When the Bill and Melinda Gates Foundation asked for new toilet designs, I wonder if they suspected what they would get?  28 designs were shown at the Reinvent the Toilet Fair in Seattle, including such delights as using urine to flush, turning excrement into charcoal, and using microwaves to turn poo into electricity.

The winner, though, was designed by a team from the California Institute of Technology.  It is solar powered, and produces hydrogen and electricity.  The toilet:

filters liquid waste through a “sun-powered electrochemical reactor” that oxidizes the chlorine in the urine and kills microorganisms, allowing the liquid to be recycled back into the toilet

I can’t imagine any story in which the design of toilets would play a major role, but it may be worth bearing in mind that in the future, even the things we think of as unchanging may not be recognisable.