In situ chemical oxidation (ISCO) with permanganate is a remedial technology that has been prevalent over the last decade. Permanganate is injected into the subsurface to oxidized reduced organic contaminants with the intent of mineralizing the organics to innocuous compounds such as water, oxygen, and carbon dioxide. However, the demand for permanganate from the naturally occurring reduced components associated with aquifer materials inhibits the ability of permanganate to effectively oxidize the target contaminants. This demand for permanganate is referred to as the Natural Oxidant Demand (NOD) and results from the presence of naturally occurring reduced aquifer species such as inorganic species containing iron, manganese, or sulfur, and natural organic matter. Traditionally, NOD has been considered to be an instantaneous sink for permanganate that required satisfaction before permanganate could propagate through the subsurface. However, recent research has suggested that NOD is kinetically controlled and not instantaneous resulting in the effectiveness of ISCO systems to be underestimated using traditional approaches. The objectives of this research were to develop a comprehensive NOD kinetic model from existing laboratory data of several aquifer materials, and then to use this model to estimate the impact of NOD kinetics on treatment efficiency. The NOD kinetic model primarily was developed using results of bench-scale experiments performed on four aquifer materials, measuring the reduction of permanganate and oxidizable materials. Data analysis indicated that there are two bulk reactions occurring: a fast reaction and a slow reaction. For both of these reactions a second-order rate law was deemed to be appropriate; first-order with respect to each reactant. The slow reaction was subject to passivation and the reaction rate coefficient decreased hyperbolically as manganese oxide reaction by-products precipitated on grains. The developed NOD kinetic model was incorporated into a 1-dimensional transport model and was used to successfully simulate the results of NOD column studies. Experimental efforts were completed to validate the 1-dimensional reactive transport model with data for organic contamination. A column study was completed to characterize the oxidation of an isolated trichloroethylene residual source zone. The chloride breakthrough data were used to represent the rate of TCE oxidation and a bromide tracer test was used as a conservative tracer to determine the dispersivity and porosity of the column. Both the simulated bromide and chloride breakthrough curves fit the experimental data well using published and calculated transport and chemical parameters. The impact of NOD kinetics on treatment efficiency was evaluated through numerical simulations of four common organic contaminants using two injection schemes: vertical well flushing and inject-and-leave. The treatment efficiency was defined as the fraction of supplied permanganate used to oxidize the organic compound. Two aquifer materials were simulated representing a wide range of NOD characteristics. The results indicated that despite a great difference in the ultimate NOD (order of 15) the treatment efficiency only varied by 0-7% between the materials. In general, the treatment efficiency of the contaminant increased as the solubility and the reaction rate coefficient increased. For treatment of organic compounds with a low solubility and reaction rate coefficient, the fast and slow NOD reaction kinetics should both be characterized since both exert a strong demand for permanganate in both the vertical flushing and inject-and-leave schemes. For organic compounds having moderate solubility and reaction rate coefficient the NOD species that require kinetic characterization depends on the injection scheme used: for a vertical well flushing scheme only the fast NOD requires characterization, whereas for the inject-and-leave scheme both the fast and slow NOD require characterization. For treatment of organic compounds with high solubility and reaction rate coefficient only the fast NOD requires characterization since the organic and fast NOD are depleted at the same time and the slow NOD does not play a significant role in permanganate consumption while free phase organic and fast NOD remain. Traditional modelling approaches were compared, using the vertical well flushing scheme, to compare the treatment efficiency with the NOD kinetic model to past methods. The model was used to simulate ISCO treatment when NOD kinetics were not included and when the ultimate NOD was assumed. The simulations with no NOD term overestimated the treatment efficiency whereas the simulations with the ultimate NOD model underestimated efficiency. These findings further stressed the importance of the NOD kinetics on treatment efficiency. The kinetics of the NOD kinetics must be characterized to determine if ISCO is a viable, cost-effective treatment option when considering ISCO as a redial strategy. Mischaracterization of these reactions could result in either over or underestimation of the treatment efficiency and poor design of pilot and full-scale treatment systems.

In situ chemical oxidation (ISCO) with permanganate is a remedial technology that has been prevalent over the last decade. Permanganate is injected into the subsurface to oxidized reduced organic contaminants with the intent of mineralizing the organics to innocuous compounds such as water, oxygen, and carbon dioxide. However, the demand for permanganate from the naturally occurring reduced components associated with aquifer materials inhibits the ability of permanganate to effectively oxidize the target contaminants. This demand for permanganate is referred to as the Natural Oxidant Demand (NOD) and results from the presence of naturally occurring reduced aquifer species such as inorganic species containing iron, manganese, or sulfur, and natural organic matter. Traditionally, NOD has been considered to be an instantaneous sink for permanganate that required satisfaction before permanganate could propagate through the subsurface. However, recent research has suggested that NOD is kinetically controlled and not instantaneous resulting in the effectiveness of ISCO systems to be underestimated using traditional approaches. The objectives of this research were to develop a comprehensive NOD kinetic model from existing laboratory data of several aquifer materials, and then to use this model to estimate the impact of NOD kinetics on treatment efficiency. The NOD kinetic model primarily was developed using results of bench-scale experiments performed on four aquifer materials, measuring the reduction of permanganate and oxidizable materials. Data analysis indicated that there are two bulk reactions occurring: a fast reaction and a slow reaction. For both of these reactions a second-order rate law was deemed to be appropriate; first-order with respect to each reactant. The slow reaction was subject to passivation and the reaction rate coefficient decreased hyperbolically as manganese oxide reaction by-products precipitated on grains. The developed NOD kinetic model was incorporated into a 1-dimensional transport model and was used to successfully simulate the results of NOD column studies. Experimental efforts were completed to validate the 1-dimensional reactive transport model with data for organic contamination. A column study was completed to characterize the oxidation of an isolated trichloroethylene residual source zone. The chloride breakthrough data were used to represent the rate of TCE oxidation and a bromide tracer test was used as a conservative tracer to determine the dispersivity and porosity of the column. Both the simulated bromide and chloride breakthrough curves fit the experimental data well using published and calculated transport and chemical parameters. The impact of NOD kinetics on treatment efficiency was evaluated through numerical simulations of four common organic contaminants using two injection schemes: vertical well flushing and inject-and-leave. The treatment efficiency was defined as the fraction of supplied permanganate used to oxidize the organic compound. Two aquifer materials were simulated representing a wide range of NOD characteristics. The results indicated that despite a great difference in the ultimate NOD (order of 15) the treatment efficiency only varied by 0-7% between the materials. In general, the treatment efficiency of the contaminant increased as the solubility and the reaction rate coefficient increased. For treatment of organic compounds with a low solubility and reaction rate coefficient, the fast and slow NOD reaction kinetics should both be characterized since both exert a strong demand for permanganate in both the vertical flushing and inject-and-leave schemes. For organic compounds having moderate solubility and reaction rate coefficient the NOD species that require kinetic characterization depends on the injection scheme used: for a vertical well flushing scheme only the fast NOD requires characterization, whereas for the inject-and-leave scheme both the fast and slow NOD require characterization. For treatment of organic compounds with high solubility and reaction rate coefficient only the fast NOD requires characterization since the organic and fast NOD are depleted at the same time and the slow NOD does not play a significant role in permanganate consumption while free phase organic and fast NOD remain. Traditional modelling approaches were compared, using the vertical well flushing scheme, to compare the treatment efficiency with the NOD kinetic model to past methods. The model was used to simulate ISCO treatment when NOD kinetics were not included and when the ultimate NOD was assumed. The simulations with no NOD term overestimated the treatment efficiency whereas the simulations with the ultimate NOD model underestimated efficiency. These findings further stressed the importance of the NOD kinetics on treatment efficiency. The kinetics of the NOD kinetics must be characterized to determine if ISCO is a viable, cost-effective treatment option when considering ISCO as a redial strategy. Mischaracterization of these reactions could result in either over or underestimation of the treatment efficiency and poor design of pilot and full-scale treatment systems.

The problems associated with the contamination of groundwater environments by non-aqueous phase liquids (NAPLs) such as chlorinated solvents, gasoline and manufacturing gas plant (MGP) residuals, including their distribution and persistence, are well accepted. The treatment of groundwater by in situ chemical oxidation (ISCO) relies on the oxidation potential of chemical reagents to destroy harmful organic compounds. The interaction of these oxidants with target and non-target compounds in the subsurface will help determine effectiveness and efficiency of an ISCO treatment system. Push-pull tests (PPTs) have the utility to estimate key properties in situ and allow for sampling a larger volume of aquifer to yield more representative estimates as compared to conventional bench-scale tests. The scale and cost-effectiveness of a PPT make it an ideal tool to collect valuable information on subsurface system behaviour so that uncertainties can be minimized. The use of PPTs to provide insight into treatment expectations or to support the design of an ISCO system requires a suitable interpretation tool. A multi-species numerical model (‘PPT-ISCO’) in a radial coordinate system was developed to simulate a PPT with the injection of a conservative tracer and oxidant (persulfate or permanganate) into the saturated zone of a porous medium environment. The pore space may contain variable amounts of immobile, multicomponent, residual NAPL. The aquifer material contains a natural organic matter (NOM) fraction and/or other oxidizable aquifer material (OAM) species. The model is capable of simulating mass transport for an arbitrary number of conservative and reactive tracers and NAPL constituents subjected to chemical reactions. The ability of PPTs to capture the in situ natural oxidant interaction (NOI) was tested with PPTISCO. Breakthrough curve (BTC) data collected from permanganate and persulfate PPTs conducted in the field were compared to simulated BTCs by assigning the same field operational parameters to the model and applying NOI kinetic information obtained from batch tests. These tests confirmed the usability of the model and PPTs to obtain the NOI kinetics from PPT BTCs. The sensitivity of PPT BTCs to variations in the field operating and NOI parameters were investigated. The results of varying the field operating parameters indicated that the oxidant BTCs could be scaled to match varying injection and extraction flow rates. Variations in NOI parameters revealed that the permanganate BTC is primarily controlled by the permanganate fast reaction rate coefficient and the quantity of OAM present in the aquifer. The spatial profiles of OAM across the test zone revealed that the majority of the OAM consumption is from the fast fraction and occurs in the vicinity of the well where the permanganate concentration is greatest. An estimate of the permanganate fast reaction rate coefficient can be obtained from a permanganate PPT BTC by employing the model to simulate the PPT with the operational parameters (used in the field) and literature estimates of the remaining NOI parameters. Calibration between the simulated and observed BTCs can be undertaken to adjust the permanganate fast reaction rate coefficient to fit the permanganate PPT BTC. Persulfate NOI sensitivity investigations revealed that persulfate PPT BTCs can be characterized by a concentration plateau at early times as a result of the increased ionic strength in the area around the injection well. The ionic strength is primarily controlled by the injected persulfate concentration, and as persulfate degrades into sulphate and acid, the ionic strength is enhanced. Graphical analysis of the BTC revealed that an underestimated value of the persulfate degradation rate coefficient can be obtained from the PPT BTC. A more representative estimate of the persulfate degradation rate coefficient can be achieved after fitting the field BTC to the simulated results, applying the underestimated value as a starting point. PPTs investigating ISCO treatability have the ability to provide insight into the effect of the NOI on the oxidation of target compounds, site-specific oxidant dosage requirements and NAPL treatment expectations. NAPL component BTCs from treatability PPTs are primarily controlled by the mass in the fast region, and the fast region mass transfer rate coefficient. Oxidation estimates extracted from NAPL component BTCs were shown to accurately approximate the mass of each NAPL component oxidized when compared to model calculations. The mass of NAPL oxidized for each of the components yields a site-specific oxidant dosage. This estimate exceeds what is prescribed by the stoichiometry between permanganate and the contaminant of concern due to the effect of the NOI. The utility of PPTs to study and quantify the interaction between injected oxidants and the aquifer material has been demonstrated with PPT-ISCO. In addition, PPT-ISCO has revealed that treatability PPTs can be tailored to investigate the dosage requirements and treatment expectations of residual NAPLs. Results from this effort will be used to support ongoing field research exploring the use of PPTs to assist in understanding the competing subsurface processes affecting ISCO applications.

Mathematical modelling was utilized to evaluate trichloroethylene (TCE) and tetrachloroethylene (PCE) dense non-aqueous phase liquid (DNAPL) source zone remediation in the subsurface environment. Semi-analytical solutions were derived, tested, and employed to evaluate the benefits of source zone concentration reduction and solute degradation mechanisms on the evolution of plumes in porous media and fractured rock domains. Simulations of treatment in complex DNAPL source zones using different remedial technologies were completed with a numerical model that was developed, tested, calibrated, and applied to nine idealized heterogeneous porous media sites. Analytical modelling revealed that, in domains dominated by matrix diffusion, aggressive and moderate source zone concentration reduction may have similar effects on the leading edge of the plume. The tailing (near source) edge of the plume may be more responsive to aggressive concentration reduction, particularly when diffusion processes are negligible. Both the near-field (near-source) and far-field plume responses were strongly influenced by the matrix decay half-life for both transient and steady-state conditions. The degradative capacity of the matrix largely dictated plume extent and life-span for the fractured bedrock site considered here. Numerical simulations of in situ source zone treatment with chemical oxidation (ISCO), enhanced bioremediation (ISEB), and surfactants (SEAR) were compared and contrasted. Treatment efficacy was site specific, with benefits observed at some sites, and detrimental impacts observed at others. Each technology demonstrated some degree of performance enhancement relative to dissolution only (no treatment). The maximum DNAPL mass depletion enhancement factors for ISCO, ISEB and SEAR, were 1.44, 2.91, and 2.70 after 10 years, respectively. Similarly, the maximum boundary mass flux enhancement factors for ISCO, ISEB and SEAR were 9.78, 3.32, and 3.97, respectively. While notable enhancements were observed for many sites during active treatment, the long-term performance of pre-maturely terminated ISCO and ISEB, and to a lesser degree SEAR, was similar to dissolution. Overall, the partial depletion of DNAPL mass from source zones produced on-going persistent boundary mass flux signatures. Only the complete removal of DNAPL mass, which was attained for one site with SEAR, successfully eliminated downgradient boundary mass flux. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-05-21 08:55:04.491

The problems associated with the contamination of groundwater environments by non-aqueous phase liquids (NAPLs) such as chlorinated solvents, gasoline and manufacturing gas plant (MGP) residuals, including their distribution and persistence, are well accepted. The treatment of groundwater by in situ chemical oxidation (ISCO) relies on the oxidation potential of chemical reagents to destroy harmful organic compounds. The interaction of these oxidants with target and non-target compounds in the subsurface will help determine effectiveness and efficiency of an ISCO treatment system. Push-pull tests (PPTs) have the utility to estimate key properties in situ and allow for sampling a larger volume of aquifer to yield more representative estimates as compared to conventional bench-scale tests. The scale and cost-effectiveness of a PPT make it an ideal tool to collect valuable information on subsurface system behaviour so that uncertainties can be minimized. The use of PPTs to provide insight into treatment expectations or to support the design of an ISCO system requires a suitable interpretation tool. A multi-species numerical model (‘PPT-ISCO’) in a radial coordinate system was developed to simulate a PPT with the injection of a conservative tracer and oxidant (persulfate or permanganate) into the saturated zone of a porous medium environment. The pore space may contain variable amounts of immobile, multicomponent, residual NAPL. The aquifer material contains a natural organic matter (NOM) fraction and/or other oxidizable aquifer material (OAM) species. The model is capable of simulating mass transport for an arbitrary number of conservative and reactive tracers and NAPL constituents subjected to chemical reactions. The ability of PPTs to capture the in situ natural oxidant interaction (NOI) was tested with PPTISCO. Breakthrough curve (BTC) data collected from permanganate and persulfate PPTs conducted in the field were compared to simulated BTCs by assigning the same field operational parameters to the model and applying NOI kinetic information obtained from batch tests. These tests confirmed the usability of the model and PPTs to obtain the NOI kinetics from PPT BTCs. The sensitivity of PPT BTCs to variations in the field operating and NOI parameters were investigated. The results of varying the field operating parameters indicated that the oxidant BTCs could be scaled to match varying injection and extraction flow rates. Variations in NOI parameters revealed that the permanganate BTC is primarily controlled by the permanganate fast reaction rate coefficient and the quantity of OAM present in the aquifer. The spatial profiles of OAM across the test zone revealed that the majority of the OAM consumption is from the fast fraction and occurs in the vicinity of the well where the permanganate concentration is greatest. An estimate of the permanganate fast reaction rate coefficient can be obtained from a permanganate PPT BTC by employing the model to simulate the PPT with the operational parameters (used in the field) and literature estimates of the remaining NOI parameters. Calibration between the simulated and observed BTCs can be undertaken to adjust the permanganate fast reaction rate coefficient to fit the permanganate PPT BTC. Persulfate NOI sensitivity investigations revealed that persulfate PPT BTCs can be characterized by a concentration plateau at early times as a result of the increased ionic strength in the area around the injection well. The ionic strength is primarily controlled by the injected persulfate concentration, and as persulfate degrades into sulphate and acid, the ionic strength is enhanced. Graphical analysis of the BTC revealed that an underestimated value of the persulfate degradation rate coefficient can be obtained from the PPT BTC. A more representative estimate of the persulfate degradation rate coefficient can be achieved after fitting the field BTC to the simulated results, applying the underestimated value as a starting point. PPTs investigating ISCO treatability have the ability to provide insight into the effect of the NOI on the oxidation of target compounds, site-specific oxidant dosage requirements and NAPL treatment expectations. NAPL component BTCs from treatability PPTs are primarily controlled by the mass in the fast region, and the fast region mass transfer rate coefficient. Oxidation estimates extracted from NAPL component BTCs were shown to accurately approximate the mass of each NAPL component oxidized when compared to model calculations. The mass of NAPL oxidized for each of the components yields a site-specific oxidant dosage. This estimate exceeds what is prescribed by the stoichiometry between permanganate and the contaminant of concern due to the effect of the NOI. The utility of PPTs to study and quantify the interaction between injected oxidants and the aquifer material has been demonstrated with PPT-ISCO. In addition, PPT-ISCO has revealed that treatability PPTs can be tailored to investigate the dosage requirements and treatment expectations of residual NAPLs. Results from this effort will be used to support ongoing field research exploring the use of PPTs to assist in understanding the competing subsurface processes affecting ISCO applications.

Minimal research has been conducted to examine dissolution and remediation of NAPL located in lower-permeability (K) media. The purpose of this research was to investigate dissolution of non-uniformly distributed residual NAPL located in lower-K media and how mass transfer was affected. Additionally, in situ chemical oxidation (ISCO) effectiveness using KMnO₄ in the laboratory and field was examined. A series of column and flow cell experiments were conducted with trichloroethene (TCE). For uniformly distributed residual NAPL control experiments, reduced interfacial pool area and resonance time were likely the most important mass transfer limitation. For non-uniformly distributed residual NAPL, by-pass flow attributed to reduced effective permeability was initially the most important factor affecting nonideal mass transfer. Dissolution times increased with physical heterogeneity due to bypass flow. Mass transfer was more non-ideal for non-uniformly distributed NAPL. Nonideal mass transfer was most pronounced for non-uniformly distributed NAPL in lower-K zones. NAPL location influences dissolution behavior and ultimately remediation. Mass flux reduction versus mass reduction comparisons for the experiments exhibited how mass transfer trends vary between systems. The effectiveness of KMnO₄ ISCO of residual TCE located in lower-K media was examined. KMnO₄ solution was flushed through a flow cell followed by water flushing to evaluate long-term mass flux behavior, which was then compared to a water-flush control. For water flushing following KMnO₄ flushing, mass flux was similar to the control experiment. However, since contaminant mass was reduced, the number of pore volumes required for complete TCE removal via water flushing was estimated to be reduced by half. 1,1-Dichloroethene (DCE) is thought to be located in lower permeability strata adjacent to the water table at the Samsonite Building Area. Eight injection wells were emplaced in the source zone area, with well screens spanning the vadose and saturated zones, and injected with ~250 kg of 1.7% KMnO₄ solution. Bench-scale studies using core material determined that DCE was readily degraded by KMnO₄, even at lower reagent concentrations (< 1 mM). The natural oxidant demand was determined to be 1.0 x 10⁻⁵ g of KMnO₄/g of sediment. Aqueous DCE levels dropped below detection after KMnO₄ solution was present.

The contamination of aquifer systems by petroleum hydrocarbons is a global problem. Underground storage tanks used for storing these hydrocarbons often leak, resulting in subsurface contamination. The hazards associated with petroleum hydrocarbon contamination are mainly attributable to the BTEX compounds, namely benzene, toluene, ethylbenzene and xylenes together with trimethylbenzenes (TMBs) and naphthalene due to their potential to impact human health and the ease with which they can enter the groundwater system. In situ chemical oxidation (ISCO) is the delivery of strong chemical oxidants to the subsurface for the purpose of treating organic contaminants. ISCO can be an effective way to remediate organic contaminants from the soil and groundwater. Sodium persulphate is one of the newer oxidants to gain widespread use in treating petroleum hydrocarbon contamination, though without being fully understood. This investigation tested the ability of unactivated sodium persulphate in treating dissolved phase and residual BTEX contamination through bench-scale laboratory tests and a pilot-scale field study. A degradation potential batch reactor test was carried out to assess the efficacy of unactivated sodium persulphate in oxidizing petroleum hydrocarbons present in contaminated groundwater as well as its effect on aquifer material from a field site. This test was carried out at a sodium persulphate concentration of 20 g/L. Results from this test did not follow the expected first-order degradation, and so subsequent experiments were carried out using a sodium persulphate concentration of 100 g/L. A test to determine the degree of interaction between the oxidant and aquifer material was also conducted. It was found that the degree of natural oxidant interaction for the field site in question was very low. 1000 kg of sodium persulphate was dissolved in nearly 10,000 L of water and injected into the subsurface. Electrical conductivity (EC), pH, sodium, persulphate, sulphate and BTEX were all monitored during the subsequent 152-day post-injection monitoring period. An empirical relationship was determined between EC and the concentration of sodium in groundwater. This enabled the use of EC as a real-time tracer to track the progress of the injectate. Field results supported predictions based on a simulation model that density-driven flow would play an important role in the delivery of the injectate. A portion of the injectate was believed to have been missed by the monitoring network. Areas that did show elevated tracer results in some cases showed a decrease in BTEX concentrations. Results were categorized in four ways. The first category had wells that showed strong evidence of injectate presence but little to no change in BTEX levels. The second category was comprised of wells that showed a reduction in BTEX levels along with the presence of injectate. BTEX levels in some wells rebounded towards the end of the study period. The third category consisted of wells that showed the presence of dilute injectate but did not show any reduction in BTEX concentrations. The fourth and final category was of wells that showed no evidence of having been affected by the injectate in any way. BTEX levels were the same as background. The oxidation of BTEX by unactivated sodium persulphate was found to be successful, though the vagaries of oxidant delivery and field sampling made difficult the accurate determination of the degree of success.

The contamination of aquifer systems by petroleum hydrocarbons is a global problem. Underground storage tanks used for storing these hydrocarbons often leak, resulting in subsurface contamination. The hazards associated with petroleum hydrocarbon contamination are mainly attributable to the BTEX compounds, namely benzene, toluene, ethylbenzene and xylenes together with trimethylbenzenes (TMBs) and naphthalene due to their potential to impact human health and the ease with which they can enter the groundwater system. In situ chemical oxidation (ISCO) is the delivery of strong chemical oxidants to the subsurface for the purpose of treating organic contaminants. ISCO can be an effective way to remediate organic contaminants from the soil and groundwater. Sodium persulphate is one of the newer oxidants to gain widespread use in treating petroleum hydrocarbon contamination, though without being fully understood. This investigation tested the ability of unactivated sodium persulphate in treating dissolved phase and residual BTEX contamination through bench-scale laboratory tests and a pilot-scale field study. A degradation potential batch reactor test was carried out to assess the efficacy of unactivated sodium persulphate in oxidizing petroleum hydrocarbons present in contaminated groundwater as well as its effect on aquifer material from a field site. This test was carried out at a sodium persulphate concentration of 20 g/L. Results from this test did not follow the expected first-order degradation, and so subsequent experiments were carried out using a sodium persulphate concentration of 100 g/L. A test to determine the degree of interaction between the oxidant and aquifer material was also conducted. It was found that the degree of natural oxidant interaction for the field site in question was very low. 1000 kg of sodium persulphate was dissolved in nearly 10,000 L of water and injected into the subsurface. Electrical conductivity (EC), pH, sodium, persulphate, sulphate and BTEX were all monitored during the subsequent 152-day post-injection monitoring period. An empirical relationship was determined between EC and the concentration of sodium in groundwater. This enabled the use of EC as a real-time tracer to track the progress of the injectate. Field results supported predictions based on a simulation model that density-driven flow would play an important role in the delivery of the injectate. A portion of the injectate was believed to have been missed by the monitoring network. Areas that did show elevated tracer results in some cases showed a decrease in BTEX concentrations. Results were categorized in four ways. The first category had wells that showed strong evidence of injectate presence but little to no change in BTEX levels. The second category was comprised of wells that showed a reduction in BTEX levels along with the presence of injectate. BTEX levels in some wells rebounded towards the end of the study period. The third category consisted of wells that showed the presence of dilute injectate but did not show any reduction in BTEX concentrations. The fourth and final category was of wells that showed no evidence of having been affected by the injectate in any way. BTEX levels were the same as background. The oxidation of BTEX by unactivated sodium persulphate was found to be successful, though the vagaries of oxidant delivery and field sampling made difficult the accurate determination of the degree of success.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to study the relationship between liquid discharge and suspended sediment discharge by various methods. The study was carried out at Menino Deus IV Fluviometric Station, located in Santa Maria/RS. It was relating to solid discharge in suspension, using all samples in full waves and without precipitation, with the liquid discharge using the integrated sampler USDH 48 and ISCO sampler punctual. The coefficient of determination of 93.4 % and 85.0 %, were obtained respectively, to the samplers USDH 48 and ISCO, can be considered a good correlation. Also were related the turbidity with the sediments concentration in suspension, obtaining the solid discharge calculated with the liquid discharge using the sampler integrator USDH 48. A correlation coefficient of 93.0 % with all samples and the ISCO 85.2 % were obtained. It was observed that the automatic measurements by turbidity become a viable alternative due to the easy to install and to possible a continuous monitoring and automatic, without the presence of a technician in place, further obtaining similar results to the traditional methods which is recommended in this study. To determine the liquid discharge, the hydrometric windlass traditional method and the acoustic method was used, using an Acoustic Doppler Profiler (ADP). It can be concluded that with the depths less than 0.28 m, the ADP did not execute the reading speed and the presented reading failures. Thus, for measurements in these conditions, it is suggested to use the hydrometric windlass, because it is a device that provides more detail and flexibility when handling. / O objetivo deste trabalho foi estudar as relações entre descarga líquida e descarga sólida em suspensão segundo diferentes métodos. O trabalho foi realizado na Estação Fluviométrica Menino Deus IV, localizada em Santa Maria/RS. Relacionou-se a descarga sólida em suspensão, utilizando todas as amostras em ondas de cheia e dias sem precipitação, com a descarga líquida utilizando o amostrador integrado USDH 48 e o amostrador pontual ISCO. Obteve-se coeficientes de determinação de 93,4% e 85,0%, respectivamente para os amostradores USDH 48 e ISCO, podendo ser considerada uma boa correlação. Relacionou-se também a turbidez com a concentração de sedimentos em suspensão, obtendo a descarga sólida calculada com a descarga líquida utilizando o amostrador integrador USDH 48. Obteve-se um coeficiente de correlação de 93,0% com todas as amostras e com o ISCO de 85,2%. Observou que as medições automáticas de turbidez tornam-se uma alternativa viável em função da facilidade de instalação e por possibilitar um monitoramento contínuo e automático, sem a presença de um técnico no local, além da obtenção de resultados próximos aos métodos tradicionais sendo este o recomendado neste estudo. Para a determinação da descarga líquida, utilizou-se o método tradicional do molinete hidrométrico e o método acústico, utilizando o Acoustic Doppler Profiler (ADP). Pode-se concluir que com as profundidades inferiores a 0,28 m, o ADP não apresentou falhas na leitura de velocidade. Assim, para medições nestas condições, sugere-se utilizar o molinete hidrométrico, pois é um equipamento que fornece mais detalhes e agilidade no momento de manuseio.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-04T20:54:55Z No. of bitstreams: 1 HermanoGomesFernandes_DISSERT.pdf: 9844659 bytes, checksum: 327ce29ed932fc4d2e4f315bf0880d02 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-01-05T22:10:46Z (GMT) No. of bitstreams: 1 HermanoGomesFernandes_DISSERT.pdf: 9844659 bytes, checksum: 327ce29ed932fc4d2e4f315bf0880d02 (MD5) / Made available in DSpace on 2016-01-05T22:10:46Z (GMT). No. of bitstreams: 1 HermanoGomesFernandes_DISSERT.pdf: 9844659 bytes, checksum: 327ce29ed932fc4d2e4f315bf0880d02 (MD5) Previous issue date: 2014-05-10 / Passivos ambientais oriundos de acidentes na ind?stria varejista do petr?leo, principalmente nas zonas urbanas, t?m representado um s?rio problema cujo impacto atinge o subsolo, a sa?de das pessoas e ainda preju?zos econ?micos com o processo de remedia??o. S? nos EUA, s?o estimados centenas de bilh?es de d?lares aplicados em processos de descontamina??o de solos. Os resultados dos laudos e relat?rios de investiga??o de passivo em postos de combust?veis distribu?dos na zona urbana do munic?pio de Natal-RN foram utilizados para estimativa do cen?rio local de contamina??o. Dessa base de dados foi poss?vel determinar os principais contaminantes (BTEX, PAH, TOC), os bairros atingidos e os tipos de solos potencialmente mais impactados. Foram realizados experimentos objetivando reverter contamina??o desse cen?rio, onde o tipo de solo foi um fator no planejamento, pois influencia diretamente na efic?cia das t?cnicas de remedia??o estudadas: Oxida??o por inje??o de per?xido de hidrog?nio e oxida??o por inje??o de persulfato de s?dio. Esses oxidantes s?o ativados formando os radicais livres (HO?-, SO4 ?-, HO2 ? , O2 ?-, S2O8 -2, etc) respons?veis por mineralizar os hidrocarbonetos e outros org?nicos (liberando O2 e CO2). No processo de ativa??o, foram estudados os ?ons ferroso (II) e f?rrico (III) bem como o per?xido de hidrog?nio na ativa??o da t?cnica com persulfato de s?dio, sendo esta ?ltima, a que apresentou melhor efici?ncia entre todas no estudo, quando ativado com Fe+3. Al?m de definir qual a t?cnica mais eficiente, foi objetivo desse estudo a avalia??o da influ?ncia entre os diferentes solos entre as t?cnicas oxidativas, caracterizando o efeito da concentra??o desses oxidantes e ainda o da concentra??o dos catalisadores. Existe na maioria dos cen?rios avaliados a presen?a de ferro total intr?nseca a matriz do solo. Os chamados latossolos apresentam colora??o avermelhada indicando ? presen?a dessas esp?cies reativas como ferro e aspecto argiloso. O estudo cin?tico foi conduzido por planejamento experimental e monitoramento do percentual de carbono total (SSM- 5000A) nas fases s?lidas e l?quidas, sabendo que 82,4% da mol?cula de diesel ? carbono. Foram analisados ainda o carbono org?nico e o pH de amostras l?quidas para as t?cnicas, caracterizando a influ?ncia do tipo de solo e sua condi??o operacional. A t?cnica (Fenton-like) H2O2 e Fe+2 apresentou oxida??o satisfat?ria, inclusive para solo arenoso, mas bem inferior ao melhor resultado. O persulfato de s?dio apenas ativado com temperatura, mesmo no solo mais favor?vel n?o apresentou boa efici?ncia. A t?cnica viabilizada no estudo teve o perfil de concentra??o com 2,2x10-1mol.L-1 de Na2S2O8 ativado com o 6,53x10-1mol.L-1 de H2O2 e 2,5x10-2 Fe3+mol.L-1, que reduziu em menos de um dia 96% a contamina??o em solo vermelho, inicialmente com 66.667mg de diesel por kg de solo limpo. / Environmental liabilities from accidents in the retail petroleum industry, especially in urban areas, have represented a serious problem whose impact reaches the underground, people's health and even economic losses with the remediation process. In U.S.A. are estimated hundreds of billions of dollars invested in soil remediation processes. The results of the reports and investigative reports of liabilities in fuel stations distributed in the urban area of Natal-RN were used to estimate the local scenario of contamination. This database has been possible to determine the main contaminants (BTEX, PAHs, TOC), affected neighborhoods and types of potentially more impacted soils. Experiments were carried out in order to reverse contamination of this scenario, where the soil type was a factor in the planning, because it influences directly on the effectiveness of remediation techniques studied: Oxidation by hydrogen peroxide and oxidation by sodium persulphate. These oxidants are activated forming free radicals (HO?-, SO4 ?-, HO2 ? , O2 ?-, S2O8 -2, etc) responsible for to mineralize the hydrocarbons and other organic compounds (releasing O2 e CO2). In the activation process, the ferrous ions (II) and ferric (III) were studied as well as hydrogen peroxide activation technique with sodium persulfate, the latter being presented the best efficiency among all the study, when activated with Fe+3. In addition to defining the most efficient technique, the aim of this study was to evaluate the influence of different soils among oxidative techniques, characterizing the effect of the concentration of these oxidants and also the concentration of the catalysts. Exists in most scenarios evaluated the presence of intrinsic total iron soil matrix. The so-called latosols present microaggregates reddish indicating the presence of these reactive species like iron and clayey aspect. The kinetic study was conducted by experimental design and monitoring of the percentage of total carbon (SSM-5000A) in the solid and liquid phases, knowing that 82.4% of the diesel molecule is carbon. Yet organic carbon and pH of liquid samples were analyzed for technical, characterizing the influence of soil type and its operating condition. The Fenton-like technique H2O2 e Fe+2 presented satisfactory oxidation, including sandy soil, but well below the best result. The sodium persulphate only activated with temperature, even in the most favorable soil, did not provide good efficiency. The best technique in the study had the concentration profile with 2,2x10- 1mol.L-1 of Na2S2O8 activated with 6,53x10-1mol.L-1 of H2O2 and 2,5x10-2 Fe3+mol.L-1 which reduced in less than a day 96 contamination in red soil, initially with 66,667 mg of diesel per kg of clean soil