Marc Deshusses, a professor of civil and environmental engineering at Duke University, studies and designs technologies to treat contaminated soil, air and water — and save lives in the process. An estimated 2.6 billion people across the globe lack access to a safe way of disposing of human waste. Poor sanitation spreads waterborne and diarrheal diseases, contributing to the deaths of over half a million children a year. One of Deshusses' solutions-in-progress is a low-tech anaerobic digester, a toilet system that relies on biogas (produced by bacteria when they break down the human waste) and a simple biogas-powered heater to sterilize the treated waste. Read more on the Duke website.