Reinventing the toilet for safe and affordable sanitation

The Bill & Melinda Gates Foundation has awarded Delft University of Technology (TU Delft, the Netherlands) a grant to 'Reinvent the toilet'. Aim of this project is to develop new technology for processing human waste without links to water, energy, or sewer lines, and at costs affordable to the poor in developing countries.

Approximately 2.6 billion people on earth currently lack access to safe and affordable sanitation. The negative health impact of poor sanitation is enormous. To change this situation the toilet has to be reinvented.

Self-sustained

The ideal new toilet facility for developing countries must be self-sustained, affordable and without links to water, energy or sewer lines. Scientists from TU Delft now think they may have such a solution. They will use a grant from the Bill & Melinda Gates Foundation to develop their ideas into a working toilet facility for the billions who need it.

Microwave technology

Assistant Professor in the field of Process Intensification Georgios Stefanidis is one of the Delft scientists who came up with the initial idea. He explains: 'We will apply microwave technology to transform human waste into electricity. 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.'

In the first step of Delft University's new technical approach, the human waste will be dried. Then the waste will be gasified using plasma, which is created by microwaves in tailor-made equipment. This process will yield syngas, a mixture of carbon monoxide (CO) and hydrogen (H2). The syngas will then be fed to a solid oxide fuel cell stack for electricity generation.

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

/Science Daily/