[Digestion] Home scale digesters

[Steve Rodda]

Principally to Mike Walter
Hello. I am wondering if you are about to make the mistake I did.

>We live in the northern latitudes and our winters easily get to -20 degrees F. In trying to achieve the 95 degree F mark I am considering building the walls a piling dirt up to 6-8 feet up the sides.  in order to take advantage of the consistent tempts below ground. 
>
Below ground temperatures are constant - from what I have read, 5 
degrees C. The point is you need insulation also - otherwise there will 
be major heat loss.
I didn't insulate beneath my digester and I can vouch that with cold 
rains - the digester slows down.
Be careful with what you read - I followed the suggestion that the 
ground would help prevent heat loss - didn't think and simply carried 
on. Also didn't drain around it, as you can see!

>Concerning scrubbers,  one report I read says that drawing the biogas through composted cow manure can remove 85% of the H2S. 
>
 From what I understand , H2S is a small component - could say a trace. 
Would you be contemplating a device that doesn't warrant the effort?

>Another solid medium is a product called Iron Sponge but I've heard it "Rat Holes".  This makes it inefficient.  There are other products on the market.  Many of these companies want to sell the equipment along with the medium.  There are liquid scrubbers using ethanol.  But I want to create a system I don't have to baby sit all the time. A passive system sounds more cost effective and easier to operate. 
>
 I use rusty cans crushed up-- rat holes? Maybe. However I have to 
change the cans periodically (in my case a few months), but no baby 
sitting. Certainly Passive!

kia ora
(a greeting from New Zealand)
Steve Rodda