[Digestion] supernatant water content

[Katahdin Energy Works]

Amen to this observation.

Anything beyond a ratio of 12% solids and you run into serious manure slurry
pumping problems.

Among the recommendations, besides limiting your solids to liquid ratio; are
using fairly wide PVC pipe, i.e. 6"; siting your digester so you can take
full advantage of gravity---you have no idea how expensive it gets to pump
manure slurries; eliminating any bends--a clogged PVC bend usually has to be
cut out, and replacing them with Tees that are capped for easy cleanout;
obtain the best manure/feedstock chopper you can get, i.e. HOULE electromix
or a FAN system since the finer the emulsified slurry the easier it is to
pump and digest.

These are the 'professionally' designed systems; some will want to keep it
simple and just fill the tank and heat it up; and let it 'cook'; then pump
it out and deal with solids settling later.

Frank.

Frank J. Heller, MPA
KATAHDIN ENERGY WORKS
12 Belmont St.
Brunswick, ME 04011-3004
207.729.6090
http://mysite.verizon.net/fjheller/

-----Original Message-----
From: digestion-bounces at listserv.repp.org
[mailto:digestion-bounces at listserv.repp.org] On Behalf Of Peter Allison
Sent: Wednesday, October 10, 2007 10:28 AM
To: digestion at listserv.repp.org
Subject: Re: [Digestion] supernatant water conten

Charles, 
The water content of a biogas charge requires to be sufficient to mobilize
the manure content to a slurry, about 1:1 with damp manure. Below this ratio
 the slurry is too thick to move and too much water is a waste of space and
diluted reactivity. The correct ratio reacts to stirring more like a gel
than either a solid or liquid mix, just pourable. 
I believe the process has great benefit beyond just producing gas. It will
reduce waste material handling problems, provide high response, sustainable,
agricultural fertilizers, a means to return carbon to the soil, several
compounds that will absorb and remediate toxic waste and effectively
scavenge oil spilled on water, provide raw feedstock for the carbon fiber
industry and food supply for aquaculture. All from pure excrement. What more
could you want?
Regards,
Peter Allison. 
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