College of Engineering, Computing and Applied Sciences

An injection of innovation: New technique could pull double duty in protecting against climate change and flooding

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A technique that has been used to clean up underground pollution could be repurposed to fight climate change and flooding, according to a research team led by Clemson University.

Larry Murdoch, a Clemson professor of environmental engineering and Earth sciences, is the principal investigator on a new project that would adapt environmental hydraulic fracturing, a technique used in environmental remediation, to inject a sawdust-based slurry underground.

Larry Murdoch

The adapted technique is called Carbon SIRGE and would pull double duty in protecting against environmental threats.

When wood degrades in the forest, it releases carbon into the atmosphere where it contributes to climate change, but injecting it deep enough underground would keep the carbon from being degraded and released, researchers said.

At the same time, the injected layer of wood raises the ground surface, helping protect low-lying areas from flooding, they said. SIRGE stands for Solid Injection to Raise Ground Elevation.

“This approach gives us a real chance to address two pressing challenges—climate change and flooding—with one innovative solution,” Murdoch said. “The results from our field tests show that this technique works, combining carbon storage with land elevation to use nature and technology together for a more sustainable and resilient future.”

The total budget for the research comes to $8.683 million, with the U.S. Department of Energy providing $6.911 million. Partners on the project come from Clemson University, Rice University, the University of North Florida, Tensora and FRx, an injection technologies firm co-founded by Murdoch and Bill Slack.

In environmental cleanup, hydraulic fracturing is used to inject materials such as sand or chemicals into the ground under pressure, creating fractures in soil or rock. The fractures help treat contaminated areas, breaking down pollutants or isolating them to prevent further spread.

When the technique is adapted for solid biomass injection, wood is used to create a slurry that is injected underground through a steel pipe.

The pressure from the pumping pushes the soil apart, creating a thin, flat layer of the material underground. As more layers are added on top of each other, the ground above slowly rises. Water in the slurry drains out, leaving only the solid material underground.

At 10 meters underground and below, wood particles are immobile and essentially inert, creating a form of carbon storage, researchers said, citing archeological and laboratory studies.

Previous research at a site near Clemson, also led by Murdoch, showed that injecting a wood-particle slurry underground could lift the surface by 1.5 millimeters per day.

That may sound small, but at that rate it would lift the ground by half of a meter in one year, which is enough to solve the nuisance flooding problem that plagues many coastal cities, researchers in that study found.

The technique could, for example, help in cities such as Charleston, where nuisance flooding often closes city streets, Murdoch said.

The team plans to build on the previous research by conducting a full-scale demonstration at a Clemson-owned research site near Charleston. As part of the project, researchers will evaluate monitoring methods with collaborators at Tensora and the Clemson Center for Geospatial Technologies.

The team also plans to demonstrate methods for assessing carbon storage permanence with partners from University of North Florida, and they will evaluate how raising elevations can reduce flood risks with collaborators at Rice University.

The Department of Energy funding is from the Office of Fossil Energy and Carbon Management, as part of the Carbon Negative Earthshot program. The department is investing $58 million in 11 projects to help develop a commercially viable carbon dioxide removal industry in the United States.

“I’m thrilled to collaborate with such an outstanding team of researchers and industry partners,” Murdoch said. “Together, we’re combining expertise and innovation to tackle some of the most pressing environmental challenges of our time, with solutions that could make a real difference for vulnerable communities.”


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