[Digestion] size and cost of a small domestic biogas plant

[Anand Karve]

Dear Members,
this question was raised in a recent flurry of messages. Instead of
repeating them, I  wish to state the following:
 Using daily 1 kg (dry weight) food waste produces daily about 700 to 800 kg
biogas, which most small families (4 to 5 persons) find quite adequate for
cooking all their meals. Our biogas plant has a digester of 1000 litres and
a moving drum type of a gas holder having a capacity of about 750 litres.
The  cost of complete biogas plant is about US$200, if it is manufactured
according instructions contained in our video which can be downloaded from
our web site www.arti-india.org by paying us US$10 through Pay Pal. The
matter was also discussed if yeast had beneficial effect on biogas
production. Frankly, I do not see why and how yeast should benefit the
process. Yeast would actually act as a competitor of the methanogens in that
the sugar that would normally have produced biogas, would be used by the
yeast in producing alcohol. It is likely that alcohol can act as substrate
for the methanogens (glycerin, which is an alcohol,  can be used by the
methanogens as a substrate), but a lot of energy would be wasted in this
process in comparison to obtaining methane directly from the sugars by using
the methanogens.
Yours
A.D.Karve
-- 
***
Dr. A.D. Karve
President, Appropriate Rural Technology Institute (ARTI)

*Please change my email address in your records to: adkarve at gmail.com *
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