The shanty towns of Africa's great cities are incubators for material innovations that easily escape the ambitions of people living in wealthier surroundings. In Nairobi's Kibera slum, the latest sensation is a "bio-latrine" that converts human waste into energy that produces gas for lighting and domestic cooking.
The technology behind the bio-latrine was developed by the governments of Kenya and France. Under a project supported by the United Nation's Habitat agency, about 20 bio-latrines that convert waste into gas will be installed in four areas of Kibera.
The bio-latrine consists of a shallow pit latrine, a "bio-digester" that produces gas and fertilizer; and a dispenser. Above the latrine are toilets, a kitchen and a community meeting room.
The bio-latrine requires cooperation among neighbors -- and that may be its undoing. Crime in Kibera runs high; so does envy and conflict between neighbors. Yet the problem of human waste in African shanty towns is large and growing. Informal settlements in cities can't wait for government to act. Small-scale technologies, under the control of ordinary people, provide one answer to the glaring need in Nairobi -- and other African cities -- for better sanitation and less costly fuel for cooking.
While the bio-latrine is surprisingly complicated for an "appropriate" technology, it does address the two most vexing problems of poor Africans in makeshift neighborhoods and even schools. And that's reason enough for more experiments with them.