Imagine using sunlight to destroy toxic waste from Alberta’s oilsands plants, or tapping the same kind of energy to quickly clean up oil and pipeline spills and purify water.

University of Calgary scientists say they’re close to commercializing technologies to do exactly that.

The research team’s innovations are based on photo-catalytic reactions. Photo-catalysts are substances that, when they adsorb ultraviolet radiation, produce a desired chemical reaction. (Adsorbence is where a substance holds or attracts particles of another substance to its surface.) Ultraviolet (UV) radiation is the energy emitted by the sun or by commercially available UV lamps.

The U of C researchers have developed a photo-catalytic system they believe will oxidize or literally burn away the hydrocarbon compounds in oilsands waste ponds. The same process can destroy toxic chemicals left over from cleaning up oil-contaminated soil.

Dave Olecko, Business Edge
Alex Starosud, Apostolos Kantzas and Cooper Langford with the photo-catalytic reactor used to purify contaminated water.

“We are burning up these wastes at low temperature,” says team member Cooper Langford, professor of chemistry and U of C’s former vice-president of research. The team has spent six years testing their patented adsorbent photo-catalytic technology in the laboratory.

“We have good lab data,” Langford says. “What we need in order to be able to develop really solid economics (on the costs and benefits) is some pilot trials.”

Team member Apostolos Kantzas, associate professor of chemical and petroleum engineering, agrees, saying: “Everybody develops technology. To take it from the laboratories and actually use it and commercialize it has its own obstacles.”

The U of C scientists are working with a local company, PERM Environmental Inc. Alex Starosud, president of PERM Environmental, says the team is in final-stage negotiations with a Calgary-based company on an agreement to take the innovations from the lab bench to the marketplace.

The potential rewards are huge. In Alberta alone, the market for cleaning up oil-contaminated soil is an estimated $300 million a year, Starosud says.

One method now used to handle soil contaminated by oil spills or pipeline leaks involves digging up all the soil, then transporting it to an approved landfill or incineration plant for disposal. Incineration is expensive, costing up to $1,000 per tonne of soil. Also, incineration and dumping the soil in a landfill both raise environmental concerns.

The other method, bio-remediation, is less costly but it takes at least half a year and typically much longer. It uses harmless bacteria to naturally break down the hydrocarbon contamination in soil.

The U of C has a new approach. It uses a chemical washing method, combined with ultrasound energy, to break apart the chemical bonds between the hydrocarbon contaminants and the soil.

“You’re just shaking the stuff off the surface of the thing you’re trying to clean,” Langford explains.

So in responding to an oil spill, for example, the contaminated soil would be mixed with water in a large vessel onsite and exposed to low-energy ultrasound. The oil “shakes loose” from the soil and collects on the surface of this slurry mixture, where it can be easily skimmed off and reused. The clean soil is then separated from the water and the soil is simply put back in place onsite.

Laboratory tests using small amounts of oil-contaminated soil, drilling fluids and oily drill cuttings showed the technology significantly reduced hydrocarbon contamination in all the test samples.

A preliminary economic analysis done by the Alberta Research Council found the technology would be less expensive than bio-remediation, but larger-scale field testing is required, Langford says.

The U of C soil cleanup technology does produce water contaminated by hydrocarbon particles.

The contaminated water can be handled conventionally by injecting it down a deep oilfield disposal well. Or, if purifying the water is desired, it can be treated in the team’s photo-catalytic reactor.

Inside the reactor, the hydrocarbon contaminants are adsorbed on to tiny glass beads. The process is similar to commercial water filter technology, which uses “activated” or highly porous carbon to trap and filter out harmful substances.

The significant difference is that in the U of C technology, the glass beads are coated with a photo-catalyst, a harmless powdery compound called titanium dioxide.

Water pumped into the reactor circulates the beads around an ultraviolet light. The titanium dioxide reacts with the UV light, destroying the contaminants that have been adsorbed onto the porous glass beads. The entire process also regenerates or cleanses the photo-catalyst for reuse.

If the system is proven to work on a large scale, it has huge implications for improving current water treatment processes.

Using chlorine to disinfect water doesn’t kill all harmful microbes, for instance. Moreover, the chlorine reacts with organic material in “raw” water supplies to produce trace chemicals suspected of causing cancer.

Studies have shown that photo-catalytic processes have the potential to kill all micro-organisms, including parasites and viruses. But the U of C team’s technology would need field testing to prove this, Langford stresses.

The team also has proposed using its photo-catalytic technology to destroy toxic compounds in large ponds used to store tailings or processing waste at Alberta’s oilsands plants.

Truckloads of floating glass beads would be dumped on to the ponds’ surface. These adsorbent beads would suck up the hydrocarbon contaminants. The photo-catalyst on the beads would be triggered by UV radiation from the sun, burning up the toxic compounds.

Tests in laboratory dishes show the concept works. With an UV lamp playing the role of the sun, the process destroyed 50 per cent of the contamination in three weeks.

The process may work much differently in the field, Kantzas cautions, adding: “We are trying to go where others cannot go.”

The team has proposed conducting a pilot test on an existing tailings pond. Their proposal is being considered by the Canadian Oilsands Network for Research and Development (CONRAD), which brings industry players together to co-ordinate research.

“There are people reviewing it at the moment,” says Chris Fordham, chair of CONRAD. Depending on that review, one or more companies might decide to help fund a large-scale test.