Methane digesting

Digester design and construction info

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BRIAN
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Methane digesting

Post by BRIAN » Wed Mar 14, 2007 12:39 am

Hey Bob,

This is Brian from the other posts. Is it possible to take the methane and
store it in another polyethylene tank after proccessing, or is this to dangerous. Also do you have to macerate the human waste that goes into the tank? Is it possible to have to ports to input waste. I was thinking one that is connected to a simple toilet, and also a port that is connected to a hand cranked sump pump to collect livestock waste. Is this feasible?

Thanks,
Brian

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Bob
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Post by Bob » Fri Mar 16, 2007 11:40 am

Is it possible to take the methane and store it in another polyethylene tank after proccessing, or is this to dangerous.
As you note, the risk (and cost and complexity) go up with the quantity of gas that needs to be stored. To minimize the risk, I think I'd try to find ways to use it as soon possible, as generated. (The energy could be stored as heated water, for example?)
Also do you have to macerate the human waste that goes into the tank?
In my system, just pumping it with a common hand-operated diaphragm pump provides all the maceration needed. Here is a picture showing an installation with a sealand microflush toilet. The pump evacuates a small holding tank directly below the toilet, pumping its contents into the digester. You could use something similar for the animal wastes. (Pump and piping are normally behind an access panel, removed for the photo.)

Image

BRIAN
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Controlling effluent

Post by BRIAN » Wed Mar 21, 2007 9:20 pm

Hey Bob,

Does the effluent naturally rise and overflow, is this part of the process? If so, is it possible to set up a simple ball valve to control the output, so the user can use it like a tap to pull fertilizer from? If possible, how many times a day/week would this need to done? Another possibility I was thinking about was to let the effluent overflow into a bigger storage tank and utilize a tap system on this, but is it safe to store large amounts of this fertilizer?

Thanks,
Brian

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Bob
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Post by Bob » Sun Mar 25, 2007 7:10 am

Does the effluent naturally rise and overflow, is this part of the process?
Yes. Every liter of new input displaces an equal amount of effluent.

If you wanted to use the effluent separately or on a different timing cycle from the feed cycle, you would need to add a storage tank. That wouldn't be unsafe, but it would add cost and complexity.

BRIAN
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Post by BRIAN » Sun Mar 25, 2007 10:16 pm

Thanks for the help Bob, I appreciate all the info you have provided me. I'll post some sketches and model pics of my design, probably won't be till the end of April.

Thanks,

Brian

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Bob
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Post by Bob » Mon Mar 26, 2007 9:45 am

Please do, Brian. I look forward to seeing them

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