HI Paul, Thanks for the last post, but you left me with a question. Our data has shown pig manure is generally (roughly) between 20-25% TS, but the VS is often 70-80% of the TS, so between 10-20% of the total mass of the wet manure. This corresponds with other data I have seen (right in front of me House uses 20% TS and VS of 70% of TS for cow manure) You mention VS of only 10% of TS. Did you mean of the total, or is this a different type of manure, or am I missing something.
On another note, related to the standards we had discussed earlier this year, can anyone comment on using TOC to evaluate waste streams and biogas potential versus using COD? We were buy some new equipment for the lab, and the equipment salesman put the hard sell on for using TOC instead of COD to evaluate waste. Any thoughts? The immediate disadvantage I see is comparing past data with new data. A On Thu, Oct 7, 2010 at 4:09 PM, Paul Harris <[email protected]>wrote: > G’day All, > > > > In the discussion below I see the term TS (Total Solids) used, and it is > important to remember that flour and sugar TS will be almost 100% VS > (Volatile Solids) and equate to very high COD per kg. It is VS/COD that is > available as substrate for anaerobic digestion, so when comparing other > substrates we really need a VS figure (or VS as % of TS) as a measure of > digestibility – manure VS is about 10% of TS so there will be huge > differences. > > > > I also noticed in an earlier post the comment about methanogens being > present in our digestive tract (I agree that they are), but why? I think it > has been suggested they balance the H+ and H2 system so our digestive system > can operate (so they may be “good” bugs) but it may also be that we provide > an environment for their survival so they compete for nutrients. I know > CSIRO have done work on reducing methane emissions from cattle so I will try > to follow that up and I will also ask a gastroenterology colleague here as > well, but comments are welcome. > > > > Happy digesting, > > HOOROO > > > > Mr. Paul Harris, Room S116b, Waite Main Building Faculty of Sciences, The > University of Adelaide, Waite Campus, PMB 1, Glen Osmond SA 5064 Ph : +61 > 8 8303 7880 Fax : +61 8 8303 4386 > mailto:[email protected] <[email protected]> > http://www.adelaide.edu.au/directory/paul.harris > > > > CRICOS Provider Number 00123M > > This email message is intended only for the addressee(s) and contains > information that may be confidential and/or copyright. If you are not the > intended recipient please notify the sender by reply email and immediately > delete this email. Use, disclosure or reproduction of this email by anyone > other than the intended recipient(s) is strictly prohibited. No > representation is made that this email or any attachments are free of > viruses. Virus scanning is recommended and is the responsibility of the > recipient. > > > > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Alexander Eaton > *Sent:* Friday, 8 October 2010 3:30 AM > > *To:* For Discussion of Anaerobic Digestion > *Subject:* Re: [Digestion] Attachment to previous Article - More > scientific based research and questions > > > > 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 > > _______________________________________________ > Digestion mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org > > 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/ > > > -- Alexander Eaton Sistema Biobolsa IRRI-Mexico Mex cel: (55) 11522786 US cel: 970 275 4505 [email protected] [email protected] sistemabiobolsa.com www.irrimexico.org
_______________________________________________ Digestion mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org 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/
