Human waste originating from the school dormitories is a big problem in the local community in Kenya. Not only does the imperfect sewage system leads to a bad stench, the antagonize the wider community – but the excess waste is polluting the local streams and waterways. A 17-year-old student at Maseno School in Kenya called Leroy Mwasaru came up with a solution for this. After winning a national competition with this idea, his team of fellow students built two prototypes, of which the second one is now being used at school's kitchen. Before his solution, cooking used to happen on wood fires, a process that sent black soot into the cooks' lungs and stripped local forests of trees. The same system could also be scaled down to work in individual houses in rural Kenya. The team of students is currently working on another iteration of the design that will separate out liquid waste, since pee can make the process less efficient.