"One-and-a-half million children die each year from diseases related to poor sanitation. We’re building a disinfecting toilet that doesn’t need running water or massive treatment plants and is cheap and odor-free.

It’s a squat toilet, which is what many people around the world prefer. The waste falls onto a sloped conveyor belt. Solids stick, and liquids run off into a bed of sand, which filters everything 10 micrometers or larger, including most parasites and their eggs. Then the liquid falls into a shallow trough, where an ultraviolet lamp—running on five watts from a solar panel on the roof—destroys any other pathogens in minutes.