Toilets in #dayZero: The surge in popularity of dry toilets in Cape Town’s water crisis
I am a biologist, chemist, now a bioprocess engineer. As part of the Future Water Institute at the University of Cape Town we work across disciplines to find solutions – engineers, legal, economists, anthropologists, scientists, everyone.
This presentation is really about this question: “What is the future of sustainable sanitation in medium to high density urban environments?” considering the need for resource recovery, but also the related costs, required infrastructure, and most importantly, how governance affects the sanitation service.
This is a typical image of Cape Town. We have affluent, leafy suburbs, right next door to informal settlements. This side is serviced by flush toilets, and this side probably chemical toilets, or broken toilets, or toilets serving many people per toilet.
We need to get to a place where both of these groups get the same quality of service.
Toilets are very political in Cape Town. In many ways it represents how Apartheid has not really ended.
People fight about toilets because toilets are a proxy for a home, which is a proxy for a job, an income, which really is about self-determination, dignity.
Fighting for dignity is a difficult thing, so people fight for toilets. Flush toilets, because that is what the rich people have. But flush toilets are not working.
How are we going to give flush toilets to everyone if we sit with this reality?
This is Theewaterskloof Dam in the Western Cape, which supplies a large amount of water to Cape Town. By March of this year it was 10% full – for all practical purposes, it was empty.
video of 3 year dam level decrease in 60 seconds
Droughts like this will become more frequent; the climate is changing.
At the same time, this is our wastewater infrastructure. It is not working. This is an image of raw seage flowing into the Vaaldam, the source of drinking water for our other large metro, Gauteng. This is the current reality of sanitation in South Africa.
This is not really about the toilet. We can’t make this better by making the toilets better. But the toilet is highly visible, as a public relations tool, in some ways it is all we have. It is a way to start talking about what is hidden, what we are ashamed of, what is taboo.
It is a way to talk about inequality, to have the conversation about equity, dignity. And it shoves the priviledge of people like me right into my face. So I ask: if rich people are not willing to use the most sustainable sanitation systems, how can we expect poor people to use it?
I have been exploring this question in various ways, for example at this conference earlier this year. We had a multi-disciplinary conversation at the African Centre for Cities International Urban Conference, asking the question “What is appropriate for African Urbanism in the context of the Circular Economy?”
It was an open-ended conversation and the key agreement was represented in this quote by Prof Andrew (Mugsy) Spiegel, an anthropologist from the University of Cape Town:
“Create a demand for sustainable sanitation, make it desirable, to allow the users to be fully fledged urban citizens. Celebrate the alternative models through the leaders of domestic appliance fashion. Pursue this in a spirit of celebration.”
So I want to ask you, do YOU have a dry toilet? Or a toilet you consider truly sustainable? If not, why not? Something to think about.
Why am I interested in Sanitation? I am interested in the bioeconomy, and through my PhD work was involved in a project mapping the wastewaters in South Africa. Municipal wastewater dwarfed any other wastewater, both in terms of volume, as shown here, and nutrients, as shown here.
This represents a large opportunity for me and formed the basis of my PhD, developing what we call ‘wastewater biorefineries’.
To give a specific example, 13 tonnes of phosphorous is released into water every day in Cape Town. That is an opportunity.
But looking at sanitation, if we want to get those resources back from a process engineering perspective, following cleaner production principles, there are two things to do. I originally looked at this from the reactor design perspective for wastewater beneficiation. One, separate the components, get the solids out, and two, separate as close to source as possible. The logical conclusion to me, is dry sanitation.
Dry sanitation has plenty of opportunities for the bioeconomy, particularly in these high value products which I believe have higher financial feasibility. I agree the nutrients must go back to the soil, and they still can. The yields of these products are low, the value is high, and the nutrients remain and is still biologically processed through this conversion. To me, that is my end game, that is where I want to go.
But let’s get back to the big picture. For this sanitation economy to work we need to convince people to use it. So why me?
Two years ago I built a house. Just a little modest house but I designed it well. It’s called house jouissance.
Why jouissance? It’s a reminder to embrace discomfort. To be brave in the face of discomfort for the end game. The definition of jouissance is “a brief flash of enjoyment achieved after excessive pursuit.
The pleasure lies in the obstacles to fulfillment – but only if that fulfillment eventually arrives, and only if there are obstacles.”
For some reason this house attracted a lot of attention, and very unusual for a scientist, the house and my approach to it was featured in two industry magazines and one mag that can be found in most supermarkets and corner shops in South Africa.
Critically, my house has a dry toilet. Because I like it.
It’s a very simple, unoptimised system, because I am still wrapping my head around what is needed, so it’s a dual chamber (two buckets) urine diversion dry toilet.
When people asked me what I do with the material, the pee goes in the garden and the faeces gets “put it somewhere else for 6 months.” We’ll get back to that.
Why now? Why did my house get featured in the magazines now?
I believe that we are ready for it. Everyday people are starting to understand the bad stuff about lock in, the things we are stuck with like sewers. We are starting to understand the windows of opportunity, and what can swing us to transition, the “transition-triggering conditions”:
A city can be said to represent a socio-technical system, where human/social sub-systems interact with technical system. For a city to change towards a more sustainable state there is a need for a socio-technical sustainability transition, which is a transition not only of technical components, but also of policy and market, consumer practices, and institutional arrangements (Geels, 2002). However, existing socio-technical systems, e.g. cities, are stabilized through various lock-in mechanisms, for example through sunk investments in infrastructure, technical competencies and supply-chains (Geels, 2010), as well as institutional commitments, power relations and shared beliefs (Unruh, 2000). In order to “speed up” socio-technical sustainability transitions it is necessary to first understand the processes governing the desired transitions. One useful framework, articulating overall patterns in socio-technical transitions, is the Multi-Level Perspective (MLP) which brings together insights from evolutionary economics and technology studies (Geels, 2002). Within the MLP framework, transitions are viewed as non-linear processes resulting from interactions between three analytical levels: niches – representing the desired practices/system we need to transition to, regimes – representing the deeply established and non-sustainable practices/systems that we need to transition from, and a landscape – representing background variables such as global markets trends, climate and geo-political events (Geels, 2002; Raven et al., 2012). Analysis of the different levels provides a base for understanding where there are “windows of opportunities” for transition (Geels, 2005). de Haan (2010) proposes that transition-triggering conditions can occur as pressure, tensions or stressors within each level. ” – Elisabeth Kvarnström, RISE
Cape Town is in the fourth year of a severe water crisis, and in April this year it was announced that we can reach Day Zero, the day there is not enough water in the pipes and we have to queue for water. We’re not in the green yet but we did not hit #dayZero, this year.
#dayZero represents a transition-triggering condition. What are the windows of opportunities? How do we leverage this?
When #dayZero was first announced, it took people all of three minutes to panic about the toilets. What is going to happen to the sewers? Will they keep flowing? If we use dry toilets, what do we do when the bucket it full? What if we don’t have a garden to put it in, would the solid waste management manage this? “put it somewhere else for 6 months” is not good enough.
But suddenly, I was famous! What do I tell these people? This is still my question. What do we tell people who do not want to, or cannot process their own waste? This is still my question and why I came to this conference.
Let’s step back again, convincing people to use it, this is what I learnt. I am assuming that the toilet is convenient, safe, dignified, of course. But I am challenging that this is delivered by a white ceramic flush toilet.
I want good natural light, I want it indoors, no flies, and no smell.
Nowhere in this list am I bothered by if it’s flush or dry. If we need to, we can make dry toilets indistinguishable from flush, or we can do even better, see my bright red box.
At this point people tend to say that dry won’t work in cities, so let’s just summarise why I love dry toilets:
1. Nutrient recovery: food security, soil health
2. Producing N, mining P bad for environment: imbalanced cycle, NOx greenhouse gas
3. Dry toilet waste more concentrated, easier to recover
4. Dry toilet infrastructure is cheaper than flush infrastructure
and most importantly:
5. Effluent even from well managed wastewater treatment works = eutrophication
* slides after end for more info
So remember that first question, let’s rephrase this as “Is the future of sustainable sanitation in medium to high density urban environments DRY?”
My civil engineering colleagues say no. They say:
1. Sewerage isn’t about the toilets, it’s about the greywater.
2. We can get the water back – wastewater reuse
3. Hydrotransportation is the most efficient
4. “proven public health success” “greatest ‘medical’ advance of the industrial era”
5. Dry sanitation, by contrast, exposes people (users, collectors etc.) to severe public health risks.
In dense urban settlements, more cost-effective, easier to manage.
I don’t believe them, but I could be convinced. Before I am, however, we need to give dry toilets a fighting chance, at least.
So what is the end game? What does it take in the big picture?
Toilet designs are easy, it’s about the servicing infrastructure, looking at circular urban planning. Allow for engineering services that enable resource recovery. Address the issue of greywater management. Address the logistics of transporting the materials, address how to process the material at scale.
To this, the concept of water sensitive design is very promising, or as the International Water Association calls it, water-wise cities. This approach considers waste, and wastewater as central to the city, but more importantly looks at this in context of the bigger picture: the way the city is designed, the way it relates to the basin, to how the people relate to the city.
In short, it is about regenerative architecture & urban planning: Using the built environment to absorb change. And the heroes in this story are the landscape architects. Make them your friends, learn to talk to them, support them.
But what is the infrastructure required? There’s no real answers yet, and it’s probably a mix of a whole bunch of things. To me it’s not ‘the toilet’ but sanitation as a service. Resource recovery needs to be integrated with other engineered services – Greywater, Stormwater (drainage), Maintenance… the road and transport infrastructure…
To me the current idea is something like this: A city built of collections of 5 floor perimeter blocks. These are buildings built around a central area, with the services, sewer, internet, road etc coming into the middle of the building, which is efficient engineering. I imagine these to be of sizes of 20 to 100 households each, but I don’t really know, and then the waste is managed in modules of about 10 000 people, so basically a neighbourhood. The services – energy, drinking water, waste is processed at appropriate scale, I say appropriate because I think it will be more decentralised, but NOT to household level.
In the public spaces rather than use pipes everywhere also use the landscape as infrastructure, use lower curbs and swales to collect stormwater and allow it to seep into the soil and be cleaned as it drains, this is known as Sustainable Urban Drainage Systems (SUDS), use bacteria, algae, plants, fungi, animals more where possible, summarised as nature based solutions (NBS). This is our current research, what this means.
I would add that healthy soils are key to this, to allow nature to do better work with us. And I agree with Bruce from yesterday, no cars :). Interestingly from an engineering perspective a current indicator for good cities is to minimise road length per person.
This talk can be found on my website.
hysteristic failure – when it breaks you can’t fix it.