Finding solution to a legacy of contaminated soils and groundwater that exist throughout Canada in the form of brownfield sites is the target of our research group. We apply innovative combinations of treatment technologies that will lead to brownfield rehabilitation and allow for subsequent re-use of the land.
Over 30,000 brownfield sites exist in Canada. Most of these sites are contaminated by chlorinated solvents, hydrocarbons, creosotes, and coal tars. Some of these contaminants are among the most difficult to remediate because they are highly recalcitrant and even spills of small amounts have large environmental impacts. For instance, 1 litre of trichloroethene—a commonly used dry cleaner—can contaminate 3 million litres of groundwater. In many cases, these contaminants are present as free phase, often referred to as non-aqueous phase liquids (NAPLs). NAPLs can contaminate water sources for decades and even centuries. Considerable advances have been made in understanding the phenomena involved in NAPL remediation and a number of remedial technologies been developed. However, these technologies rarely achieve cleanup goals at contaminated sites within reasonable time frames and costs. More than two decades of research of bench and field scale studies has revealed that no single technology working in isolation can achieve stringent groundwater cleanup goals at these industrially polluted sites.
Our research team is investigating the application of innovative remedial technologies, by combining two or more technologies among in situ chemical oxidation, electro kinetics, chemical reduction by nanoscale zerovalent iron, and bioremediation. Each of these technologies alone has potential for rapid removal of large amounts of contaminant. The combination of one two or more technologies will permit more timely and cost-effective cleanup of brownfield sites in Ontario and throughout the industrialized world. Technology combinations can treat groundwater more effectively than each one alone. This is because partnering complementary technologies addresses complexities, such as targeting both very high contaminant concentrations at some locations (or at early time) and low (but still toxic) concentrations at other locations (or at late time). However, little fundamental research or technology demonstration for innovative combined remedies has taken place.
Our research team will test innovative combinations of the aforementioned treatment technologies, both at laboratory and field scales. We hope that the application of these technology combinations will help redevelop brownfield sites, in many cases, prime urban land, that are currently derelict, into a more sustainable environment. Remediation of brownfield sites will improve water quality, enhancing environmental and ecosystem health with associated long term and widespread benefits to society.