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Screen capture from video posted by Cranfield Water Science Institute

Bill Gates Is Backing a Waterless Toilet That Uses Nanotechnology to Treat Waste

It could be the future of sanitation.

| 3 min read

It could be the future of sanitation.

It’s been five years since the Bill and Melinda Gates Foundation challenged the world to design a sustainable and inexpensive toilet, and now, researchers from Cranfield University may have finally developed one. It is known as the Nano Membrane Toilet, and it was funded by the Gates Foundation in September 2012 for US $710,000.

The Nano Membrane design is waterless, easy to use, and could be a part of the future of sanitation.

According to Alison Parker, a lecturer in International Water and Sanitation at Cranfield Water Science Institute, her team’s new design is meant to serve poor urban areas.

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“It will be very hard to carry out the scheduled maintenance” in remote areas, Parker told Tech Insider, mostly because the toilet requires maintenance at a minimum of every six months to replace certain parts. “Instead, the toilet will be used in dense urban areas where a number of factors make providing good sanitation very challenging, but where it would be possible to facilitate visits from a maintenance technician.”

The toilet’s design is quite complex: After a person has done what they need to do and closes the lid, the rotating toilet bowl turns 270 degrees to deposit the waste into a vat underneath. A scraper tool then wipes off any residual waste from the bowl. This solid waste stays on the bottom, while the liquid rises to the top.

Thin nanofibres are arranged in bundles inside the chamber, and they help move the water vapor that exists as part of the liquid waste into a vertical tube at the back of the toilet. Next, it passes through specially designed beads that help condense the vapor into actual water, which flows down the tube and settles into a tank at the front of the toilet.

As for the solid waste, a battery-powered mechanism lifts the remaining matter out of the toilet into a separate holding chamber. There, it is coated in a scent-suppressing wax and left to dry.

Every week, a local technician will have to visit the community to remove the solid waste and water, and replace the toilet’s batteries if needed. Residents can then use the water for whatever their needs require, and the solid waste ends up at a thermo-processing plant to be turned into energy for the community.

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According to Parker, one toilet can accommodate up to ten people for no more than $0.05 per day, per user, which is in line with Bill and Melinda Gates Foundation’s original criteria. Field testing will begin later this year, according to Parker.

However, there are still some challenges moving forward. The first is scalability — even though a design works in theory, actually getting the toilets to the countries that need them is not easy. Local communities have to create jobs specifically so that the toilets are maintained safely and correctly, and this process can take time.

Second, there is still the problem of what to do with the toilet paper. Currently, users have no choice but to toss the paper into a nearby waste bin. However, the team is working on an effective way to burn the paper.

This toilet will improve sanitation and potentially add years onto people’s lives.

Take a look at the video below explaining the toilet’s design.

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