[Digestion] plastic

[Paul Harris]

G'day Joshua,

I agree with your applications for biogas!

Black plastic will be fine (most large digesters are
steel/concrete/fibreglass!) - you may get a benefit as photosynthetic
bacteria/algae won't be able to produce oxygen (I'm an engineer, not a
biologist) but on the down side photosynthetic sulphur bacteria won't be
able to break down H2S (but that's minor!).

Long and skinny is fine (better plug flow) but it is the total volume
(compared to the input volume to give retention time) that is critical.
I can send you an excel model for you to have a try with if you like.

I would also be interested in any information about gas lighting.

Happy digesting,
HOOROO

Joshua Bogart wrote:
> 
> I am working on a project putting in small biodigestors to be used with
> household and livestock waste to provide cooking and possible lighting in
> rural honduras. I have three questions, and please forgive me I am an
> ecologist not an engineer
> 
> 1)We have not been able to locate suitable clear plastic here in Honduras
> but we ahve been able to locate black plastic tubes of suitable dimensions.
> I can't see that there should be a difference between the clear and dark
> plastic as we are not using a photosynthetic process. but can anyone tell me
> otherwise.
> 2) The systems I have seen here have a diameter of 2 meters and a lenght of
> 10 meters which gives them a volume of 31.41 cubic meters. the plastic we
> are thinking about we caon only find in tubes of 90 cm which gives at ten
> meters long a volumn of 6.36 cubic meters. in my original readingthe length
> ahs more to do with retention time and killing off all possible pathogenic
> organisms , I was wondering how much this difference in volumn would affect
> methand output.
> 
> the third question has to do with using low presure mehtane for these
> digestors to burn in lamps I have read of some designs in the chinese biogas
> manual using clay bodies I was wondering if anyone knows of a simple design
> to make this type of lamp. I am interested in the diameter of the gas
> entrance and size of the air mixing chamber.
> 
> thank you very much
> --
> Joshua D Bogart
> Apartado postal Numero 3
> Guaimaca, FM Honduras, CA
> cellular 967-8187
> _______________________________________________
> Digestion mailing list
> Digestion at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org

-- 
Mr. Paul Harris
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The  University of Adelaide, Roseworthy Campus, AUSTRALIA 5371
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