 1 pound of clay from each ten pounds, but you got pretty good
>> purity of that clay.  Would that be acceptable?  Alternatively, what if a
>> process gave you 4 pounds of product from each 10 pounds of soil, but that
>> product was 50% clay?  Would that be useful?  If not, what sort of purity
>> percentage would be worthwhile?
>> 
>> Does this process need to be human-powered, or could electrical or gasoline
>> motors be a part of the machinery?  What is your "easy enough" process for
>> separating the sand and gravel?  Perhaps the clay separation process could be
>> added to the sand/gravel separation phase.
>> 
>> I have some ideas, and have done some small-scale tests, but I'm not sure
>> they would fit your needs.
>> 
>> Dere-"particulate"-lict
>> 
>> Derek Roff
>> Language Learning Center
>> Ortega Hall 129, MSC03-2100
>> University of New Mexico
>> Albuquerque, NM 87131-0001
>> 505/277-7368, fax 505/277-3885
>> Internet: derek at unm.edu
>> 
>> 
>> --On Sunday, January 2, 2011 1:46 PM -0800 Bruce King
>> <bruce at ecobuildnetwork.org> wrote:
>> 
>>> Happy New Year, baleheads.
>>> 
>>> We have a lot of soil in Haiti that is rich in both clay and silt.
>>> Easy enough to separate the sand and gravel, but we haven't figured
>>> out a good way to separate silt from clay.  So far we've tried:
>>> 
>>> 1) Asking nicely
>>> 2) Offering every silt particle a chance to win a Hawaiian dream
>>> vacation if it separates itself from the clay
>>> 3) Telling the silt that if it just leaves quietly now, no one will
>>> get hurt
>>> and, getting really hardball,
>>> 4) Hanging a few "example particles" of silt by their silica
>>> crystals  in the public square, with warning notes attached.
>>> 
>>> Still no luck!  Anyone have a good low-tech field method for
>>> separation?
>>> 
>>> Thanks,
>>> 
>>> Bruce "Hang 'em High!" King
>> 
>> 
>> Derek Roff
>> Language Learning Center
>> Ortega Hall 129, MSC03-2100
>> University of New Mexico
>> Albuquerque, NM 87131-0001
>> 505/277-7368, fax 505/277-3885
>> Internet: derek at unm.edu
>> 
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