Bill Gates has drunk a glass of water made from human faeces, to showcase technology he said could provide clean water in the developing world. The Microsoft founder said he wanted to begin sending processing plants around the world after tests later this year.
The project was welcomed by WaterAid, which said that it could particularly help in urban areas.
According to the charity, some 748 million people worldwide lack clean drinking water.
In a video posted on his blog, Mr Gates watched as the human waste was fed into the processor, before drinking the end product from a glass.