[Digestion] plastic

[Joshua Bogart]

I am working on a project putting in small biodigestors to be used with
hosehold 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