[Digestion] Digestion Digest, Vol 2, Issue 5

Mon Oct 4 19:47:25 CDT 2010

Dear Ivo and Danesh,
Our own experiments showed that one gets daily about 100 litres biogas from
a daily input of about 1 kg green leafy material. The leaves have to be
mechanically macerated in a chaff cutter. We are happy with the numbers, but
the difficulty with our ARTI biogas plant is that the undigested veins and
midribs of the leaves remain behind as undigested sediment so that once
every 3 months, the digester has to be cleaned by removing the movable gas
holder, and then to restart the biogas plant. In two stage processes, use of
aerobic predigestion or silaging the biomass would increase the daily rate
of the biogas production, but the total biogas obtained from a specific
weight of biomass is always reduced, because a part of the carbon, which
should have contributed to methane production is lost in the pretreatment.
When using an agricultural crop like maize plants as feedstock, one must
take into consideration the cost of the feedstock. Green fodder of maize is
used in India as cattle fodder and it has a certain value in the
market. At the current (subsidized) rates of LPG, and the high value of
maize fodder, biogas from fodder maize cannot economically compete with
LPG. Such a feedstock should therefore only be considered if LPG is not
readily available at the particular location or if the feedstock is
available at zero or very low cost.
Yours
A.D.Karve

On Tue, Oct 5, 2010 at 12:31 AM, Ivo Oliveira <ivomdb at gmail.com> wrote:

> Mr Danesh Kumar,
>
> Thanks for sharing your personal information and your knowledge about
> Biomass use as feedstock in anaerobic digestion.
>
> I'm currently working in Guatemala and I'm interested in using different
> types of biomass feedstocks. In particular I would like to use Maize stalks.
> However, when using polyethylene plug-flow or ARTI type biodigesters this is
> somewhat difficult to do and risky. Definitely concrete digesters like the
> one you are using (I think) or the 3-zone plug flow digesters are more
> efficient. I wonder if you could share more about the biodigester design you
> are working with for example how many entrances the digester has, is it
> possible to get inside the biodigester once it's emptied, did you have any
> problems with biogas leaks in the past, what pressure it is achieved with
> this type of concrete plug-flow.
>
> I also would like to ask you about low-cost pre-treatments for example
> ensilage process or other biological process.
>
> I'm interested in working more on ensilage of maize stalks and leafs or
> other similar material and using the liquid as a feedstock. I think it's
> necessary to maintain a certain amount of TS %, using small particles and
> sometimes also necessary adding additives to accelerate the fermentation
> process. However, I never done it and I wonder if it's feasible to do it in
> a very small scale (biodigesters between 1-6 m3). Have you ever done it
> without the help of any machinery (for example: using machetes, covering it
> in nylon, dig a hole and covering it with soil), what are the types of
> additives I should add, what is the feasible volume to work with to have
> good yields of silage, etc.
>
> Probably, it's a lot of work and not feasible method to implement on a
> small scale but I wonder if it could be done to co-digest with other
> substrates.
>
> Also If anyone had already worked with ensilage and knows how to do it I
> would be thankful If you could share your knowledge as well.
>
> Thanks,
>
> Ivo Oliveira
>
>
>
> On Sat, Oct 2, 2010 at 12:00 PM, <
> digestion-request at lists.bioenergylists.org> wrote:
>
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>>   1. Argentina (Patricio Gil)
>>   2. FW: Basic Information of Self (Erin Rasmussen)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 2 Oct 2010 11:25:57 -0700 (PDT)
>> From: Patricio Gil <patriciogils at yahoo.com.ar>
>> To: digestion at lists.bioenergylists.org
>> Subject: [Digestion] Argentina
>> Message-ID: <388363.29386.qm at web112616.mail.gq1.yahoo.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> I am a student at KIT Karlsruher Institute f?r Technology....
>> ?
>> I am married, 1 child.......
>> ?
>> I love biogas
>> ?
>> Lets do someting together for it.....
>>
>>
>>
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>> ------------------------------
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>> Message: 2
>> Date: Sat, 2 Oct 2010 11:45:33 -0700
>> From: "Erin Rasmussen" <erin at trmiles.com>
>> To: <digestion at bioenergylists.org>
>> Subject: [Digestion] FW: Basic Information of Self
>> Message-ID: <00ef01cb6261$ff2ab5d0$fd802170$@com>
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>>
>> forwarded o On Behalf Of Dhanesh Kumar daquab4u at gmail.com
>>
>>
>>
>> From:
>> Sent: Friday, October 01, 2010 6:36 AM
>> To: digestion-owner at lists.bioenergylists.org
>> Subject: Basic Information of Self
>>
>>
>>
>> I am Mr Danesh Kumar from India, I have been in the field of promoting
>> biogas technology at Grass Root level, I have been building biogas plants
>> for family size , the building material from bricks and concerte, has
>> been,
>> changed to ferrocement, lesser volume of materials, but need highly
>> skilled
>> mason to complete.
>>
>> I have been toying with idea of using biomass directly, my previous
>> experience has been with batch fed system, using simple technologies-
>> plastics for lining the pit and nylon based polymers for collection of
>> gas,
>> it was useful to understand the whole concept, found the gas production
>> was
>> high, means you get about 30-40% of the gas produced within a month, hence
>> it will not be useful for a small sieze family, but use ful to meet the
>> enrgy needs of certain operations- like threshing or irrigation,
>> approximately 1000 Kgs of dry biomass produces about 280-320 CuM of gas.
>> The certain problems have cropped up, more with removing of the material
>> after decomposting, the gas produced in the system, have low pressure,
>> thus
>> it is difficult to use in ordinary biogas stove, but can be stored, as use
>> a
>> supplemetary fuel for running diesel engines
>>
>> Currently I am working on a new system evloved and developed from Indian
>> Institute of Science, bangalore, it is called Plugflow biogas digester, it
>> can take a biomass (soft)- leaves, leftover of crops, kitchen and food
>> waste, in it is native state, it needs no refilling of water, about 20 Kgs
>> of green of 6 Kg of dry biomass can meet the need of small size family,
>> producing about 1.75 CuM of gas, the only draw back, what goes into the
>> system, must be pulled out manually, otherwise it is good system, even if
>> you donot recharge a for couple of weeks, you make it function within a
>> week
>> back
>>
>> Have been trying to improve the methane content of the gas, by using Oil
>> seed cakes, and also with small doses of trace elements, to speedup the
>> anaerobic digestion
>>
>> the left over materiel, is soft can be further composted and used as
>> manure
>> for improving the soil organic carbon, the liquid can be collected
>>
>> any one having questions, can get back to me, on this platform
>>
>> danesh
>>
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>> End of Digestion Digest, Vol 2, Issue 5
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-- 
***
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)

*Please change my email address in your records to: adkarve at gmail.com *
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