G'day Rex, If you have a lagoon check the likely Retention Time - it may be so long that you don't have to worry about mesophilic/heating and so save the cost/complexity. Dairies need hot water for washing, so that will use some of the heat.
Happy digesting, HOOROO Mr. Paul Harris, Room 202 Charles Hawker 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] 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. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Rex Zietsman Sent: Saturday, 11 June 2011 6:21 PM To: [email protected] Subject: [Digestion] AD for cow manure Hi Steve, It has been a long time since we last communicated. I hope you are well. I see that you are still experimenting as ever. As you can see, it appears that I am back in the AD business for my neighbour and another farmer in the district. You are spot on with respect to being caught between two sizes - hence my use of second hand 3 litre motors driving generators. Brent has come up with a number of suggestions that I believe have merit and should be able to help keep the overall cost down. So I will look at those for sure. The fact is that all of the dairies have existing lagoons and if we can modify them, it makes life a lot easier. I agree with your idea of pre-heating the charge before feeding it to the lagoon. This means that there has to be a large intake pit to take all of the washings in one go, heat them up and let them go to the lagoon. I believe that the cost of this should not be exorbitant and it will allow the lagoon to operate in the mesophilic range. Surprisingly, I have been involved with dry digestion over the past year with the objective of generating biogas for transport purposes. The gas is upgraded to about 92% CH4 before compression, chilling and liquefaction. The bio LNG is then pumped into cylinders in cassettes. The cassettes are mounted on trucks and the gas reduces the diesel consumption. The empty cassettes are swapped out for full ones as required. Clearly this is on a much larger scale than farm digestion and the capital is much larger as well. The requirement for the biomass raw material is that it must be able to ferment. Essentially, the rule of thumb is: "if a cow will eat it, we can ferment it". So your grass attempts are not far off the mark. How well does the fixed film work? Kind regards Rex _______________________________________________ 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/
