[Digestion] Food-waste anaerobic digester at University of Colorado

[Art Krenzel]

Jason,

It all depends upon what your definition of viable means.

If you want to recover energy, anaerobic digestion is a great choice for a 
small scale demonstration.

If you want to do waste disposal, composting is a good option.  There is 
little or no chance to collect energy from composting.

Small scale energy production does not have all the big numbers associated 
with it that a production facility might but if you include the educational 
aspect and energy from small scale waste design concept, such a sized system 
is viable.  At 1500 tons (70% moisture) collected over 9 months would be a 
nice little green education project for the University to undertake.  Making 
a small system work has a great deal of challenges, especially in Boulder, 
CO which has a REAL winter.

Art Krenzel, P.E.
PHOENIX TECHNOLOGIES
10505 NE 285th Street
Battle Ground, WA 98604
360-666-1883  voice
phoenix98604 at msn.com




----- Original Message ----- 
From: "Jason Woods" <jdwoods21 at hotmail.com>
To: <digestion at listserv.repp.org>
Sent: Wednesday, October 24, 2007 10:43 AM
Subject: [Digestion] Food-waste anaerobic digester at University of Colorado



Hello,

I'm a mechanical engineering student at the University of Colorado in 
Boulder and I'm currently working with a professor and four undergraduate 
students on a feasibility study about using anaerobic digestion on campus. 
The university produces around 1500 tonnes of food waste per year.  There 
will also be some yard waste, but from what I've seen, it still seems the 
waste stream is still too small to make the project viable.  Would 
composting make more sense in this instance?

I was also trying to figure out how much waste water will be generated, and 
it seemed pretty high.  If the waste stream is ~70% moisture content and the 
process is run as a "high-solids" digester, and the digestate/compost is 
dried to 50% moisture content, my mass balance showed lots and lots of waste 
water.  Am I forgetting something?  Is there very much water lost to 
evaporation?

Any other advice, suggestions, or comments are welcome.

Thanks much,
jason woods
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