
Now tell me this is not the prettiest compost toilet block you have ever seen. Go on. I dare you.
The issue of poo at Milkwood has been a long-standing source of discussion. We know that when poo is processed into humanure it contains valuable nutrients that would greatly help establish aspects of our farm. We know it can be processed effectively and safely by simple means, especially on a small scale. And we’ve been doing just that, ever since we arrived.
But what do you do once you’ve got 120 people descending on your farm for 2 days for a workshop with Joel Salatin? There was no way our small domestic humanure system was going to be able to cope!
Essentially our options in this scenario were: dig pit toilets and stick a shack on them (solves the problem short term, but isn’t the best use of this valuable resource as it’s very hard to use elsewhere), hire in porta-loos (and export the poo, the chemicals and the impact at the end of the event – hmm no thanks), or bite the bullet and make a kick-ass compost toilet system that can handle all comers.
We chose option 3. It took much longer than we wanted it to (in the way of such things) but the result is just gorgeous – although i never thought i’d say that about a toilet.
We now have a composting toilet system which can handle large volumes of people, has no smell, is pleasant and comfortable to use and results in a shitload (sorry) of humanure later down the track, perfect for increasing fertility in the soil of our food forests and other tree-crop systems.
To back-track ever so slightly: up until this point we were using a variety of bucket-style humanure systems, and they had served us well. Simple to make and easy to maintain, they were built in response to researching the important work of Joseph Jenkins, he of the Humanure Handbook.
Jenkins now sells a bucket system compost toilet called a Lovable Loo which is essentially the same idea as our bucket system: a box with a bucket it in and a toilet seat on top. After every deposit you put a scoop of sawdust (or rice husks, or woodchips) in the bucket and when it’s full, you take it out, put a well-sealed lid on it and put an empty bucket into the box. Simple.
The next step is processing the contents of that bucket. If you have a lot of buckets, you could just leave it in there for a year. We opted for active processing via a humanure hacienda. Whenever we were running out of buckets we would do a trip to the hacienda, empty all the full buckets into the bay currently in use and cover them with a thick mulch. Then we hosed out the buckets and took them back to the toilet.
This system is fine for domestic scale use, and it’s the system we’ve been using so far at Milkwood. This system can (just) handle our busy periods when we have 30 people around 24/7 during a PDC, or 70 during the day for one of our RegenAG courses. It’s also the system we’ll use in our tinyhouse once we’re finally living in it.
However 120 people around for days in a row was going to be just too much. So we designed and built a new compost toilet based on wheelie bins, which have a much bigger capacity, and also composts the humanure in the bin. No more daily shit-schlepping for us.
This wheelie bin system has one big difference to most wheelie bin systems: no chute between the seat and the bin. That means the lip of the bin is hard up under the seat. And this, in turn, means no cleaning a splattered toilet chute for us!
This design feature also reduces the overall height of the structure considerably, which means less materials used. And we don’t end up with the common ‘toilet tower’ effect. Less steps up to the toilet seat means more access for everybody.
Within this system, the humanure is processed in the bin. When a bin is full, it’s rolled out and placed in the sun. It essentially sits there for a year, composting quietly, and then, when it’s ready, we use the humanure!
It’s a ‘sortof-dry-compost-toilet system’. There is a sieve in each bin about 1/4 above the base. Liquids fall through, solids stay above. There isn’t that much liquid though – the woodchips we add after every deposit seem to absorb the most of it.
The liquid then goes out through a tap at the bottom of the bin and ends up in a trench of rocks and soil just near the block. It then proceeds to fertilise the twisted willows planted on the downhill side of the trench, which we then use for stickwood for our rocket powered shower nearby.
One of the great things about this new system is removing the task of regularly emptying buckets of poo + woodchips into the hacienda. Not that the poo factor bothered me that much, but it was heavy work – what with everything in them, those buckets sometimes weighed 20kg. And it was much easier to run out of buckets and then have a crisis.
With this new system you just roll the wheelie bin out, wheel a new one in, put the full bin in the sun and come back to it a year later. I like that. I like it a lot. And one wheelie bin lasts far longer than one bucket (of course, given that it’s 50 times the volume). Which means a lot less labour on our part and no more early-morning crises where we run out of room in the last bucket all of a sudden.
Here’s the details of making the wheelie bins to suit this toilet.
We also decided to make a urinal, since that would further lighten the load, and give us access to a nitrogen source. We made the urinal out of an old watertank, and as you can see it’s pretty basic.
The trough is a slightly sloped roofing gutter that runs the length of the wall with a steel splashback, and the liquid drains to a pipe which empties into in a big drum down hill.
Twice a day when it’s in use (we only use it during on-farm courses and events), we throw a bucket of water in the trough to keep it smelling lovely. After an event, we have a big drum of urine which we dilute and spray out over various paddocks.
The high nitrogen content in the urine makes it an incredibly valuable, natural fertiliser. And this urinal is a great way to collect that nutrient simply and effectively.
Have I grossed you out yet? I’m sorry. But seriously, this is the reality of taking responsibility for your inputs and your outputs. It’s gotta be done.
And once you realise what a valuable (and free) resource humanure and urine is, harvesting, processing and using it starts to sound like a bloody good idea.
In fact, now that we’re starting to get on top of utilising our waste-streams, we’re seeing this for what it is: just a necessary part of permaculture design. The problem is the solution. Catch and store energy. Every output is an input. All that stuff.
[slideshow]
With elegant, efficient design of these waste-stream systems, the yuck factor is minimised. And there’s no need to hide it all. It is what it is, and it all contributes towards closed-loop abundance.
And besides, let’s face it. You gotta poo somewhere! So why not make it a kick-ass compost toilet which cycles fertility back through the farm?
I think I like the doors best.
Elegant and relatively inexpensive solution. What about the local govt requirements? I assume you didn’t trouble your local council!!!
Can’t wait to try out the NEW loo next tiime we come and visit for a course.. Well done. It looks amazing!
This is just great guys! If we keep shitting in clean drinking water what will become of us?
“Have I grossed you out yet?”
On the contrary, for me it was your most engrossing post yet.
I was left with curiosity about the source of all the materials, and level of skill inputs.
We also use the sawdust toilet here, its great isn’t it. But yes, totally can imagine the stress factor of running out of buckets with lots of visitors around!
Yes, our wastes are a useful and undervalued resource. we need to stop turning useful stuff into pollution.
Nice to see the finished product…they are great but Rainbow Valley Farm’s toilets (worm system) are in my humble opinion much better looking…sorry about that Nick! The Milkwood toilets are very special though…Love Darren
Can’t wait to come back and have a look! Well done!
Looks great, after reading the Human manure handbook I had a go at it, Couldn’t convince the rest of the family though :-(. They said they would Ban any veggies from the garden if I used the compost on it.
One concern, if the buckets are heavy those wheelie bins are going to be super heavy. You might want to fill one with water and get an idea of what it is like to move.
Hi Michael, the wheelie bins are quite movable when full due to: 1) the fact that they’re on wheels, and designed to be lugged around when full of garbage, and 2) the fact that the taps take the liquids out, so the bins are not full of liquid, just the dry(ish) stuff…
poo poo poo, i love a post about poo! thanks for open-sourcing your crapper!
but really, tell the truth – you guys only run those courses at milkwood in order to harvest the poo of the folks who come along, right?
I am super super impressed…love your work! A bit more plush than our space ship…but hey…character goes a long way…especially when we get the decos happening! xoox
Love
Georgie
That is my type of loo – I love it, hope I can contribute to it one day!!! Love the newsletter, thanks for sharing your info. Leonie
I’m a little concerned about spread of disease. Only takes a fly to waddle in it then land on your morning tea scone to transmit Hepatitis. If everyone who visits is 100% healthy and not incubating some dreaded bug then all would be well.
Ozeboy it is possible to get Hep A from a mis-managed compost toilet. It is also possible to get Hep A from a conventional toilet, at Macdonalds and from swimming near ocean sewage outfalls, or froma fly that landed on a baby’s dirty nappy in landfill and then landed on your sandwich, to name but a few places. The Hep virus is killed rapidly in the the thermophilic composting process (over 60ºC), and a well-managed toilet has each poop covered with sawdust or woodchips. We’re aiming with this system to also make it as fly proof as possible. We’re doing… Read more »
Well I always had a soft spot for the previous bog – but this is very smart.
One question though – how do you get the shit out of the wheelie bins in to the Humanure boxes ? It was easy with the buckets – we just heaved the stuff over the top !
Very nice work though…. well done
Great post!
I’ve been thinking about doing something like this for ages but not actually done it yet.
One suggestions/ question:
I was thinking of having the ventilation tube below the sieve to encourage air flow through the contents of the wheelie bin.
I note, however, that you have placed them higher up. Is this because having them higher up help prevent odours more effectively? Or what?
Thanks,
Josef.
PS – personally I think our first ever compost toilet is pretty damn lovely:
http://www.flickr.com/photos/uniteddiversity/3747333643/in/photostream/
It looks great. I was wondering whether the microbial action is at all affected by people’s consumption of antibiotics and preservatives?
Hi Jude, yep those things would effect the microbial action. The cumulative effect seems to work no matter what the individual diets, however. We have an amazingly resilient range of microbes and bacteria in our digestive systems!
Can you guys explain the ventilation? Where’s the end we can’t see connected to?
We bucket pee in sawdust filled buckets in the house and it stinks quite quickly – within a day – and well before the bucket’s full. The sawdust being hydrophobic doesn’t help…
Hi Greg, the end of the pipe connected to the back of the bins ends in a chimney above. The other end of the pipe screws onto a vent at the top edge of the bin side, with a screen on it. we’ll be posting a full explanation of this ventilation shortly.
Re your stinky sawdust, have you tried adding more sawdust on top of each wee? It’s the dry layer above the deposit that helps keep things smelling nice in our experience…
How did you go with Council Regulations?
Hi Deborah – council regs here specify a toilet must be 50m from watercourses (it is) and have contained output (it does).
Looks good – did not see a mention of orientation of the toilet block?
Just wondering if having the bins facing North or West would make sense for solar boosting thermophilic processes / increasing evaporation through the vents?? Or can you get too hot?
Also how effective is the venting??? The black vent pipe is going to lead to some updraught – but do you think there is room to improve on the design – methinks I will find this out and more in your future post 😉
hey, great site. we have a similar composting toilet system at our school. however our bins are smaller (30gallons?) and our toilet seats have a urine separator, urine is collected in a 1000L bin and later diluted and used as fertilizer.
one issue we have been fighting with are flies, regular house flies and other very small flies.
i noticed on a picture there is something hanging on the corner, seems like some type of herb? is that for smell or to avoid flies?
any input would be greatly appreciated !
thanks
–fernando
hi fernando – we dont have any prob with flies – have a look at the construction of the bins here: https://www.milkwood.net/2011/04/18/compost-toilet-specifics-the-bins/ – re the herb, it’s lavender – more for aesthetics than anything – but it contributes to a pleasant environment int here, for sure!
Hi Fernando
We’re currently building a compostoilet in north west Scotland; and looking for the most effective design for separating the liquid element. aAny thoughts on that, from your school one?
Sebastian
hi, great toilets! I have a couple of questions if thats ok…, I’m just researching composting toilets so pls bear with me:) I read the excellent Jenkins humanure book last night so its all theory we me at the moment:) how do you deal with the ‘poo mountain’ effect, from two angles (excuse the pun) 1) how do you ‘flatten’ and 2) with such a large area as a wheelie bin I kind of imagine it might be difficult to cover the fresh deposits if they have scattered down the slopes… Jenkins seems cool with urine going into the toilet… Read more »
hey phil, – combating the poo mountain effect: we take the bin out maybe 2-3 times during its active service and just give it a jiggle with the handle. This flattens the poo mountain. – the poo (time to get specific) lands in one place. People generally aim for that one place with their scoop of woodchip, which covers it. even if they don’t it’s pretty dark down there and as it’s dark and doesn’t smell, you don’t really notice what is or isn’t covered immediately – it all seems to work out… – smell and urine leaching. i’m not… Read more »
For anyone else who’s appropriately fascinated about this topic, there’s a new podcast entry from Sustainable World Radio on this: http://pdcastsusworldradio.libsyn.com/what-a-waste-the-scoop-on-poop-and-ecological-wastewater-management I know the whole C:N theory, but while experimenting with a pee bucket and sawdust, I found that I always got an ammonia smell (aka. stinky anaerobic conditions) in a few days, no matter how much sawdust I used. Has something to do with it being hydrophobic. Tried newspaper, leaves… same result every time. Also note there was an E.Coli outbreak in Europe recently, partly traced back to an organic farm’s manure. So monitor those bins with an actual… Read more »
Hi Greg, we’ve always found it to be fine if you add sawdust *after* each event, so it sits as a layer on top – have you not found this to be the case? Also with the euro e-coli thing, wasn’t that traced to sprouts, in the end, not manure?
I have found that not to be the case… the urine ends up sitting at the bottom, mostly dry sawdust ends up at top, and a bad, ammonia ridden smell for all.
As an experiment, I might see if that potassium-based wetting agent magically causes the sawdust to become absorbent. I also should try some other materials. I’ve used composting toilets that had absolutely no smell, so I know it works – but I still wanted to get confident with a simple pee-only bucket first!
ah a pee-only bucket – i think that might be yr prob. in a jenkins-style system, all deposits go into the bucket (poo and wee) and the bucket therefore fills up quicker and had a larger variety of things in it (diversity!)… so i would assume you’d be changing such a bucket quicker than one just filling up slowly with pee/sawdust. we have used buckets of sawdust for pee only before (for farmers, during a short course) and they stank within a day. yet the other buckets for the girls toilets, with both poo and wee going into them, were… Read more »
My understanding is that the “sawdust urinals” already have nearly all the sawdust in them (e.g., ~4gal prefilled for a 5gal bucket). I haven’t had a problem with odor when prefilling with absorbent carbon material. By the time it smells, it’s because the bucket’s full, and then it’s one final layer of cover material, and set aside. In general, though, unless you have a very diuretic population that pees an awful lot (which can happen with avid tea drinkers or people with cortisol dysregulation), no need and perhaps some detriment to actively separating urine from poop.
This is an awesome website. Leave it to the Aussies to come up with a really great composting toilet system! Thank you for some excellent ideas.
1 of these days I’m coming down to check out ‘the most lovable loo in the west’. What a huge difference from the old ‘Thunder Boxes’ we had as a child on our farm – reguired regular emptying & every now & again, digging a huge hole 8 – 10′ deep to cater for more material.Luv this concept!
I know this may sound like a silly question, but what about wiping our bums?
Not all poo comes out clean…
Do you use newspaper or some such thing? I didn’t see any toilet paper.
We use regular toilet paper 🙂
And where do you dispose of the TP? In the Loo Poo Bucket or a separate one? Thx.
Yep it just goes into the bucket – increases the carbon content.
Hi Kirsten, I would like to make one of these systems in one of my projects here in Italy. There is only one detail which is not clear enough for me. I read somewere that this system has hinges to close the toilet sit/lid on top of the bin. Is that correct? is it possible to have a bigger picture of this detail? I have experience with another kind of compost toilet, which I designed and made, and I am aware of few things I do not want to replicate. I really like your design, thank you for sharing!
Elena I’m not at the farm for a couple of weeks but email nick and he can sort you out with a photo? 🙂 In the meantime, Eugenio took a bunch. the seat box is hinged on the room side and lifts away from the wall side, coming back to sit directly on the bin rim, with the underside sealed with a rubber rim when it’s in place, if that helps at all? https://plus.google.com/photos/108598852373932121255/albums/5665089022267642881?banner=pwa
It is clear now, thank you! 🙂 Eugenio always takes loads of photos 🙂 have a
great time, will update you if we can make “the most lovable loo in Italy” 😉 Ciao!
Thanks for the inspiration. We have a school project in rural Malawi and just built a “lovable loo” following your instructions. The plan is to eventually put the poo in a bio-digester for methane gas and then the waste from the bio-digester will feed the worms. The castings will go onto the garden and the excess worms will feed the fish in the aquaponics system. You can see the loo pics at E3 Worldwide on Facebook and the aquaponics pic at my page; David Epperson.
Great project, and wonderfully explained! I’m planning a similar design, and have a few questions: how critical is the gasket seal between the seat box and the bin, and what is the gasket made from? It looks like a bicycle tire inner tube, judging from the pic at the google+ link from your reply to comment #26. Why did you frame down with 2x4s instead of resting the plywood seat box lid directly on the trash bin? Is there any issue with the 2x4s getting pee on them? Also, I’ll be including a sink, and I wonder if there’s any… Read more »
A brilliant post. Fascinating reading of how you deal with this necessary end product.
How do you get one of these systems approved? I live in southern tas and want to make a composting toilet system. but it seems that down here it has to be certified. that means I have to pay in excess of $3000 for essentially a couple for barrels to poo in. Then ill need a plumbers approval maybe another $1000. do you know how to get around this? if not I am going to build one any way and the council can get stuffed I don’t need someone sitting at a desk to tell me how to manage my… Read more »
Many folks we know have a regular toilet (that doesnt get used) and build another lean-to for their composting toilet.
Hi, I am living in Belgium, Europe, in a moderate sea climate. I really love your system of the wheelly bins and how you let everything compost in the bins. We don’t have much sun in winter. Will this be enough for the composting?
yes, that would probably work better as the humidity will aid the composting process 🙂
Very cool. Do you think this wheelie bin system could be used indoors in a domestic setting?
Yep i rekon it would be fine 🙂 – infact we know a few folks who have implemented this system into their houses 🙂
How about adding some charcoal