Fuel spill at Alert cleaned naturally
Bioremediation touted as option for disasters in sensitive Arctic environments
Casey Lessard
Northern News Services
Monday, May 25, 2015
NUNAVUT
When 22,000 litres of fuel spilled at CFS Alert in 2006, the National Research Council took the opportunity to allow the environment to turn a disaster into a success story.
CFS Alert, seen here from the air, was the site of a 2006 fuel spill that saw 22,000 litres of heating fuel spew from a ruptured pipe. The National Research Council has spent the last six years remediating the soil through natural biological methods. - photo courtesy of National Research Council of Canada |
The test at Canada's northernmost settlement proves bioremediation is an effective and affordable decontamination alternative in the North.
"There's a lot of knowledge being generated that could be used for anything ranging from community sites to oil and gas activities, mining activities," said the research council's Arctic program lead Anne Barker. "We can look at the potential to be prepared that we have this tool in our back pocket, and we know it has worked and can be used."
Bioremediation is a method of inspiring bacteria that naturally occur in the soil to eat the hydrocarbons and clean the site organically. All humans need to do is spur them into action by creating a critical balance of nutrients.
If there's too much carbon - as there is in a fuel spill situation - just add nitrogen and phosphorous. The National Research Council does it by adding commercially available fertilizer.
"All we're doing is enhancing the natural activities that are already there," said Dr. David Juck, the technical leader, who has been working at the site for six years. "Most of the biological activity we're looking for, specifically breakdown of diesel fuel or petroleum hydrocarbons, oils, things like that, that capability is naturally present everywhere in the environment."
The experiment at Alert was inspired by a fuel line break on Sept. 8, 2006 that saw 22,000 litres of JP-8 fuel spill on the ground.
Remediators removed the affected soil down to permafrost and made a pile nearby. At the time, diesel was present in the soil at a rate of 2,000 parts per million (ppm), almost eight times the federally regulated limit of 260 ppm.
Scientists wanted to see if bioremediation would be an effective solution in an environment where there is only one metre of soil above permafrost, and where the treatment period is only two months a year. The process is slow, so it doesn't suit every situation. More commonly, soil is chemically treated or incinerated to eliminate the contamination. But those are expensive and intensive processes, and can require the soil to be moved, not a great option in the North.
After six years of treatment, the research council said this month that the Alert site is now at the federally regulated limit again. Some areas are ready for decommissioning, Juck said, and once the soil is clean, it will be returned to its original location.
"We don't have to be transporting dirt south," Barker said. "We can be treating it there, and be prepared for it in advance on site."
The research council is particularly encouraged that the process can be used in situations where the mess is too large to dig up or where the spill occurs in a place that butts against a building.
"What we're trying to do is leave the environment as undisturbed as possible, use as natural as techniques as possible," Juck said, noting that even at Alert, the soil has a very active ecosystem.
"You'd be surprised how many bacteria are naturally present," he said. "In a gram (the size of the tip of your finger) of soil, there are anywhere from 10 million to one billion bacteria naturally present. When we have a contamination event with diesel, there's a lot of carbon that goes into the system. The bacteria can use it, consume it, but they also need those other nutrients. They turn (the diesel) into carbon dioxide and water."
Juck said bioremediation can be used on land or in the sea, but works best on light hydrocarbons, such as fuel oils, since oils, greases and PCBs take much longer to eliminate. The method was also used after the massive Gulf of Mexico Deepwater Horizon spill, he explained.
The research council noted in a release that with diesel being the main source of energy in the North spills are not uncommon and the method can help communities, businesses and governments save millions of dollars in clean-up fees simply by encouraging natural processes to occur.
