Sustainability
A revolutionary toilet

There is a death zone in the middle of Europe. It is twice as large as Switzerland and lies between Sweden and the Baltic States around the island of Gotland. The Baltic Sea is dead there. There is practically no more oxygen in the water. Hardly any living creatures can survive there for any length of time. And this environmental catastrophe is also man-made. The reason: for decades there has been too much nitrogen and phosphorous in rivers that subsequently gets washed into the sea. As the Baltic Sea is almost totally surrounded by land, this “over-fertilizing” particularly affects the sea, as there is limited water exchange with the North Sea and the coasts line consists largely of highly industrialized countries. That said, the problem has long since taken on global dimensions. While in 1960 there were roughly ten dead zones in the oceans, according to the Federal Environment Agency in 2008 there were as many as 405, and the number is on the rise. Coastal areas and river estuaries are especially affected. Environmentalists describe the death of the oceans as one of the gravest and most dangerous ecological problems we face – as dramatic as climate change but one that has been much less visible in the public perception to date.

One reason for the problem is the excessive use of fertilizers in agriculture. This fact has been known for some time and attempts are being made – at least in Europe – to gradually reduce use through stricter laws. However, the other reason for this over-use of fertilizers or eutrophication, as scientists refer to it, is caused by man. Since human urine also contains large amounts of nitrogen and phosphorous it also contributes to the death of large stretches of water when it enters our ecosystem untreated. Similarly large amounts of hormones and pharmaceutical residues in urine also enter our waste water. In highly developed industrialized nations modern sewage treatment technology helps to keep the problem in check, but at great expensewird dies. Moreover, just one and a half liters of urine contaminates 180 liters of water. The mouth of the Seine is massively endangered despite all the treatment the waste-water has undergone. In the Global South, enormous amounts of feces enter rivers and seas untreated.

For over two decades Tove Lasson from Eawag, the Swiss Federal Institute of Aquatic Science and Technology in Dübendorf near Zurich, has been working on solutions to prevent water being overfertilized by urine. And it was clear to her early on that the answer is seemingly banal. You simply need to prevent urine and the flushing water from mixing in the toilet. Afar all, once it has mixed it is practically impossible to separate the two liquids. Separated and chemically transformed urine can even be a valuable resource. So how can the two substances be kept apart in the toilet? Every attempt undertaken to date has proved to be too complicated and unsuitable for large-scale production.

Enter Harald Gründl. For 24 years Gründl and two partners have run Vienna’s EOOS – Austria’s most famous and internationally successful design studio. When the economic crisis erupted in 2008 the EOOS founders began to ask themselves what social role their designs should play in future. “Do we simply want to design another bath tub without asking ourselves where the water comes from and where it ends up?”, is how Gründl describes the doubts he had at the time. There had to be more to it than that. While when researching into water as a resource he came across researcher Lasson he swiftly contacted her to ask whether she had any use for a designer. “I expected her to commission us with some abstract brief or other,” recalls Harald Gründl. “But she had a crystal-clear product briefing for us: “Design me a urine separation toilet that works! The ones that exist are not good enough.” Gründl and EOOS set about their task initially with very limited funds. But that altered abruptly in 2011: “Tove called me to say that the Bill & Melinda Gates Foundation had invited us to take part in the “Reinvent the Toilet Challenge” and that the Foundation would make research grants available.”

This article could also have started as follows: Some 1.8 million people die every year from diarrhea-related illnesses including half a million children under the age of five. The main reason: Globally over 2.5 billion people have no access to safe and affordable sanitary facilities. This problem is becoming increasingly dramatic thanks to the global spread of urbanization, the growth of megacities especially in the southern hemisphere, not to mention the expansion of slums that have neither a water/sewage or electricity infrastructure. In Kampala, the capital of Uganda, only 16% of the poor households have a private toilet. The great majority has to rely on public toilets and they are often in a disastrous hygienic state. To tackle this problem in 2011 the Gates Foundation commissioned eight universities and institutions with developing toilet systems that work without any infrastructure. The Foundation made the following stipulations: The toilets should not need to be connected to a water or electricity network, cost less than 0.5 US cents per user and day, be able to kill bacteria in the feces, and be able to recover valuable resources such as water and nutrients.

Unlike the teams active on most of the other projects supported by the Gates Foundation, EOOS and Eawag took an approach that was not specifically tailored to use in the Global South. They had recognized that the concept of the separation toilet was potentially an ideal candidate for use in regions lacking sufficient infrastructure. “Of course, mobile phones were not made for slums either but they are the ideal means of communication there,” says Harald Gründl. “We wanted to design a high-tech toilet that would work everywhere."

The key question: How could urine separation function? First of all, Gründl and his employees thought of a sensor that could distinguish between water and urine. And indeed, there is such a product on the market, but the sensor manufacturer and the Gates Foundation were unable to agree on the terms of their collaboration. “And so there we were. We suddenly had the research grants but no idea how to solve the problem,” recalls Gründl. Not willing to sit around idly twiddling their thumbs, he and his team began to conduct ergonomic studies, because to the surprise of the EOOS designers there are hardly any scientific studies on human behavior when using the toilet. So EOOS staff began using infrared cameras to observe themselves on the toilet. They conducted research into the angle and speed of the urine flow and the areas impacted. Finally, they were able to construct a simple mechanical device that allows them to imitate male and female urination in the laboratory: The “Urinator”.

With this new tool Gründl and his staff then began to research into mechanical solutions for trapping the urine and finally hit on the so-called “tea-pot effect”: If tea is poured too slowly out of a full pot then the liquid does not run into the cup in the form of an arch but drips down the spout. Gründl and his team exploited this effect by using the different speeds of the liquids to separate them. The slow urine is diverted off through a specially formed outlet while the quick flushing water simply bypasses it. The efficiency of the method is impressive: It allows almost 80 percent of the urine to be separated.

This liquid separation according to the tea pot principle represented the breakthrough in advancing the “Blue Diversion Toilet” that EOOS and Eawag jointly developed for the Gates Foundation. The toilet has already proven its worth in field tests in countries including Uganda and South Africa. While the “Blue Diversion Toilet” cleans the water itself and subsequently reuses it the feces are collected in a closed container. Subsequently the urine is processed to fertilizer using a new technique developed by Eawag. To this end it is first chemically “stabilized” which eliminates the typical urine odor and subsequently it is distilled to reduce the amount of liquid to just under 7 percent of the original volume. The distillate contains the same nutrient concentration as a commercial fertilizer making it a valuable and urgently needed product for agriculture. Researchers at Eawag are working on how to achieve this conversion not in a factory but in situ in an additional module on the toilet.
Research work is aready being conducted on further applications for the urine. Scientists at Bristol University have long been working on a technology that allows energy to be generated from urine: Electricity is produced using microbial fuel cell technology which involves bacteria breaking down urine. Around 200 milliliters of urine suffice to charge a smartphone.

Naturally, urine separation and conversion would also be an ideal means of mastering the environmental damage caused by overfertilizing in the Global North. Harald Gründl believes that if the technology is to be a success in Africa or Asia the problem must also be robustly addressed in industrialized countries: “Otherwise, we will soon be asked: You aren’t changing your behavior but are asking us to change ours?” What is still needed is a manufacturer who is prepared to advance the separation toilet into an industrial product. In “2017 sanitary ceramic maker Laufen contacted us and asked if we could design their new Vienna showroom,” relates Gründl. “I knew that Laufen was always a technology leader in its field. It was Laufen that made the wall-mounted WC the European standard and they also invented the sapphire ceramic that has enabled completely new washstand designs.” On the spur of the moment, impulse Gründl invited the people in charge to his studio and showed them the first prototypes of the separation WC that had just been completed. And equally spontaneously Laufen agreed to develop a separation toilet of ceramic through to mass production. Just a few months later the company presented the finished product to the public for the first time at the ISH 2019. Christened "save!" this revoluationary WC not only looks like a normal toilet it can also be used like a normal toilet. With one restriction: For the separation to work propery you do have to sit down. First pre-series models of "safe!" are meanwhile being trialed at various locations around the world, at ETH Zürich but also Bauhaus University Weimar, Durban University of Technology in South Africa and the Rich Earth Institute in Brattleboro, the United States. The official sales start is planned for spring 2020. Incidentally, Laufen is not only involved in the project with a toilet to suit European needs: Laufen is also developing a pared down version for use in the poorest regions of the world but one that will nonetheless be capable of capturing and separating urine.

Ultimately, it might be a lack of the necessary infrastructure that prevents the system’s breakthrough in industrialized countiresNoch gibt es nur Prototypen. First of all, naturally every separation toilet requires the installation of a second outlet pipe for the urine. Then the urine could either be centrally stored in a building, converted, concentrated and regularly collected. Or it has to be piped off separate from the remaining waste water through a new sewage network. Alternatively, it might be possiblw to use the existing sewers for both types of liquid by say storing the urine during and day and having it transported through the pipes at night. It will require a great deal of political will to launch urine separation on a large scale. However, there suddenly seems to be a means of mitigating the problem of overfertilizing and the damage it causes to oceans. A handful of people have developed a technology that could be used by the whole of humanity. How did they manage that? Gründl thinks for a moment and then says: “Working on something meaningful brings out the best in you.” And then adds: “Or at least it does in our case.”