Sparks

A greener clean

 By Michelle Leslie

Tailings from oil developments have long been criticized for their appearance and toxicity. Tailing ponds can be the size of freshwater lakes, and they contain the silt, sand and chemicals that are left over from the process of separating bitumen from sand. Birds often fall victim to tailings ponds, poisoned when they wade into the waters. But a team of researchers may have found a solution to take the toxicity out of tailings. It’s found in algae. Their research could revolutionize the oil industry; cleaning up toxic wastewater, while at the same time reducing emissions created by the extraction process…

(Cover photo credit: imaginations.csj.ualberta.ca)

Algae. It’s a simple green plant-like organism that you will find almost anywhere there is water. Adaptable, quick breeding and able to produce its own food, algae have one trait that makes them eco-superstars. They suck in CO2 and produce oxygen.

There are almost 150,000 species of algae ranging in color and size from small microscopic green or brown plants to large scale seaweed kelp that can measure over 100 ft (30 m) long. And now these robust, grass-like structures may hold the key to unlocking another environmental challenge.

Tailings from oil developments have long been criticized for their appearance and toxicity. Tailing ponds, which can be the size of freshwater lakes, contain the silt, sand and chemicals that are left over from the process of separating bitumen from sand. According to a 2015 report on the management of the Athabasca oil sands tailings, their environmental footprint was approximately 220 sq km (85 sq mi); an area larger than the size of Florence, Italy.

Birds often fall victim to tailings ponds, poisoned when they wade into the waters.

Of all the tailing contaminates, naphthenic acids are the most toxic. Toxilogical Sciences reported that these water soluble acids can cause liver and heart damage. These conclusions have been drawn from testing the effects of higher concentrations of naphthenic acids on rats in a case study. But now a team of researchers may have found a solution to take the toxicity out of tailings. And it’s found in algae.

AlgaeBase is a database of information on algae that includes terrestrial, marine and freshwater organisms

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Gordon Chua, is an Associate Professor in Integrative Cell Biology at the University of Calgary. In 2009, Chua and a team of researchers began taking a look at how these simple plants might be able to address a complicated problem. “Naphthenic acids are responsible for most of the toxicity (in oil sands tailings) and we realized algae can break down the toxins,” states Chua.

Algae is often found in tailings but in very low concentrations. In order for the team to be successful in reducing the amount of acid in tailings, they knew that this would require high concentrations of algae. The team tested different nutrients and what they found was that a combination of phosphate and sunlight increased the concentrations of algae present.

Following up on initial success in the lab, Chua and his team did preliminary studies using large scale, 5-10 gallon fish tanks using tailings waters with native algae, algae already present in the tailings waters in low concentrations. The results replicated early lab tests.

What they found was astonishing. The algae not only reduced the levels of naphthenic acids but they also lowered the levels of toxicity within the water. By breeding algae, the toxicity of tailings waters was reduced by upwards of 25%. In some cases, this result was achieved in a matter of a few months, the average time being 6-12 weeks. This research could revolutionize the oil industry; cleaning up toxic wastewater, while at the same time reducing emissions created by the extraction process.

 

SEE MORE: Fuel from algae by Nicholas Newman

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The petroleum industry already recycles most of its water and that water is reused in industrial processes. However, a lot of tailings water contains a high amount of organics, which means that the water is quite corrosive. By being able to reduce the amount of acid in the water through the break down of the chemical structures in the naphthenic acids, algae blooms allow for an overall improvement of water quality.

Chua points out that they have found more success with the algae where the chemical structures are less complicated. In other words, the simpler the chemical, the more easily the algae can break it down.

There are some apparent challenges when it comes to measuring toxicity. Because different organisms respond differently to toxins, responses will also be different depending both on how various plants, animals and other living beings respond to toxins. Another consideration is the level of tolerance an organism has when it comes to specific toxins.

The other major challenge is understanding exactly how the algae work to clean acid from water. “We just don’t know if the acids go into the cells and the plant breaks them down.” Chua goes on to say, “we just know that when we grow algae these compounds disappear and the toxin levels are reduced.”

The next step is to apply the work done in the lab to the field and grow algae blooms in full size tailings ponds. It’s work that Chua and his team hope to do once the economics improve in Alberta. The project was halted following the slide in oil prices. While it may not be a silver bullet to cleaning up industrial waste, growing blooms of algae plants in ponds could definitely have a significant impact on the health of tailings waters.

about the author
Michelle Leslie
Alberta, Toronto and now Ottawa. Meteorologist, Journalist & Munk School Of Global Affairs Fellow.