Reinvent the Toilet Fair

This week, the Bill and Melinda Gates Foundation’s Reinvent the Toilet Fair brought together innovators seeking to define the next generation of toilet technologies. After receiving grants over a year ago, university teams, small firms, and non-profit groups set to work, meeting a short deadline and compelling criteria: toilets must remove pathogens, recover energy and nutrients, operate off-grid, cost less than 5 cents per user per day, and appeal to people in both high-income and low-income nations. On Monday, teams from all over the world set up and fake poop was distributed. On Tuesday, Bill Gates awarded prizes to teams from Cal Tech, Longborough University and the University of Toronto and announced new grants. On Wednesday, PHLUSH was there. Jack Sim of World Toilet Organization helped get the invitation and I (Carol McCreary) was able to go, following the lead of Poonam Sharma and Abby Brown who represented PHLUSH at a Reinvent the Toilet event earlier in the summer. Members of more than than two dozen research teams were on hand all day long to demonstrate wild-looking prototypes, to get feedback from one another, and to find avenues for future collaboration. The conversations were extremely rich. What got my attention? Lots, especially some low-tech solutions the enthusiastic teams kindly helped me understand. The Toronto team (that got the bronze and have to get right back to work) linked together a whole series of fairly low-tech processes. Urine passes through a sand filter and UV lights. Feces falls upon a mechanical dehydrator inspired by the bakery industry. A final smoldering unit sanitizes feces within 24 hours using low temperature flames less combustion. The prototype unit could serve about 10 people with continuous processing and is easily scalable.  Here’s a University of Toronto team video on the concept that won third prize. This 2 minute Gates Foundation video shows set up.

The Toronto team uses a conveyor belt inspired by the food industry to dry out poop before it’s sanitized by smoldering.

Tiger worms and black soldier fly larvae drive ingenious toilet systems being prototyped by researchers from the London School of Hygiene and Tropical Medicine. It was great fun to see wiggly things go to work and do the job in a way far cleaner, more efficient, and compact than sceptic systems while safely enriching soils. User interfaces, i.e. toilets, were integrated on containers in ways attractive and practical.

Five dry toilet stalls sit atop a boxed compost pile until it fills and top structure is moved.

Andrew Larsen and Andrea Koestler of the Fontes Foundation have developed an attractive and very low cost emergency sanitation structure. Five toilet units are grouped on a vented pentagonal structure which allows pee and poop fall directly into a box containing the composting pile. When it’s filled up, the toilet structure and steps are unbolted and moved to a new pentagonal composting box at a different location. Learner says that people really don’t like emptying toilets. Used plastic billboard ads are used for the walls and roof and to cover the wooden box commodes and floors of each stall, making them easy to clean. The attractive structures are being used in Haiti, but would be suitable for outdoor festivals and events anywhere in the world.

In their 20-foot container field factories, re:char produces UD toilets which double as biochar reactors.

Finally, there’s re:char, a small firm whose exhibit was unpacked from their “factory”, a 20 foot container. Using old oil drums, they build and deploy low-cost prylosis reactors to produce biochar. A urine diverting toilet sits atop the drum. The biochar replaces both wood charcoal and chemical fertilizers.  The team led by Jason Arambaru has conducted agricultural tests that confirm the high quality of the soil amendment and its income-generating potential. Wow!   The rest of my photo stream is here. Here’re details of additional projects at the Fair.   Watch this space as we keep adding info as we find it.
  • special design award went to the Swiss research group EAWAG and the Austrian design firm EOOS for their urine-diverting toilet that uses membrane technology to recover water for flushing.   The striking blue plastic tower can be built into a new home or incorporated into an existing latrine.  Very short Gates Foundation video here.
  • The Cal Tech team won first place with their solar-powered toilet that generates hydrogen and electricity.  Watch video as well as a photo stream that shows how their approach works   Very short Gates Foundation video shows set up but little technical detail.
  • Washington Post coverage shows the toilet designed for a large low cost housing development in Ecuador uses a bicycle chain operated dry flush and an auger screw to move material through the pipe. When I remarked to Marcos Fiovavanti of Fundacion In Terris that urine diverting bowl was very small (see photo in stream and first photo in MSNBC story), he pointed out that this kept collected urine clean and urine that falls into the other chamber facilitates the process.   Good thinking.
  • The Longborough Team that placed second in the contest is led by Sohail Khan, interviewed here in this BBC video.  A new 6 minute video by the university introduces the years of experience that led to the development of the winning prototype. Here’s the short Gates Foundation video overview.
  • Video coverage by the Los Angeles Times shows black soldier fly larvae and features a segment with Jim McHale of American Standard, demonstrating a plastic pan designed for Bangladesh.  A simple hinged water seal that blocks  odors and opens when waste and a small amount of flush water are added.
  • A sanitation system that converts human waste into biological charcoal is a fairly comprehensive biochar system from  Stanford University and the Climate Foundation.  Here’s the short Gates video.
  • South Africa’s University of Kwazulu-Natal proposed a community bathroom block that recovers clean water, nutrients, and energy   Gates Foundation’s short video isa good overview.
  •  A toilet that converts human waste to fuel gas from Delft University of Technology requires lots of energy to recover energy, as they explain in short video from Gates Foundation.
  • Interesting urine-diverting combustion toilet has been prototyped by the National University of Singapore.  Basic set up is shown in this short video.

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