Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Groundwater contamination by petroleum hydrocarbons and chlorinated solvents is a serious threat to human and ecosystem health. Aggressive thermal remediation methods such as thermal conductive heating, electrical resistance heating, and steam flushing are effective for volatile organics in relatively homogeneous soils. However, these methods are technologically complex and expensive with complexity and cost increasing substantially for less volatile organics in more heterogeneous subsurface systems. The costs of these technologies on a dollar per volume basis are particularly high for small sites.

Chemical oxidation and in situ bioremediation have been widely implemented at contaminated sites in Canada and globally. At ambient subsurface temperatures, particularly in Canada, the rates of contaminant removal by these processes may be quite slow. Moderately increasing temperatures by 30 to 40 o C through hot air flushing, hot water flushing, or electrical heating may lead to significant enhancement of these remediation methods at modest cost and technical complexity.

The long term objective of the proposed research program is to develop and optimize more sustainable groundwater remediation methods based on thermal enhancements, coupled technologies, and alternative energy sources. The short term objectives are to investigate the role of thermophiles in thermally enhanced bioremediation and to determine the effectiveness of thermally activated persulfate oxidation coupled to bioremediation under sulfate reducing conditions. The research will involve lab studies in columns and two-dimensional tanks packed with heterogeneous soils and groundwater and soil from industry partner field sites. With a unified approach of relating temperature, geochemistry, and microbial community changes to remediation outcomes, new much needed guidelines for field scale design of thermally enhanced bioremediation will be possible. A comprehensive simulation model will be developed as a tool for industry to design field scale thermally enhanced remediation schemes. Alternative more sustainable methods of heating will be investigated with respect to cost, complexity, and carbon footprint, including solar electric heating methods, solar water heating, and industrial waste heat recovery.

This research will significantly advance the understanding of the impact of heat on enhancement of subsurface remediation processes. As the uncertainty in these processes is currently a barrier to their implementation this will lead to more widespread application of thermal methods, resulting in effective cleanup of more sites. This will benefit Canadians through improved protection of groundwater . Transfer of the knowledge to Canadian companies through publications, conference addresses, and training of graduate students will lead to increased business opportunities for these companies.