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Hi,<br>
<blockquote cite="mid:4CC63522.20008@h4c.org" type="cite"> It is
well known that batch digestion does not produce the same amount
of biogas every day. Obviously it takes some time for the ecology
of the digester to get established (during which time, of course,
gas production is low), and it is surely something approaching a
law of biology that the more digestible components of the
substrate will be used up first, and then some of the more
recalcitrant materials will-- eventually-- be digested. The
succession of these stages offers a well-known curve, which is
either bell-shaped, if it plots daily production, or a long S
(ogee) curve if we are plotting cumulative production.<br>
<br>
<div class="moz-signature">-- <br>
<div style="" ;=""><span style="font-size: 110%;">David William
House<br>
</span>
<div style="padding-left: 3em; font-size: 80%;">"The Complete
Biogas Handbook" <code><a moz-do-not-send="true"
href="www.completebiogas.com">www.completebiogas.com</a></code><br>
<em>Vahid Biogas</em>, an alternative energy consultancy <code><a
moz-do-not-send="true" href="www.vahidbiogas.com">www.vahidbiogas.com</a><br>
<br>
</code></div>
<br>
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</blockquote>
<br>
Yes, this is also my experience. And if you have already an active
microbial population in the beginning (e.g. taking digestate of an
active digester as an inoculum), the gas production starts quickly.<br>
For having a look at some data, I just added 2 old plots to my
webpage, one showing the "bell shape" (upper image), the other the
"S curve" (lower image).:<br>
<a class="moz-txt-link-freetext" href="http://www.schlattmann.de/biogas/3-substrate/biogas3-batch-test.php">http://www.schlattmann.de/biogas/3-substrate/biogas3-batch-test.php</a><br>
<br>
Most of the gas in batch operation is produced in the first 2 weeks,
after that it keeps long at a low level.<br>
<br>
<pre class="moz-signature" cols="72">--
Mit freundlichen Grüßen
Markus Schlattmann
--------------------------------------
schlattmann sustainables
schlattmann.de
Dipl.-Ing. agr. Markus Schlattmann
Grünseiboldsdorfer Weg 5
85416 Langenbach
Tel.: +49 (0)8761 72162-60
Fax.: +49 (0)8761 72162-61
E-Mail: firmen@schlattmann de
Web: <a class="moz-txt-link-abbreviated" href="http://www.schlattmann.de">www.schlattmann.de</a>
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