Neighborhood-Scale Sewage Treatment Using Supercritical Water Oxidation

Engineers at Duke University are developing a system to treat human waste and reuse some of the byproducts. The goal is to sanitize the collected waste of approximately 1200 people, providing a neighborhood-scale solution. The initial prototype has been built on the Duke campus. It fits into a 20 ft. shipping container and has been undergoing testing since the beginning of 2015.

The technology being employed to meet this challenge, supercritical water oxidation (SCWO), is promising because it works quickly and generates energy in the forms of hot water and steam from the treatment of human waste. It does not require prior dewatering or drying of fecal sludge, and it effectively eliminates all types of harmful organisms. SCWO technology has already been implemented in several research and commercial applications to treat waste products, including polychlorinated biphenyls (PCBs), chemical weapons and sewage sludge. Duke and the University of Missouri seek to determine whether SCWO and supercritical water gasification (SCWG), a related technology, have prominent roles to play in solving the world’s sanitation challenges.