A Lithuanian company claims that their three stage process can remove oil from contaminated soil using only environmentally friendly chemicals, bacteria, and plants.
Oil contaminated soil comes from both accidents and industrial processes. The refining of oil often results in large amounts of highly contaminated sludge. But oil soaked into soil requires different cleaning techniques than oil spills on water.
The company Biocentras first uses a surfactant, a chemical which breaks down the chemically repellent barriers between substances. The surfactant, mixed with water, is used to wash the soil and can be used up to ten times, Biocentras reports. Afterward, the chemical breaks down into a “natural” compound, according to a press release by Eureka, a European business technology advocacy group.
The second stage uses microorganisms to break down the oil remaining in the soil.
"The bacteria used in the process lie dormant in negative temperatures, but then come to life as the temperature rises. However, some organisms can start to degrade oil at temperatures that are only a little more than is required to melt ice," said Monika Kavaliauske, manager at Biocentras, in a press release by the company. But, she added "it is much more effective in warmer climates."
Microorganisms break the oil down to a point where hardy plants can be used to further break down the oil. Using plants to clean up the environment is called “phytoremediation.”
Don't try this at home, only certain plants can take that kind of abuse. Moviegoers might remember the scene in Fight Club where members of Project Mayhem put up a billboard that says, “Did you know used motor oil can be used as fertilizer?”
It can't.
The whole process takes about one year, and leaves soil that can be used by other, less hardy plants. Biocentras has cleaned soils with up to .67 pounds (300 grams) of oil per kilogram (2.2 pounds) of soil.
So far more than 22,000 tons of soil have been cleaned using this process, mostly in Lithuania. But Biocentras hopes to expand into the Middle East, where warmer temperatures will make the process even more effective.
“We have no clients in the Middle East and are actively looking for them. There are potential applications for most of the world and we are keen to develop it further,” said Kavaliauske.