One man experimental humanure biogas digester and microbial fuel cell project - Page 2

 On 7/4/2013 5:07 PM, Kanon Kubose wrote:

Thanks, interesting reading.
How much power do you expect to produce?
And how much power do you expect to consume by pumps etc.

  I'll be excited if I get anything at all. It's just an initial, uninformed  
proof of concept type of thing for me at this point, and I'm only doing it  
because it's so simple and yet so fun--electricity from poop! Mostly, I'm d
oing it for the compost and the need to get rid of my waste. The methane to
o is just for fun, though I hear there are off-grid houses that get all the
ir cooking fuel from their methane producing compost pile. Some people also
 harvest the heat and get 140 degree water.

As for the pumps, zero. It'll be gravity fed. Approximately the same amount
 of fertilizer (4-6 weeks of fermentation) comes out the other end when new
 black water from the trailer enters the input. Do it right, and it's safe  
for using on food crops, but I wouldn't do it with this prototype since I'm
 not planning to carefully monitor the carbon nitrogen ratio, the temperatu
re, etc. Good for flowers, though.

Kanon

On Friday, July 5, 2013 7:56:09 PM UTC-7, mike wrote:

 Ok, I think I figured it out.  

1. In biogas digesters where an upside down floating drum is used, the outp
ut level will be close to the level inside the tank.

2. In digesters where the methane is under pressure, the pressure will push
 the effluent upwards to some extent. I'm sure this is where know-how comes
 in to determine just how much. Also note that the input pipe must be long  
enough so that this pressure doesn't push the manure out of it as well.

3. When new manure is put in, this will raise the level inside the tank whi
ch can push the effluent out the output pipe if its height is correct as in
 #1 and #2 above.