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Professors studying soil samples

Building a Solid Foundation: Idaho Research Rock Solid

Written by Amanda Cairo

University of Idaho professors and students will soon be building bridges around the world; but instead of spanning wide gaps, those bridges will connect soil particles and help stabilize buildings and roads in hard to reach areas.

Three professors and a graduate student have teamed up with TerraFusion, a soil stabilization industry leader, to export a University patent-protected process that uses bacteria to solidify soil, stabilize existing foundations in earthquake risk soils, and facilitate rudimentary road-building to the rest of the world at a low cost.

“It’s a great process we can bring to all corners of the world to improve soil stability because bacteria work for free, as long as we keep them happy,” says Barbara Williams, Idaho associate professor of biological and agricultural engineering.

The Idaho team includes Williams; Ronald Crawford, professor emeritus and former director of the Environmental Biotechnology Institute; Thomas Weaver, former civil engineering professor and current scientist with the U.S. Nuclear Regulatory Commission; and Malcolm Burbank, microbiology molecular biology and biochemistry doctoral student.

Funded by the National Science Foundation, the University of Idaho research that led to the new technology centers on building up indigenous bacteria. Burbank explains that a food source and urea solution, added to bacteria already indigenous to the soil, will help create an evenly distributed area that is strengthened as the bacteria build bridges between soil particles – rather than pumping in bacteria which might not thrive in a new environment, or might clog up around the injection point.

“Indigenous bacteria are already spread out; we’ve developed a process that will enrich the soil, increase and overpopulate the other bacteria to create the ‘rock’ that we want,” says Burbank.

The Idaho team is the only group working on soil stability with indigenous bacteria. Burbank says they have proved their theories both in the lab and in the field with every soil type they have tested – seven in all.

With the bacteria, the team injects urea, a compound of two parts ammonia and one part carbonate and a source of calcium. A carbon food source, like molasses, is added to wake up the bacteria’s metabolism so it will produce more bacteria. When mixed all together, the solution precipitates calcite to cement the soil particles together. The process has been proven to more than double soil strength more than two meters below the soil surface.

During an earthquake, the cemented particles in treated soil would keep the soil from liquefying under buildings. Williams says recent earthquakes in Haiti, especially, and Chile show that stable foundations will save lives and clean-up recovery costs.

“The most rewarding part of this technology is the potential to save lives and improve post- earthquake conditions,” says Williams.

She adds the technology is great because it is low cost and easy, especially when it is pumped into wells and directed around already built buildings to stabilize the foundation.

“You can pre-treat soil before you build on it, but it is very difficult to do after the building is put up,” says Burbank. “Thomas (Weaver) wanted to develop an easier way to stabilize existing buildings in the U.S.”

Weaver initiated the research to look at how to make soil more stable and stronger, especially in places at risk for liquefaction during earthquakes. TerraFusion is looking to take the idea one step further to create roads in rural and inaccessible areas.

In the application of building a road, Burbank says the solution is sprayed on the surface. And since the materials are relatively inexpensive and easy to transport and mix up, TerraFusion is looking to expand into Third World countries and remote areas where officials struggle with whether or not a needed road is cost prohibitive. Burbank says this technology could lay the ground work for building roads to bring in equipment to build wind farms in remote area that are currently inaccessible. Testing continues.

Once the science of the process was laid out, Crawford encouraged the University to secure a patent on the process. The University then began advertising the technology, which TerraFusion was aggressively looking for. A visit to campus and discussion led to a partnership that will benefit the University, TerraFusion and clients around the world.

“We see this as an extremely productive relationship for both parties,” said TerraFusion CEO Omri Dahan. “While this helps TerraFusion expand both its R&D efforts and its market reach beyond road construction, the University gets to see its hard work, experience and knowledge capital brought to life in real applications.”