[Digestion] Attachment to previous Article - More scientific based research and questions

Anand Karve adkarve at gmail.com
Thu Oct 14 21:37:37 PDT 2010

Dear Alex,
I give below the philosophy of our biogas work. Our first assumption is that
because the methanogenic archaea reside in the guts of animals, they eat
what the animals eat. Our second assumption is that these organisms are
universally found in the fecal matter of animals because they are thrown out
of the body along with the dung. Therefore we do not accept that dung serves
as food for the methanogenic archaea. In fact, it is mentioned in the
textbooks on biogas technology that several species of bacteria are involved
in reducing the dung to acetic acid and that the methanogens turn the acetic
acid into methane. Our third assumption is that using the terms VS and BOD
to describe the feedstock are wrong. Neither of these parameters is
correlated with the quantity of the biogas generated. The use of these
parameters in biogas work is comparable to using the phlogiston theory in
chemistry. We therefore propose that digestibility of the feedstock be
considered as the correct parameter to describe the feedstock. Methods are
available to determine the in vitro dry matter digestibility (IVDMD) and
these values are available in books on cattle fodder. We ask the users of
our biogas plants to ask themselves the question if the feedstock would be
digested by animals. If the answer is yes, it is the right feedstock. We
also feel that the fetish of C/N ratio should be discarded. We have operated
our biogas system for months on end, using only green leaves, or oilseed
cake, which have a C/N value of less than 10, some time as low as 5.
We make only sparing use of a biphasic system. In fact, my advice is to
avoid the use of a biphasic system. In a biphasic system, in order to break
down the difficult to digest material, one makes use of an aerobic
fermenter. In this phase, a lot of the easy to digest material, which would
have yielded methane in the anaerobic phase, is lost, being converted into
carbon dioxide.
You can now understand, why the biogas workers hoot me out and don't believe
in me.

>> On 07/10/2010 01:39, Alexander Eaton wrote:
>> Dr Karve,
>> Your innovation and work in the field is quite appreciated, and your
>> system really opens doors for us who are also not technically focused in the
>> biology of biogas, but rather its application to families and communities.
>> That is why it seems your use of food waste and loading rates based on gas
>> production for a family really widens the populations we may be able to work
>> with globally.  Do you have a paper or document that has this data and other
>> user data available?
>> Best,
>> Alex
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