Bill Gates challenges research team to reinvent the toilet

Bill Gates has given Dutch researchers the task of creating a toilet that works without links to water, sewage or power networks.

The Bill & Melinda Gates Foundation has awarded Delft University of Technology a grant to develop a way of using microwaves to process human waste and create electricity.

The researchers hope the new toilet could be produced at an affordable cost for people in developing countries with limited access to reliable infrastructure.

Waste will be dried and then gasified using plasma created by microwaves. The resulting syngas, a mixture of carbon monoxide and hydrogen, will be fed into a solid oxide fuel-cell stack to generate electricity.

Delft’s Georgios Stefanidis, assistant professor of process intensification, said the process would generate enough power to become 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.

‘Preliminary calculations show that microwave plasma gasification may be energy self-sufficient, provided that the efficient transformation and high throughput of human waste matter can be obtained. It is also affordable.’

The foundation announced the grant yesterday at the AfricaSan conference in Rwanda as part of more than $40m in investments in its new water, sanitation and hygiene strategy.

‘To 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,’ said Sylvia Mathews Burwell, president of the foundation’s Global Development Program.

Delft’s Prof Andrzej Stankiewicz said: ‘The current project presents an excellent example of how modern chemical engineering science serves not only the chemical process industries but also helps in resolving some crucial societal issues in the world.’



Reinventing the toilet