We are developing the Nano Membrane Toilet which will be able to treat human waste on-site without external energy or water.

Key Facts

    • The Nano Membrane Toilet is being developed to enable those without plumbing to have access to safe and hygienic facilities.
    • We have come up with an innovative solution which uses nanotechnology to convert human waste to water and ash.
  • Funded byThe Bill & Melinda Gates Foundation ‘Reinvent The Toilet’ challenge
Toilet sheme
Nano Membrane Toilet DIagram

Impact of our research

Some two and a half billion people worldwide do not have access to safe and affordable sanitation. In cities, 497 million people use a shared toilet outside of their home, and every day two million tonnes of human waste is disposed in water courses. This project has the potential to solve these issues.

Designed for single-household use, the toilet is designed to accept urine and faeces as a mixture. The toilet flush uses a unique rotating mechanism to transport the mixture into the toilet without water while simultaneously blocking odour and the user’s view of the waste.

Solids (faeces) are separated through sedimentation. Loosely bound water (mostly from urine) is separated using low glass transition temperature hollow-fibre membranes. The unique nanostructured membrane wall facilitates water transport in the vapour state rather than as a liquid state which reduces pathogens and volatile compounds. A novel nano-coated bead enables water vapour recovery as water droplets are formed at the nanobead surface. Once the droplets form a critical size, the water drains into a collection vessel for reuse at the household level in washing or irrigation.

Following release of unbound water, the residual solids are transported by a mechanical screw into a gasifier which converts them into ash and energy. The energy powers the membrane processes and there may be extra energy available for charging mobile phones or other low voltage items.

The toilet will be rented by the households and maintenance will be undertaken with a trained operative responsible for the franchised area.

Why the research was commissioned

The research was commissioned by the Bill and Melinda Gates Foundation to find innovative approaches – based on fundamental engineering processes – for the sustainable management of human waste.

Why Cranfield?

We have long-standing expertise in water and sanitation research, including being a founding member of Water and Sanitation for Urban Poor (WSUP). For the Nano Membrane Toilet project, we have brought together researchers from a variety of disciplines to meet the challenge of reinventing the toilet.

Facilities used