Gates Tags Toilet as Top Tech Challenge

The Bill & Melinda Gates Foundation is challenging the engineering community to develop innovative toilets that can neutralize or extract energy from human waste.

Alexander Wolfe

July 20, 2011

2 Min Read
Gates Tags Toilet as Top Tech Challenge

The distasteful but technically challenging issue of coming up with more cost-effective ways of neutralizing human waste is very much in the news today, thanks to the Bill & Melinda Gates Foundation.

The foundation used the setting of the Third African Conference on Hygiene and Sanitation in Rwanda to announce on Tuesday a $41.5 million program to promote safe, affordable sanitation in developing countries. The effort will include research and tech development funding "to spur innovations in the capture and storage of waste, as well as its processing into reusable energy, fertilizer, and fresh water," according the group's press release.

The centerpiece of the project, under the umbrella of sanitation science and technology, is what's succinctly called the "Reinvent the Toilet Challenge." The foundation has awarded eight grants, totaling $3 million, to universities, to spur the "concept development, design, and prototyping of a waterless, hygienic toilet that costs less than $0.05 per user per day," according to the program's documentation.

Such stringent cost constraints are directly connected with the goal of making the designs affordable and thus deployable among the 2.6 billion people worldwide, who, the foundation says, don't have access to conventional flush toilets. The announcement cites 1.5 million annual child deaths from diarrheal disease as part of the devastation caused by lack of access to safe sanitation.

The technical component of the round of grants also includes at least $2.6 million in funding for what are called "Grand Challenge Explorations" of the next generation of sanitation technologies. In addition, the London School of Hygiene and Tropical Medicine is getting $4.8 million to develop better ways to break down human waste biochemically.

Design challenges
For the design engineering community, the product-focused work is occurring at the eight universities funded under the "Reinvent the Toilet Challenge." The eight projects variously attempt to neutralize the waste or to process it to extract energy:

  • Loughborough University. The toilet transforms solid waste into charcoal, with water and salt as byproducts.

  • Delft University. Microwaves are used to convert waste into a gas, which is then fed into a solid oxide fuel cell to generate electricity.

  • Swiss Federal Institute of Electric Science. The toilet diverts urine and recovers water.

  • University of KwaZulu-Natal. A community toilet system that can safely dispose of pollutants and recover water and carbon dioxide.

  • Climate Foundation and Stanford University. A self-contained system that converts waste into charcoal.

  • University of Toronto. Mechanical dehydration and smoldering are used to sanitize feces.

  • CalTech. A solar-powered toilet.

  • National University of Singapore. A pneumatic-flushing community toilet that separates urine and feces.

About the Author(s)

Alexander Wolfe

Alex is Content Director of Design News. Previously, he was Editor-in-Chief of In his more than two decades in the electronics and mechanical engineering sectors, he has served as Managing Editor of Mechanical Engineering magazine and written for, McGraw-Hill's Electronics magazine, and IEEE Spectrum. He spent the 1990s at UBM's Electronic Engineering Times, where he broke the nationally known story of Intel's Pentium floating-point division bug in 1994. Alex has appeared as an industry analyst on CNN, CNBC, Fox News, and MSNBC. He's a frequent panelist and moderator at industry conferences and holds a degree in electrical engineering from Cooper Union. He can be reached at [email protected].

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