Keeping the loop in mind

Presentation at the UCT Summer School, the pdf is available on the Future Water Institute website.

Kevin asked me to present on Innovations in Urban Water Management, through talking about my house. Instead I wanted to talk about systems, and took a term from the start-up scene ‘keeping the end in mind’, as in, keep your goal in mind, what you want to achieve, or what you want to sell it for. But really, we’re working with systems, and I want to focus on where these systems, these loops come full circle.

Continue reading “Keeping the loop in mind”

Jouissance toilet 2.0 – the foam flush

Why? We’re in drought, so we don’t have water to flush toilets. The nutrients in shit should be re-used, and that is difficult when we dilute it with loads of water and mix it with god knows what else to be shipped off somewhere to be so-called ‘treated’. Also, flushing toilets mean we are flushing nutrients into receiving water bodies (even with excellent wastewater treatment, we’re still not doing well enough). So flushing is just a stupid idea. More about this in a presentation (pdf, 5MB) I recently gave.

If you don’t know already, I have a dry toilet. I love my dry toilet. It’s indoors, I’m affluent, privileged. This is not about toilets for poor people. This is about dry toilets for everyone.

But, many people don’t like the idea of looking at their shit, so we’re trying to get the experience of the white ceramic sparkly-clean ‘flush and forget’ ‘out of sigh(t) out of mind’ toilet, with the cost-saving benefits and environment and resource recovery goodness of dry toilets. I think currently the foam flush may be our best bet.

NOTE: When I start talking to people, lots of people have lots of ideas, but invariably, these are about the user interface. I don’t care about the user interface – that is whatever you want it to be (except copious amounts of water). The colour, ceramic or plastic, sit or squat, wipe or wash, lid or hole, I don’t care. I am concerned about collecting and storing it for beneficiating later. Don’t give me your fancy ideas at the user interface unless you’ve thought through how this affects the process downstream.

What do we need the foam flush to do? (apart from the usual dignity, hygiene, yadda yadda). This really comes down to what is in the foam to make it do its job:

  1. Act as a lubricant.
    Unlike a standard issue dry toilet that drops your nutritious product straight down, to sit there in the darkness staring back at you (apparently), this goes down an angle, to out-of-sight land.  So the lubricant needs to be lubricating. No getting stuck or smear marks.
  2. Smell nice.
    Not just like nothing, or slightly earthy, but seriously amazingly nice (ala PooPourri – I love this product! (doesn’t work in my dry toilet though))
  3. Contribute to the bioprocess.
    Or at the least don’t impede it. This means: No bleach. Probably needs to be a neutral-ish pH (no actual soap, or acid). If it has the bugs that work well with poo, that would be epic – an inoculum, like the yeast that makes your beer, the seed that grows your tree… (see circular economy, resource recovery)

Overall, I keep coming back to giraffe spit. Or, you know, whatever lubricates our assholes (biomimicry: ‘how does nature move shit?’), but giraffe spit seems to be more PC.

Other things that may help:

  • Urine diversion is important and a no-regret measure. For now, pee in the garden.
  • A trap door jobbie that works with the lid to guarantee no smells coming back.
  • A hydrophobic layer on the tube that helps or replaces the lubricant. Like the no-dirt layers on car windscreens, for example.

Some links that show foam flush constellations (yes, that’s a sortofa pun)

The short and sweet by treehugger.

Clivus Multrum composting toilets – according to this site, with images, the foam flush toilet eliminates the ‘dark opening’ of the waterless toilet. For some reason it ‘requires both a water and electric connection, and costs more’. I don’t see this as a real requirement. From this website:

The New England site has even more. Their pics remind me that I’m not all that keen on trying to imitate the standard shape and colour of a toilet – how boring! So I might not know exactly how to get this into mass production (nor do I care). But, colleagues at Isidima may be well placed, see for example their arumloo (still a flushing solution though currently)

This post by the Green Building Alliance (GBA) which reminds me to state clearly that after the user interface and storage bits, there is the collection and transport bits. I do not expect users to deal directly with their shit. This is also not a pit latrine solution, it needs to be above ground and easily collected – consider the weekly solid waste/trash collection idea.

Also, the trapdoor future idea is a way to deal with what the ‘S-bend’ tried to do – avoid odour. With a well functioning composting process, odour is not a problem, and instead of trying to create all sorts of fail-safes to deal with odour, I would rather have the foam solution be something that contributes to a more robust well functioning process.


Toilet-love in the time of drought

(who got the movie reference?)

Cape Town is in the worst drought ever, and asides from all the panic this is generating some lovely publicity for the dry toilet. I’m getting a lot of emails.

Here’s the short version of my replies:

  1. Pee in the garden (toilets should have urine diversion)
  2. Foam flush is probably the closest dry toilet experience to the flush toilet
  3. The challenge is what to do with your product.

The longer answer:

This compendium of dry toilets that is not just aimed at ‘giving poor people toilets’ is a nice recent find:

A no regret measure is to have urine diversion, it saves volume and keeps the matter drier (less potential for stinky). Pee in the garden!

My experiences with my toilet is written up here.

The big challenge is processing the faecal product. If you have a garden, or space to store it for 6 months or so, then you can put it in a closed container (I use a 20L bucket with lid, R50 at plastics shops – takes a month or two to fill up with one person) and forget about it for 6 months, then bury it under a tree or simply dig it in for non-food compost (because it has not been purposefully processed, I am not happy to suggest growing food on it eventhough it may be fine).

With the drought, a friend, Carlos, and I are working on proper processing our matter in Muizenberg to compost and then maybe linking up with someone like GreenPop to use it for planting trees and marketing this as a way to cope with the drought. The nice thing with compost, including humanure, is it acts more as a soil conditioner and helps to retain moisture, more than providing a complete nutrient source.

Carlos has been working with me to develop a prototype dry toilet for Day Zero (or to extend not getting to Day Zero). He is much more astute about the user interface. To me, a bucket composting toilet works just fine. Dyllon Randall, a colleague at UCT is working on urine beneficiation and we are thinking about faecal stuff next.

According to Richard Holden, dry toilet practitioner, and Chris Buckley, the shit expert, who is doing the best research on this in South Africa, the Separett is the creme de la creme of dry toilets, as the incineration means you just never have to think about it again. They are about 3 000 EUR though and need to be imported.

I’m currently contemplating foam-flush toilets – the foam lubricates the matter just enough to slide out of sight as opposed to straight down, while keeping the liquid down to a minimum.

Where to buy these? Carlos is making some, and hiking shops like Outdoor warehouse has some basic ones.

Then there’s the bigger ones, for example my first dry toilet was the ecosan.
While they look tempting because you don’t have to think about emptying them for a while, they didn’t quite work as planned, and got blocked occasionally (an experience others had too), and once full it was a mission to maintain them. I prefer to keep the collection containers small and easy to move around – hands free of handling the actual matter, of course.

For interest, my recent presentation about why we should all go dry is here, and generally these presentations are listed on the resources page.

Jouissance toilet

My house was featured in Earthworks. Obviously I’m thrilled, but also a tad apprehensive. While I have a dry toilet in an affluent (medium density) urban environment, I am not suggesting that people at large use this; the practitioners (specifically Richard Holden) seem to agree that flush toilets remain the best default option – from a (rather centralised) waste management perspective. I don’t know how much of that is user psychology, I don’t think we’ve explored the options from the city planning, health, waste management and engineering sides… hence my interest. On the other hand, it’s worth taking a leap and seeing where it goes. So, one step at a time.

Please note: Don’t just bury your shit fresh, when there’s lots of people living around you. Diseases. Worms. Parasites. These things are in shit. Even if you are healthy. And even if you stay healthy there may be people around you who are vulnerable and could become affected from your adventures. It could contaminate groundwater. Think it through a bit, ask questions, let’s figure it out, together. We need several bits of the ecosystem (mostly bacteria and fungi) to work on your shit before it can rejoin the bigger picture.

I have been having some requests for more info, so in the interest of convenience, here’s my default response. Don’t hesitate to get in touch anyway 🙂 (

Oh, and if you’re squeamish and this offends you, get the fuck over yourself. Someone, somewhere has to deal with this on your behalf if you don’t.

The general questions are along the lines of ‘custom or commercial‘?

I have custom: I have a bucket in a wooden box that’s got ergonomic proportions for optimal bowel movement and makes it look nice. Designed from scratch, iteratively based on what I thought about during every squat, and made my builders chuckle, especially at the request to paint it all bright red. Each to their own.

Because I live alone and want to experiment on my shit, I wanted something that can easily be removed, moved and minipulated. The plan is to take the bucket – a 25L plastic bucket with lid works a charm, which I bought for cheap at someplace like Plastics for Africa – once full, covered, outside, where it either stands for a few months to stabilise itself before getting buried under a new tree or gets put in a managed compost heap or gets experimented on.

The plan is also to look at systems that a single fragile woman can empty on her own if government/other services doesn’t empty the thing… I see many toilets that fall in disrepair when the pit is full, because either the local community don’t want to or can’t maintain it, or the government/ the company contracted to empty and maintain the thing didn’t. It’s usually in such a format that you need to be a few people or need equipment or something to maintain it – for reasons of economy of scale, trucks with vacuum pumps or people with spades only want to come occasionally, and if you need to dig a new pit, you’d rather dig a big one less often than a smaller one once a month/few months. But it leaves single women, or the mothers and children who get stuck with the unmet needs, unable to do something about it. That’s my opinion, anyway. I’m coming from a view not of ‘service should be delivered to us’ (it should, but it doesn’t, and ‘should’ doesn’t make things happen), but the apocalypse where it’s everyone for themselves. Or reality, whatever. Or, you know, guesthouses or bush bomas or holiday homes or shacks.

From some visitors, the dignity thing came up, and I was wondering what makes a toilet dignified. Some visitors wanted the white-flush-ceramic-toilet. But I think it may be more nuanced. Good ventilation. No bad smells. Good light. Safe. Being able to go inside your house, at any hour. And cleaning it in a way that doesn’t make you gag.

OK, so you need a toilet, and you’re thinking of a dry one.

The things to consider are:

  • Size of the toilet – who will be using it? How often?
  • Cover material (not a have to have but I like it, and it could clog some systems up)
  • Ventilation (more for flies than for smells, in my experience, but also, ducks eat flies, so there’s that) and then
  • Obviously what to do with the stuff afterwards. This is the place where you need to do most of the thinking, as this will determine if you look forward to your throne or dread it.

While living in the shack I had an EcoSan (, which is advertised to last 8 people a year (I think) before it needs to be emptied. It got clogged a bit with the sawdust I use as cover material, which also absorbs the liquids and most of the smells. I would recommend using any sort of grassy, sand, ash, saw dust (‘low in nutrition’ – high in carbon (if you can), low in nitrogen, low in phosphorous’) sort of thing – plant clippings, because it makes it look loads nicer too. The EcoSan was way too big for someone living alone, and I can’t empty it on my own (well, I can, with a bucket which I use to empty it one bucket at a time as I’m setting out the garden, trees dig it, but hauling the bucket around is a schlep, and this is after having it digest itself, taking up space, for two years), but could work for a guesthouse? If you don’t use the cover material, you could get a company to suck it out with a vacuum pump. I’m not sure what they would do with it if there’s cover material in, haven’t asked.

The toilets in the Silvermine nature reserve is (similar to) the Enviro-Loo (

Urine diversion

At first I was all like, this is way too much effort and the urine has good nutrients for what I’m going to grow in the waste and it’s not a big deal and all, but in a dry toilet where things don’t drain away, it’s actually a lot of liquid (or it’s all my beer…) and it did get a bit of a musty, damp kind of a smell, and it’s heavy to carry all that stuff once the bucket is full. I didn’t feel like emptying out my drum twice as often either. So I would also highly recommend a urine diversion of some sort as the liquids fill up the thing very quickly, and could make it rot. And it’s epic fertiliser. I haven’t optimised this part yet, I’m squatting over a small ~8L bucket at the moment, and then when it’s full-ish (about once a week, twice a week if I’ve been working at home all week) I dilute it about one part to 10 parts water and water the plants. Guys are encouraged to pee in the garden. For (shy) guys a urinal is probably going to be a great thing, but I’ll probably just make a separate drum for those who prefer to sit (due to anatomy or otherwise). As a sitter, you could pee in the garden as well, but then I’d suggest not wearing underwear and wearing flowy skirts, if you want to do it with any grace.

Go high(-priced) or go low(-priced)

For single people, you can probably get away with doing whatever you like. For multiple people, the recommendations from e.g. Chris Buckley(UKZN) is either the permaculture solution ( a sortof raised long-drop, with sawdust – I saw this in Ladismith, the one in the Western Cape, at Berg-en-Dal) or the Separett, which is the creme de la creme of toilets with the princely price tag to match.

  1. The cheap version: a Urine diversion (UD) pedestal with a chamber underneath the floor and emptied from the rear (needs to be against an outside wall with external composting, or
  2. The expensive ‘just make it all go away’ Separett toilet, which can sit on the slab, with external composting. The Separett is from Sweden and would need to be imported but is less effort once installed.

Your final choice is more about what do you want to do – how many people, how do you want to deal with the stuff afterwards…

Does it smell?

Yes and no. If you don’t look after it, it might smell bad. It won’t smell like bleach, because killing all living things in the vicinity will defeat the whole point of using biological systems to manage your waste (we’re working with eco-SYSTEMS. Systems need multiple partners. Don’t kill them). It smells of your cover material, pine sawdust or plant clippings (which I find pleasant). It can smell like the soil just before the rain. So it smells natural, and for some people that means it smells bad because the toilet doesn’t have that synthetic perfume smell (a housemate used to call the spray can ‘shitty lilies’. Touche), they don’t have a smell that we’ve been trained to think smells ‘clean’. If you’re one of those people, good luck, you’ll just have to hold it in at my place.

Looking after it means:

  • Don’t drown it in liquid. If it can’t dry out and it doesn’t have air, it gets anaerobic (rots). It’s the sulphur, apparently.
  • Adding a cover material (hand full for taking a shit, a sprinkling for a wee) makes a big difference here, and I think the smaller bucket size (removed more often) may help too.
  • Ventilation can take the smell away, and urine diversion helps too. It keeps flies away too. With my EcoSan I didn’t have flies (but I did have a gecko family living in the gappy wendy house set-up), but I do have an occasional fly with my current setup (when perfect is too good). To be optimised. The ducks dig it though.
  • Once a month, for a menstruating female, it gets a shock overload – a whackload of nutrients. It can smell a bit more earthy than usual. Still beats having to while away time in the bathroom, covering evidence with toilet paper, while the white ceramic flush toilet flushes and flushes and flushes the blood from the menstrual cup (doesn’t really do big dumps well either). Gosh I hate flush toilets. Just chuck double the usual cover material in (two hands full).
  • Don’t throw anything non-organic in there, but anything organic goes – it’s like a compost heap: Can an earthworm eat it? (There are worm systems too – Otter’s Bend has a nice system based on a flush toilet)  Then it can go in, no worries about blockages! Empty toilet rolls, toilet paper, tissues are fine. Newspaper works too. Straw’s good. Another reason why I think menstrual pads and tampons are dumb, but I put them in there too if I have to. But really, menstrual cups for the win. Fungi seem to cope with the occasional foreign organic object, but try to minimise this.

Sometimes it smells funny just because. Your bugs (the bacteria that gives the rain-soil smell, I think, not sure) got unhappy. The bugs that eat the sulphur stuff and fart a lot got the upper hand. I would like to get to a point where I know how to deal with this (I think throwing in a tub of yogurt could work to rebalance it, haven’t had the opportunity to need to fix it again yet), and I would like to see if fragrant oils like Poopourri can help, but when this happens, which isn’t often (less than monthly, for sure), I just drown it in cover material, sorts it out quick-quick (there’s a reason for that: organic (as in, rich in carbon, low in nitrogen and phosphorous) compounds gives energy to help the good bugs recover. Absorbing liquid is a bonus.

The bottom line

(I love all these puns I can just throw around)

There’s a lot of work done on this, and so many practitioners and experts and NGO’s and Bill Gates and stuff. But I don’t think anyone really has it figured out. There’s a lot of taboo, and there’s a LOT of patronising going on (WE will teach you how to shit like a civilised person). There’s a lot of tech-heavy narrow-minded approaches, there’s a lot of expectation, sometimes how bad it’s going to be (the number one comment I get as people come into my bathroom, or go to the sewage works is ‘but it doesn’t smell?’ .. No, well maintained systems don’t smell. Perhaps earthy, yes, but not that shitty last-day of a festival’s porta-loo smells.) and sometimes that someone else will take care of it. I think we’re at a time of crisis – of governance, of environment, of economics – that we just can’t trust expectations. Let’s experiment. Keep safe, wash your hands, think, do some research, but experiment. Let me know how you’re doing, let’s help each other out.

The Earthworks article is the Jan/Feb 2017 edition, issue 36. The online version doesn’t have the pics.