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To maximize dry matter digestion, a pH of 6.2 +/- .2 is best, as high as 7 is OK<span style="font-size: 10pt; "> , < 5.8 digestion slows > 7.2 it slows as well. The digestion process will naturally stabilize your biodigester at that 6.2 level with consistent feedstock, recycle as much of the liquid as possible. Aluminum Hydroxide works well as a buffer in biodigesters to lower pH to around 7, it doesn't take much. Check the normal pH of soils in your region, many times, with high pH water the soil can be quite acid and contain high levels of Al. </span><div><br><div><div id="SkyDrivePlaceholder"></div><hr id="stopSpelling">From: tallerbiogas@hotmail.com<br>To: digestion@lists.bioenergylists.org<br>Date: Fri, 31 Aug 2012 12:55:27 -0400<br>Subject: Re: [Digestion] Alkalinity<br><br>
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Hi Alex<div>we found that in some places of the Altiplano of bolivia the PH of the water used to mix with the manure a feed the digester has PH of 8-8,5. what we found at the effluent are similar PH values or a bit bit lower, never higher.</div><div>Our digester with this PH are working well. Maria Ceron, one of my master thesis studients that has been monitoring 12 digesters in bolivia (she is in this list, i think), told me that she found literature where is explained that with high PH the bacterias can still work, but they need a adaptation process.</div><div>In my case, digesters with PH higher than 8, of one and two years old are working, and also a 4 years digester that I visit last monday, was working properly.</div><div><br></div><div>To down the PH, you could use vinager (any one, also limon juice).... should be something like 1l of vinager in 100 liters of water with PH8, to down it to PH5,5</div><div><br></div><div>my recomendation iis to stop feeding the digester, leaving time for the adaptation of the bacteria (No feeding=no bacteria washing). One or two weeks. if the digester do no react, i would try with vinager...</div><div><br></div><div>keep in touch</div><div>jaime<br><br><p class="ecxMsoNormal" style="margin-bottom:0.0001pt"><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A;background:white">-----</span><span lang="EN-US" style="font-size:10pt;color:rgb(42, 42, 42)"><br>
<b><span style="background-color:white">Jaime Martí Herrero</span></b></span><span lang="EN-US" style="font-size:12pt"></span></p>
<p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><i><span lang="EN-US" style="font-size:12.0pt;color:#2A2A2A">CIMNE (</span></i><span style="font-size:10pt;color:rgb(42, 42, 42)"><a href="http://www.cimne.com/beegroup" target="_blank"><span lang="EN-US" style="font-size:12pt;color:rgb(0, 104, 207)">www.cimne.com</span></a></span><span lang="EN-US" style="font-size:12.0pt;color:#2A2A2A">). <i>Building
Energy and Environment Group</i></span><span lang="EN-US" style="font-size:10pt;color:rgb(42, 42, 42)"></span></p>
<p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:12.0pt;color:#2A2A2A">Cochabamba · Bolivia</span><span lang="EN-US" style="font-size:10pt;color:rgb(42, 42, 42)"></span></p>
<p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:12.0pt;color:#2A2A2A">Tel. (+591)-73 090 621</span></p>
<p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:10.0pt;color:#2A2A2A"> </span><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A"><br>
<b><u>BIOGAS AND BOLIVIA</u></b><br>
-RedBioLAC:</span><a href="http://redbiolac.org/" style="font-size:10pt" target="_blank">http://redbiolac.org/</a></p><p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A"></span></p>
<p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A">-Taller Biogas Bolivia:</span><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A"><a href="http://tallerbiogas.blogspot.com/" target="_blank"><span lang="EN-US" style="color:#0068CF">http://tallerbiogas.blogspot.com </span></a></span><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#2A2A2A"> <br>
-Video: Biodigester installation in bolivian Altiplano:</span><a href="http://es.youtube.com/watch?v=3Sl0XEN5Bgo" style="font-family:Tahoma, sans-serif;font-size:10pt;background-color:white" target="_blank"><span lang="EN-US" style="color:#0068CF">http://es.youtube.com/watch?v=3Sl0XEN5Bgo</span></a></p><p class="ecxMsoNormal" style="margin-bottom:0cm;margin-bottom:.0001pt;background:white"><span lang="EN-US" style="font-size:10pt"><span style="font-family:Tahoma, sans-serif;color:rgb(42, 42, 42);font-size:10pt;background-color:white">-Manual gratuito-Biodigestores familiares: Guía de diseño y manual de
instalación: </span></span><a href="http://grecdh.upc.edu/publicacions/llibres/documents/2008_jmh_guia_biodigestores.pdf" style="font-family:Tahoma, sans-serif;font-size:10pt;background-color:white" target="_blank"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0068CF">http://grecdh.upc.edu/publicacions/llibres/documents/2008_jmh_guia_biodigestores.pdf</span></a></p><br><br><div><div id="ecxSkyDrivePlaceholder"></div>Date: Fri, 31 Aug 2012 18:16:36 +0400<br>From: jean-luc.sallustro@eventure-international.com<br>To: digestion@lists.bioenergylists.org<br>Subject: Re: [Digestion] Alkalinity<br><br><pre>Hi all,<br> <br>We had to face such a problem and we have positively dealt with in<br>managing a "buffer reaction" (week acid / week base) producing acetates<br>The more efficient and cost effective reactor agent was acetic acid<br>This shall be done with proper doses at the acidogenic stage.<br>Regards<br> <br>e.venture Ltd Jean-luc Sallustro Managing Partner<br>42, Quartier du Baobab, Labourdonnais, Mapou, Ile Maurice<br>Tel (230)266 94 94 Mob (230) 250 83 36<br> <br>On 08/31/2012 06:03 PM, Alexander Eaton wrote:<br>> Dear List,<br>> <br>> Yesterday I was visiting a handful of "problem" digesters to help get them<br>> back on track. The issues is almost always acidity due to overloading<br>> (either stemming from too much waste, not enough water, or dropping<br>> temperatures), and a big dilution, some bicarbonate, and a new "seeding"<br>> from another nearby system is almost always the fix.<br>> <br>> However, yesterday I went to a system that had a pH of 7.2 (in the range of<br>> OK), but was producing almost no gas. I checked everything before I<br>> decided to check the pH of the irrigation water from a deep well they used<br>> with the waste. It had a pH of 8.6. That was the most alkaline reading I<br>> had seen in input water, which must indicate it is highly mineralized.<br>> This pH seems out of a healthy range for AD, but there is no other water<br>> source. So, two questions:<br>> 1. Please confirm that input water with such high alkalinity could be<br>> inhibiting the AD process, and;<br>> 2. What could be done to cost effectively (eg no cost) lower the<br>> alkalinity, or at least the impact on the AD process.<br>> <br>> I had them start using less water, arriving at the lowest possible dilution<br>> levels for the cow manure, hoping that less water would mean less<br>> inhibition of the process. Thought?<br>> <br>> Best<br>> <br>> <br>> <br>> _______________________________________________<br>> Digestion mailing list<br>> <br>> to Send a Message to the list, use the email address<br>> Digestion@bioenergylists.org<br>> <br>> to UNSUBSCRIBE or Change your List Settings use the web page<br>> <a href="http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org</a><br>> <br>> for more information about digestion, see<br>> Beginner's Guide to Biogas<br>> <a href="http://www.adelaide.edu.au/biogas/" target="_blank">http://www.adelaide.edu.au/biogas/</a><br>> and the Biogas Wiki <a href="http://biogas.wikispaces.com/" target="_blank">http://biogas.wikispaces.com/</a><br>> <br> <br></pre><br>_______________________________________________
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