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G'day Dr A.D. Karve et al,<br>
<br>
A number of years some students were investigating AD and feeding (I
understand) just glucose - they wondered why the process kept
stopping.<br>
<br>
I do agree that the actual C:N ratio (like temperature and pH) is
not critical, but must be somewhere in the range.<br>
<br>
The combination of sugars etc without nitrogen and proteins or other
feedstocks containing nitrogen is necessary to provide the necessary
N , as I understood that the C:N ratio of most living things
(microbes included) was approximately 25:1 (hence dung was also
about 25:1). The composting fraternity has this quite well worked
out.<br>
<br>
We are learning all the time,<br>
Happy digesting,<br>
<pre class="moz-signature" cols="72">HOOROO
Mr Paul Harris</pre>
<div class="moz-cite-prefix">On 10-Jun-16 5:29 PM, Anand Karve
wrote:<br>
</div>
<blockquote
cite="mid:CACPy7Sctk6GqCZktfR1=yafpoYxq=jVr9VdeteZgAYmjNBe0zA@mail.gmail.com"
type="cite">
<div dir="ltr">Dear Paul,
<div>the so called ideal C/N value of 20 to 30 represents the
C/N of cattle dung, which is not an ideal feedstock. Almost
90% of the dry weight of dung consists of non-digestible
matter. Only the mucus and the load of bacteria in the dung
are digestible. I reproduce below the part of my original
article to clarify what I meant::</div>
<div> <span
style="font-size:12.8px;line-height:19.2px;text-indent:48px">Textbooks
lay a lot of emphasis on a value called Carbon/Nitrogen
(C/N) ratio of the feedstock. The textbooks state 25 to be
the ideal C/N ratio. This is the C/N ratio of dung, but it
is a relic of the past when dung was universally considered
to be the ideal feedstock. It has already been discussed how
dung, representing the effluent slurry of a living biogas
plant, can hardly be considered to be the ideal feedstock.
Sugars, starches, cellulose, fats and digestible proteins
show 100% digestibility. Of these substances, sugars,
starches, cellulose and fats have C/N=</span><b
style="font-size:12.8px;line-height:19.2px;text-indent:48px"><span
style="font-family:'Times New Roman',serif">∞, </span></b><span
style="font-size:12.8px;line-height:19.2px;text-indent:48px">whereas
the C/N ratio of proteins is just 4 or 5. And yet, all of
them show the v.s.% value of 100. One should realize that as
a living system, a biogas plant requires all the inorganic
components that a living cell needs, and that it is
illogical to take only the nitrogen content of the system
into consideration.</span></div>
<div><span
style="font-size:12.8px;line-height:19.2px;text-indent:48px">Yours</span></div>
<div><span
style="font-size:12.8px;line-height:19.2px;text-indent:48px">A.D.Karve</span></div>
</div>
<div class="gmail_extra"><br clear="all">
<div>
<div class="gmail_signature" data-smartmail="gmail_signature">***<br>
Dr. A.D. Karve<br>
<br>
Chairman, Samuchit Enviro Tech Pvt Ltd (<a
moz-do-not-send="true" href="http://www.samuchit.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="http://www.samuchit.com">www.samuchit.com</a></a>)<br>
<br>
Trustee & Founder President, Appropriate Rural
Technology Institute (ARTI)</div>
</div>
</div>
</blockquote>
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