Bill Gates' New Toilet Tech

It’s hardly a secret that very few columnists and bloggers who were once adolescent boys can resist a press release about toilets. Before he semi-retired, Miami Herald humorist Dave Barry practically made a career of it.

Bill Gates views winning CalTech entrant in Reinvent the Toilet Challenge

So, as much as we tried to withstand the urge, we report that Bill Gates has announced the winners of the “Reinvent the Toilet Challenge” on 14 August at the Reinvent the Toilet Fair, which drew participants from 29 countries to Seattle.

The prizes are one tool in a serious effort to develop devices that “deliver safe and sustainable sanitation to the 2.5 billion people worldwide who don’t have it,” the Gates Foundation says. And the best-in-show ribbons—which come with cash awards of up to US $100 000 and a shot at follow-on development grants of $1 million or more—focus technical talent and imagination on an area that is humble, easy to mock, and absolutely fundamental to public health. After all, tainted food and water kill about 1.5 million children each year, according to the Gates Foundation.

Winning Caltech RTTC entry

The $100 000 first prize went to a California Institute of Technology team for designing and prototyping a system that converts waste into hydrogen and electricity.  The solar-cell-powered device uses electricity to disinfect solid waste for use as fertilizer, producing in the process hydrogen that can be used for cooking or PEM (proton exchange membrane/polymer electrolyte membrane) fuel cells. The Caltech team estimates that with 15 months and $50 000, it can produce a fully functioning prototype of a toilet that would cost $1500 to $2000 to manufacture, and would yield energy, fertilizer, and reliable sanitation at a cost of about 3 cents per person per day.

Second place ($60 000) went to the U.K.’s Loughborough University. Their entry, offering continuous hydrothermal carbonization, zaps wastes to produce “biological charcoal, minerals, and clean water.” The system is scaled so that one unit can accommodate up to 1000 people, producing 700 joule per hour per person, 150 grams of water per day per person, and 10 grams of fertilizer per day per person, at an amortized cost of around 5 cents per person per day even if there is no revenue for energy, water, or fertilizer.

Setting up University of Loughborough 2nd place winnerA University of Toronto team took third place (and a $40 000 prize) for a conveyor-belt approach to drying and sterilizing wastes. (For technical descriptions of all of the entrants, see the Technical Guide on the Gates Foundation media page.)

Photos: Gates Foundation

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