A video demonstrates the working of the prototype of the solar-powered toilet that won the first prize of US$ 100,000 in the Reinventing the Toilet Challenge issued by the Bill and Melinda Gates Foundation. The Solar-Powered Self-contained Human Waste Water Treatment System was developed by Prof. Michael Hoffmann‘s research group at the California Institute of Technology (Caltech).
In 2011 the Caltech team was awarded a US$ 400,000 grant to create a toilet that can safely dispose of human waste and reuse water for just five US dollar cents per user per day.
Solar energy powers an electrochemical reactor, which converts human waste into fertiliser and hydrogen, which is stored in hydrogen fuel cells as energy. The treated water can be reused to flush the toilet or for irrigation.
The toilet, which could cost US$ 1,000 or more per unit according to the Seattle Times, is still a prototype and would need to be adapted before it can be launched commercially.