"Something positive coming from human waste. The population keeps growing, but there are hardly any toilets because of no sewage system. Public toilets are rare. A local organization constructed latrines. From the waste they make biogas. The gas is used to cook..."Watch Ruud's Bio-Latrine Kibera videoreport for yourself...(This biogas stove flames photo by Kai Ross, btw.)
In the domain of off-grid energy and environmental solutions, I'm very interested in the prospect for both household-scale micro-utilities -- for instance, MIT alum development venture FertilGas supplying biodigestors for farm waste-to-gas in Honduras, a clean-burning fuel to replace wood -- as well as village-scale or slum neighborhood-scale mini-utilities -- for instance, this Bio-Latrines Kibera project, which both is more sanitary and supplies fuel-gas, or another MIT alum development venture blueEnergy supplying off-grid wind-power and clean water solutions in rural Nicaragua.