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

Alexander Eaton alex at sistemabiobolsa.com
Thu Oct 7 09:59:42 PDT 2010


Thanks All for the background documents.  These are extremely useful.

Best,

A

On Thu, Oct 7, 2010 at 7:56 AM, David Fulford <davidf at kingdombio.com> wrote:

>  Hello Alex and Listers,
>
> The best independent papers on the ARTI system are by EAWAG (
> www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_swm/<http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_swm/index_EN#owm>)
> who have also looked at the digestion of food residues from markets in
> Kerala, South India. While food residues have an average TS of 50% or less,
> Dr Karve bases his results on starch residues (e.g. flour dropped on the
> floor from milling). Suich residues have a TS of almost 100%. This means
> that we need to consider his gas production results as per kg total solids,
> rather than per kg of wet material.
>
> As the assessor from Ashden Awards who visited ARTI in 2006 (see
> www.ashdenawards.org/winners/arti06), I had to evaluate Dr Karve's
> statements.and his technology. The biogas plant uses simple cylindrical
> drums, so there is nothing special about the design. The major difference is
> the use of food residues rather than dung as the feed material. Since an
> animal has used as much of the input energy in the food as it can before it
> evacuates the rest, the gas production from undigested food is likely to be
> much higher than that from dung. Processed food (flour, sugar and cooked
> food) is likely to have a higher gas output than raw food, as much more of
> the material is accessible to the microbes. There are several other biogas
> projects in India using food residues as feed material, that started at
> about the same time as the ARTI one. I have visited the first Biotech Ltd
> project in Kerala (www.ashdenawards.org/winners/biotech) about which the
> EAWAG report was written and another in Mumbai called the Nisargruna system
> developed by BARC (see www.green-ensys.org/site/Biogas_Plant.html), which
> uses a two-stage digestor design.
>
> Looking at the basic thermodynamics of the process, it seems quite feasible
> to generate 1 kWh of electrical energy from 1 kg of starch, as Dr Karve
> suggests, although it does suggest a very high efficiency for the conversion
> of starch to biogas. However, in practice, a 1 cu.m ARTI biogas plant is too
> small to run an ic engine, as small ic engines are not very efficient.
>
> Regards,
>
> David Fulford
>
>
> 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
>
> On Wed, Oct 6, 2010 at 5:40 PM, Anand Karve <adkarve at gmail.com> wrote:
>
>> Dear Alexnder,
>> to be quite frank, I do not call myself an expert in biogas technology. I
>> developed my system as a layman. Being a biologist, I argued that since all
>> industrial fermentation systems used sugar, why not try it in a biogas
>> plant. Because sugar was costly, I used only 1 kg sugar in a biogas plant
>> that consumed daily 40 kg cattle dung. To my surprise I found that I got
>> about 700 to 800 litres of biogas, just 24 hours later. Since sugar was
>> costly, I shifted to using flour of cereal grains, which also gave similar
>> results. Then we tested spoilt milk, oilcakes of various edible and
>> non-edible oilseeds and peels of fruits like banana, mango and papaya, and
>> got similar results. We then constructed biogas plants geared to using food
>> waste as feedstock. It was by trial and error, that we arrived at our
>> present configuration which is just a conventional moving dome biogas plant.
>> The rule of thumb is to use 1 g (dry weight) of food waste per litre of
>> digester capacity.  When I started talking about our system in conferences
>> on biogas, I used to be hooted out by the experts. Once they found out that
>> I had no theoretical knowledge of the biogas plants, they would embarass me
>> by asking questions like C:N ratio, volatile solids % etc. It was only after
>> our system received the Ashden Award in London (2006), that the world
>> started believing in me.
>> Yours
>> A.D.Karve
>>   On Thu, Oct 7, 2010 at 7:00 AM, Alexander Eaton <
>> alex at sistemabiobolsa.com> wrote:
>>
>>> Hi Dr. Karve,
>>>
>>> I recently had the pleasure of meeting your associate and representative
>>> for Tanzania at a conference in Sweden.  He explained much of the same thing
>>> about the ARTI system.  When you describe your system as primarily a biogas
>>> generation system (as opposed to waste treatment), do you mean that you
>>> optimize HRT and loading rates for biogas production, rather than balancing
>>> biogas production with the reduction of organic load (TOC or COD?).
>>> Reviewing the plans of your systems, it does not seem as though the vessel
>>> itself holds massive differences with any other AD reactor, so can we assume
>>> that this is a management practice, versus technology comparison?
>>>
>>> Best,
>>>
>>> Alex
>>>
>>> On Wed, Oct 6, 2010 at 4:45 PM, Anand Karve <adkarve at gmail.com> wrote:
>>>
>>>> Dear Alexander,
>>>> thanks for the correction. In our system, 1 kg (dry) food waste provides
>>>> 1 kW electricity for 1 hour. I am absolutely sure of these figures, because
>>>> we are daily generating electricity on our own campus by using food waste
>>>> from our own hostel. If your calculations show our system to be 3 times as
>>>> efficient as the one reported in the article, then it must be so. All I can
>>>> claim is that our biogas production system is currently the cheapest and the
>>>> most efficient biogas system in the world. Scientists of a prestigeous
>>>> Institute of the Government of India had come to us to have a look at our
>>>> biogas system, because using the same amount of waste, our system
>>>> produced 10 times as much biogas as the two phase system developed by them.
>>>> The report submitted by them to their bosses explained the difference in the
>>>> performance of the two systems being due to the fact that their system was
>>>> primarily a waste disposal system, whereas ours was primarily a biogas
>>>> generating system. So far, we have installed about 5000 such biogas plants
>>>> all over India and also about 50 on the African continent.
>>>> Yours
>>>> A.D.Karve
>>>>
>>>>       --
>
> ********************************************************************
> Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
> d.j.fulford at btinternet.com, Tel: +44(0)118 326 9779 Mob: +44(0)7746 806401
>
> Kingdom Bioenergy Ltd, www.kingdombio.com, davidf at kindombio.com
>
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-- 
Alexander Eaton
Sistema Biobolsa
IRRI-Mexico

Mex cel: (55) 11522786
US cel: 970 275 4505

alex at sistemabiobolsa.com
alexanderb.eaton at gmail.com
sistemabiobolsa.com
www.irrimexico.org
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