Bill & Melinda Gates Foundation

Going Beyond Fake Poop to Win the Prize: A Look at the Reinvent the Toilet Fair Winners

August 22, 2012

Now that the toilets and fake poop have vanished from the foundation’s campus, it is time to reflect on the success of the Reinvent the Toilet Fair, our winners, and how the foundation can continue to play a unique and catalytic role in funding the development of affordable, sustainable and scalable sanitation technologies that service the poor.

The foundation’s first Reinvent the Toilet Fair showcased prototypes of all shapes and sizes (and even smells) selected by the Water, Sanitation & Hygiene team as the most promising innovations of the Reinvent the Toilet Challenge (RTTC), a call to develop a toilet that:

  • Destroys human waste or converts it into valuable resources such as gas, fertilizer combustible fuel and electricity;
  • Operates “off the grid” without connections to water, sewer, or electrical lines;
  • Costs less than $0.05 per user per day in combined capital and operation expenses; and
  • Is a truly aspirational “next generation” product that everyone will want to use – in wealthy as well as developing nations.

Exhibits at the Reinvent the Toilet Fair featured components and early-stage versions of the reinvented toilet. The eight RTTC grantees were vying for the “Reinvent the Toilet Challenge Awards,” and four received prizes. A judging committee selected the winners based on who has made the best progress so far given the specifications of the first round of the Reinvent the Toilet Challenge, listed above.  Overall, we were very impressed by the eight first round grantees for this challenge and we were blown away by what each has accomplished in one year or less with approximately $400,000, or less, in funding from the foundation.


While science and technology are integral to the success of a reinvented toilet, it is the interface, the look and feel of a toilet, which attracts the user. We must create a reinvented toilet that people worldwide will want to use – one that is not only easy on the eyes but easy to operate as well. That’s why we gave Eawag: Swiss Federal Institute of Aquatic Science and Technology and EOOS Design GmbH special recognition for their urine-diverting toilet. Their prototype captured the attention of all fair participants with its beautiful, streamlined design and attention to aesthetic detail. The genius behind the Eawag toilet is its ability to be retrofitted and used anywhere there is existing toilet housing. And it’s really brilliant. Here’s how it works: a sealed toilet opens when you move into the squatting position; it’s cleaned using recycled water that is treated with a system built, invisibly, into the back of the unit; a foot pump pumps the recycled water into a holding tank and you can watch the “fruits of your effort” splash down, the ‘entertainment’ (their words), through a clear plastic window. This isn’t just a toilet that people would not mind using, this is a toilet that people would go out of their way to use, and invite family, neighbors and friends to use. This is a toilet that has the potential to drive behavior change.  For this, Eawag and EOOS received $40,000 and “Special Recognition for Toilet User-Interface.”


Third prize and $40,000 went to the University of Toronto in Canada for their reinvented toilet that sanitizes feces and urine separately and recovers resources and energy. Here’s how this one works: wet solids are flattened on a drying belt, then smoldered (combusted) and sanitized within 24 hours. Urine and cleansing water are passed through a sand filter and disinfected with ultra-violet light, resulting in clean water. What we found most appealing in the Toronto toilet was its simple system – one that a local bike mechanic could easily assemble – that followed the RTTC specifications without using extra power or generating extra waste. Toronto’s reinvented toilet is conceptually sound; the next steps will involve improving the individual component operations and then the integration of each of the pieces into a single operational prototype.


Loughborough University in the United Kingdom was awarded the second prize and $60,000. The Loughborough toilet accepts all bodily waste and transforms feces into a biological charcoal (biochar) through a chemical process called hydrothermal carbonization – think of this toilet as a pressure cooker that cooks the solids and converts them to a fuel source or fertilizer. The toilet generates biochar, minerals and even clean water from feces and urine. Since the byproducts can also be harnessed to power the toilet system, the Loughborough toilet is not just energy efficient but self-sufficient. The first generation of this toilet will be developed for community and public toilets (i.e. in slums) where the operational cost offsets the capital investment. Future development will include a family-scale version.


As king of the throne, the first prize and $100,000 was awarded to the California Institute of Technology. The Caltech toilet is a self-contained, solar-powered toilet and wastewater treatment system.  A solar panel will produce enough power to run an electrochemical reactor that is designed to break down water and human waste into hydrogen gas. This system is designed to process all bodily waste and all wastewater produced by a family, sanitizing the water for flushing or local usage. The toilet produces hydrogen gas that can be stored for use in fuel cells or burned to power the system under low-sunlight conditions. The hydrogen gas can also be used for cooking. The water used in the system is recycled, allowing it to be repeatedly used for flushing. The next steps for this project will address methods to ensure fully sanitized sludge, and additional effort to lower the cost of materials and equipment to meet our specific criteria for a single household unit. The research team at Caltech has already indicated that this challenge is within their reach.

During the fair, we were particularly pleased to see all the solutions on display, with a majority representing a radical approach to the current pit latrines. While there may still be a debate on the completeness of these solutions (pathogen removal efficiency, water recovery, energy recovery, appealing/aspirational), most development experts who visited the fair, as well as country representatives from Africa and Asia, recognized that it is time to push some of these technologies into the field with our partners. The good news is that most inventors are ready to mass produce their affordable, safe, appealing sanitation solutions – ones that don’t generate waste – to the people who need it.

We showed the world our crap and it approved, the Toilet Fair was a thrilling success. Scientists and inventors have proven, once again, that it is possible to rethink the sanitation solutions with innovative technologies, and that resources and energy can be harnessed from poop!

After one year of investment in this field, our partners are showing us the way to an alternative to the pit latrines and flush toilet. The reinvented toilet is no longer a dream, but an expected deliverable, which we are all aiming at for the years to come.

When you enter the foundation’s Conference Center, there’s an African proverb displayed on the wall, “If you want to go fast, go alone. If you want to go far, go together.” The fair embraced this message and new working relationships were forged between all the attendees. We believe this exemplifies our work at the foundation; together with our partners, we will develop sustainable sanitation services and stimulate community demand for improved sanitation where needed.

As it was demonstrated at the fair, the reinvented toilet is the next generation of sanitation technology, something that everyone in developed and developing economies will want to use, and that transforms human waste into valuable products (clean water, combustible fuel, natural gas, electricity, fertilizer or minerals).

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