methane anerobic digester/ septic tank

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demi
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methane anerobic digester/ septic tank

Post: #234620 demi
Tue Jun 07, 2011 11:31 am

does anyone know if its possible to connect the sewage directly from the toilet into an anerobic digester to make methane gas. we're buliding a new house and i was wondering if we could combine the septic tank with the anerobic digester. all the gray water from the sinks/bath ect would be re-cycled for the garden but the sewage just from the toilet would have to go into a septic tank. so instead of building 2 tanks ( one septic and one digestor) can we just build 1 to do both jobs. obviously we would be adding more manure to the digester because the sewage just from the toilet wouldnt be enough. is this possible?
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Re: methane anerobic digester/ septic tank

Post: #234706 grahamhobbs
Wed Jun 08, 2011 1:39 pm

Seems unlikely because as I understand it to create methane the sewage needs to be kept warm and not too wet, each flush of the toilet would bring a load of cold water.

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Re: methane anerobic digester/ septic tank

Post: #256800 the.fee.fairy
Thu Mar 22, 2012 11:04 am

What about if it had some kind of composting toilet system instead of a flushing system?
This is an interesting concept. I'm interested in whether it's viable.

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Re: methane anerobic digester/ septic tank

Post: #256963 The Riff-Raff Element
Sat Mar 24, 2012 7:44 pm

The short answer is probably not. The addition of the flush water would "quench" the anaerobic fermentation, plus the valving to accept the mixed solid / liquid feed via the soil pipe would be challenging. I think the idea of a composting loo would be a better one.

I don't know what you're planning to keep in the way of livestock, but the amount of crap you need to produce a useful amount of gas is pretty formidable. There is a town in the Vendée whose electricity is generated via fermeneted duck shit, but, boy, do they have a lot of ducks!
Last edited by The Riff-Raff Element on Sun Mar 25, 2012 8:33 am, edited 1 time in total.

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Re: methane anerobic digester/ septic tank

Post: #256971 oldjerry
Sun Mar 25, 2012 5:32 am

They once had one at the NCAT,but it wasn't a huge success for the reasons above.Compost toilets are definately the way to go,one inside,one outside.

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Re: methane anerobic digester/ septic tank

Post: #256981 demi
Sun Mar 25, 2012 9:39 am

how do you make a composting toilet inside your house?

iv seen them made as a shed in the garden on a platform so you go up steps into it. the poo and everything then all falls back down to ground level into a container which can be removed and emptyed onto the garden.

doesnt it smell? and how do you clean it?
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Re: methane anerobic digester/ septic tank

Post: #256995 The Riff-Raff Element
Sun Mar 25, 2012 6:57 pm

We've not got one - the layout of our house doesn't permit it and we'd need to extend to do this. But friends of ours have one. Am I right in thinking you are building? If so, and if you have convenient slope to work with so that somewhere in your property you have a floor level 50cm or more above the outside ground, then that is where you could build a composting loo inside, which is what our friends have done.

Basically, they have a concrete chamber divided into two by a solid wall to give two volumes of about a cubic meter each. There is a round hole above each to act as the loo and access for emptying is through a sliding metal door from the outside, one for each compartment.

There is an ordinary wooden loo seat. Basically, all your bodily waste goes down the hole. There's no flush (obviously - and it's odd how you miss this at first and - to be blunt, crapping over a bloody great void is a bit weird at first too ) and instead you chuck down a good handful of sawdust after each visit. After about a year the chamber gets pretty full and then they take off the seat and transfer it to the next hole. Then they close over the full chamber with a circle of wood and leave it to rot for about six months. At the end of this, they open up the access door and shovel out the compost which they add to the general manure pile (they have pigs and horses). They chuck the used cat litter down there too (wood based).

Oddly, it doesn't really smell - just a not-unpleasant earthy odour. They keep the seat clean with soapy water as bleach and so on would slow down the composting.

I could ask for some piccies, but I don't think they'd show you a great deal of useful stuff. But if you Google "composting toilet" there are loads of really clear diagrams.

If we were to ever move, then it's a system I'd like. As it is I can just about persuade the girls to sometimes piddle in a cunningly arranged bucket and frame affair up the garden so that I can feed the compost heaps.

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Re: methane anerobic digester/ septic tank

Post: #256996 The Riff-Raff Element
Sun Mar 25, 2012 7:04 pm

Here you go: this is very similar to what they've got, except that they have built it so that one can sit rather than squat:

http://kitchentablesustainability.com/the-blessings-of-a-composting-toilet/farallones-composting-privy-1976/

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Re: methane anerobic digester/ septic tank

Post: #257019 the.fee.fairy
Mon Mar 26, 2012 7:43 am

Read the Humanure Handbook. Can't remember the author's name, but it's really good for people interested in composting toilets. I think (if i remember rightly) that the author has an inside loo, or -plans for one.


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