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Hi Mel,<br>
<br>
<br>
You can calculate the theoretical COD-demand of CH4:<br>
CH<sub>4</sub> + 2 O<sub>2</sub> -> CO<sub>2</sub> + 2 H<sub>2</sub>O<br>
<br>
You can also take a look at this page I set up some years ago:<br>
<a class="moz-txt-link-freetext" href="http://www.schlattmann.de/biogas/6-simulation/biogas6-umrechnung_csb">http://www.schlattmann.de/biogas/6-simulation/biogas6-umrechnung_csb</a><br>
<br>
With values given in the table you can get the idea of the
theoretical background to the conversion factors.<br>
<br>
Markus<br>
<br>
Am 13.02.2011 20:24, schrieb <a class="moz-txt-link-abbreviated" href="mailto:finstein@envsci.rutgers.edu:">finstein@envsci.rutgers.edu:</a>
<blockquote
cite="mid:50697.184.13.2.18.1297625067.squirrel@webmail.envsci.rutgers.edu"
type="cite">
<pre wrap="">Thanks Marcus for your response to my query:
</pre>
<blockquote type="cite">
<pre wrap="">All,
Do you know of (have) a way to "translate" BOD and/or COD to methane
potential? It would of course have to be in terms of BOD/COD removed
giving rise to so much methane.
Mel
</pre>
</blockquote>
<pre wrap="">
Hi Mel,
</pre>
<blockquote type="cite">
<pre wrap="">
if you consider the removed COD is completely transferred to CH4 in the
Biogas (CO2=0 COD) you can calculate:
1g COD removed -> 0,25g CH4
Or 1g COD removed -> 0,35 L CH4 (273K, 1013 mbar).
If you want to estimate more exactly you may consider that some fo the
removed COD flows into H2 and microbial biomass.
Markus
</pre>
</blockquote>
<pre wrap="">
Your calculation, however, is at odds with the statement in Grady et al.
1999, page 600 in "Biological Wastewater Treatment 2nd edition" Marcel
Dekker. The statement is that 4 kg COD removed generates 0.35 m3 of
methane (0.35 L CH4/4 g COD removed). Also that figure or nearabouts is
found in other documents. Apparently it was derived from theoretical
calculation (not understood by me) and also from serious observation of
real systems. If repetition = validity, thhan th figure is usable.
Perhaps others can weigh in on the theoretical end, or report other
"sightings of the translation.
Mel
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for more information about digestion, see
Beginner's Guide to Biogas
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and the Biogas Wiki <a class="moz-txt-link-freetext" href="http://biogas.wikispaces.com/">http://biogas.wikispaces.com/</a>
</pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Mit freundlichen Grüßen,
Markus Schlattmann
--------------------------------------
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</pre>
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