Field trials on a «consortium» of bacteria that thrive on naphthenic acids are set to begin this summer in northeastern Alberta with a major oilsands bitumen producer.
UBC engineers are using directed evolution and genomic tools to encourage naturally occurring bacteria to eat the toxins in oilsands tailings ponds.
Field trials on a “consortium” of bacteria that thrive on naphthenic acids are set to begin this summer in northeastern Alberta with a major oilsands bitumen producer.
Heated water pumped into the ground to loosen the gooey bitumen absorbs dozens of different toxins, which require a huge amount of energy to remove, said Vikram Yadav, a professor of chemical and biological engineering.
Bitumen can be processed into gasoline and other fuels in much the same way as conventional crude oil.
While much of the water used in the process can be recycled, there are vast ponds full of contaminated water, silt and sand recovered from the extraction of bitumen.
Yadav and his students have identified six bacteria that consume various forms of naphthenic acid, “a family of chemicals that is especially toxic,” he said.
“A conservative estimate is that there are (800 billion litres) of water held in man-made ponds,” he said. “The Government of Alberta published a report suggesting they cover between 75 and 100 square kilometres.”
Some of the chemicals present in the water bioaccumulate in wildlife and tend not to degrade, even over decades.
“The dream solution is treatment that runs passively, that doesn’t require a lot of energy or infrastructure, and at the end purifies the water so it can be safely discharged,” said Yadav.
PhD student Parisa Chegounian and Yadav have teamed up with private investors to form a company — Metabolik Technologies — to commercialize their bioremediation solutions.
Chegounian recently won an NSERC postgraduate scholarship to pursue her research.
Metabolik is one of 10 startup technology companies to receive financial support from oilsands giants Suncor and Cenovus to accelerate solutions to environmental problems in the oil-and-gas value chain, according to Suncor’s 2018 Report on Sustainability.
Oil firms are keen to encourage and fund an economical solution to what has emerged as the biggest headache in the oilsands’ industry, said Mike Schoen, a senior engineering instructor and former oil-industry executive.
“We have reduced the energy intensity of bitumen production by 50 per cent in the past decade, so tailing ponds are the biggest problem they have by far,” he said.
The upgraded strains of bacteria will be put to the test in simulated tailings ponds about the size of two swimming pools near the Athabasca oilsands, which are home to 19 major tailings ponds.
Work on biological solutions have been going on for decades, but advances in genomics have produced powerful new tools for bioengineering.
“In the past five or 10 years genomics has been completely revolutionized,” said Yadav. “You can sequence a lot of things and study these organisms in ways that was not imaginable 20 years ago.”
Once the chemical-eating organisms were identified, Yadav’s lab could figure out how they worked.
“It was a combination of genomic engineering and directed evolution that gave us strains that would eat naphthenic acids at a significantly higher rate, but essentially strains that were already present in the environment,” he said.
Ideally, multiple strains of bacteria could be introduced to the cocktail of potentially hundreds of toxins in a tailings pond, each specializing in consuming a different toxin.
“You want a microbial consortium with specialists in a whole bunch of diverse molecules and they would collectively degrade that massive collection of molecules,” he said.
The goal for oil companies and their regulators is to reduce the absolute level of toxins in tailing water by 98 per cent.
“We know when we do this that toxicity is reduced and the water is fit to be discharged in the native environment,” he said.
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