<div>Dear Mr. Eaton,</div>
<div>Is this a newly constructed biogas plant? Please check the biogas holder for a possible leak. Has the biogas output been satisfactory in the beginning and become low now, or has it been low right from the beginning? Please check what the high pH of water is due to. At our own farm, we have water with high calcium bicarbonate content. We get good biogas production in spite of having such water. In fact, all cells, except the methanogens, produce acetic acid as the end product of intracellular catabolism. If the non-methanogenic organisms in the dung produced enough acetic acid, it should neutralize the alkalinity.</div>
<div>Yours</div>
<div>A.D.Karve<br><br></div>
<div class="gmail_quote">On Fri, Aug 31, 2012 at 7:33 PM, Alexander Eaton <span dir="ltr"><<a href="mailto:alex@sistemabiobolsa.com" target="_blank">alex@sistemabiobolsa.com</a>></span> wrote:<br>
<blockquote style="BORDER-LEFT:#ccc 1px solid;MARGIN:0px 0px 0px 0.8ex;PADDING-LEFT:1ex" class="gmail_quote">Dear List,
<div><br></div>
<div>Yesterday I was visiting a handful of "problem" digesters to help get them back on track. The issues is almost always acidity due to overloading (either stemming from too much waste, not enough water, or dropping temperatures), and a big dilution, some bicarbonate, and a new "seeding" from another nearby system is almost always the fix. </div>
<div><br></div>
<div>However, yesterday I went to a system that had a pH of 7.2 (in the range of OK), but was producing almost no gas. I checked everything before I decided to check the pH of the irrigation water from a deep well they used with the waste. It had a pH of 8.6. That was the most alkaline reading I had seen in input water, which must indicate it is highly mineralized. This pH seems out of a healthy range for AD, but there is no other water source. So, two questions:</div>
<div>1. Please confirm that input water with such high alkalinity could be inhibiting the AD process, and;</div>
<div>2. What could be done to cost effectively (eg no cost) lower the alkalinity, or at least the impact on the AD process. </div>
<div><br></div>
<div>I had them start using less water, arriving at the lowest possible dilution levels for the cow manure, hoping that less water would mean less inhibition of the process. Thought?</div>
<div><br></div>
<div>Best <br clear="all">
<div><br></div>-- <br>Alexander Eaton<br>Sistema Biobolsa<br>IRRI-Mexico<br>RedBioLAC<br><br>Mex cel: (55) 11522786<br>US cel: 970 275 4505<br><br><a href="mailto:alex@irrimexico.org" target="_blank">alex@irrimexico.org</a><br>
<a href="mailto:alex@sistemabiobolsa.com" target="_blank">alex@sistemabiobolsa.com</a><br><br><a href="http://sistemabiobolsa.com/" target="_blank">sistemabiobolsa.com</a><br><a href="http://www.irrimexico.org/" target="_blank">www.irrimexico.org</a><br>
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<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></blockquote></div><br><br clear="all"><br>-- <br>***<br>Dr. A.D. Karve<br>Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)<br><br><br>