Bringing salt to the surface

By The Bakken Magazine Staff | January 18, 2016

At NDSU, researchers, led by Aaron Daigh, a soil scientist, are studying whether it is feasible to use the chemical iron (3) hexacyanoferrate to reclaim oilfield land that has been damaged by storing of salt water or salt water spills.

The iron (3) hexacyanoferrate brings the salt to the soil surface so it can be removed, said Kevin Sedivec, an NDSU range management professor who is coordinating the research project.

In contrast, other chemicals bind with the salt particles and are pushed further into the soil when it rains, Sedivec said.

“It’s a fix, but over time you have the same problem,” he said. “What we wanted to do was look at something that brings salt to the surface, and then remove it from the surface.”

The salt that rises to the surface is removed by either a machine that power sucks the salt or scrapes it off with a tractor/loader, Sedivec said. The salt would need to be disposed or injected into an approved site that is already approved for brine products, he said.

Laboratory research conducted at NDSU showed that application of the iron (3) hexacyanoferrate, which is mixed with water and ammonia, brought nearly 70 percent of the salt on high-salt soil, to the top, Sedivec said.  The NDSU research team believes that the chemical could be applied shortly after a salt water spill, before the salt penetrates deeply into the soil, he said.

The legacy or old brine contaminated sites will present more of a challenge because the salt in those locations is deep in the soil, Sedivec said. Some of the sites are from the 1970s, Sedivec noted. On those old sites, additional techniques may be needed in addition to the application of the iron (3) hexacyanoferrate, he said.

An advantage of using the iron (3) hexacyanoferrate on salt spills or storage sites is that it is available on the market and is non-proprietary so anyone can buy it, Sedivec said. Using the chemical is a more affordable option than hiring a company to remove the soil that has been ruined by the salt, and then hauling in new soil to replace it, Sedivec said.

Meanwhile, using the chemical is a more sustainable option than the “dig and haul” technique because it doesn’t involve replacing the ruined soil with good soil from another location, he said.

Next summer, Sedivec will plant grass on sites in which the salt has been removed. The research team has been experimenting in the laboratory with different breeds of grasses and is looking at planting species which are native to the area, he said.