Re: DIG-L: straw in digestion

[Simm <simm@mozcom.com>]

Straw tends to float; you want to to stir your substrate, and maybe chop it first then let your hogs go over it. 

I know a hog farmer who, according to his carbon input/output balance, makes more gas from straw than from manure at a retention time of three weeks. He threshes the straw not very well, and his pigs nibble on it all day searching for the odd grain, apparently mechanically (with their teeth) and biochemically (with their sulliva), preparing the fibres. With or without straw, the water content needs to be in the usual range. 

I doubt that CSTR digesters can handle straw but you better ask EnTec. Good luck. Its a two stage process. The gas builds up pressure in the facility then swells over. No mechanical stirring as far as I recall. I only know one of their plants in Germany, at a destillery, and for that waste material it seemed to work o.k.  

See www.biogas.at/A$_CSTRsludge_eng.pdf if you like

Anthony Simm

At 07:47 PM 3/26/02 -0000, R.Edwards wrote: 
>>>>
>    Has there been any work recently on the use of straw in Anaerobic digestion.
>   
> In pig excreta digestion, does the feedstock entering, say a CSTR digester, have to be in a slurry form? Can manure be used with straw (obviously as long as it is pumpable). If straw can be used,, does it need to be diluted with dirty water, yard run-off etc?
>   
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