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G'day All,<br>
<br>
Good to see some discussion again - well done (but be sure to be
nice to each other!).<br>
<br>
Some people see a biogas plant as an energy machine, some as a waste
treatment process and some as a way of making nutrients more plant
friendly. Can I nicely say that the smartest people (anyone working
in biogas MUST be smart!) see it as all three. I admit that in some
applications external factors may dictate some decisions. For
example Dr Karve has focused his work on urban users who have
limited space and limited access to manure, so his compact units
using food waste (which they do have!) are ideal in this situation.
I worked with a nursery owner who was interested in the nutrients,
so for him the energy was a bonus. Early digesters were often "waste
treatment" units (part of a treatment plant), the nutrients were
just a nuisance to be disposed of and the gas may have been just
flared off to get rid of it<br>
<br>
If you dry and burn dung (which will work, cow dung is widely used
in India I believe) it is a bit smelly during drying, messy and time
consuming. You get rid of the waste and pathogens (except for the
workers being exposed to infection) and generate energy but you lose
all the nutrients and organic carbon (important for crop production)
and the combustion process is not very efficient and generates smoke
(causing eye and throat problems, like with burning wood, I expect).<br>
<br>
As an aside (I am not being critical here) one of my favourite
quotes is "Minds are like parachutes, they only work when open!"
(Lord Thomas Dewar) and a while back I realised both are usually
used in emergencies.<br>
<br>
Happy digesting,<br>
HOOROO<br>
<br>
<div class="moz-cite-prefix">On 28/06/2013 6:21 AM, paul perrin
wrote:<br>
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<div dir="ltr">What I have read does say that human waste is
pretty useless for biogas (I saw a figure of 1 cubic foot per
day from one humans waste) - but I understand that animal like
elephants have massively inefficient digestion systems (much
food passing through almost entirely undigested) so their dung
will be entirely different and contain much more raw ingredients
for biogas generation (would dried elephant dung even burn?).
There is a calculation to be done, and it can't be based on
'averages' across species.</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On 27 June 2013 20:28, Anand Karve <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:adkarve@gmail.com" target="_blank">adkarve@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>Dear Rabin,</div>
<div>all animals, including humans, function as live biogas
plants. The fecal matter represents slurry coming out of a
biogas plant. Using animal dung as feedstock in a biogas
plant is a highly inefficient way of producing biogas. You
get about 800 litres biogas from just 1 kg starch. To get
the same amount of biogas from cattle dung, you need 40 kg
of it. One gets much more energy from dung if it can be
dehydrated and burned directly<br>
Yours</div>
<div>A.D.Karve<br>
</div>
<div class="gmail_quote">
<div>
<div class="h5">On Wed, Jun 26, 2013 at 11:35 AM, Rabin
Shrestha <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:rshrestha@winrock.org.np"
target="_blank">rshrestha@winrock.org.np</a>></span>
wrote:<br>
</div>
</div>
<blockquote style="BORDER-LEFT:#ccc 1px solid;MARGIN:0px
0px 0px 0.8ex;PADDING-LEFT:1ex" class="gmail_quote">
<div>
<div class="h5">
<div vlink="purple" link="blue" lang="EN-US">
<div>
<p class="MsoNormal">Hello,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Will it be a good idea to
install biogas plant at zoo to manage and
generate energy from the animal waste in the
zoo???</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Regards,</p>
<p class="MsoNormal">Rabin</p>
</div>
</div>
<br>
</div>
</div>
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for more information about digestion, see<br>
Beginner's Guide to Biogas<br>
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</blockquote>
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<span class="HOEnZb"><font color="#888888"><br>
<br clear="all">
<br>
-- <br>
***<br>
Dr. A.D. Karve<br>
Trustee & Founder President, Appropriate Rural
Technology Institute (ARTI)<br>
<br>
</font></span><br>
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<br>
for more information about digestion, see<br>
Beginner's Guide to Biogas<br>
<a moz-do-not-send="true"
href="http://www.adelaide.edu.au/biogas/" target="_blank">http://www.adelaide.edu.au/biogas/</a><br>
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href="http://biogas.wikispaces.com/" target="_blank">http://biogas.wikispaces.com/</a><br>
<br>
<br>
</blockquote>
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<pre wrap="">_______________________________________________
Digestion mailing list
to Send a Message to the list, use the email address
<a class="moz-txt-link-abbreviated" href="mailto:Digestion@bioenergylists.org">Digestion@bioenergylists.org</a>
to UNSUBSCRIBE or Change your List Settings use the web page
<a class="moz-txt-link-freetext" href="http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org</a>
for more information about digestion, see
Beginner's Guide to Biogas
<a class="moz-txt-link-freetext" href="http://www.adelaide.edu.au/biogas/">http://www.adelaide.edu.au/biogas/</a>
and the Biogas Wiki <a class="moz-txt-link-freetext" href="http://biogas.wikispaces.com/">http://biogas.wikispaces.com/</a>
</pre>
</blockquote>
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