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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Dear all,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I like to start a new discussion on a different topic,
namely the dry-fermentation process (discontinuous) similar to the digesters
developed by the companies Bekon or Bioferm in Germany. The organic waste is filled
batch-wise into simple garage-like digesters for about 30-40 days.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Experts report that this process has a high potential for
application in developing countries as it has the simplest design and the solid
waste digesters are the least expensive ones. Also, substrates that lead to
operating problems during wet fermentation due to their structure or the
proportion of impurities they contain can still be processed using dry
fermentation methods. However, up to date, there is no experience with this
technology in developing countries. Therefore, our idea is to develop a
dry-fermentation biogas plant adapted to the situation in developing countries
using locally available material. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>After visiting a Bekon biogas plant in Switzerland, I’m
especially concerned regarding the opening of the digester for emptying and
refilling. Before opening the door, the digester has to be vented in order to
avoid a gas-air-mixture which is explosive. This installation seems to me
rather complicated.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>- Is anybody of you familiar with discontinuous dry-fermentation
systems and has an idea how the security can be assured in a developing country
context? Is it possible to install a simpler venting system?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>- Likewise, when removing the drum from a floating-drum
digester for emptying, how is ensured that at no time an explosive
gas-air-mixture occurs?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks for your ideas,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Yvonne</span></font><font size=5><span style='font-size:
18.0pt'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=5 face="Times New Roman"><span style='font-size:
18.0pt'>°°°</span></font><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Yvonne Vögeli<br>
Eawag / Sandec<br>
Überlandstrasse 133<br>
P.O. Box 611<br>
8600 Dübendorf<br>
Switzerland<br>
Phone: +41 (0)44 823 54 20<br>
Fax: +41 (0)44 823 53 99<br>
yvonne.voegeli@eawag.ch<br>
</span></font><span lang=DE-CH><a href="http://www.sandec.ch"><font size=2
face=Arial><span lang=EN-US style='font-size:10.0pt;font-family:Arial'>http://www.sandec.ch</span></font></a></span><span
lang=DE-CH> </span><o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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