Stuffy and cumbersome to use: the disadvantages of the first urine-diverting toilets
“The slow change is largely due to the toilets themselves,” says Tove Larsen, chemical engineer at the Swiss Federal Institute for Water Supply, Wastewater Treatment and Water Protection (Eawag) in Dübendorf, Switzerland. Most urine-diverting toilets that hit the market in the 1990s and 2000s have a small bowl in the front to catch the liquid—which requires some accuracy when peeing. Other designs feature a foot-operated conveyor belt that directs feces into a composting bin while urine drains away. Still others are equipped with sensors that operate valves to direct urine to separate drains. In European pilot projects, however, users failed the toilets, reports Larsen. They are too unwieldy for people, too stuffy, too unreliable.
Such concerns also accompanied the first large-scale deployment of urine-diverting toilets in the South African metropolitan community of eThekwini. After the end of apartheid, the municipal boundaries in South Africa suddenly expanded. “As a result, the authorities suddenly had a responsibility for poor rural areas with no toilet infrastructure and a poor supply of fresh water,” explains Anthony Odili, who researches sanitation at the University of KwaZulu-Natal in Durban. After a cholera outbreak in August 2000, authorities hastily installed various types of sanitation facilities, including some 80,000 urinary-separating dry toilets, most of which are still in use today. In these urine-diverting toilets, the urine flows into the floor below the seat and the faeces fall into a large tank, which the municipality has only emptied every five years since 2016.
»Sometimes people could no longer breathe normally when going to the toilet«(Anthony Odili, wastewater expert)
According to Odili, the project has helped improve the safety of sanitary facilities in the region. However, social science studies have identified a number of problems with the systems. So most people find the urine-diverting toilets better than nothing at all. But studies – including some that Odili himself was involved in – show that many don’t like the toilets very much, partly because they are made of inferior materials and are awkward to use. And although the separation toilets should theoretically prevent bad smells, urine keeps getting into the holding tank, where it then causes a pathetic stench. “Some of the people could no longer breathe normally when going to the toilet,” says Odili. In addition, the collected urine remained largely unused.
Ultimately, the decision to use the urine-separating dry toilet was made with public health in mind, without considering people’s preferences, Odili concludes. A 2017 study found that more than 95 percent of those surveyed in eThekwini want the convenient, odorless flush toilets that urban whites have—many also expressed intentions to install this standard type of toilet once their circumstances change allow it.
A new design may therefore be needed to help the urine-diverting toilet to make a breakthrough. Led by designer Harald Gründl and in collaboration with Larsen and other researchers, the Austrian design agency EOOS (now spun off into the company EOOS Next) presented in 2017 a concept for a urine-diverting toilet that would eliminate the need for users to aim and urinate is almost invisible (see »Innovative toilet«).
The new system makes use of the so-called teapot effect: it is based on the tendency of water to stick to surfaces. In the EOOS urine-diverting toilet, it causes urine to run out of its own accord over the front inside of the toilet into a separate hole. This »urinal trap« was developed with the financial support of the Bill & Melinda Gates Foundation from Seattle. The EOOS urine trap can be installed in all types of toilets, from high quality ceramic base models to the plastic throne. The Swiss manufacturer LAUFEN is already producing a urine-diverting toilet for the European market based on the concept. However, the place called »save!« is still too expensive for the mass market.