[Digestion] Digestion Digest, Vol 2, Issue 33

Srinivas Kasulla srinivaskasulla at gmail.com
Sat Oct 16 12:15:08 PDT 2010


Dear Dr Karve,
We are really proud of you being an INDIAN and making the entire Nation
proud with the work you have done in the field of Biogas/Anaerobic digestion
in India, but after reading some of your views it has confused me very much
and even after 2-3 days of continuous research ONLINE and going thru some
books i could find some of the answers for the data you have mentioned
earlier, I would appreciate if you clear my doubts:
1) As am into this field from quite a long time but not as much as you have
been and whatever you have mentioned about TS, VS, Cowdung, BOD etc is
making me so confuse that it seems that i have to start from the basics and
all my knowledge which i have accumulated till date will be waste.......
you have mentioned that VS and BOD - neither of these are corelated to
quantity of biogas generated?
you said digestibility of the feedstock is to be considered for biogas
generation? if not TS? if not VS? if not BOD? then what is this
digestibility of the feedstock?
I can agree that the mistake is to expect the same biogas yields per kg of
VS or of BOD from a different feedstock may vary.

2) You have mentioned that DUNG cannot serve as a food for the methanogens
because they are THROWN OUT of the body alongwith the dung??

3) The methanogens in the dung are very slow workers and they need
retenntion time which we give in the digesters and which is missing (the
number of days for holding - the gut of an animal is limited). the
methanogens in dung keep on working even when the dung is thrown out of the
body, and the process becomes slow due to exposure to the oxygen and once
again they start producing the methane when they are put inside the
digester........

4) you have mentioned that the FETISH C/N values should be discarded? how
can I DISCARD THESE VALUES AND RATIOS? can you please teach me to discard
the C/N values from my digesters? and you have mentioned the C/N values to
be 10 or 5 but is it for C or for N?

would be eagerly waiting for your answers to the above questions only, as in
my earlier few mails i have asked you certain questions and had received
answers from different experts in the blog and have received some answers
from you which were not at all connected to my questions.

with warm regards
SRINIVAS KASULLA
+91 9004689601


On Sat, Oct 16, 2010 at 12:30 AM, <
digestion-request at lists.bioenergylists.org> wrote:

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>   1. Re: Attachment to previous Article - More scientific based
>      research and questions (Anand Karve)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Fri, 15 Oct 2010 12:37:37 +0800
> From: Anand Karve <adkarve at gmail.com>
> To: For Discussion of Anaerobic Digestion
>        <digestion at lists.bioenergylists.org>
> Subject: Re: [Digestion] Attachment to previous Article - More
>        scientific based research and questions
> Message-ID:
>        <AANLkTinPEb_k_6gu06EaKu0QPs7zJnuKJ+QjFcoT0KAh at mail.gmail.com<AANLkTinPEb_k_6gu06EaKu0QPs7zJnuKJ%2BQjFcoT0KAh at mail.gmail.com>
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> 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.
> Yours
> A.D.Karve
>
> >
> >> 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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