Contaminated Water Gets Clean

Microorganisms do the dirty work


Story by Anthony Ngai, a U of G student writer with SPARK (Students Promoting Awareness of Research Knowledge)

Front row, from left: Sandra Dworatzek, Prof. Hung Lee and Jennifer Webb . Back row, from left: Peter Dollar, Prof. Jack Trevors and Phil Dennis

Microorganisms found in water are being used by researchers as a new way to decontaminate, protect and clean local water sources that people drink and use.

Profs. Jack Trevors and Hung Lee from the School of Environmental Sciences in partnership with SiREM, a Guelph remediation services company, are growing naturally occurring microorganisms that make groundwater safer by feeding off of harmful pollutants – such as chloroform – and rendering them non-toxic.

“Healthy environment equals healthy people,” says Trevors. “And healthy people want to live in a clean environment.”

Presently, there are numerous groundwater sites across Canada containing toxic compounds such as carbon tetrachloride, chloroform, dichloromethane, trichloroethene and perchloroethene – each a type of chlorinated contaminant.

Trevors says these pollutants are residues from previous toxic waste dumping. Chemicals from contaminated sites can converge with clean drinking water, making it unfit for human consumption.

As a result, many affected communities are looking into bioremediation, a cost-effective process that involves the use of natural microorganisms instead of other more expensive cleanup processes to remove toxins.

After analyzing groundwater and soil samples, SiREM identified some that appeared to have the unique ability to break down specific chlorinated compounds.

Trevors says that’s because the contaminated water contained chemical-degrading microorganisms. Researchers were able to enrich these microorganisms for use in cleaning up some of the contaminated water sites.

But the microorganisms aren’t completely unstoppable. For example, chloroform can prevent the microorganisms from cleaning up other toxic chemicals such as trichloroethene and perchloroethene, a dry-cleaning solvent found in water.

Now, Trevors, Lee and SiREM researchers are in the process of understanding microorganisms that also degrade chloroform and its degradation byproduct, dichloromethane. They’re testing microorganisms that eat away at the chloroform and dichloromethane, while “spitting out” a non-toxic molecule.

When the researchers find chloroform-destroying microorganisms, they are transferred to sterile containers and enriched for future use. Promising microorganism enrichments can then be scaled up in large stainless steel vessels.

Then, when a site requires detoxification, these vessels can be shipped anywhere in the world where chloroform or dichloromethane contamination is present and injected through groundwater wells.

With these newly discovered microorganisms, Trevors, Lee and the SiREM researchers are confident that they will be able to work towards decontaminating soil and groundwater sites across Canada and around the world safely and naturally.

“This research is bringing researchers, the University and the private sector together, because we all want to improve the environment we live in,” says Trevors.

Collaborators include research technician Jennifer Webb and Carlos Puche, previously a microbiology student at the University of Guelph, as well as SiREM’s Phil Dennis (a Guelph graduate), Peter Dollar and Sandra Dworatzek.

This research was funded by the Federal Development Agency for Southern Ontario, the Natural Sciences and Engineering Research Council and SiREM.