Sanergy

The World Health Organization estimates that 2.6 billion people worldwide lack access to hygienic toilets, causing the spread of disease.  Enter M.I.T. grad David Auerbach and his organization Sanergy and the unique business model of the franchise public toilet.

He sells prefabricated concrete toilets to local entrepreneurs for about $500 - - either cash or from a microlender.  The owner is responsible for supplies and maintenance - - each is stocked with toilet paper, soap, and water.  Operators profit by charging about $0.05 per visit.