Sanitation is one of the biggest challenges for the developing world, and this week the Gates Foundation announced $3.4 million in new funding for solutions. In total, the foundation has invested about $6.5 million in its “Reinvent the Toilet” challenge.

The first-place winner of the challenge was a team of researchers from CalTech, who have designed a solar toilet. The toilet recycles water and creates storable energy from human waste. Though it looks like a regular toilet, it works very differently. Waste is flushed into a holding tank under the floor, and liquid waste flows into a solar-powered electrochemical reactor. The reactor kills bacteria, and the treated water is reused for the next flush. Hydrogen from the waste can be captured for energy.

Around the world, 2.6 billion people lack access to sanitation. This leads 1.5 million children under the age of 5 to die each year. Though toilets haven’t received as much attention in the past, the Gates Foundation has brought a new focus to the issue.

Since the flush toilet was invented in 1775, it hasn’t fundamentally changed. Gates believes that innovations for the developing world will lead to new solutions for wealthy nations as well.

Main image credit: Brian Lee