[Digestion] about C/N

Anand Karve adkarve at gmail.com
Tue Jul 22 23:46:50 CDT 2014

Dear Herrero,
the C/N ratio of 25 is a relict of the era when cattle dung was used
as feedstock. Please note that almost 80 to 90% of the dung consists
of non-digestible matter, contributed  mostly by lignin from plant
biomass.  The carbon in lignin is not available for methane
production.  Counting the carbon in the undigestible part of the
feedstock is unscientific. Our own biogas plants are made of plastic,
which is also non-digestible. But we don't count the carbon in the
plastic while calculating the C/N ratio.

On Tue, Jul 22, 2014 at 11:28 PM, Jaime Marti Herrero
<tallerbiogas at hotmail.com> wrote:
> hi every body
> i would like to ask about the parameter C/N that use to be measured and
> refered in a lot of places. usually it is consider that for a good anaerobic
> digestion a relation C/N of 20-25 is the optimum, but is this recomendation
> still used?
> is the C/N ratio a good parameter to be used in order to know if a substrate
> is good for anaerobic digestion?
> i would like to know your opinion
> keep in touch
> jaime
> -----
> Jaime Martí Herrero, PhD.
> INER (www.iner.gob.ec). Biomasa
> CIMNE (www.cimne.com). Building Energy and Environment Group
> Quito · Ecuador. Tel. (+593)-09 857 03726
> BIOGAS and Latin America
> -RedBioLAC:http://redbiolac.org/
> -Taller Biogas Bolivia:http://tallerbiogas.blogspot.com
> -Biodigestores familiares: Guía de diseño y manual de instalación:
> http://grecdh.upc.edu/publicacions/llibres/documents/2008_jmh_guia_biodigestores.pdf
> -Desarrollo, difusión e implementación de tecnologías
> apropiadas:Biodigestores en Bolivia:
> http://grecdh.upc.edu/publicacions/llibres/documents/2014_Biodigestores-Lecciones-Bolivia.pdf
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Dr. A.D. Karve
Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)

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