Thanks All for the background documents. These are extremely useful. Best,
A On Thu, Oct 7, 2010 at 7:56 AM, David Fulford <[email protected]> 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 <[email protected]> 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 < >> [email protected]> 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 <[email protected]> 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 > [email protected], Tel: +44(0)118 326 9779 Mob: +44(0)7746 806401 > > Kingdom Bioenergy Ltd, www.kingdombio.com, [email protected] > > _______________________________________________ > Digestion mailing list > [email protected] > > http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org > > -- Alexander Eaton Sistema Biobolsa IRRI-Mexico Mex cel: (55) 11522786 US cel: 970 275 4505 [email protected] [email protected] sistemabiobolsa.com www.irrimexico.org
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