rin Guiltenane reports that a research project underway at the University of Calgary, in Alberta, Canada, aims to clean up oil sands tailings ponds by using native algae already found in them to do the job.
Oil sands mining produces pools of wastewater that are difficult to treat and pose a threat to the surrounding eco-system. The current methods oil companies use to clean them are expensive. To try to provide possible solutions to both of these problems, a team of researchers in the biological sciences and geoscience departments came together to find a new “homegrown” approach to removing toxins from tailings ponds – by using algae already present in the ponds to break down some of the organic byproducts of oil and gas processing.
“Our goal was to clean up the tailings ponds,” said Gordon Chua, an associate professor specializing in genetics and integrative cell biology. “There are a lot of toxins in them. There are ways to clean them, but none of these ways are cost effective.”
Algae break down substances in bioremediation, so when Dr. Chua and his team decided to start their initial testing in 2009, they knew that their work had solid roots. “Since some tailings ponds have high salt content, we guessed and ordered marine algae for testing with similar compounds to what’s found in tailings,” he says. “It worked to break down some of the organic byproducts.”
With the successful first step, Dr. Chua’s team moved on to figuring out how to reproduce the results with algal species native to Alberta, that already grow in the tailings ponds. With initial funding from Canadian oil sands operators, Dr. Chua and the team began further research, which also included studying the impacts of oil sands process-affected water, or OSPW, on various test organisms to evaluate the effectiveness of remediation by algae.
After several tests using different nutrients to stimulate algal bloom growth in the tailings samples, phosphate proved to be the most effective. The team found that leaving the sample of tailings and native algae with added phosphate in sunlight for several weeks resulted in the breakdown of organic byproducts and reduction in toxicity of the water. The results of this study were recently published in the journal Environmental Science & Technology.
“If you can reduce the organic load in the water, which can be very corrosive and difficult to recycle, you can help the companies re-use the water. They’re recycling a lot already – over 90 per cent – but every little way helps,” Dr. Chua says. “The challenge lies in: can we reproduce this on a large scale? Can we do it within a specific time requirement? And how can it be done cost-effectively?”
Possible next steps for the team include collaboration with industry and conduct these studies in the field. Dr. Chua believes that the possibilities for his team’s findings could have far-reaching impacts. “A benefit of using algae is that using a little bit of phosphate is enough to get them going,” he says. “They produce their own food, and sugars, and can also sequester carbon dioxide to absorb greenhouse gases. Algae could also have biofuel content that could be harvested.”
This research was funded by Suncor Energy Inc., Shell Canada Energy, Imperial Oil Resources Ltd., Syncrude Canada Ltd., and Total E&P Canada Ltd. Lab infrastructure and instrumentation was funded by the Canada Foundation for Innovation.