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Road salt threatens drinking water supplies and can harm plants and animals. But a new cost-effective, non-invasive technology can reverse or stop the damage caused by salt and other contaminants, with little disturbance to the environment.
During Canadian winters, salt keeps our roads safe. But salt is also one of the greatest soil contaminators and, come spring, poses a risk to groundwater.
Salt, or sodium chloride, can enter waterways, either by direct runoff into surface water or by moving through soil and groundwater. When it does, the saline water threatens drinking water supplies and can harm fish, freshwater plants and other organisms, while putting at risk wildlife, birds, vegetation and soil organisms in the surrounding ecosystem.
Previously, there was no cost-effective way to treat salt-contaminated soils or groundwater in place. Salt-contaminated soils — such as those near roadways that apply high levels of de-icing salt in winter — have typically been excavated and moved to a landfill, or require expensive pump-and-treat groundwater remediation programs.
However, the Regina-based Ground Effects Environmental Services Inc. has developed an innovative process — called EK3 Electrokinetic Remediation Technology — to reverse or stop the damage caused by salt, soluble metals and chlorinated hydrocarbons. The process can also remove other contaminants such as nitrates, chlorides, sulfates, diesel and fuel oil, with little disturbance to the environment. What’s more, it can work in low-permeable soil, such as clay, which no other technology can do.
Since remediation is done “in situ,” the EK3 process eliminates the need for “dig and dump” procedures for relocating contaminated soil to another location.
How it works
EK3 uses in-ground electrodes — 100 metres in length or longer — to apply a low-voltage, direct current electric field across a section of contaminated soil to move and extract salt. Using the principle of “electromigration,” the process separates sodium (Na+) and chloride (Cl-) ions present in the groundwater from dissolved NaCl (salt), moving the charged ions toward electrodes of opposite charges (sodium ions go toward the negative electrode or cathode; chloride ions are pulled to the positive electrode or anode).
The technology also involves “electro-osmosis,” which facilitates the uniform movement of water and contaminants from an anode to a cathode. By harnessing electro-osmosis, EK3 can flush water through a polluted area, carrying contaminants such as salt with it.
“This system is unique in the world in that it not only can get contaminants out of soil, including tightly packed clay, but can also clean up a site in a cost-effective, environmentally friendly manner without being invasive,” says Blaine Ganong, an industrial technology advisor with the NRC Industrial Research Assistance Program (NRC-IRAP) in Regina.
NRC has helped Ground Effects by providing financial support and advice for the company’s research and development efforts, and played an instrumental role in bringing its EK3 technology to market, says Sean Frisky, president and chief executive officer of Ground Effects. He also credits Communities of Tomorrow, a public-private partnership in Saskatchewan that includes the NRC Centre for Sustainable Infrastructure Research, with helping to commercialize EK3.
EK3 is now being used by government and private-sector highway maintenance organizations in Ontario, Saskatchewan and Alberta, as well as oil and gas companies in the latter two provinces.