Virgilio Góngora Echeverría

In recent decades, with the expanding development of industry, large amounts of nitrogen-containing compounds (e.g. ammonium, nitrate) and organosulfur compounds (e.g. sulfolane) are being released into the environment. While processes are available for the ex-situ treatment of contaminated soils and groundwater, in situ treatment approaches such as bioremediation represents an effective, economical and less invasive alternative. For example, the Grand River discharging into the Canadian side of Lake Erie has presented elevated concentrations of NO3- and NH4+ and other nutrients; this is related to the agricultural activity and small Wastewater Treatment Plants in the watershed. The problems related to nitrogen-based compounds presence in soil and water are a concern and it is estimated that in Canada the site clean-up has a cost of $500,000 in five years and relies typically on mitigation of nitrate/nitrite byproducts rather than the ammonium source directly. Sulfolane due to its physical and chemical properties, has also been used as a solvent in a variety of applications. Sulfolane mobility in soil is very high but it does not interact significantly with soil organic matter or with the clay mineral portion of the soil, and is relatively inert; thus, it can not be retained on soil particles via sorption mechanisms, degradation seems to be the best option to reduce its presence in soil and water. While the bioremediation of NH4+ and sulfolane could be achieved in situ using individual treatment systems, a recommended approach would be an integrated bioremediation strategy. The importance of Nitrogen (added as NH4Cl and KNO3) and Phosphorus (added as KH2PO4 and K2HPO4) on sulfolane and diisopropanolamine degradation in soil sediments has been studied. NH4+ (and NO3-) present at a site could provide the Nitrogen source for sulfolane degradation and these could be co bioremediated at the site. The aim of the project is to: evaluate the integrated NH4+ (and NO3-) and Sulfolane bioremediation at bench-scale and investigate at mesocosm level the integrated biorremediaion of NH4+ (and NO3-) and Sulfolane under conditions previously established.