I am currently building a research program that will focus on the use of supercritical fluid extraction (SFE) for environmental applications. As part of this program, a pilot-scale fully-continuous SFE system has been built at the University of Alberta, in collaboration with the University of Guelph. The main focus of this program is currently the development of SFE for the treatment of oil-contaminated waste streams. In addition, research will also investigate the use of SFE for the remediation of metal contaminated and hydrocarbon contaminated soils.
In the Athabasca oil sands, bitumen production using caustic warm-water extraction leads to large... more In the Athabasca oil sands, bitumen production using caustic warm-water extraction leads to large quantities of fluid tailings. The resulting tailings require storage in above-grade deposits or secure settling basins. Significant changes in groundwater systems occur from disruption during mining or changes in hydrology with tailings deposition. Intentional release into local groundwater systems is not practiced and release by seepage is minimized by engineering means. Waters produced from oil sands processing have unique properties that can be used as indicators of interaction with surface and groundwaters. In this paper, water from an above-grade tailings sand deposit is examined as a recharge into a surface water drainage system. The changes in water properties occurring during seepage of this process-affected water are examined, and analytical tools for better estimating the attenuation processes in receiving aquatic systems are described.
A 620-day laboratory mesocosm study was conducted to investigate the effect of added terminal ele... more A 620-day laboratory mesocosm study was conducted to investigate the effect of added terminal electron acceptors and nutrients on the anaerobic biodegradation of benzene, ethylbenzene, mand p-xylenes (BEX) and CCME F1 fraction hydrocarbons (F1) in contaminated groundwater. High removal of BEX and F1 was observed in most mesocosms. The calculated first order biodegradation rates ranged from 0.0020 to 0.033 d for benzene, 0 to 0.029 d for ethylbenzene, 0.0020 to 0.036 d for mand p-xylenes, and 0 to 0.0089 d for F1, under the tested conditions. The results suggest that biodegradation of BEX was enhanced with both nitrate and sulfate amendment, while sulfate amendment significantly stimulated F1 biodegradation. The effect of nutrient amendment was difficult to identify from the obtained results. RÉSUMÉ Cette étude en laboratoire avait pour but de déterminer l’effet de l’addition d’accepteurs d’électrons et de nutriants sur la biodégradation anaérobie de benzène, ethylbenzène, m-xylène, ...
Oil-based drilling fluids are essential for challenging drilling operations. However, their use r... more Oil-based drilling fluids are essential for challenging drilling operations. However, their use requires costly handling, treatment and disposal. Supercritical fluid extraction is herein investigated as a novel technology to treat this waste. Supercritical fluid extraction employs a substance above its critical temperature and pressure as a solvent. In this state, the substance has both liquid- and gas-like properties that can be controlled by the pressure and temperature of the extraction process. In this paper, results of studies using supercritical carbon dioxide to remove the base oil from drilling waste are presented. Current work investigates the extraction of hydrocarbons (i.e. base oil) from a synthetic oil-based centrifuge underflow drilling waste. Extraction efficiencies as high as 98% have been observed. Additionally, results of both past and current studies indicate that the hydrocarbons are unchanged by the extraction process and that they may be recovered and potential...
Introducción: La extracción de hidrocarburos en el Noreste de Alberta, en Canadá, genera una gran... more Introducción: La extracción de hidrocarburos en el Noreste de Alberta, en Canadá, genera una gran cantidad de residuos conocidos como “arenas de alquitrán”. Las arenas de alquitrán son una suspensión acuosa de arcillas finas, arena, betún de petróleo e hidrocarburos. Estos residuos son depositados y retenidos en estanques de sedimentación, donde los sólidos coloidales precipitan y se concentran muy lentamente por efecto de la gravedad y el agua intersticial que se libera se colecta para reúso. La concentración, también llamada densificación, de las arenas de alquitrán mediada por los microorganismos nativos que producen metano o dioxido de carbono, es un fenómeno observado in situ e in vitro, a través del cual, los residuos se precipitan, y se libera agua intersticial más rápidamente que la sedimentación por gravedad.Método: En este trabajo, se aplicaron enmiendas orgánicas para estimular la actividad de microorganismos nativos de los estanques de sedimentación, con el objetivo de a...
Water environment research : a research publication of the Water Environment Federation, 2015
A review of the literature from 2014 related to automotive wastes is presented. Topics include so... more A review of the literature from 2014 related to automotive wastes is presented. Topics include solid wastes from autobodies and tires as well as vehicle emissions to soil and air as a result of the use of conventional and alternative fuels. Potential toxicological and health risks related to automotive wastes are also discussed.
In the Athabasca oil sands, bitumen production using caustic warm-water extraction leads to large... more In the Athabasca oil sands, bitumen production using caustic warm-water extraction leads to large quantities of fluid tailings. The resulting tailings require storage in above-grade deposits or secure settling basins. Significant changes in groundwater systems occur from disruption during mining or changes in hydrology with tailings deposition. Intentional release into local groundwater systems is not practiced and release by seepage is minimized by engineering means. Waters produced from oil sands processing have unique properties that can be used as indicators of interaction with surface and groundwaters. In this paper, water from an above-grade tailings sand deposit is examined as a recharge into a surface water drainage system. The changes in water properties occurring during seepage of this process-affected water are examined, and analytical tools for better estimating the attenuation processes in receiving aquatic systems are described.
A 620-day laboratory mesocosm study was conducted to investigate the effect of added terminal ele... more A 620-day laboratory mesocosm study was conducted to investigate the effect of added terminal electron acceptors and nutrients on the anaerobic biodegradation of benzene, ethylbenzene, mand p-xylenes (BEX) and CCME F1 fraction hydrocarbons (F1) in contaminated groundwater. High removal of BEX and F1 was observed in most mesocosms. The calculated first order biodegradation rates ranged from 0.0020 to 0.033 d for benzene, 0 to 0.029 d for ethylbenzene, 0.0020 to 0.036 d for mand p-xylenes, and 0 to 0.0089 d for F1, under the tested conditions. The results suggest that biodegradation of BEX was enhanced with both nitrate and sulfate amendment, while sulfate amendment significantly stimulated F1 biodegradation. The effect of nutrient amendment was difficult to identify from the obtained results. RÉSUMÉ Cette étude en laboratoire avait pour but de déterminer l’effet de l’addition d’accepteurs d’électrons et de nutriants sur la biodégradation anaérobie de benzène, ethylbenzène, m-xylène, ...
Oil-based drilling fluids are essential for challenging drilling operations. However, their use r... more Oil-based drilling fluids are essential for challenging drilling operations. However, their use requires costly handling, treatment and disposal. Supercritical fluid extraction is herein investigated as a novel technology to treat this waste. Supercritical fluid extraction employs a substance above its critical temperature and pressure as a solvent. In this state, the substance has both liquid- and gas-like properties that can be controlled by the pressure and temperature of the extraction process. In this paper, results of studies using supercritical carbon dioxide to remove the base oil from drilling waste are presented. Current work investigates the extraction of hydrocarbons (i.e. base oil) from a synthetic oil-based centrifuge underflow drilling waste. Extraction efficiencies as high as 98% have been observed. Additionally, results of both past and current studies indicate that the hydrocarbons are unchanged by the extraction process and that they may be recovered and potential...
Introducción: La extracción de hidrocarburos en el Noreste de Alberta, en Canadá, genera una gran... more Introducción: La extracción de hidrocarburos en el Noreste de Alberta, en Canadá, genera una gran cantidad de residuos conocidos como “arenas de alquitrán”. Las arenas de alquitrán son una suspensión acuosa de arcillas finas, arena, betún de petróleo e hidrocarburos. Estos residuos son depositados y retenidos en estanques de sedimentación, donde los sólidos coloidales precipitan y se concentran muy lentamente por efecto de la gravedad y el agua intersticial que se libera se colecta para reúso. La concentración, también llamada densificación, de las arenas de alquitrán mediada por los microorganismos nativos que producen metano o dioxido de carbono, es un fenómeno observado in situ e in vitro, a través del cual, los residuos se precipitan, y se libera agua intersticial más rápidamente que la sedimentación por gravedad.Método: En este trabajo, se aplicaron enmiendas orgánicas para estimular la actividad de microorganismos nativos de los estanques de sedimentación, con el objetivo de a...
Water environment research : a research publication of the Water Environment Federation, 2015
A review of the literature from 2014 related to automotive wastes is presented. Topics include so... more A review of the literature from 2014 related to automotive wastes is presented. Topics include solid wastes from autobodies and tires as well as vehicle emissions to soil and air as a result of the use of conventional and alternative fuels. Potential toxicological and health risks related to automotive wastes are also discussed.
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Papers by Selma Guigard