Green Toilet Turns Waste into Electricity and Clean Water


Researchers at Cranfield University, UK, have come up with a green toilet, which is cheap, easy to maintain, needs no water to operate, and is capable of turning human excrement into electricity and clean water. It is called the Nano Membrane Toilet and they will soon begin testing the first versions of it, most likely Ghana. Should it prove successful, it will give access to safe and hygienic toilets to about 2.3 billion people who have no access to it right now.

The process by which this toilet turns waste into water and electricity is very simple. Once the lid is closed, a rotation mechanism in the bottom of the bowl is used to sweep the waste into a sedimentation chamber, which also prevents odors from escaping. This waste is then passed through a nanotech membrane which is capable of filtering vaporized water molecules from the rest of the excrement. Due to this, pathogens and solids are prevented from being carried along by the water.


The next step is for the vaporized water to travels through to a chamber filled with so-called nano-coated hydrophilic beads. These allow the vapor to condense and then pass into the collection bowl located under this chamber. This water is already filtered and can be used for washing or irrigation.

The solid waste, on the other hand, is driven by an Archimedean screw into a second chamber. The developers have not yet finalized this step of the process, but plans are in place for this waste to be converted into ash and energy by incineration. The energy obtained in this way will power the water filtration process, while there should also be enough left over for charging small devices, such as phones and tablets.

Ash will be the only waste product if this process, but it will be pathogen free, and nutrient-rich, so it can be used in farming. Each toilet is capable of managing the waste of up to 10 people.

The project was partially funded by the Bill & Melinda Gates Foundation’s Reinvent the Toilet Challenge, and they will try to keep the cost of the toilet to 5 cents per unit in order to make it accessible to as many people as possible.



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