[Terrapreta] composting toilet

[MFH]

Jim, lots of.

Consulted for a while to a company making on-site domestic sewage systems.
Size for a 5-person house was 1600 litres, about the normal size for a
septic tank. The heart of the system was a media bed made of cocopeat
(www.starfibre.com.au), laced with composting worms. A bit more detailed
than that description but that's essentially the process. 

Various other media was trialled, including various ratios of cocopeat and
char, up to 100% char. In general there didn't seem to be any detectable
lowering of performance with char levels up to, say, 50%, but higher than
that caused a drop of worm populations. Char is pretty rough under the
microscope and maybe worms were abraded?

I've replicated the process down to 20 litre drum experiments. Its so
blindingly simple that its no wonder it has escaped the minds of the
politicians. If only people would put just poo and wee down their toilets,
instead of sump oil and left-over pharmaceuticals and rat baits, this
worm-based sewage treatment could replace traditional sewage farms, and give
a valuable waste product.

The system treats sewage and grey water, and can in fact survive just
treating grey water. Humans shed a couple of kilos of skin per annum, and
this plus hair plus fats from the bath can keep a worm population alive. And
you can route the output from your kitchen sink disposal unit into it.

When working properly, the water output tests to the potable level. No state
in Australia allows this (surprise?) but some states allow re-cycling for
toilet flushing and washing machine use. All allow for garden use.

The media normally lasts for years without changing. But if the system was
designed as such, processed waste mixed with the cocopeat and some char
could be extracted from the bottom of the stack, and used in the garden.
There won't be nay worms removed because they live in the upper layers.

At its simplest:

- a 20 litre bucket under a seat
- part fill with cocopeat and some char
- add a couple of 1000 composting worms
- have a container with dry cocopeat and another with some char beside the
seat and a small scoop
- have a poo then add a scoop of char and cocopeat
- when the drum is full, set aside and cover with hessian until the worms
have finished the conversion to castings
- in the meantime, take a scoop full of worms from the upper layer and use
these for the replacement bucket

This is different to a composting toilet, but worth a try is:

- the addition of char, and
- why not see whet happens by adding worms?

M


-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Jim Joyner
Sent: Thursday, 15 May 2008 11:55 PM
To: Terra Preta
Subject: [Terrapreta] composting toilet

Anyone have any experience with putting charcoal in a composting toilet 
(how much, etc.)? My wife and I use such a toilet. I reason that it 
would break down the material faster, give off less smell and (since I 
use the end product on trees and scrubs) it would sequester CO2.

Probably not world shaking . . . unless everyone got a composting 
toilet. . .

Jim

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