digester design and costs estimates

Digester design and construction info


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Tom Braford
Joined:Tue Jan 01, 2008 1:40 pm
digester design and costs estimates

Post by Tom Braford » Tue Jan 01, 2008 2:21 pm

I am part of a collaborative group that is planning on collecting kitchen waste from local restaurants and combining it with cellulose based demolition and other waste as feedstock for a biodigester.

The gas produced will be used to preheat water and/or power an electricity generator.

The slurry after further treatment if necessary will be used to fertilize CSA gardens.

We are applying for a grant and need some idea of the scale to shoot for and numbers for our line item budget. The digester will eventually process all the organic waste for an 86 home urban ecovillage which will probably house about 150 people, their pets, 100 chickens, thirty rabbits and an acre of rooftop gardens and greenhouses. So we would like to scale the digester for that eventually and collect enough waste in the interim to utilize that amount of capacity from the start.

We already have a dozen heavy duty plastic tubs that are about 42" in diameter by 48" tall that we would like to use if possible.

Could we just scale up the prototype plans to fit the size of our tubs?

Any sugestions would be greatly appreciated.


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Joined:Tue Jul 03, 2001 11:01 pm
Location:Willow, Alaska USA

Post by Bob » Sat Jan 05, 2008 6:53 pm

Hi Tom,

Sounds like a great project. Did you plug the feedstocks into the online calculator? It can give you a rough estimate of overall tank volume required.

Yes, you should be able to scale up the prototype plans, but that may not be the best idea. With multiple tanks like you have, I think I'd consider something like a 'hybrid' batch/continuous feed design, where you maintain a number of batch feed acid-phase tanks all generating feedstock for a methane-phase digester.

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