[Digestion] Hi

Thu Jun 9 12:52:59 CDT 2016

Good day to all,

I do agree with the views of Mr. Paul Harris. Dr. Karve's opinion about
digestion process and the role of microbes in the animals' stomach is
absolutely right but the conditions in the stomach of animals are
altogether different to that of  digester' stomach/internals. Replication
and immobilzation of microbes to the required degree cannot be
achieved/dictated in the anaerobic digester. Hence, HRT plays a vital role
in anaerobic digesters. To hasten the breaking-down process of certain
feedstocks, we may have to opt for aerobic fermentation for a given amount
of time.

Murali Krishna

Murali Krishna.

On Wed, Jun 8, 2016 at 11:45 AM, Paul Harris <harrisfm at aapt.net.au> wrote:

> G'day All,
>
> While I am happy to agree to differ on some of Dr A,D.Karve's ideas I
> disagree with points 6) and 7) below (if taken at face value).
>
> 6) There should be a C:N ratio of approximately 20-30:1. The exact value
> is not critical, but microbes need both these nutrients (and other
> elements) to survive. Too much N will result in ammonia and too much C
> probably reduces the biogas quality.
>
> 7) Retention Time (RT) is reasonably important! Too short a RT results in
> "washout", which stops digestion. The actual "washout" RT depends on
> operating temperature, as this influences microbial growth rate. Best use
> of digester volume occurs at a RT about twice the "washout" time, but
> longer RTs result in more biogas per unit influent and more robust
> operation.
>
>
> Retention Time
> Temp. Gwth Rte Washout "Optimum"
> (OC) (days-1) (days) (days)
> 5 0.020 49.0 97.9
> 10 0.034 29.4 58.9
> 15 0.056 17.7 35.5
> 20 0.093 10.8 21.6
> 25 0.150 6.7 13.3
> 30 0.233 4.3 8.6
> 35 0.336 3.0 6.0
> 40 0.434 2.3 4.6
> 45 0.502 2.0 4.0
> I hope this is some help,
>
> HOOROO
> Mr Paul Harris
>
> On 06-Jun-16 1:30 PM, Anand Karve wrote:
>
> *Biogas technology revisited*
>
> Dr.A.D.Karve
>
> Samuchit Enviro Tech P. Ltd. Law College Road, Ekata Park Co-Op. Housing
> Society, Behind Nirmitee Showroom, Erandawane, Pune 411 004 (
> adkarve at gmail.com)
>
> Abstract: In spite of new knowledge gained since the advent of the 21st
> century the biogas researchers still use some of the older concepts.  The
> new concepts pointed out in this article are 1) Because the biogas
> producing microbes reside in the intestines of animals, they eat what the
> animals eat. 2) Breeding super-methanogens can be achieved, but their use
> in a biogas plant would not be practical, as it would be impossible to
> maintain them. 3) All animals represent living biogas plants, and therefore
> the fecal matter of animals is the effluent slurry of a biogas plant. The
> biogas producing microbes are found universally in the fecal matter of
> animals because they exit the animal body along with dung.  4)Even the
> anaerobic microbes need oxygen for their metabolism. They extract the
> chemically bound oxygen from their feedstock.  Therefore, feedstock of a
> biogas plant must have oxygen in its chemical make up. The same is also
> true of food eaten by animals. 5)The value called % volatile solids
> actually represents the % digestibility of the concerned substance. 6)There
> is no justification for laying emphasis on the C/N ratio of a feedstock. 7)
> There is no justification for laying emphasis on the hydraulic retention
> time of a biogas plant. It is a useless concept. 8) In a biphasic system,
> the feedstock is first treated aerobically and then subjected to anaerobic
> conditions. This is wrong, because most of the organic carbon, which would
> have yielded methane in the anaerobic phase, gets oxidized in the aerobic
> phase itself, leading to drastic reduction in the methane yield.
>
> ***
> Dr. A.D. Karve
>
> Chairman, Samuchit Enviro Tech Pvt Ltd ( <http://www.samuchit.com>
> www.samuchit.com)
>
> Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
>
> On Mon, Jun 6, 2016 at 6:44 AM, Kelvin masule <kmasule97 at gmail.com> wrote:
>
>> Guys do u have any information about biogas?
>>
>> _______________________________________________
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>> for more information about digestion, see
>> Beginner's Guide to Biogas
>> http://www.adelaide.edu.au/biogas/
>> and the Biogas Wiki http://biogas.wikispaces.com/
>>
>>
>>
>
>
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>
> for more information about digestion, see
> Beginner's Guide to Biogashttp://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
>
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>
> for more information about digestion, see the Biogas Wiki
> http://biogas.wikispaces.com/
>
>
>

-- 

Regards.

Murali Krishna

Protect Mother Nature
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