Bill Gates looks to new toilets to improve world sanitation

                                Prof Michael Hoffman shows off his winning design - a solar-powered toilet

Bill Gates is, in a manner of speaking, flushing his money down the toilet.

His charitable organisation, the Bill & Melinda Gates Foundation, is looking for future loos that can improve sanitation around the world.

At the Reinvent the Toilet fair, hosted at its Seattle campus this week, designs included a lavatory that used microwave energy to turn poo into electricity.
Another turned excrement into charcoal, while a third used urine for flushing.
In total 28 designs were shown off at the fair and the winner was a team from the California Institute of Technology.