He handed me a glass vial containing a clear liquid and said, “Here, smell this.” It didn’t smell like anything and it looked like water.
“That used to be dog poop.”
And so began my meeting with Marc Deshusses, a professor of Civil and Environmental Engineering. Deshusses’ research focuses on sanitation, bioenergy production and bioreactor design for treating various environmental contaminants.
If you’ve ever walked towards Twinnie’s Café from Grainger Hall, you’ll notice a large shipping container on the sidewalk. That shipping container holds the equipment required for Marc Deshusses’ novel sanitation technology, called Supercritical Water Oxidation (SCWO). SCWO technology utilizes high pressure and temperature conditions to transform human and animal waste into safe drinking water. The prototype being tested on Duke’s campus has the capability of treating waste produced by 1,000 people.
Benefits of SCWO for Sanitation
This research project is funded by the Bill & Melinda Gates Foundation and is designed to address the United Nations’ Sustainable Development Goals focused on clean water and sanitation. Despite increased awareness of the need for proper sanitation and water treatment, 892 million people practice open defecation1; 4.5 billion people lack access to safely-managed sanitation services (i.e fecal waste goes untreated into the environment); and over 40% of the global population face water scarcity1.
A system using SCWO technology has the ability to meet the need of treating waste and producing safe drinking water, while also generating energy and operating self-sufficiently. This unique design produces a sustainable system that can meet critical needs of resource-scarce areas in both developed and developing countries.
The SCWO technology could fill an important niche in the field of sanitation because it:
- can be implemented on-site
- works within seconds
- eliminates all pathogens
- does not produce polluting emissions
On top of that, the SCWO units can be produced at different scales and for different loading rates. Deshusses and his team have designed units to treat waste from:
- 6,000 people (village)
- 30,000 people (small town or medium-large animal farm)
- 200,000 people (small city)
Deshusses and his team have started a company to commercialize these units, which could be used in refugee camps, in disaster relief settings, and as additional units in modern wastewater treatment plants. The company is called 374water and they are currently raising money to develop prototypes of units at different operation scales.
What does the system look like in operation?
The three frames below are pictures of the dog poop sample that Deshusses offered me in his office. Frame A shows what the original sample looked like, Frame B shows what the sample looked like immediately after being treated by SCWO, and Frame C shows that the sample looks like after it is treated and allowed a few hours for particles to settle. The settled material is comprised of minerals and inert residues (such as sand) and can be safely used as a fertilizer.
Below are two videos produced by the SCWO research team that show the system in operation and the transformation of the input and the treated product!
Other articles about the SCWO technology:
- “Water and Sanitation – United Nationas Sustainable Development.” United Nations, un.org/sustainabledevelopment/water-and-sanitation/.