Subject:  biogas from grass
Date: Thu, 3 Sep 1998 13:42:55 +0200 
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It is possible to produce biogas from grass. But You have to use
specific technology. The best technology seems to be for this substrate
two stage digestion with recirculation of liquid phase. The inoculation
by microorganisms is very important as well. The production of methane
can be enhanced by addition of trace amounts of Co (Jarvis 1997).
Successful process need optimisation of pH, temperature and some other
variables.
Some cofementations are also possible.
Production of biogas from plants will be after a few years or decades
very important, because not all plants are good for combustion - it
depends on water content and C/A - and biogas can easily replace natural
gas. Grass is better for anaerobic digestion (low C/N approx. 20, high
water content). At the present time is the economics of the digestion
the main limit. I don't know what amount of gas should be produced to
make the process feasible.
At this time is more important anaerobic digestion of organic waste.
{Not mechanically separated organic fraction of mixed municipal solid
waste which is very frequently contaminated by heavy metals and other
contaminants, but biowaste separated by producer (on side)}
Some scientists try to use some other plants for production of biogas
and even wood, which must be pretreated by milling.

Antonin Slejska

Research Institute of Crop Production
Drnovska 507; Prague 6 - Ruzyne; 161 06
Czech Republic
E-mail: slejska@hb.vurv.cz  
Tel.: 420 2  33 02 23 54
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