A study was carried out in a sedimentary fractured rock site located in south central Wisconsin, US, which was impacted by DNAPL releases estimated to occur in the 1950’s and 1960’s. The majority of the DNAPL has accumulated in the upper portion of the Lone Rock Formation at a depth between 140 and 180 ft bgs referred as Layer 5 in this study. A groundwater VOC plume of more than 3km long has formed in this Layer. The DNAPL is mainly composed of 1,1,1-TCA, PCE, TCE and BTEX, while large amounts of biodegradation products such as cis-DCE and 1,1-DCA are present in the plume. Long term VOC data have been collected at the site and diverse geological and hydrogeological techniques have been applied to have a better understanding of the DNAPL history and behavior of the VOC plume. Evidence of biodegradation was also documented near the DNAPL source in these studies. The thesis objectives of the present study aimed first to have a better understanding of the long term contaminant distribution and degradation history at the site. This objective was accomplished reviewing the VOC historical concentration data collected from 1992 to 2006 in the wells tapping the most contaminated. hydrogeological unit in the bedrock (Layer 5) and in the overburden aquifer (referred as Layer 2). The second objective aimed to evaluate the current degree or extent of biodegradation of chlorinated compounds, which was accomplished evaluating the current groundwater redox conditions and using a combined analysis of VOC concentration and carbon isotope data collected in groundwater in September 2007. The historical data collected between1992 to 2006 showed the degradation of the VOC plume in Layer 5 was controlled by the availability of electron acceptors and redox conditions in the fracture bedrock aquifer. This pattern and the extension of the VOC plume were linked to different DNALP pumping events in the source zone and the operation of a Hydraulic Barrier System. The current geochemical and isotope study showed a different pattern of biodegradation of chlorinated compounds in different parts of the plume. The cis-DCE tend to accumulate in the area from the source to the middle of the plume and around 80 % of biodegradation of 1,1,1-TCA to 1,1-DCA was observed in this area. The fringes of the plume were characterized by a dominant presence of TCE and 1,1,1 TCA. These patterns were linked to different redox conditions and amount of electron acceptors. The cis-DCE dominated area is characterized by anaerobic conditions and the presence of relative high amount of BTEX. The TCE-dominated area is under aerobic condition and no BTEX was found in this area. The operation of the Hydraulic Barrier System seems to have change redox condition which influenced the extent of degradation in the plume, especially in the area between the extraction wells. The formation of large amounts of VC in Layer 2 and the more reducing (at least sulfate reducing and maybe methanogenic conditions) of the groundwater in this Layer compared to Layer 5 confirmed the extent of VOC biodegradation is linked to the availability of electron donors. This study provides information about the current degree of the biodegradation of chlorinated compounds at a fracture rock site. This information is very valuable for the evaluation of natural attenuation as strategy for long term plume management or for future remediation strategies such as biostimulation or bioaugmentation at the site. This study also shows the present and long term behavior of the chlorinated compounds (degradation history) in the most contaminated hydrogeologic unit (Layer 5), has mainly been controlled by plume management strategies including DNAPL pumping in the source and the creation of a Hydraulic Barrier System. The ketones and BTEX, that acted as electron donors and carbon substrate for the microbial community responsible for the dechlorination of chlorinated compounds were shown to have controlled the past and current redox conditions and thus the degree and potential of biodegradation of chlorinated ethenes and chlorinated ethanes at the study site.

A study was carried out in a sedimentary fractured rock site located in south central Wisconsin, US, which was impacted by DNAPL releases estimated to occur in the 1950’s and 1960’s. The majority of the DNAPL has accumulated in the upper portion of the Lone Rock Formation at a depth between 140 and 180 ft bgs referred as Layer 5 in this study. A groundwater VOC plume of more than 3km long has formed in this Layer. The DNAPL is mainly composed of 1,1,1-TCA, PCE, TCE and BTEX, while large amounts of biodegradation products such as cis-DCE and 1,1-DCA are present in the plume. Long term VOC data have been collected at the site and diverse geological and hydrogeological techniques have been applied to have a better understanding of the DNAPL history and behavior of the VOC plume. Evidence of biodegradation was also documented near the DNAPL source in these studies. The thesis objectives of the present study aimed first to have a better understanding of the long term contaminant distribution and degradation history at the site. This objective was accomplished reviewing the VOC historical concentration data collected from 1992 to 2006 in the wells tapping the most contaminated. hydrogeological unit in the bedrock (Layer 5) and in the overburden aquifer (referred as Layer 2). The second objective aimed to evaluate the current degree or extent of biodegradation of chlorinated compounds, which was accomplished evaluating the current groundwater redox conditions and using a combined analysis of VOC concentration and carbon isotope data collected in groundwater in September 2007. The historical data collected between1992 to 2006 showed the degradation of the VOC plume in Layer 5 was controlled by the availability of electron acceptors and redox conditions in the fracture bedrock aquifer. This pattern and the extension of the VOC plume were linked to different DNALP pumping events in the source zone and the operation of a Hydraulic Barrier System. The current geochemical and isotope study showed a different pattern of biodegradation of chlorinated compounds in different parts of the plume. The cis-DCE tend to accumulate in the area from the source to the middle of the plume and around 80 % of biodegradation of 1,1,1-TCA to 1,1-DCA was observed in this area. The fringes of the plume were characterized by a dominant presence of TCE and 1,1,1 TCA. These patterns were linked to different redox conditions and amount of electron acceptors. The cis-DCE dominated area is characterized by anaerobic conditions and the presence of relative high amount of BTEX. The TCE-dominated area is under aerobic condition and no BTEX was found in this area. The operation of the Hydraulic Barrier System seems to have change redox condition which influenced the extent of degradation in the plume, especially in the area between the extraction wells. The formation of large amounts of VC in Layer 2 and the more reducing (at least sulfate reducing and maybe methanogenic conditions) of the groundwater in this Layer compared to Layer 5 confirmed the extent of VOC biodegradation is linked to the availability of electron donors. This study provides information about the current degree of the biodegradation of chlorinated compounds at a fracture rock site. This information is very valuable for the evaluation of natural attenuation as strategy for long term plume management or for future remediation strategies such as biostimulation or bioaugmentation at the site. This study also shows the present and long term behavior of the chlorinated compounds (degradation history) in the most contaminated hydrogeologic unit (Layer 5), has mainly been controlled by plume management strategies including DNAPL pumping in the source and the creation of a Hydraulic Barrier System. The ketones and BTEX, that acted as electron donors and carbon substrate for the microbial community responsible for the dechlorination of chlorinated compounds were shown to have controlled the past and current redox conditions and thus the degree and potential of biodegradation of chlorinated ethenes and chlorinated ethanes at the study site.

" Hydrodechlorination is the reaction of a chlorinated organic compound (R-Cl) with hydrogen to form a carbon-hydrogen bond and HCl: R-Cl + H2 = R-H + HCl. This reaction is used in refrigerant manufacturing, industrial by-product reclamation and waste management. These practical applications require in-depth understanding of hydrodechlorination reaction. In this research work, we studied four families of chlorinated compounds; CF3CF3-xClx(x=1-3), CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-), on supported palladium catalysts to create a theory capable of predicting the hydrodechlorination rate on chlorinated compounds and to explore the reaction mechanism. A possible set of elementary reaction steps of hydrodechlorination reaction was proposed from our kinetics study of all these compounds. In this set of reaction steps, the irreversible scission of the first C-Cl bond in a chlorinated compound was proposed to be the rate-determining step; gas phase H2 and HCl were suggested to be in equilibrium with surface H and Cl species; adsorbed Cl was assumed to be the most abundant surface intermediate. The overall rate of hydrodechlorination reaction could be derived from these reaction steps as r=k'[R-Cl]/(1+K'[HCl]/[H2]0.5). In this rate equation, k'is the product of the adsorption equilibrium constant of the chlorinated compound on catalyst surface times the rate constant for the scission of the first C-Cl bond scission step, and K'is the square root of the equilibrium constant for the equilibrium between H2, HCl and their corresponding surface species: 2HCl + 2* = H2 + 2Cl*. The hydrodechlorination reaction of CF3CFCl2 was performed in the presence of H37Cl to study the reversibility of C-Cl bond scission, and the removal of the first Cl atom from CF3CFCl2 was found to be an irreversible step. Hydrodechlorination experiments of CF3CFCl2 with D2 and HCl mixture revealed that D2 and HCl were in equilibrium with surface adsorbed hydrogen and chlorine during reaction. The forward rate and reverse rate of this equilibrium were at least 400 times higher than the overall hydrodechlorination rate. This result supported the assumption of equilibrium for 2HCl + 2* = H2 + 2Cl*. Additionally, the activation energy for the rate determining step was extracted from hydrodechlorination reaction kinetics results of CH4-xClx (x=1-4), CF4-xClx (x=1-4) and dichloropropanes (1,1-, 1,2-, 1,3-, 2,2-) compounds. It was found that for each of the series compounds, a linear relationship existed between C-Cl bond scission activation energy and gas phase C-Cl bond strength. This observation corroborates our assumption that the removal of the first Cl atom from a chlorinated compound is the rate-determining step in the hydrodechlorination reaction. Thus, all kinetic and isotope experimental results obtained from this study are consistent with the proposed reaction steps for the chlorinated compounds tested. This set of reaction steps can also be used to predict the hydrodechlorination reaction rate of a chlorinated compound, once its gas phase C-Cl bond energy is calculated and the turnover rate of a reference chlorinated compound with similar structure is known. Some work has been done to study hydrodechlorination reaction steps and reaction intermediates beyond the rate-limiting step. Isotope tracing experiments with D2 indicated that CH3-, CH2- groups adjacent to a C-Cl bond could undergo deuterium exchange. The study of reactions steps using ab initio methods, including calculation of rate constants, is also under way. Calculations for the CH4-xClx (x=1-4) family showed that the heat of adsorption and C-Cl bond dissociation energy on a Pd surface were linearly related to their gas phase C-Cl bond strength."

Orientador: Wilson de Figueiredo Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-05T13:56:31Z (GMT). No. of bitstreams: 1 Arruda_TatianaLangbeckde_M.pdf: 1545576 bytes, checksum: 2e2b76b3f7f23e5e8b1087d0e9dc7912 (MD5) Previous issue date: 2005 / Mestrado / Quimica Analitica / Mestre em Química

O presente trabalho foi desenvolvido com o objetivo de verificar a eficiência de um reator anaeróbio híbrido (RAH) alimentado com uma mistura de ácidos orgânicos acético, propiônico, butírico, e láctico, bem como do álcool metanol, perfazendo uma DQO de 6,88 g/L, e avaliar nessas condições, a degradação do pentaclorofenol (PCP) na faixa de 2,0 a 21,0 mg/L. O RAH apresentou adequada performance na ausência de PCP, tendo sido inoculado com um lodo com AME cerca de 0,57 g DQO-CH4/g SV.d. Durante os 21 meses de operação do RAH na ausência de PCP verificou-se uma remoção média de DQO de 93% produção média de metano de 84%. Através de testes de toxicidade realizadas em batelada com o lodo granulado do RAH, antes da adição de PCP no reator, calculou-se o IC50, cujos valores foram 10, 12 e 13,69 mg/L. Na presença de PCP na faixa de 2,0 a 2,1 mg/L, o RAH apresentou remoção média de DQO de 96,7%, produção média de metano de 85,5% e remoção dos ácidos voláteis próxima a 74% do acético, 93% do butírico e 64% do propiônico. Individualmente, na presença da maior concentração de PCP adicionada, ocorreu decréscimo na remoção dos ácidos voláteis, principalmente do ácido propiônico e na taxa de conversão DQO/biogás. O PCP foi removido do sistema na ordem de 99% pela ação do lodo granulado com predominância do grupo das Archaea metanogênicas, verificada por exames microscópicos e hibridação \"in situ\". Valores da ordem de grandeza microbiana para os microrganismos metanogênicos nos períodos anteriores e posteriores a adição de PCP permaneceram na faixa de 105 e 106 céls./mL, quando cultivados em metanol e lactato mais sulfato, respectivamente. Os resultados sugerem que as Archaea metanogênicas podem estar envolvidas na degradação do PCP. A velocidade de remoção do organoclorado foi igual a 1,07 mg PCP/g SV.d quando a maior concentração de PCP foi estudada (21,0 mg/L). / The present research aimed to verify the efficiency of an Anaerobic Hybrid Reactor (AHR) supplied with a mixture of fatty acids, acetic, propionic, butyric and lactic and methanol as well. The total amount of COD was 6.88 g/L. The performance of the reactor was remarkably stable and efficient during PCP additions at range from 2.0 to 21.0 mg/L. The AHR showed a great performance in the PCP absence, inoculated with sludge with an specific methanogenic (SMA) activity of 0,057 g.COD-CH4/g. VS.d. During the 21 months of operation without PCP, the reduction of COD was around 93% and methane was up to 84% in the biogas. Before PCP addiction, two toxicity batch tests conducted with the granular sludge presented IC50 values around 10.12 mg/L and 13.69 mg/L. In the presence of PCP, at the range of 2.0 to 21.0 mg/L, the efficiency of volatile fatty acids breakdown was 93%, 64% and 74% respectively for butyric, propionic and acetic acids. Individually, at the presence of the higher PCP concentration studied, a decrease in the conversion of COD to biogas and organic acids removal occurred, mainly with propionic acid. PCP total removal of more than 99% was reached by granular sludge activities formed by the total time of reactor operation with a prevalence of methanogenic Archaea, verified under direct microscopy exams and in situ hybridization. Methanogenic cells predominance was noticed with 105 to 106 cells/mL during enumeration on methanol and lactate plus sulfate culture media, respectively. The results suggest that methanogenic Archaea can be involved in PCP degradation. The organochlorine removal rate was 1.07 mg PCP.g-1 VS.d-1 during the highest PCP (21.0 mg/L) concentration addition.

<p>Soil bottles and soil slurry experiments were conducted to investigate the effect of some additives on the aerobic and anaerobic biodegradation of chlorinated aliphatic hydrocarbons; tetrachloroethylene (PCE), trichloroethylene (TCE) and dichloroethylene (DCE) in a contaminated soil from Startvätten AB Linköping Sweden. For the aerobic degradation study the soil sample was divided into two groups, one was fertilised. The two groups of soil in the experimental bottles were treated to varying amount of methane in pairs. DCE and TCE were added to all samples while PCE was found in the contaminated soil. Both aerobic and anaerobic experiments were conducted. For aerobic study air was added to all bottles to serve as electron acceptor (oxygen). It was observed that all the samples showed a very small amount of methane consumption while the fertilised soil samples showed more oxygen consumption. For the chlorinated compounds the expected degradation could not be ascertained since the control and experimental set up were more or less the same.</p><p>For the anaerobic biodegradation study soil slurry was made with different media i.e. basic mineral medium (BM), BM and an organic compound (lactate), water and sulphide, phosphate buffer and sulphide and phosphate buffer, sulphide and ammonia. To assure anaerobic conditions, the headspace in the experimental bottles was changed to N2/CO2. As for the aerobic study all the samples were added DCE and TCE while PCE was found in the contaminated soil. The sample without the soil i.e. the control was also given PCE. It was observed that there was no clear decrease in the GC peak area of the pollutants in the different media. The decrease in GC peak area of the pollutants could not be seen, this may be so because more susceptible microorganisms are required, stringent addition of nutrients and to lower the risk of the high concentration of PCE and petroleum products in the soil from Startvätten AB.</p>

Soil bottles and soil slurry experiments were conducted to investigate the effect of some additives on the aerobic and anaerobic biodegradation of chlorinated aliphatic hydrocarbons; tetrachloroethylene (PCE), trichloroethylene (TCE) and dichloroethylene (DCE) in a contaminated soil from Startvätten AB Linköping Sweden. For the aerobic degradation study the soil sample was divided into two groups, one was fertilised. The two groups of soil in the experimental bottles were treated to varying amount of methane in pairs. DCE and TCE were added to all samples while PCE was found in the contaminated soil. Both aerobic and anaerobic experiments were conducted. For aerobic study air was added to all bottles to serve as electron acceptor (oxygen). It was observed that all the samples showed a very small amount of methane consumption while the fertilised soil samples showed more oxygen consumption. For the chlorinated compounds the expected degradation could not be ascertained since the control and experimental set up were more or less the same. For the anaerobic biodegradation study soil slurry was made with different media i.e. basic mineral medium (BM), BM and an organic compound (lactate), water and sulphide, phosphate buffer and sulphide and phosphate buffer, sulphide and ammonia. To assure anaerobic conditions, the headspace in the experimental bottles was changed to N2/CO2. As for the aerobic study all the samples were added DCE and TCE while PCE was found in the contaminated soil. The sample without the soil i.e. the control was also given PCE. It was observed that there was no clear decrease in the GC peak area of the pollutants in the different media. The decrease in GC peak area of the pollutants could not be seen, this may be so because more susceptible microorganisms are required, stringent addition of nutrients and to lower the risk of the high concentration of PCE and petroleum products in the soil from Startvätten AB.

O presente trabalho foi desenvolvido com o objetivo de verificar a eficiência de um reator anaeróbio híbrido (RAH) alimentado com uma mistura de ácidos orgânicos acético, propiônico, butírico, e láctico, bem como do álcool metanol, perfazendo uma DQO de 6,88 g/L, e avaliar nessas condições, a degradação do pentaclorofenol (PCP) na faixa de 2,0 a 21,0 mg/L. O RAH apresentou adequada performance na ausência de PCP, tendo sido inoculado com um lodo com AME cerca de 0,57 g DQO-CH4/g SV.d. Durante os 21 meses de operação do RAH na ausência de PCP verificou-se uma remoção média de DQO de 93% produção média de metano de 84%. Através de testes de toxicidade realizadas em batelada com o lodo granulado do RAH, antes da adição de PCP no reator, calculou-se o IC50, cujos valores foram 10, 12 e 13,69 mg/L. Na presença de PCP na faixa de 2,0 a 2,1 mg/L, o RAH apresentou remoção média de DQO de 96,7%, produção média de metano de 85,5% e remoção dos ácidos voláteis próxima a 74% do acético, 93% do butírico e 64% do propiônico. Individualmente, na presença da maior concentração de PCP adicionada, ocorreu decréscimo na remoção dos ácidos voláteis, principalmente do ácido propiônico e na taxa de conversão DQO/biogás. O PCP foi removido do sistema na ordem de 99% pela ação do lodo granulado com predominância do grupo das Archaea metanogênicas, verificada por exames microscópicos e hibridação \"in situ\". Valores da ordem de grandeza microbiana para os microrganismos metanogênicos nos períodos anteriores e posteriores a adição de PCP permaneceram na faixa de 105 e 106 céls./mL, quando cultivados em metanol e lactato mais sulfato, respectivamente. Os resultados sugerem que as Archaea metanogênicas podem estar envolvidas na degradação do PCP. A velocidade de remoção do organoclorado foi igual a 1,07 mg PCP/g SV.d quando a maior concentração de PCP foi estudada (21,0 mg/L). / The present research aimed to verify the efficiency of an Anaerobic Hybrid Reactor (AHR) supplied with a mixture of fatty acids, acetic, propionic, butyric and lactic and methanol as well. The total amount of COD was 6.88 g/L. The performance of the reactor was remarkably stable and efficient during PCP additions at range from 2.0 to 21.0 mg/L. The AHR showed a great performance in the PCP absence, inoculated with sludge with an specific methanogenic (SMA) activity of 0,057 g.COD-CH4/g. VS.d. During the 21 months of operation without PCP, the reduction of COD was around 93% and methane was up to 84% in the biogas. Before PCP addiction, two toxicity batch tests conducted with the granular sludge presented IC50 values around 10.12 mg/L and 13.69 mg/L. In the presence of PCP, at the range of 2.0 to 21.0 mg/L, the efficiency of volatile fatty acids breakdown was 93%, 64% and 74% respectively for butyric, propionic and acetic acids. Individually, at the presence of the higher PCP concentration studied, a decrease in the conversion of COD to biogas and organic acids removal occurred, mainly with propionic acid. PCP total removal of more than 99% was reached by granular sludge activities formed by the total time of reactor operation with a prevalence of methanogenic Archaea, verified under direct microscopy exams and in situ hybridization. Methanogenic cells predominance was noticed with 105 to 106 cells/mL during enumeration on methanol and lactate plus sulfate culture media, respectively. The results suggest that methanogenic Archaea can be involved in PCP degradation. The organochlorine removal rate was 1.07 mg PCP.g-1 VS.d-1 during the highest PCP (21.0 mg/L) concentration addition.

La produzione e l’uso del Metile di Bromuro, un fumigante estesamente usato in agricoltura, sono stati sottoposti a severe restrizioni dovute alla sua azione di depletore dello strato di ozono. Questa tesi è rivolta ad indagare il destino e le caratteristiche ambientali di due tra le più importanti alternative chimiche all’uso del Bromuro di Metile: l’ 1,3-Dicloropropene (1,3-D) e la Cloropicrina (CP). 1,3-D è un fumigante del suolo, con spiccata attività nematocida, consistente di due isomeri (Z), e (E)-1,3-D; nella sua formulazione sono presenti, inoltre, un esteso numero di impurezze clorurate potenzialmente correlate al processo produttivo. In laboratorio, è stato effettuato uno studio per valutare la stabilità idrolitica delle impurezze clorurate e per prevederne, quindi, il destino ambientale. Allo stesso tempo un piano di monitoraggio è stato svolto per valutare il leaching dell’1,3-D, dei suoi metaboliti, e delle impurezze clorurate. La CP è anch’essa un fumigante del suolo, caratterizzato da un importante profilo tossicologico. Questo lavoro ha valutato l’esposizione degli operatori e l’emissione in atmosfera durante e dopo l’applicazione nel suolo, secondo le pratiche agronomiche vigenti. Infine tramite l’applicazione di modelli matematici quali FOCUS PELMO e FOCUS PEARL si è valutato il destino ambientale della CP rispetto alle acque di falda. La simulazione è stata eseguita in 5 scenari europei realistici. / Production and use of methyl bromide, a soil fumigant, are being restricted because of this chemical’s deleterious effects on stratospheric ozone concentrations. This research examines the environmental fate and properties of methyl bromide replacement: 1,3-Dichloropropene (1,3-D), and Chloropicrin (CP). 1,3-D is a broad-spectrum soil fumigant used to control numerous species of soil-borne plant-parasitic nematodes. 1,3-D consists of two isomers, (Z)- and (E)-1,3-D, and has a number of low-level chlorinated compounds that could potentially be part of the manufacturing process. This study has investigated the hydrolytic stability, under biotic and abiotic conditions, of an extensive representative list of 1,3-D potentially related chlorinated compounds. Furthermore, a monitoring programme was carried out to investigate the leaching of all of this compounds. CP is a broad-spectrum fumigant chemical which is extensively used in agriculture and has an important toxicological profile. This study has assessed CP emission in the atmosphere and operator exposure during and after application in soil through injection of the test substances with routine agronomical application. Finally the environmental fate of CP and its metabolite dichloronitromethane in groundwater were investigated through the use of simulation model FOCUS PELMO and FOCUS PEARL using fully justified input parameters in five realistic scenarios.