[permaculture] Composting toilets

Nick Ritar nick at milkwood.net
Wed May 21 19:20:47 EDT 2008

As Christopher said, the humanure handbook is a fantastic resource and it's
author has made it available online for free, although you are probably
better off purchasing a copy than printing it all out.

We have built one small composting toilet based on 20 litre buckets and a
long/slow compost heap (*unturned* and left for 12 months). This system is
fine for a couple or small family. We do not separate urine, but change the
bucket frequently and add lots of carbon. Changing the bucket regularly is
important otherwise the material starts to become starved of oxygen, giving
off methane and encouraging anaerobic bacteria.

We are working on a larger system for student use during courses using a 60
litre "wheelie bin", again not separating urine, and changing containers

It is important to note that you should not turn your compost heap, if you
do you will start to produce airborne pathogens, endangering your health.
After you empty a bucket onto your pile, cover it with a thick layer of high
carbon material.

Probably the best method I have seen is that used by a large scale portable
toilet provider here in Australia called Hamish. He calls himself the Poo
Dude and he provided portable composting toilets to many large scale
festivals and events here in Australia. I met him at the Australian
Permaculture Convergence earlier this year. http://www.naturalevent.com.au/

Hamish uses an "in bin" composting system using large 240 litre "wheelie
bins" like this
http://www.freefoto.com/images/11/29/11_29_72---Wheelie-Bin_web.jpg He has
over 20,000 bins currently composting.

He adds a drain tap at the bottom of each bin with a basic filter to stop
solids blocking it, the drain tap is connected to a standard 18mm garden
hose with snap  on fittings. This allows liquids to drain to a vegetated
area away from people. If you were doing this at home you would be best to
harvest this very high nitrogen resource for use in one of your growing

Once the bin is full with humanure and lots of high carbon material
(sawdust, woodchips, straw, leaves etc etc) he simply turns off the drain
tap disconnects the bin from the drain pipe and wheels it to it's storage
location. It then sits there composting for 12 months.

The 240 litre bins are very cheap here in Australia (around $25) and you
would only need three or four for a normal sized family. They have a big
advantage over small non-separating systems in that they do not need to be
emptied regularly as they will not go anaerobic because the liquids have
been drained off. The only disadvantage of the 240 litre bins are that they
are tall, and you therefore need to make a toilet with an elevated floor.

It's all about leaving the humanure to break down for an extended period. As
Hamish said to me "Even if you kept a pooh in the fridge after 12 months it
would be safe enough to eat". A disgusting thought, but somehow re-assuring.

The Poo Dude then puts all his compost through an industrial scale worm farm
to further reduce the volume. He only does this because he hasn't developed
another use for his fantastically fertile compost.

To paraphrase Joseph Jenkins (author of the humanure handbook), If you are
particularly worried about your donors having a high concentration of
pathogens then leave your compost for 2 years.


nick ritar

life - http://www.milkwood.net
work - http://www.milkwoodpermaculture.com.au
art - http://www.cicada.tv

phone - 02 6373 7763
mobile - 0407 194 593

On Thu, May 22, 2008 at 12:39 AM, christopher nesbitt <
christopher.nesbitt at mmrfbz.org> wrote:

> Hi Cuauhtemoc,
> We have a very good design, which is a modified Vietnamese double
> vault latrine, which we use. It is two ferrocement vaults, with doors
> on the down hill side. Each vault is fed by two latrines. Judicious
> applications of sawdust, rice hulls, etc, maintain a healthy carbon/
> nitrogen ration. We are working on a manual to distribute locally,
> will put it up on out web page as a down loadable PDF, and should
> have it done in a month or two. I will email you a copy.
> We have problems here of high water table through the rainy season,
> so dealing with shit migrating through the ground to the rivers and
> streams (a common source of drinking water for many rural communities
> in the southern Maya lowlands), is essential. Our latrine is about
> two years old, and we are still filling in the first vault. Sometime
> later this year, or early next year, we intend to close this latrine
> and move onto the secondlatrine. By the time the second vault is
> filled, this one should be all composted.
> Unlike other latrine designs, we do not separate urine since the
> ethnic communities of Belize have no tradition of dealing with urine,
> preferring to add more carbon in the form of sawdust or rice hulls
> (bamboo leaves work, too, but need a HUGE volume!). Some local
> schools are now using our design thanks to a great NGO called Plenty
> Belize who has built them.
> We have had groups of over 40 people here with very little smell at
> the toilet itself.
> A good book is "The Composting Toilet System Book by David Del Porto
> and Carol Steinfeld
> Another great book, wonderfully written, informative and extremely
> funny is "the Humanure Handbook" by Jenkins.
> Where are you located?
> Best wishes,
> Christopher
> On May 21, 2008, at 8:21 AM, cuauhtemoc landeros wrote:
> >
> > Howdy all. I am working on getting a dry composting toilet going in
> > a small urban lot, hopefully the future community activation site.
> > I was wondering if anyone has any resources or reccommendations
> > (books, websites, experience) as how to build one of these things.
> > Thanks all and enjoy the sunshine.
> > For the future...................................
> > Cuauhtemoc
> > _________________________________________________________________
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> _____________________________
> Christopher Nesbitt
> Maya Mountain Research Farm
> San Pedro Columbia, Toledo
> PO 153 Punta Gorda Town, Toledo
> Central America
> www.mmrfbz.org
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