[Terrapreta] Biogas digesters and Biochar

[bakaryjatta]

Dear  Gary and Terrapreta practitioners.

Gary Frase <GaryFrase at CommunityProducts.com> wrote:

> Does anyone have experience of biogas digesters such as commonly used in
> India and China?  Would running biochar through a digester be a good way
> to "charge" it before land application?

Yes, I have a biogas digester based on Dr A.D Karve's design. (India)  The
feedstock is carbohydrate containing, i.e. spoiled fruit, Jatropha oil press
cake or peelings of tubers, etc. The diluted effluent and diluted urine are 
used to 'charge' the char
with good results.

Just considering how a digester works I would not add char to the feedstock 
slurry. Char is not digestable to the micro-organisms that do such a good 
job producing gas for us. Why give them 'indigestion'? It also takes up 
space in the digester and probably increases retention time. In the case of 
digesters using cow dung, the volume is very large and the slurry will have 
to be diluted before use as fertilizer too.

Just my thoughts, I am not an expert. You may try and let me know the 
results. I do not want to risk my routine gas supply for any day. To remedy 
an unbalanced system takes time and I don't want to go backusing very 
expensive LP gas, or less convinient wood for that time.

Good luck!

Bakary Jatta
>
> - Gary Frase
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