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<div>Mr. Harris,</div>
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<div>I like your suggestion of smaller digesters. The problem is I have not been able to find a digester design robust enough yet cheap enough for a 100 cow dairy. Do you know where such a design exists? I have just about given up the notion that such a thing
exists.</div>
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<div>Thanks for your help with this.</div>
<div><br>
M. Charles Gould
<div>Extension Educator-Bioenergy and On-farm Energy Conservation<br>
<div>Michigan State University Extension</div>
<div>(C) 616/834-2812</div>
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On Jan 9, 2012, at 12:51 AM, "Paul Harris" <<a href="mailto:paul.harris@adelaide.edu.au">paul.harris@adelaide.edu.au</a>> wrote:<br>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">G’day Rex,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Apparently a lot of the biogas comes from the fines/solutes in the liquid – I noticed that with piggery effluent the raw effluent was almost impermeable to
water (it would hold puddles for quite a while) but after treatment the solids were pretty free draining (water disappeared in minutes).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">I will also raise my usual point in favour of distributed systems – why not put smaller (cheaper!) digesters at each farm and if necessary pipe the biogas
to a central generator (depending on distance)? You will be spending a lot of energy on trucking waste in and then you have to truck the digestate out from the central facility again. The total capital cost may be higher, with more units to maintain, but you
can start with one or two and spread the finances out a bit as well as helping local employment (I guess people will be working on digesters instead of driving trucks!).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Happy digesting,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">HOOROO<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">--
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D">Mr. Paul Harris, Room 202, Charles Hawker Building
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D">Faculty of Sciences, The University of Adelaide, Waite Campus,
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D">PMB 1, Glen Osmond SA 5064<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D">Ph : +61 8 8303 7880 Fax : +61 8 8303 4386<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D"><a href="mailto:paul.harris@adelaide.edu.au"></a><a href="mailto:paul.harris@adelaide.edu.au">mailto:paul.harris@adelaide.edu.au</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.5pt;font-family:Consolas;
color:#1F497D"><a href="http://www.adelaide.edu.au/directory/paul.harris"></a><a href="http://www.adelaide.edu.au/directory/paul.harris">http://www.adelaide.edu.au/directory/paul.harris</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">CRICOS Provider Number 00123M<o:p></o:p></span></p>
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color:#1F497D">-----------------------------------------------------------
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<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:
"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;
font-family:"Tahoma","sans-serif"">
<a href="mailto:digestion-bounces@lists.bioenergylists.org">digestion-bounces@lists.bioenergylists.org</a> [mailto:digestion-bounces@lists.bioenergylists.org]
<b>On Behalf Of </b>REX<br>
<b>Sent:</b> Sunday, 8 January 2012 5:26 PM<br>
<b>To:</b> <a href="mailto:digestion@lists.bioenergylists.org"></a><a href="mailto:digestion@lists.bioenergylists.org">digestion@lists.bioenergylists.org</a><br>
<b>Subject:</b> [Digestion] 5000 dairy cow AD system<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">Hi All,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">I have been approached to put together a proposal for a centralised AD using the manure from 5000 dairy cows. The intention is to pre-concentrate the dairy manure slurry and to truck
the solids to a central processing unit. As silage and grass is extensively used as feed, we would be able to co-digest this with the manure to increase the gas output. Furthermore, it is intended to use the exhaust gas and the AD liquor to grow macro algae
or a plant such as hyacinth (an indigenous variety that is not likely to become an invader should it get out) which can be shredded and added back to digestion. We aim to use the gas for power generation and to use the heat to keep the digester(s) warm.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">Questions:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">1. By leaving the water behind, do we lose most/all/some of the FFA? What impact would it have on gas production?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">2. Can anyone recommend a supplier of technology for this size of plant?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">3. 5000 cows is an arbitrary amount at this stage - 10 farms of 500 cows each. Is there a better/more economical size?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">Kind regards<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">Rex Zietsman<o:p></o:p></span></p>
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<span>and the Biogas Wiki <a href="http://biogas.wikispaces.com/"></a><a href="http://biogas.wikispaces.com/">http://biogas.wikispaces.com/</a></span><br>
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