Environment

Cheap, waterless toilet that turns waste into clean water and power to be trialed in Africa

Cheap, waterless toilet that t...
Nano Membrane toilet prototype
Nano Membrane toilet prototype
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Nano Membrane toilet design

A cheap, easy to maintain, "green" toilet that uses no water and turns human waste into electricity and clean water will be trialed in 2016, possibly in Ghana. Dubbed the "Nano Membrane Toilet" by its creators from Cranfield University, UK, this new approach to managing waste could help some of the world's 2.3 billion people who have no access to safe, hygienic toilets.

The toilet's magic happens when you close the lid. The bottom of the bowl uses a rotation mechanism to sweep the waste into a sedimentation chamber, which helps block any odors from escaping. The waste is then filtered through a special nanotech membrane, which separates vaporized water molecules from the rest of the waste, helping to prevent pathogens and solids from being carried further by the water.

The vaporized water then travels through to a chamber filled with "nano-coated hydrophilic beads", which helps the water vapor condense and fall into a collection area below. This water is pure enough to be used for household washing and farm irrigation.

The residual solid waste and pathogens are driven by an archimedean screw into a second chamber. This part of the design is still being finalized, but the current plan is for the solid waste to be incinerated to convert it into ash and energy. The energy will power the nanomembrane filtration process, with enough left over to charge mobile phones or other small devices.

Nano Membrane toilet design
Nano Membrane toilet design

The only waste product of the whole process is ash from the burning of solids, which is nutrient-rich and pathogen free, and therefore, usable in farming. The toilet can manage the waste generated by households of up to 10 people.

Funded in part by the Bill & Melinda Gates Foundation's Reinvent the Toilet Challenge, and winner of the CleanEquity Monaco 2015 award, the nano membrane toilet is to be trialed and tested in 2016, possibly in Ghana.

Currently, more than 650 million people in the world do not have access to clean water, and more than 2.3 billion don't have access to a safe, private toilet. Researchers around the world are working to help solve this problem, but high-tech solutions, such as adding solar panels, are usually too expensive to be practical.

Sociological issues also play a role. As toilet infrastructure deteriorates, people prefer to go outside rather than use a smelly room inside their house. This makes women vulnerable to rape, and creates further sanitation and hygiene issues.

The nano membrane toilet is clean, odorless and aspirational, and it should be capable of working in environments that lack sewage, external power and water. So it will be interesting to see how it works in the field.

The plan is for the toilet to be rented to households through a local organization, helping to spread the costs to stay within the Gate Foundation's challenge of keeping the cost of the toilet below US 5 cents per person per day.

If all goes well, the toilet could also find applications elsewhere like the military, construction industry, yachts, or outdoor events.

The video below, created by the Cranfield Water Science Institute, was developed for the Reinvent the toilet fair in 2014. It showcases some earlier ideas of how the toilet could work in the field.

Source: Cranfield University

Cranfield Nano Membrane Toilet

20 comments
Paul van Dinther
Looks very complex, and assumes people will actually sit on the toilet. That is a typical western toilet style. It looks like a great invention if it works but my first thought is, get a production going and a money flow. In other words start selling to yachts and holiday homes and homes where there is a septic tank that struggles. Lots of potential there in a rich western market. Make money first, then try to adapt it and send it to poor countries. This way is bound to fail.
Rui
I was expecting a industrial design based on the old (as in milenia old) dry toilet. This thing compared is heavy on the maintenance side, usually a big no no in the less infrastructure areas.. Africa.
Toffe Carling
Like the idea it self, but the ones behind it do not understand how Africa or its people work. (Says me who have lived there for over 2 years and still are very active there.)
KeithFarnish
Bringing a high-tech "solution" into a low-tech environment is a recipe for disaster: not only is it NOT zero-waste - look at the infrastructure needed to make it, and to produce the nano-coating - it creates a dependency on technology, rather than encouraging the use of perfectly hygienic methods that have existed for millennia, such as dry-composting, urine diversion and long drops. As for publicising this piece of technology as a way of preventing rape, words fail me! The way you prevent women from getting raped, is by stopping men from raping people, not creating a synthetic bubble of fear. Disgraceful.
DomainRider
This looks complicated and expensive. How long will it work before needing maintenance or parts replacement - how long before the nano membranes clog or fail?
Daishi
@Toffe Carling This is the case with almost every "oh, let's help the people of africa" invention I tend to see. They are usually well meaning (I think) but tend to do poorly. Mass market viable solutions tend to be what usually ends up winning the day but people almost never seem to learn this and constantly create one-off solutions for Africa that continually fail.
Trevor Wrn
Better to adapt to industrialized countries toilets are so wasteful of clean water and costly sewage infrastructure etc
Powell Gammill
Sad to see Gate's continue to waste money on this insane 3rd world solution. Inexpensive composting toilets that actually work well producing safe compost and nitrogen sources for agriculture are already operating and sure could have used additional funding if the Gate's actually gave a damned. https://www.youtube.com/watch?v=MXuOTahHj9w https://www.youtube.com/watch?v=xOOUxa4_K1g
macssam
how can you forget the most important aspect of this business I like to wash my butt and I never use toilet paper this system is useless
cloa513
The basic operation of this toilet is actually extremely low tech- could have existed about 4000 BC and its supply is designed to be a whole package of maintenance and supply. All the inhabitants have to know they excrete into a toilet. Those alternative are high maintenance and moderate tech doomed to failure with the general population involved.