Bill Gates invests in new toilet

The Bill & Melinda Gates Foundation is funding an effort to ‘reinvent the toilet’.

Glamorous it may not be, but there’s a pressing need, say researchers at the Delft University of Technology, for new ways to process human waste without links to water, energy, or sewer lines – and at a cost that’s affordable to the poor in developing countries.


As many as 2.6 billion people on earth currently lack access to safe and affordable sanitation. More than 1.2 million children under the age of five die of diarrhea each year, says UNICEF, and contact with human feces is the main cause. While waste can be buried in sparsely-populated areas, this isn’t an option in crowded slums.

But the Delft team believes it may have the answer.

“We will apply microwave technology to transform human waste into electricity,” says assistant professor in the field of Process Intensification Georgios Stefanidis.

“Starting from this innovation, we aim to realize a design and modular prototype for a full toilet facility that satisfies the urgent needs of users in developing regions of the world.”

First, the human waste is dried; then it’s gasified using plasma, which is created by microwaves using tailor-made equipment.

This process will yield syngas, a mixture of carbon monoxide and hydrogen, which will then be fed to a solid oxide fuel cell stack for electricity generation.

“In order for the process to be energetically self-sufficient, part of the electricity produced will be used to activate plasma gasification, while heat recovered from the syngas stream and from the fuel cell exhaust gas will be used for waste drying,” says Stefanidis.

He says that the team’s preliminary calculations show that microwave plasma gasification could be energy self-sufficient, so long as it can be done efficiently and there’s enough human waste to process – so get pooing, chaps. It should also be affordable, he says.

‘”o address the needs of the 2.6 billion people who don’t have access to safe sanitation, we not only must reinvent the toilet, we also must find safe, affordable and sustainable ways to capture, treat, and recycle human waste,” says Sylvia Mathews Burwell, president of the Global Development Program at the Bill & Melinda Gates Foundation.

“Most importantly, we must work closely with local communities to develop lasting sanitation solutions that will improve their lives.”