Making it easier to clean up polluted groundwater

Five years ago the American Petroleum Institute (API), the U.S. oil and gas industry's trade association, started to seriously worry about a potential environmental problem in North America's increasingly biofuel-oriented future.

What was the ethanol, which depending on the mix could make up anywhere from 15 to 85 per cent of future biogasoline, going to do to groundwater if there was a spill? The bad news was that nobody was absolutely sure, and the good news was that API knew exactly where it had to go to find out.

Borden, Ontario.

Why Borden?

There, researchers can contaminate and then decontaminate wells drilled into the ground on the site of a Canadian Forces base.

The significance of that, explains James Barker, a professor of geochemistry and geology at the University of Waterloo, is, "There are lots of good people in the U.S. to do laboratory studies but not many places allow you to actually contaminate groundwater. In that regard, Borden is almost a unique facility in the world, but," he quickly adds, "of course, the contamination is done under the most stringent controls and approvals."

Just as important, the facility is part of a group of seven monitoring sites both in and outside the province that Barker and fellow researchers at Waterloo, the University of Guelph, Wilfrid Laurier University and Sir Sanford Fleming College have developed together to understand the effect of various pollutants on groundwater.

The group's ethanol studies have revealed some important findings that will be relevant in the real world. It appears that one problem with ethanol is that it may break down far too quickly and much too readily for a water ecosystem's good.

"Ethanol is usually very easily biodegradable, so theoretically it shouldn't be a problem in water," says Barker. "But because it's so easily broken down, the bacteria which attacks things in the subsurface would attack ethanol first."

He likens it to a person having a choice between eating spinach and eating ice cream. The bacteria immediately start consuming - that is, breaking down - what tastes better to them - and that is ethanol. "However, in breaking down, the bacteria uses up the nutrients and oxygen which are required for them to subsequently degrade benzene. Thus the remaining benzene persists longer and travels further in groundwater," he says. "So even if ethanol replaces 20 per cent of the benzene entering an ecosystem, the benzene that you leave behind may be more of a groundwater problem."

While it still remains to be determined how much of a problem ethanol really is, API is grateful for the new data.

"Things often seem to work differently when you are trying to confirm them in a real-world system," points out Bruce Bauman, Soil/Groundwater Research Program coordinator for API.

The counterintuitiveness of real-world ethanol-testing results mirrors more general counterintuitiveness in the project.

The original hypothesis, when the group organized the testing sites, consisted of a one-way translation of theory to application. "At the start," says Barker, "our view was we have the ideas so let's just commercialize them."

What they subsequently learned is that, on some occasions, the sites were better used as incubators for new technologies than as test beds of scientific hypotheses.

"A field site designed and instrumented to evaluate the migration of gasoline contaminants in groundwater turned out to be much more useful as a place to evaluate a variety of technologies to clean up such contaminants. These technologies were not developed from our research, but came from Canadian companies," says Barker.

This realization had led the facilities to expand their mandates and become test sites for anti-pollution technologies and approaches from around the world.

"We've become a kind of Cape Canaveral for new biological or technological approaches to cleaning up polluted groundwater," explains Barker. "Companies bring us their products, and we see if they will fly."

And sometimes, they fly down a well.