"When you heat water above 705 degrees Fahrenheit under pressure, it becomes a 'supercritical fluid,' thicker than steam but less dense than water," said co-principal investigator William Jacoby, associate professor of biological engineering at Missouri and director of its Carbon Recycling Center. "When we add oxygen to the process, it quickly 'burns up' any carbonaceous materials, including human waste."
Jacoby said that the SCWO process has been used to treat hazardous wastes, such as polychlorinated biphenyls (PCBs) and chemical weapons.
"In terms of human waste, the process is faster than other treatment methods, and it produces hot, and potable, water and excess energy in the form of heat," Jacoby said.
The reaction produces clean water, heat, carbon dioxide, benign salts and nitrogen, which can be used by the community or turned into business opportunities to support the system, the researchers said. For example, the water could be used in community showers or clothes-washing facilities and the heat could generate electricity.
While one team of engineers works on the technical aspects of the project, another will work in parallel on developing business plans to make the endeavor feasible not only economically, but also from a regulatory and cultural standpoint.
"The technology to treat the waste is not necessarily low-tech, but it is very sustainable, with no adverse environmental impacts, so our challenge is to make it cost-effective and self-sustaining," said co-principal investigator Jay Golden, who directs Duke's Center for Sustainability & Commerce. He is also on the faculty of Pratt and Duke's Nicholas School of the Environment.
"By working with people on the ground, we'll develop a plan for linking the system and its byproducts to specific community needs," Golden said. "More broadly
|Contact: Richard Merritt|