Dissertations / Theses: 'Chlorinated hydrocarbons'

1

Carter, Oliver William. "Molecular fluorescence based measurement of chlorinated hydrocarbons." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267336.

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2

Mullick, Anjum. "Intrinsic bioremediation of chlorinated hydrocarbons at cold temperatures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0021/MQ47074.pdf.

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3

Chavez-Rivera, Rafael Alfredo. "A biofilm reactor for degradation of chlorinated hydrocarbons." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339503.

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4

Odutola, A. O. "Sorption of chlorinated and fuel derived hydrocarbons inlimestone." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397881.

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5

Ticknor, Jonathan. "Analysis and Remediation of Chlorinated Hydrocarbons in Environmental Media." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4242.

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The two objectives of this work were to develop a simplified method for the analysis of chlorinated organics in water samples and to improve an existing soil remediation technology. The contaminants considered for these studies were chlorinated hydrocarbons because of their relative frequency of appearance at contaminated sites. The first half of this study involved the analysis of chlorinated ethenes by gas chromatography with flame ionization detection (GC-FID). I tested the hypothesis that the FID response factor is the same for all chlorinated ethene compounds. The rationale for this investigation is that if the hypothesis is correct, a single calibration curve can be used for GC/FID analysis of all chlorinated ethene compounds, saving time and money during sample analysis. Based on my measurements, a single calibration curve fits PCE, TCE, and cis-DCE (R2=0.998). However, the apparent slope of the calibration curve for vinyl chloride is approximately 45% lower, indicating that a separate calibration curve must be used to quantify vinyl chloride. I believe this difference in vinyl chloride is due to loss of analyte mass due to volatilization. The second half of the study considered the effect of solvent composition for a soil remediation technology, entitled remedial extraction and catalytic hydrodehalogenation (REACH), developed by Dr. Hun Young Wee and Dr. Jeff Cunningham (Wee and Cunningham, 2008). The objective of this thesis is to convert 1,2,4,5-tetrachlorobenzene (TeCB) to cyclohexane, thus improving on the work of Wee (2007). Recent work by Osborn (2011) tested successfully the use of palladium and rhodium catalysts for this conversion, though it took twelve hours for full conversion. Osborn (2011) performed her experiments in a 50:50 water-ethanol solvent; previous work by Wee and Cunningham (2008) suggests that using a 67:33 water-ethanol composition may dramatically reduce the reaction time. Therefore, the goal of this research was to use palladium and rhodium catalysts with a 67:33 water-ethanol solvent composition, with an aim of reducing the reaction time required to fully convert benzene to cyclohexane. The data suggest that the time required for conversion of the analyte to its product was improved dramatically compared to previous experiments. However, powdered palladium catalyst was used in this study instead of pellet form as in previous studies. The powdered palladium allowed for full conversion of the target chemical, TeCB, to benzene in less than 5 minutes. Benzene was fully converted to cyclohexane within 45 minutes in the batch reactor when a rhodium catalyst was used jointly with palladium. This study suggests that the 67:33 water-ethanol solvent composition be utilized in continuous flow tests in the future to improve the efficiency of the REACH system. The results also suggest that powdered palladium catalyst be considered because of its ability to force the reaction to completion in significantly less time than previous experiments.

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6

Hunt, James. "Quantifying environmental risk of groundwater contaminated with volatile chlorinated hydrocarbons." Thesis, The University of Sydney, 2009. http://hdl.handle.net/2123/5138.

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Water quality guidelines (WQGs) present concentrations of contaminants that are designed to be protective of aquatic ecosystems. In Australia, guidance for assessment of water quality is provided by the ANZECC and ARMCANZ (2000) Guidelines for Fresh and Marine Water Quality. WQGs are generally provided for individual contaminants, not complex mixtures of chemicals, where interaction between contaminants may occur. Complex mixtures of contaminants are however, more commonly found in the environment than singular chemicals. The likelihood and consequences of adverse effects occurring in aquatic ecosystems resulting from contaminants are generally assessed using an ecological risk assessment (ERA) framework. Ecological risk assessment is often a tiered approach, whereby risks identified in early stages, using conservative assumptions, prompt further detailed and more realistic assessment in higher tiers. The objectives of this study were: to assess and investigate the toxicity of the mixture of volatile chlorinated hydrocarbons (VCHs) in groundwater to indigenous marine organisms; to present a ‘best practice’ ecological risk assessment of the discharge of contaminated groundwater to an estuarine embayment and to develop techniques to quantify the environmental risk; and to evaluate the existing ANZECC and ARMCANZ (2000) WQGs for VCHs and to derive new WQGs, where appropriate. Previous investigations at a chemical manufacturing facility in Botany, Sydney, identified several plumes of groundwater contamination with VCHs. Contaminated groundwater containing a complex mixture of VCHs was identified as discharging, via a series of stormwater drains, to surface water in nearby Penrhyn Estuary, an adjacent small intertidal embayment on the northern margin of Botany Bay. A screening level ecological hazard assessment was undertaken using the hazard quotient (HQ) approach, whereby contaminant concentrations measured in the environment were screened against published trigger values (TVs) presented in ANZECC and ARMCANZ (2000). Existing TVs were available for 9 of the 14 VCHs present in surface water in the estuary and new TVs were derived for the remaining 5 VCHs. A greater hazard was identified in the estuary at low tide than high tide or when VCH concentrations from both high and low tides were assessed together. A greater hazard was also identified in the estuary when the toxicity of the mixture was assessed, rather than the toxicity of individual contaminants. The screening level hazard assessment also identified several limitations, including: the low reliability of the TVs for VCHs provided in ANZECC and ARMCANZ (2000); the limited applicability of the TVs to a complex mixture of 14 potentially interacting contaminants; the use of deterministic measures for each of the exposure and toxicity profiles in the HQ method and the associated lack of elements of probability to assess ‘risk’. Subsequent studies were undertaken to address these identified shortcomings of the screening level hazard assessment as described in the following chapters. A toxicity testing methodology was adapted and evaluated for suitability in preventing loss of VCHs from test solutions and also for testing with 6 indigenous marine organisms, including: oyster (Saccostrea commercialis) and sea urchin larvae (Heliocidaris tuberculata); a benthic alga (Nitzschia closterium); an amphipod (Allorchestes compressa); a larval fish (Macquaria novemaculeata); and a polychaete worm (Diopatra dentata). The study evaluated possible VCH loss from 44 mL vials for small organisms (H.tuberculata, S.commercialis and N.closterium) and 1 L jars for larger organisms (M.novemaculeata, A.compressa and D.dentata). Vials were effective in preventing loss of VCHs, however, an average 46% of VCHs were lost from jars, attributable to the headspace provided in the vessels. Test jars were deemed suitable for use with the organisms as test conditions, i.e. dissolved oxygen content and pH, were maintained, however, variability in test organism survival was identified, with some control tests failing to meet all acceptance criteria. Direct toxicity assessment (DTA) of groundwater contaminated with VCHs was undertaken using 5 indigenous marine organisms and site-specific species sensitivity distributions (SSDs) and TVs were derived for the complex mixture of VCHs for application to surface water in Penrhyn Estuary. Test organisms included A.compressa, H.tuberculata, S.commercialis, D.dentata and N.closterium. The SSD was derived using NOEC data in accordance with procedures presented in ANZECC and ARMCANZ (2000) for deriving WQGs. The site-specific SSD adopted was a log-normal distribution, using an acute to chronic ratio (ACR) of 5, with a 95% TV of 838 μg/L total VCHs. A number of additional scenarios were undertaken to evaluate the effect of including different ACRs (i.e. 5 or 10), inclusion of larval development tests as either acute or chronic tests and choice of SSD distribution (i.e. log-normal, Burr Type III and Pareto). TVs for the scenarios modelled varied from 67 μg/L to 954 μg/L total VCHs. A site-specific, quantitative ERA was undertaken of the surface water contaminated with VCHs in Penrhyn Estuary. The risk assessment included probabilistic elements for toxicity (i.e. the site-specific SSD) and exposure (i.e. a cumulative distribution function of monitoring data for VCHs in surface waters in the estuary). The joint probability curve (JPC) methodology was used to derive quantitative estimates of ecological risk (δ) and the type of exposure in the source areas in surface water drains entering the estuary, i.e. Springvale and Floodvale Drains, Springvale and Floodvale Tributaries and the Inner and Outer Estuary. The risk of possible adverse effects and likely adverse effects were each assessed using SSDs derived from NOEC and EC50 data, respectively. Estimates of risk (δ) of possible adverse effects (i.e. based on NOEC data) varied from a maximum of 85% in the Springvale Drain source area to <1% in the outer estuary and estimates of likely adverse effects (i.e. based on EC50 data) varied from 78% to 0%. The ERA represents a ‘best practice’ ecological risk assessment of contamination of an estuary using site-specific probabilistic elements for toxicity and exposure assessments. The VCHs identified in surface water in Penrhyn Estuary are additive in toxicity and act under the narcotic pathway, inhibiting cellular processes through interference with membrane integrity. Lethal toxicity to 50% of organisms (i.e. LC50) is typically reported at the internal lethal concentration (ILC) or critical body residue (CBR) of ~2.5 mmol/kg wet weight or within the range of 1 to 10 mmol/kg wet weight. To evaluate the sensitivity of the test organisms to VCHs and to determine if toxicity in the DTA was due to VCHs, the internal residue for 6 test organisms was calculated for the mixture of VCHs in groundwater and toxicity testing with seawater spiked individually 2 VCHs, chloroform and 1,2-dichloroethane. Calculated residues (at LC50/EC50) were typically between 1 and 10 mmol/kg, with the exception of the algal and sea urchin toxicity tests, which were considerably lower than the expected minimum. Mean internal residues for the groundwater, chloroform and 1,2-dichloroethane were 0.88 mmol/kg, 2.84 mmol/kg and 2.32 mmol/kg, respectively, i.e. close to the predicted value of ~2.5 mmol/kg, indicating that the organisms were suitably sensitive to VCHs. There was no significant difference (P>0.05) between the mean residues of each of the three treatments and the study concluded that the additive toxicity of the VCHs in groundwater was sufficient to account for the observed toxicity (i.e. VCHs caused the toxicity in the DTA undertaken). Evaluation of the existing low reliability ANZECC and ARMCANZ (2000) TVs for chloroform and 1,2-dichloroethane was undertaken to determine if these guidelines were protective of indigenous marine organisms. NOECs, derived from toxicity testing of 1,2- dichloroethane and chloroform with 6 indigenous marine organisms, were screened against the existing low reliability TVs. The TVs for 1,2-dichloroethane and chloroform were protective of 4 of the 6 species tested (A.compressa, D.dentata, S.commercialis and M.novemaculeata), however, the TVs were not protective of the alga (N.closterium) or the sea urchin larvae (H.tuberculata). As the existing TVs were not considered to be adequately protective, SSDs were derived using the NOEC data generated from the testing in accordance with procedures outlined in ANZECC and ARMCANZ (2000). Moderate reliability TVs of 3 μg/L and 165 μg/L were derived for chloroform and 1,2- dichloroethane, respectively, i.e. considerably lower than the existing TVs of 770 μg/L and 1900 μg/L. Differences between the existing and newly derived TVs were considered to result from the sensitive endpoints selected (i.e. growth and larval development rather than survival) and from variability inherent when deriving SSDs using a small number of test species. Ongoing groundwater monitoring indicated that the plumes of VCHs in groundwater, identified in the 1990s, were continuing to migrate towards Botany Bay. Discharge of these groundwater plumes into Botany Bay would result in significant increases in the concentrations of VCHs in the receiving environment and would likely lead to significant environmental impacts. In 2006, a groundwater remediation system was commissioned to prevent the discharge of groundwater containing VCHs into Penrhyn Estuary and Botany Bay. The success of the project had only been measured according to chemical and engineering objectives. Assessment of changes in ecological risk is vital to the success of ERA and central to the ERA management framework. Whereas monitoring of chemical concentrations provides qualitative information that risk should decrease, it cannot quantify the reduction in ecological risk. To assess the ecological risk following implementation of the groundwater treatment system, the risk assessment was revised using surface water monitoring data collected during 2007 and 2008. The ERA indicated that, following remediation of the groundwater, ecological risk in Penrhyn Estuary reduced from a maximum of 35% prior to remediation, to a maximum of only 1.3% after remediation. Using the same methodology applied in the initial risk assessment, the success of the groundwater remediation was measured in terms of ecological risk, rather than engineering or chemical measures of success. Prior to the present investigation, existing techniques for assessing ecological risk of VCH contamination in aquatic ecosystems were inadequate to characterise ecological risk. The current study demonstrated that through monitoring of surface water at the site and DTA using indigenous marine organisms, ecological risk can be assessed using site-specific, quantitative techniques for a complex mixture of VCHs in groundwater. The present investigation also identified that existing ANZECC and ARMCANZ (2000) low reliability TVs were less protective of indigenous test organisms than previously thought and therefore, new TVs were derived in the current work. The present study showed that revision of the risk assessment as conditions change is crucial to the success of the ecological risk management framework.

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7

Hunt, James. "Quantifying environmental risk of groundwater contaminated with volatile chlorinated hydrocarbons." University of Sydney, 2009. http://hdl.handle.net/2123/5138.

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Doctor of Philosophy
Water quality guidelines (WQGs) present concentrations of contaminants that are designed to be protective of aquatic ecosystems. In Australia, guidance for assessment of water quality is provided by the ANZECC and ARMCANZ (2000) Guidelines for Fresh and Marine Water Quality. WQGs are generally provided for individual contaminants, not complex mixtures of chemicals, where interaction between contaminants may occur. Complex mixtures of contaminants are however, more commonly found in the environment than singular chemicals. The likelihood and consequences of adverse effects occurring in aquatic ecosystems resulting from contaminants are generally assessed using an ecological risk assessment (ERA) framework. Ecological risk assessment is often a tiered approach, whereby risks identified in early stages, using conservative assumptions, prompt further detailed and more realistic assessment in higher tiers. The objectives of this study were: to assess and investigate the toxicity of the mixture of volatile chlorinated hydrocarbons (VCHs) in groundwater to indigenous marine organisms; to present a ‘best practice’ ecological risk assessment of the discharge of contaminated groundwater to an estuarine embayment and to develop techniques to quantify the environmental risk; and to evaluate the existing ANZECC and ARMCANZ (2000) WQGs for VCHs and to derive new WQGs, where appropriate. Previous investigations at a chemical manufacturing facility in Botany, Sydney, identified several plumes of groundwater contamination with VCHs. Contaminated groundwater containing a complex mixture of VCHs was identified as discharging, via a series of stormwater drains, to surface water in nearby Penrhyn Estuary, an adjacent small intertidal embayment on the northern margin of Botany Bay. A screening level ecological hazard assessment was undertaken using the hazard quotient (HQ) approach, whereby contaminant concentrations measured in the environment were screened against published trigger values (TVs) presented in ANZECC and ARMCANZ (2000). Existing TVs were available for 9 of the 14 VCHs present in surface water in the estuary and new TVs were derived for the remaining 5 VCHs. A greater hazard was identified in the estuary at low tide than high tide or when VCH concentrations from both high and low tides were assessed together. A greater hazard was also identified in the estuary when the toxicity of the mixture was assessed, rather than the toxicity of individual contaminants. The screening level hazard assessment also identified several limitations, including: the low reliability of the TVs for VCHs provided in ANZECC and ARMCANZ (2000); the limited applicability of the TVs to a complex mixture of 14 potentially interacting contaminants; the use of deterministic measures for each of the exposure and toxicity profiles in the HQ method and the associated lack of elements of probability to assess ‘risk’. Subsequent studies were undertaken to address these identified shortcomings of the screening level hazard assessment as described in the following chapters. A toxicity testing methodology was adapted and evaluated for suitability in preventing loss of VCHs from test solutions and also for testing with 6 indigenous marine organisms, including: oyster (Saccostrea commercialis) and sea urchin larvae (Heliocidaris tuberculata); a benthic alga (Nitzschia closterium); an amphipod (Allorchestes compressa); a larval fish (Macquaria novemaculeata); and a polychaete worm (Diopatra dentata). The study evaluated possible VCH loss from 44 mL vials for small organisms (H.tuberculata, S.commercialis and N.closterium) and 1 L jars for larger organisms (M.novemaculeata, A.compressa and D.dentata). Vials were effective in preventing loss of VCHs, however, an average 46% of VCHs were lost from jars, attributable to the headspace provided in the vessels. Test jars were deemed suitable for use with the organisms as test conditions, i.e. dissolved oxygen content and pH, were maintained, however, variability in test organism survival was identified, with some control tests failing to meet all acceptance criteria. Direct toxicity assessment (DTA) of groundwater contaminated with VCHs was undertaken using 5 indigenous marine organisms and site-specific species sensitivity distributions (SSDs) and TVs were derived for the complex mixture of VCHs for application to surface water in Penrhyn Estuary. Test organisms included A.compressa, H.tuberculata, S.commercialis, D.dentata and N.closterium. The SSD was derived using NOEC data in accordance with procedures presented in ANZECC and ARMCANZ (2000) for deriving WQGs. The site-specific SSD adopted was a log-normal distribution, using an acute to chronic ratio (ACR) of 5, with a 95% TV of 838 μg/L total VCHs. A number of additional scenarios were undertaken to evaluate the effect of including different ACRs (i.e. 5 or 10), inclusion of larval development tests as either acute or chronic tests and choice of SSD distribution (i.e. log-normal, Burr Type III and Pareto). TVs for the scenarios modelled varied from 67 μg/L to 954 μg/L total VCHs. A site-specific, quantitative ERA was undertaken of the surface water contaminated with VCHs in Penrhyn Estuary. The risk assessment included probabilistic elements for toxicity (i.e. the site-specific SSD) and exposure (i.e. a cumulative distribution function of monitoring data for VCHs in surface waters in the estuary). The joint probability curve (JPC) methodology was used to derive quantitative estimates of ecological risk (δ) and the type of exposure in the source areas in surface water drains entering the estuary, i.e. Springvale and Floodvale Drains, Springvale and Floodvale Tributaries and the Inner and Outer Estuary. The risk of possible adverse effects and likely adverse effects were each assessed using SSDs derived from NOEC and EC50 data, respectively. Estimates of risk (δ) of possible adverse effects (i.e. based on NOEC data) varied from a maximum of 85% in the Springvale Drain source area to <1% in the outer estuary and estimates of likely adverse effects (i.e. based on EC50 data) varied from 78% to 0%. The ERA represents a ‘best practice’ ecological risk assessment of contamination of an estuary using site-specific probabilistic elements for toxicity and exposure assessments. The VCHs identified in surface water in Penrhyn Estuary are additive in toxicity and act under the narcotic pathway, inhibiting cellular processes through interference with membrane integrity. Lethal toxicity to 50% of organisms (i.e. LC50) is typically reported at the internal lethal concentration (ILC) or critical body residue (CBR) of ~2.5 mmol/kg wet weight or within the range of 1 to 10 mmol/kg wet weight. To evaluate the sensitivity of the test organisms to VCHs and to determine if toxicity in the DTA was due to VCHs, the internal residue for 6 test organisms was calculated for the mixture of VCHs in groundwater and toxicity testing with seawater spiked individually 2 VCHs, chloroform and 1,2-dichloroethane. Calculated residues (at LC50/EC50) were typically between 1 and 10 mmol/kg, with the exception of the algal and sea urchin toxicity tests, which were considerably lower than the expected minimum. Mean internal residues for the groundwater, chloroform and 1,2-dichloroethane were 0.88 mmol/kg, 2.84 mmol/kg and 2.32 mmol/kg, respectively, i.e. close to the predicted value of ~2.5 mmol/kg, indicating that the organisms were suitably sensitive to VCHs. There was no significant difference (P>0.05) between the mean residues of each of the three treatments and the study concluded that the additive toxicity of the VCHs in groundwater was sufficient to account for the observed toxicity (i.e. VCHs caused the toxicity in the DTA undertaken). Evaluation of the existing low reliability ANZECC and ARMCANZ (2000) TVs for chloroform and 1,2-dichloroethane was undertaken to determine if these guidelines were protective of indigenous marine organisms. NOECs, derived from toxicity testing of 1,2- dichloroethane and chloroform with 6 indigenous marine organisms, were screened against the existing low reliability TVs. The TVs for 1,2-dichloroethane and chloroform were protective of 4 of the 6 species tested (A.compressa, D.dentata, S.commercialis and M.novemaculeata), however, the TVs were not protective of the alga (N.closterium) or the sea urchin larvae (H.tuberculata). As the existing TVs were not considered to be adequately protective, SSDs were derived using the NOEC data generated from the testing in accordance with procedures outlined in ANZECC and ARMCANZ (2000). Moderate reliability TVs of 3 μg/L and 165 μg/L were derived for chloroform and 1,2- dichloroethane, respectively, i.e. considerably lower than the existing TVs of 770 μg/L and 1900 μg/L. Differences between the existing and newly derived TVs were considered to result from the sensitive endpoints selected (i.e. growth and larval development rather than survival) and from variability inherent when deriving SSDs using a small number of test species. Ongoing groundwater monitoring indicated that the plumes of VCHs in groundwater, identified in the 1990s, were continuing to migrate towards Botany Bay. Discharge of these groundwater plumes into Botany Bay would result in significant increases in the concentrations of VCHs in the receiving environment and would likely lead to significant environmental impacts. In 2006, a groundwater remediation system was commissioned to prevent the discharge of groundwater containing VCHs into Penrhyn Estuary and Botany Bay. The success of the project had only been measured according to chemical and engineering objectives. Assessment of changes in ecological risk is vital to the success of ERA and central to the ERA management framework. Whereas monitoring of chemical concentrations provides qualitative information that risk should decrease, it cannot quantify the reduction in ecological risk. To assess the ecological risk following implementation of the groundwater treatment system, the risk assessment was revised using surface water monitoring data collected during 2007 and 2008. The ERA indicated that, following remediation of the groundwater, ecological risk in Penrhyn Estuary reduced from a maximum of 35% prior to remediation, to a maximum of only 1.3% after remediation. Using the same methodology applied in the initial risk assessment, the success of the groundwater remediation was measured in terms of ecological risk, rather than engineering or chemical measures of success. Prior to the present investigation, existing techniques for assessing ecological risk of VCH contamination in aquatic ecosystems were inadequate to characterise ecological risk. The current study demonstrated that through monitoring of surface water at the site and DTA using indigenous marine organisms, ecological risk can be assessed using site-specific, quantitative techniques for a complex mixture of VCHs in groundwater. The present investigation also identified that existing ANZECC and ARMCANZ (2000) low reliability TVs were less protective of indigenous test organisms than previously thought and therefore, new TVs were derived in the current work. The present study showed that revision of the risk assessment as conditions change is crucial to the success of the ecological risk management framework.

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8

Brewster, Ryan Jude Stephen. "Cometabolic Modeling of Chlorinated Aliphatic Hydrocarbons using SEAM3D Cometabolism Package." Master's thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/37103.

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Bioremediation of chlorinated aliphatic hydrocarbon (CAH) compounds commonly found at contaminated sites has been an area of focus in recent years. The cometabolic transformation of CAH compounds is important at sites where the redox condition does not favor natural attenuation or populations of indigenous microorganisms are relatively low. At sites where the ground-water system is aerobic, monitored natural attenuation strategies will not meet remediation objectives, or both, enhanced bioremediation via cometabolism is an option. Models are needed to simulate cometabolism in an effort to improve performance and design. The SEAM3D Cometabolism Package was designed to address this need. The objective of this report is to model field data to determine the ability of SEAM3D to simulate the performance of cometabolism. A ground-water flow and transport model was designed based on reported parameters used in the field experiments at Moffett Field. Electron donor and acceptor breakthrough curves were also simulated in an effort to calibrate the model. Several data sets describing the cometabolism of CAHs were used in the cometabolism modeling for calibration to field data. The cometabolism modeling showed areas of best fit calibration with modification to the model parameters reported for the pilot tests at Moffett Field. The overall performance of the SEAM3D Cometabolism Package described in this report establishes validation of the model using field experiment results from the literature. Additional model validation is recommended for other contaminants.
Master of Science

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9

Johansson, Glenn. "Using PCA to reveal hidden structures in the remediation steps of chlorinated solvents." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-33397.

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Chlorinated solvents such as trichloroethene (TCE) and perchloroethene (PCE) are commonly found in industrialized areas and can have major impact on human health and groundwater quality. The techniques for removing these substances from the subsurface environment is constantly being tuned and revised, and as such, the need for monitoring at such remediation sites is crucial. To find important correlations and hidden patterns between variables principle component analyses (PCA) and correlations matrixes were used on sets of field data from an existing remediation site in southern Sweden. Four important components were extracted in the following order; End products of dechlorination (EPD), second wave of dechlorination (SWD), first wave of dechlorination (FWD) and indicators of dechlorination (ID). The underlying pattern found in the data set was most likely derived from thermodynamic preference, explaining important correlations such as the correlation between iron and sulfate, the correlation between redox and degree of dechlorination. The law of thermodynamic preference means that we can (roughly) estimate the level of difficulty and/or the time it will take to remediate a polluted site. These findings show that similar results shown in theory and laboratory environments also applies in the field and also that PCA is a potent tool for evaluating large data sets in this field of science. However, it is of great importance that the correlations are examined thoroughly, as correlation it not equal to causation.

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10

Qin, Tianyu. "Comparison of in-situ bioremediation of soil contaminated with chlorinated hydrocarbons." Thesis, Högskolan i Halmstad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-43062.

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In recent years, due to the continuous development of machinery, electronics, leather, chemical companies and dry-cleaning industry, more and more chlorinated hydrocarbons accumulate in the soil, causing serious harm to the environment. The accumulation of chlorinated hydrocarbons and the teratogenic, carcinogenic, and mutagenic hazards seriously threaten human health. Therefore, the remediation of chlorinated hydrocarbons is imminent. Under this premise, in-situ bioremediation has gradually received attention. For in situ bioremediation of soil contaminated with chlorinated hydrocarbons, the most commonly used methods are biostimulation alone, bioaugmentation alone, and a combination with biostimulation and bioaugmentation. The removal rate of trichloroethylene in the case of using biostimulation products alone is significantly lower than that of using bioaugmentation products alone. The removal rate of trichloroethylene by biostimulation products alone does not exceed 60%, and “DCE pause” occurred, but did not occur in the case of using bioaugmentation products. The removal rate of trichloroethylene by bioaugmentation products is generally higher than 98%, and it will promote the degradation of trichloroethylene or tetrachloroethylene to non-toxic ethylene. Therefore, only cases containing bioaugmentation can achieve non-toxic degradation of chlorinated hydrocarbons and take into account the high removal rate of them. In addition, the biostimulation duration is significantly shorter.

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11

Lachance, Russell Philip. "Oxidation and hydrolysis reactions in supercritical water : chlorinated hydrocarbons and organosulfur compounds." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/33533.

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12

Chihara, Kazuyuki, Kenta Saito, Hidenori Nakamura, and Yosuke Kaneko. "Diffusion measurement of chlorinated hydrocarbons into high-silica zeolite by chromatographic method." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193946.

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13

Choi, Wonyong Hoffmann Michael R. "Photooxidative and photoreductive degradation of chlorinated hydrocarbons on aqueous titanium dioxide colloids /." Diss., Pasadena, Calif. : California Institute of Technology, 1996. http://resolver.caltech.edu/CaltechETD:etd-05052006-084215.

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14

Jung, Bahng Mi. "Reductive dechlorination of chlorinated aliphatic hydrocarbons by Fe(ii) in degradative solidification/stabilization." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4975.

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This dissertation examines the applicability of the iron-based degradative solidification/stabilization (DS/S-Fe(II)) to various chlorinated aliphatic hydrocarbons (CAHs) that are common chemicals of concern at contaminated sites. The research focuses on the transformation of 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2,2-tetrachloro-ethane (1,1,2,2-TetCA) and 1,2-dichloroehtane (1,2-DCA) by Fe(II) in cement slurries. It also investigates the degradation of 1,1,1-TCA by a mixture of Fe(II), cement and three iron-bearing phyllosilicates. Transformation of 1,1,1-TCA and 1,1,2,2-TetCA by Fe(II) in 10% cement slurries was characterized using batch reactors. Dechlorination kinetics of 1,1,1-TCA and TCE* (TCE that was produced by transformation of 1,1,2,2-TetCA) was strongly dependent on Fe(II) dose, pH and initial target organic concentration. Degradation of target organics in DS/S-Fe(II) process was generally described by a pseudo-first-order rate law. However, saturation relationships between the rate constants and Fe(II) dose or between the initial degradation rates and target organic concentration were observed. These behaviors were properly described by a modified Langmuir-Hinshelwood kinetic model. This supports the working hypothesis of this research that reductive dechlorination of chlorinated ethanes occurs on the surface of active solids formed in mixtures of Fe(II) and cement. Transformation products for 1,1,1-TCA and 1,1,2,2-TetCA in mixtures of Fe(II) and cement were identified. The major product of the degradation of 1,1,1-TCA was 1,1-DCA, which indicates that the reaction followed a hydrogenolysis pathway. However, a small amount of ethane was also observed. TCE* was rapidly produced by degradation of 1,1,2,2-TetCA and is expected to undergo ÃÂ²-elimination to produce acetylene. Dechlorination of 1,1,1-TCA in suspension of Fe(II), cement and three soil minerals (biotite, vermiculite, montmorillonite) was characterized using batch reactors. A first-order rate model was generally used to describe the dechlorination kinetics of 1,1,1-TCA in this heterogeneous system. The rate constants for 1,1,1-TCA in mixtures of Fe(II), cement and soil minerals were influenced by soil mineral types, Fe(II) dose and the mass ratio of cement to soil mineral. It was demonstrated that structural Fe(II) and surface-bound Fe(II) in the soil minerals affect dechlorination kinetics and the effects vary with mineral types. Furthermore, it suggests that the reductant formed from Fe(II) and cement hydration components is also effective in systems that include soil minerals.

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15

Pathare, Salil Milan. "P-x Measurements For 2-Ethoxyethanol and Four Chlorinated Hydrocarbons at 303.15 K." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000196.

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16

Wang, Lei. "Development of an Electrochemical Reactor for the Aqueous Phase Destruction of Chlorinated Hydrocarbons." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195095.

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A cylindrical electrochemical reactor with a 3 in diameter copper or nickel metal foam cathode and a concentric carbon cloth anode was used to destroy aqueous phase carbon tetrachloride (CT). The results show that a high CT conversion can be achieved in regions of the cathode near the anode, but a low CT conversion is obtained in the region around the center of the cathode. This CT conversion distribution in the radial current-conducting direction suggests that a portion of the cathode worked inefficiently even though the overall CT conversion is still adequate. Further research by changing the solution pH and conductivity suggests that the radial conversion distribution is due to radial variations in cathode surface availability. The inherent difficulties that these results imply with regards to reactor scale up suggested a new approach to the design. An annular reactor, consisting of a thin (3.2 mm) nickel foam cathode wrapped around an inert Plexiglas core and separated for an external concentric anode by a semi-permeable membrane was adopted. Under compatible operating conditions, the annular reactor showed a high overall effluent CT conversion. However, experiments at low pH (2.25) yielded higher conversions than under neutral pH conditions. This result suggests that CT conversion is favored by a relatively high proton concentration. This reactor can be simulated by a one dimensional model. The annular reactor was used to destroy PCE and TCE successfully, which suggests that this technique can be employed to treat groundwater contaminated with complex mixtures of chlorinated hydrocarbons.A multi-layer reactor based on the principle of the annular reactor was developed as an option for the scale up of the system. This reactor exhibited high and uniform radial CT conversion.

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17

Walger, Ellen. "Undersökningsmetodik för klorerade lösningsmedel i marken." Thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88842.

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Chlorinated solvent are volatile organic substances that can be harmful for humans and for the environment. Examples of common chlorinated solvents are perchloroethene, PCE, and trichloroethene, TCE. Chlorinated solvents appear as contaminants in soils primarily where they have been used as washing fluids in dry-cleaning facilities or as degreasers in metal industries. Chlorinated solvents are DNAPLs (dense non-aqueous phase liquids), which means that they are not easily dissolved in water and that they sink to the bottom of the aquifer. Adsorption to soils is low so chlorinated solvents are mobile in soils. Chlorinated solvents can be harmful at low concentrations. Complete degradation can only occur under specific conditions. Because of the properties of these substances, investigation and analysis methodology are extra important for determining transport and risks in a contaminated area.

In this work, investigation and analysis methods for chlorinated solvents are described. Planning, fieldwork, modeling and risk analysis are described.

Projects concerning chlorinated solvents completed by Golder Associates AB have been compiled and analysed. Based on the compilation, conclusions have been drawn and statistics have been calculated. Investigations of the relation between concentrations in different media have been made as well as investigations of the relation between degradation products at different distances from the source and at different times after release. The data from the environmental investigations have been compared with theoretical literature values and modelling results.

The results show that there is a large natural variation in the data and that the differences between different areas are quite large. The results confirm the theory that the percentage of degradation products increases with distance from the source and with time from release. In addition, solvents with a higher degree of chlorination seams to appear to a greater extent in the soil and the more volatile substances seams to appear to a greater extent in the soil air.

Klorerade lösningsmedel är flyktiga klorerade organiska ämnen som kan vara skadliga för människor och miljön. Exempel på vanliga klorerade lösningsmedel är perkloreten, PCE och trikloreten, TCE. Klorerade lösningsmedel förekommer som markföroreningar främst efter användning som tvättvätska i kemtvättar och som avfettningsmedel i metallindustrin. Klorerade lösningsmedel är DNAPLs (dense non-aqueous phase liquids), det innebär att de är svårlösliga i vatten och att de sjunker och lägger sig på botten av akviferen. Fastläggningen i jorden är liten hos klorerade lösningsmedel som därmed är rörliga i marken. De är farliga redan vid små koncentrationer och fullständig nedbrytning sker endast under vissa förutsättningar. Ämnenas egenskaper gör att undersöknings- och analysmetodiken är viktig för att riktigt kunna bestämma deras utbredning och risk på ett förorenat område.

I detta arbete beskrivs undersöknings- och analysmetodiken för områden förorenade med klorerade lösningsmedel. Upplägg, fältarbete, modellering och riskbedömning beskrivs.

Projekt som handlar om klorerade lösningsmedel utförda av Golder Associates AB har sammanställts. Sammanställningen har analyserats och utifrån den har olika slutsatser dragits och statistik beräknats. Bland annat har samband mellan halter i olika medier samt samband mellan halter av nedbrytningsprodukter på olika avstånd från källan respektive efter olika lång tid från läckage har undersökts. Data från miljöundersökningarna har även jämförts med teoretiska litteraturvärden samt modelleringsresultat.

Resultatet visar att den naturliga spridningen av data är stor samt att resultaten skiljer sig åt mellan olika områden. Resultaten bekräftar teorierna att halten nedbrytningsprodukter ökar med avståndet från källan och med tiden samt att ämnen med högre kloreringsgrad finns i större utsträckning i jorden och att flyktigare ämnen finns i större utsträckning i porluften.

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18

Cushman, Christopher Scott. "Destruction of chlorinated hydrocarbons by zero-valent zinc and bimetallic zinc reductants in bench-scale investigations." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1398342299.

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19

Elsner, Martin. "Reductive dehalogenation of chlorinated hydrocarbons by surface-bound Fe(II) : kinetic and mechanistic aspects /." Zürich, 2002. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14955.

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20

Brooks, George Patrick 1955. "Forced ventilation removal of chlorinated hydrocarbons in layered, unsaturated soil material: A laboratory evaluation." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276975.

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Helium tracer experiments were conducted to characterize conservative tracer behavior in a wedge-shaped lysimeter containing alternating layers of unsaturated silty sand, and clay loam. Experiments were conducted with trichloroethylene and 1,1,1-trichloroethane to determine if air stripping in unsaturated soil could be characterized by mass transfer from the sorbed to the liquid to the vapor phase. Batch experiments were conducted to measure liquid--vapor mass transfer. Solid-liquid-vapor mass transfer was characterized by measuring the vapor phase re-equilibration after the air stripping experiment. The Discrete State Compartment model was used to simulate a conservative gas tracer. The results were compared to the helium tracer. Liquid-vapor, and solid-liquid-vapor mass transfer were modeled by fitting simulated data to experimental data. The conservative tracer, and mass transfer models were combined to simulate air stripping in unsaturated soil.

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21

Chihara, Kazuyuki, Kenta Saito, Hidenori Nakamura, and Yosuke Kaneko. "Diffusion measurement of chlorinated hydrocarbons into high-silica zeolite by chromatographic method: Diffusion measurement of chlorinated hydrocarbonsinto high-silica zeolite by chromatographic method." Diffusion fundamentals 6 (2007) 58, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14237.

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22

Crowley, O. A. "Stable carbon isotopes as a tool to investigate parameters affecting natural attenuation of chlorinated hydrocarbons." Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411099.

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23

Chowdhury, Md Abu Raihan. "Removal of Select Chlorinated Hydrocarbons by Nanoscale Zero-valent Iron Supported on Powdered Activated Charcoal." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1496150130687849.

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24

Hoyle, Rene Alwyn Stuart. "The efffect of chlorinated hydrocarbons on the corrosion resistance of austenitic stainless steels in chloride solutions." Thesis, University of Sunderland, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246188.

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25

Chihara, Kazuyuki, Yuki Teramura, Shinji Tomita, and Kenta Saito. "Diffusion of chlorinated hydrocarbons in high silica zeolite - comparison between chromatographic data and molecular dynamic simulation." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189478.

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26

Chihara, Kazuyuki, Yuki Teramura, Shinji Tomita, and Kenta Saito. "Diffusion of chlorinated hydrocarbons in high silica zeolite - comparison between chromatographic data and molecular dynamic simulation." Diffusion fundamentals 11 (2009) 24, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A13965.

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27

McIntosh, Grant Jason. "Experimental and theoretical studies into the laser pyrolytic formation of chlorinated polycyclic aromatic hydrocarbons and fullerene precursors." Thesis, University of Auckland, 2010. http://hdl.handle.net/2292/5829.

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Fullerenic materials are likely to play an important role in technologies of the future. To ensure that production techniques will be able to keep up with demand, a thorough understanding of their mechanism of formation, which has thus far proved elusive, is required. Hydrocarbon pyrolysis is a potentially viable fullerene production technique, and the pyrolysis of chlorohydrocarbons has also shown promise. However, decomposition of the latter produces toxic and environmentally hazardous chlorinated polycyclic aromatic hydrocarbons, also formed in industrial waste incinerators, as a byproduct. Close study of the high temperature chemistry of chlorohydrocarbons may aid both the mitigation of hazardous byproducts and implementation of more effective fullerene synthesis techniques. To this end, we have studied the formation mechanisms of dichloromethane degradation products generated via Infrared Laser Powered Homogeneous Pyrolysis. This unique technique is well known for having a non-uniform temperature profile, which has a number of attractive features for this work. The most important of these are the absence of complicating surface catalysed reactions, and the potential for allowing annealing reactions necessary for fullerene growth. Time resolved product yields are monitored via GC-MS and FTIR, and mechanistic deductions are supported heavily by Density Functional Theory calculations and kinetic arguments. Results indicate that the initial growth of chlorinated compounds deviate significantly from the radical-based growth found with hydrocarbons. Facile Cl-loss in important radicals and stabilisation of carbenes by chlorine permits novel C4 and C6 production channels. Conventional channels involving acetylene addition to aromatic radicals are eventually restored in C8--C12 formation, although we do suggest some amendments to the mechanism. Bimolecular polycyclic aromatic hydrocarbon addition reactions may also play an important role. Acenaphthylene (C12H8) congeners also allow for the first studies of the migration of five-membered rings about chlorinated polycyclic aromatic hydrocarbon frameworks, a vital process in fullerene annealing; it is found that the presence of chlorine significantly stabilises transition states, suggesting these reactions are much more facile in heavily chlorinated systems.

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28

Lai, Chun Kit. "Laboratory and full-scale studies of a permeable reactive barrier on the dechlorination of chlorinated aliphatic hydrocarbons /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20LAI.

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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.
Includes bibliographical references (leaves 203-227). Also available in electronic version. Access restricted to campus users.

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29

Mendez, Eduardo III. "Natural Attenuation Software (NAS): Assessing Remedial Strategies and Estimating Timeframes." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27679.

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Natural Attenuation Software (NAS) was developed as a screening tool to estimate remediation timeframes for monitored natural attenuation (MNA) to lower groundwater contaminant concentrations to regulatory limits, and to assist in decision-making on the level of source zone treatment in conjunction with MNA using site-specific remediation objectives. In addition, NAS facilitates the combined use of MNA with engineered remedial actions (ERAs) so that the benefits of each technology can be maximized while minimizing costs of remediation. The primary expected benefit of NAS is to increase regulatory acceptance of MNA, thereby decreasing overall remediation costs. NAS is designed for application to ground-water systems consisting of porous, relatively homogeneous, saturated media, and assumes that groundwater flow is uniform and unidirectional. NAS consists of a combination of analytical and numerical solute transport models implemented in three main interactive modules to provide estimates for: (1) target source concentration required for a plume extent to contract to regulatory limits, (2) time required for NAPL contaminants in the source area to attenuate to a predetermined target source concentration, and (3) time required for a plume extent to contract to regulatory limits after source reduction. Natural attenuation processes that NAS models include advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation. NAS determines redox zonation, and estimates and applies varied biodegradation rates from one redox zone to the next. Recently, NAS was enhanced to include petroleum hydrocarbons, chlorinated ethenes, chlorinated ethanes, chlorinated methanes, and chlorinated benzenes, or any user-defined contaminants (e.g., heavy metals, radioisotopes), and has included the capability to model co-mingled plumes. To enable comparison of remediation timeframe estimates between MNA and specific ERAs, NAS was modified to incorporate an estimation technique for timeframes associated with pump-and-treat remediation technology for comparison to, or in conjunction with, MNA. NAS also expanded analysis tools for improved performance assessment, as well as the assessment of sustainability of natural attenuation processes over time. A Department of Defense (DoD) Environmental Security Technology Certification Program (ESTCP) demonstration was undertaken to evaluate the capability of the NAS software to provide reasonable estimates of MNA cleanup timeframes in a variety of environments and sites throughout the United States. Overall, results suggest that NAS was satisfactory in meeting performance objectives set forth in the demonstration, and that because NAS is based on sound science, it can serve as an effective tool for decision-making and data analysis at a wide range of contaminated sites and is not limited to a small subset of “simple sites” because of its simplicity. At some sites, NAS-estimated timeframes were crucial for winning regulatory acceptance of MNA, with cost-benefit analyses providing estimates of savings associated with using MNA as a final remediation strategy.
Ph. D.

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30

Filippini, Maria <1986&gt. "Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6812/1/Filippini_Maria_tesi.pdf.

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Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants themselves and on features of the hydrogeological system. The main goal of the thesis is to provide new knowledge for the future investigations of sites contaminated by DNAPLs in alluvial settings, proposing innovative investigative approaches and emphasizing some of the key issues and main criticalities of this kind of contaminants in such a setting. To achieve this goal, the hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated at different scales (regional and site specific), both from an intrinsic (i.e. groundwater flow systems) and specific (i.e. chlorinated solvent DNAPL behavior) point of view. Detailed investigations were carried out in particular in one selected test-site, known as “Caretti site”, where high-resolution vertical profiling of different kind of data were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. This allowed to achieve a deep geological and hydrogeological knowledge of the system and to reconstruct in detail the architecture of contaminants in relationship to the features of the hosting porous medium. The results achieved in this thesis are useful not only at local scale, e.g. employable to interpret the origin of contamination in other sites of the Ferrara area, but also at global scale, in order to address future remediation and protection actions of similar hydrogeologic settings.

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31

Filippini, Maria <1986&gt. "Geological and hydrogeological features affecting migration, multi-phase partitioning and degradation of chlorinated hydrocarbons through unconsolidated porous media." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6812/.

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Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last five decades. They generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL). This phase can migrate through aquifers, and also through aquitards, in ways that aqueous contaminants cannot. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase), as well as their transformations (e.g. degradation), depend on the physico-chemical properties of the contaminants themselves and on features of the hydrogeological system. The main goal of the thesis is to provide new knowledge for the future investigations of sites contaminated by DNAPLs in alluvial settings, proposing innovative investigative approaches and emphasizing some of the key issues and main criticalities of this kind of contaminants in such a setting. To achieve this goal, the hydrogeologic setting below the city of Ferrara (Po plain, northern Italy), which is affected by scattered contamination by chlorinated solvents, has been investigated at different scales (regional and site specific), both from an intrinsic (i.e. groundwater flow systems) and specific (i.e. chlorinated solvent DNAPL behavior) point of view. Detailed investigations were carried out in particular in one selected test-site, known as “Caretti site”, where high-resolution vertical profiling of different kind of data were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. This allowed to achieve a deep geological and hydrogeological knowledge of the system and to reconstruct in detail the architecture of contaminants in relationship to the features of the hosting porous medium. The results achieved in this thesis are useful not only at local scale, e.g. employable to interpret the origin of contamination in other sites of the Ferrara area, but also at global scale, in order to address future remediation and protection actions of similar hydrogeologic settings.

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32

Poltorak, Matthew Robert. "Field and Greenhouse Studies of Phytoremediation with California Native Plants for Soil Contaminated with Petroleum Hydrocarbons, PAHs, PCBs, Chlorinated Dioxins/Furans, and Heavy Metals." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1338.

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Native and naturalized California plant species were screened for their phytoremediation potential for the cleanup of soil contaminated with petroleum hydrocarbons (PHCs), poly-aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated dioxins/furans, and heavy metals. This screening was followed by controlled greenhouse experiments to further evaluate the phytoremediation potential of the best candidates. Field specimens and soils used for this study were collected from the former Energy Technology Engineering Center (ETEC) at the Santa Susana Field Laboratory in Southern California that was operated by the Department of Energy (DOE). Soils at this site contain all of the contaminants of interest (COIs). Nine plant species were screened in the field: Purple Needlegrass (Nassella pulchra), Blue Elderberry (Sambucus nigra), Laurel Sumac (Malosma laurina), Mule Fat (Baccharis salicifolia), Palmer’s Goldenbush (Ericameria palmeri), Summer Mustard (Hirschfeldia incana), Narrowleaf Milkweed (Asclepias fascicularis), Coyote Brush (Baccharis pilularis), and Thickleaf Yerba Santa (Eriodictyon crassifolium). In the field three samples of each species growing in contaminated soil and one of each species growing in uncontaminated soil were selected for harvesting and analysis. The roots, above ground plant tissue, and soil around the roots were sampled separately and analyzed for the COIs: PHCs, PAHs, PCBs, chlorinated dioxins/furans, and metals (which include mercury, silver, cadmium, and lead). All of the plants in the field appeared to generate compounds which result in higher measured PHC concentrations than those measured in the associated soil. The highest concentrations of PAHs in the roots were observed for Blue Elderberry (1740 ug/kg), Purple Needlegrass (703 ug/kg), and Yerba Santa (200 ug/kg). No uptake of PCBs was observed in the roots or foliage of any species. The highest concentrations of total chlorinated dioxins/furans in the roots were observed for Purple Needlegrass (2237 ng/kg), Blue Elderberry (1026 ng/kg), Palmer’s Goldenbush (432 ng/kg), and Yerba Santa (421 ng/kg). The highest concentrations of total chlorinated dioxins/furans in the foliage were observed for Yerba Santa (901 ng/kg), Palmer’s Goldenbush (757 ng/kg), and Purple Needlegrass (694 ng/kg). No uptake of mercury was observed in the roots or foliage of any species. The highest concentration of silver in the roots was observed for Laurel Sumac (7.34 mg/kg). Summer Mustard (SM) was the only species that showed uptake of silver into the foliage (0.405 mg/kg). The highest concentrations of cadmium in the roots and foliage were observed for Mule Fat (1.84 mg/kg and 3.64 mg/kg) and Coyote Brush (1.52 mg/kg and 2.12 mg/kg) and the greatest concentration of lead in the roots and foliage was observed for Purple Needlegrass (8.92 mg/kg and 1.17 mg/kg). Plants with a wide variety of observed contaminant uptake in the field were selected for a second phase of research in which three of the most promising species were grown in greenhouse microcosms to quantify the removal of contaminants from the soil. The three species selected based on preliminary results from the field study were Coyote Brush, Mule Fat, and Purple Needlegrass. Microcosms consisted of 2.17 kg of soil in 4-L glass jars with glass marbles for an underdrain. Plants were watered with deionized water and no leachate was collected. Five replicates of each microcosm type were created and incubated for 211 days with soil sampling at 85 and 211 days. Soil, plant roots/above ground tissue, and volatilization from the plants were analyzed for COIs to determine the mechanisms of phytoremediation. One set of microcosms was used to test the effect of addition of achelating agent (ethylenediaminetetraacetic acid) and another set was used to test the effect of fertilizer addition on phytoremediation potential. Three control treatments were tested: sterilized (gamma irradiation) soil planted with Purple Needlegrass, unplanted soil, and sterilized unplanted soil. None of the plant species demonstrated volatilization of COIs under these conditions. Volatilization of mercury was not tested for. The average PCB concentration (measured as Aroclor 1260) reductions in soils with Purple Needlegrass and chelated Coyote Brush were 49.4% and 51.4% respectively (p < 0.05). However, the sterilized unplanted control also had a decrease of Aroclor 1260 concentrations in the soil of 36.6% (p < 0.05). None of the species phytoextracted PCBs, so the mechanism of PCB remediation appears to be phytostimulation of the rhizosphere. Purple Needlegrass showed the greatest uptake of dioxins/furans into the foliage but did not appear to reduce the dioxin/furan concentrations in the soil. Coyote Brush, fertilized Coyote Brush, and Mule Fat also showed uptake of dioxins/furans into the roots and foliage. Only the Coyote Brush and fertilized Coyote Brush significantly (p = 0.036, p = 0.022) reduced the total dioxin/furan concentration in the soil (17.8% and 19.8% respectively). Coyote Brush may have stimulated microbes in the rhizosphere to better degrade the dioxins/furans. None of the plants were identified as hyper-accumulators of metals, and none of the soil metal concentrations significantly decreased in any of the microcosms. All of the metals (except mercury) were taken into the roots of plants to some degree, with Purple Needlegrass showing the most promise for metal extraction as it showed some of the highest concentrations of metals in roots and was the only species that contained mercury and silver in the foliage. This study suggests that there is some potential for phytoremediation of PCBs and chlorinated dioxins/furans. The results for petroleum hydrocarbons were inconclusive. Metal uptake was not substantial enough to lower metal concentrations in the soils. Thus phytoremediation of COIs at the site is limited and more aggressive forms of remediation may be required to reduce the concentrations of COIs quickly.

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33

Nordborg, Daniel. "Provtagning av trädkärnor för att bedöma föroreningsgraden av klorerade lösningsmedel i grundvatten." Thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88820.

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Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.

The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons. The aim has also been to gain an understanding of the uptake process, as well as to identify the limitations of the method and important issues to consider when sampling.

Trees were sampled in March and June on Helgö 1:25, 1:26 in Växjö, Småland. Metal degreasing earlier conducted at this site has lead to the CAH contamination of soil and groundwater (PCE, TEC c-DACE). Mostly PCE, TCE, and chloroform were detected in tree cores. The CAH concentration was higher in June. Using the sum of PCE+TCE+c-DCE in trees to delineate the spread gave a result that was quite consistent with a delination done based on groundwater sampling.

The uptake of CAH by trees is governed by the uptake of water at the root. The water usage, together with the origin of the water used is important for the ability of the tree to take up CAH. The CAH concentration within trees is also dependent on the chemical properties of the compound (Log kow, solubility etc), the concentration of the compound in the soil as well as degradation processeses. The position and height of sampling in the trees, tree species as well as tree size are important factors to consider when sampling. Sampling during summer is preferred when the concentration of CAH in trees is likely to be higher.

The analysis of CAH in tree cores has potential to be used as a screening tool in soil investigations under Swedish conditions. It is a cheap and easy to use method, which would be a good complement to other investigative measures. However, an increased understanding of the processes involved, together with more analysis are needed., as this is a new method.

Klorerade lösningsmedel (CAH) användes i stor omfattning som bl a kemtvättmedel och avfettningsmedel tills dess att deras toxiska egenskaper blev kända. Perkloretylen (PCE) används än idag som kemtvättmedel. CAH återfinns ofta i markmiljö på de platser där de tidigare använts. Analys av CAH-koncentration i trädkärnor har uppmärksammats som en billig och effektiv metod för att översiktligt bedöma utbredningen av dessa föroreningar. Metoden har inte tidigare använts i Sverige.

Syftet med detta examensarbete är att undersöka om trädprovtagning kan användas för att bedöma utbredningen av föroreningar i markmiljö under svenska förhållanden vid olika årstider.

Analyserade CAH-halter i träd har jämförts med tidigare registrerade halter av CAH i grundvatten. Syftet har också varit att beskriva CAH-upptaget i träd, undersöka metodens begränsningar samt att sammanfatta viktiga aspekter vid provtagning.

Provtagningar av träd har genomförts under mars och juni på fastigheterna Helgö 1:25 och 1:26 i Växjö, där tidigare metallavfettning har medfört att mark och grundvattnet förorenats av CAH; perkloretylen (PCE), trikloretylen (TCE) och nedbrytningsprodukten dikloretylen (c1,2-DCE). Vid analys av trädkärnor detekterades främst PCE, TCE samt TCM (kloroform). Koncentrationen av CAH var högre i juni. Halten PCE+TCE+c-DCE i trädproverna gav en översiktlig bild av föroreningssituationen som överensstämde väl med de grundvattenprover som tidigare tagits på fastigheten.

CAH tas upp i vattenlöst fas vid trädens rötter. Trädets vattenbehov och vilket vatten det utnyttjar är därför viktigt för dess möjlighet att ta upp CAH. Ämnets kemiska egenskaper (log kow, flyktighet, mm.), samt förekomst och nedbrytning påverkar den halt som registreras i trädet. Vid provtagning bör provtagningspunkternas höjd över marken och position, trädart samt trädstorlek beaktas. Provtagning under sommaren är att föredra eftersom halterna då är högre.

Jämförelsen med grundvattenprovtagning visar att metoden har potential att användas i Sverige för att bedöma utbredningen av en CAH-förorening i markmiljö. Den är enkel att använda och kan vara ett alternativ på platser där konventionella metoder är svåra att genomföra. En ökad förståelse för involverade processer, samt utökade undersökningar av metoden är nödvändiga då metoden är ny.

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Positano, Chad J. "A Study of the Mass Emission Rates of Small Spills of Chlorinated Hydrocarbons Based on the Vapor Pressure and Surface Area to Volume Ratio of the Spill." University of Toledo Health Science Campus / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=mco1096393449.

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Acker, Marc van. "Application of chlorine stable isotope analysis of chlorinated aliphatic hydrocarbons to environmental monitoring and development of new analytical method." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445748.

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Powell, Christina Lynn. "Biodegradation of Groundwater Pollutants (Chlorinated Hydrocarbons) in Vegetated Wetlands: Role of Aerobic Microbes Naturally Associated with Roots of Common Plants." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1289918991.

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Yu, Fang. "Abiotic Degradation of Chlorinated Hydrocarbons (CHCs) with Zero-Valent Magnesium (ZVM) and Zero-Valent Palladium/Magnesium Bimetallic (Pd/Mg)-Reductant." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1373881146.

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Calderer, Perich Montserrat. "Study of Denitrification and Reductive Dechlorination Processes Applied to Groundwater Bioremediation." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6996.

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La present tesi es basa en l'estudi dels processos de bioremediació com a tecnologies de descontaminació d'aqüífers.
Concretament, es pretén estudiar la desnitrificació i la decloració reductiva com a tecnologies de bioremediació per eliminar, respectivament, els nitrats i els hidrocarburs alifàtics clorats (o CAHs, de chlorinated aliphatic hydrocarbons) de les aigües subterrànies contaminades. A més, es pretén aplicar tecnologies avançades que permetin millorar en el coneixement d'aquests processos.
L'aqüífer associat a la riera d'Argentona, situat a Argentona (Espanya), ha estat la zona d'estudi per tal d'investigar el procés de desnitrificació. En primer lloc, s'han dut a terme experiments en batch amb aigua subterrània i sòl subsuperficial del mencionat aqüífer. A partir d'aquests primers estudis, s'ha observat la baixa capacitat de l'aqüífer per eliminar els nitrats de manera natural, però alhora s'ha vist la viabilitat d'aplicar un procés de bioremediació com és l'addició de matèria orgànica. Paral·lelament, s'ha estudiat la influència de diferents factors com ara la presència d'oxigen i la tipologia de donador d'electrons sobre el procés de desnitrificació.
Posteriorment, s'ha desenvolupat un model matemàtic per descriure el consum d'oxigen, de nitrats i de matèria orgànica per part de la població microbiana facultativa i heterotròfica present en el material d'aqüífer. Alguns paràmetres del model han estat calibrats i s'ha estudiat la qualitat d'aquests paràmetres. El model desenvolupat constitueix una primera aproximació per tal d'obtenir un model de desnitrificació in situ.
Per tal d'avançar en l'estudi del procés de desnitrificació en condicions naturals, s'han realitzat experiments en dinàmic simulant el flux d'aigua subterrània a través de l'aqüífer. L'eficiència d'injectar matèria orgànica en aquestes condicions s'ha demostrat.
Paral·lelament, s'han estudiat els efectes hidrodinàmics de l'aplicació de la bioremediació i, els resultats han demostrat la importància de dissenyar acuradament les tecnologies de bioremediació a escala de camp. Per altra banda, s'ha descrit la desnitrificació en condicions dinàmiques integrant en un model matemàtic les reaccions bioquímiques i els processos de transport que tenen lloc a la columna experimental.
Finalment, s'han aplicat les noves tecnologies de biologia molecular per entendre els efectes de l'aplicació d'un procés de bioremediació a nivell microbià. Per una banda, l'aplicació de la tècnica de la reacció en cadena de la polimerasa a temps real (o real-time PCR, de real-time polymerase chain reaction) ha demostrat el creixement de la població microbiana i, concretament, de la població desnitrificant en el material d'aqüífer estimulat. Per altra banda, l'electroforesi en gel de gradient desnaturalitzant (o DGGE, de denaturing gradient gel electrophoresis) ha permès investigar els canvis en la població microbiana indígena del material d'aqüífer a causa de l'estimulació amb matèria orgànica.
Amb l'objectiu d'avançar en el coneixement dels processos de bioremediació en aigües subterrànies, s'ha estudiat també la decloració reductiva de CAHs. En aquest cas, s'han aplicat metodologies experimentals destinades a l'estudi de la posible aplicació d'una barrera reactiva permeable per eliminar una ploma que conté majoritàriament cis-1,2-dicloroetilè i clorur de vinil, i que flueix cap al riu Zenne, prop de la ciutat de Brussel·les (Bèlgica).
L'estudi ha inclòs experiments en batch per tal d'investigar el potencial degradatiu del material d'aqüífer i dels propis sediments del riu Zenne. Així mateix, també s'han dut a terme experiments en columna que simulaven el flux d'aigua subterrània a través dels sediments del riu o del material d'aqüífer. Els resultats han demostrat el gran potencial degradatiu dels sediments, que a la llarga es podrien potenciar com a biobarrera natural del sistema per tal de prevenir que les aigües contaminades arribin a l'aigua superficial del riu Zenne.
This thesis is based on the study of bioremediation processes as reliable technologies to remove contaminants from groundwater.
Specifically, it is aimed to study denitrification and reductive dechlorination as bioremediation technologies to remove nitrates and chlorinated aliphatic hydrocarbons (CAHs), respectively, from polluted groundwater. In addition, it is aimed to apply advanced technologies which allow improving on the knowledge of these processes.
The aquifer associated to the Stream Argentona, located in Argentona, Catalunya (Spain), was selected as study site to investigate the denitrification process. In the first part, microcosm experiments containing groundwater and subsoil from the aquifer were performed. From these first studies it was observed the low capacity of the aquifer to eliminate nitrates under natural conditions, but, at the same time, it was noted the feasibility of applying a bioremediation process such as the addition of organic matter. In addition, the influence of different factors such as the presence of oxygen and the type of electron donor on the denitrification process was studied.
Afterwards, a mathematical model was developed to explain the microbiological processes that occur when stimulating the aquifer material with an organic carbon source. The model could successfully explain the consumption of oxygen, nitrates and organic matter by the indigenous facultative heterotrophic microbial population from aquifer. Some parameters of the model were calibrated from experimental data and the quality of these parameters was investigated. The developed model constitutes a first approach in order to have reliable models for in situ denitrification.
In order to advance in the study of the denitrification process in natural conditions, dynamic experiments were carried out simulating the groundwater flow through the aquifer. The efficiency of injecting organic matter under these conditions was demonstrated. At the same time, hydrodynamic effects of the process were observed, indicating the importance to design properly bioremediation technologies before its application in field-scale. Furthermore, an integrated model coupling the biochemical reactions and the transport processes inside the column was developed and applied to describe denitrification under dynamic conditions.
Finally, molecular microbiological techniques were applied to investigate microbial changes due to the application of enhanced denitrification. On the one hand, real-time polymerase chain reaction (real-time PCR) assays revealed the growth of microbial population, specially of denitrifying bacteria in aquifer material stimulated with an organic carbon source. On the other hand, the denaturing gradient gel electrophoresis (DGGE) method allowed to investigate changes in the indigenous microbial community due to the amendment with organic matter.
In order to advance in the knowledge of bioremediation processes in groundwater, reductive dechlorination of CAHs in groundwater was studied. In this case, experiments at laboratory scale were applied, aimed to study the possible application of a permeable reactive barrier (PRB) to eliminate a CAH-contaminated plume, containing basically cis-1,2-dichloroethene and vinyl chloride, which flows to the River Zenne near Brussels, Belgium.
The study included batch experiments in order to investigate the degradation potential in aquifer and sediments of the River Zenne, as well as column experiments which simulated the groundwater flow through the sediments of the river or the aquifer material. The results demonstrated the high degradation potential of the sediments, which in the long term could be enhanced to act as a natural biobarrier of the system in order to prevent groundwater contaminants from arriving at the surface water of the River Zenne.

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Smith, Madelyn M. "Cometabolic Degradation of Halogenated Aliphatic Hydrocarbons by Aerobic Microorganisms Naturally Associated with Wetland Plant Roots." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341854406.

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Rauschenberger, Richard Heath. "Developmental mortality in american alligators (alligator mississippiensis) exposed to organochlorine pesticides." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008223.

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Thesis (Ph.D.)--University of Florida, 2004.
Typescript. Title from title page of source document. Document formatted into pages; contains 233 pages. Includes Vita. Includes bibliographical references.

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Lundberg, Rebecca. "Persistent organic pollutants and bone tissue : studies in wild and in experimental animals /." Stockholm : Karolinska institutet, 2007. http://diss.kib.ki.se/2007/978-91-7357-410-5/.

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Therrien, Annamarie F. "Degradation of Chlorinated Hydrocarbons in Groundwater Passing Through the Treatment Wetland at Wright-Patterson Air Force Base: Analysis of Results Collected During 2001-'06." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1363477561.

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Kim, A. "The effects of twelve chlorinated aliphatic hydrocarbons upon the cell cycle of Chinese hamster cell lines : V79d-MZ and genetically engineered cell lines expressing CYP2E1." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637798.

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Chlorinated organic chemicals are widely used in industry and are present in the environment. Twelve chlorinated aliphatic hydrocarbons, namely carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, hexachloroethane, 1,2-dichloroethylene, trichloroethylene, 1,3-dichloropropane, 1,2,3-trichloropropane, 2,3-dichlorobutane, 1-chlorohexane and 1,1,3-trichloropropene were investigated to determine their influence upon the fidelity of cell division in cultured mammalian cells. In order to determine the influence of these chemical compounds upon the fidelity of cell division, a technique known as differential staining of chromosomes and spindle was performed with two genetically engineered cell lines and their parental cell line. The genetically engineered cell lines used in this study expressed a human P450 enzyme, CYP2E1. Four chemicals, trichloroethylene, 1,2-dichloroethane, 2,3-dichlorobutane and 1-chlorohexane required bioactivation in order to induce spindle damage in cultured mammalian cells whereas all the other chemicals were direct-acting spindle poisons with the exception of 1,1,1-trichloroethane which hardly influenced the fidelity of cell division in all three cell lines. Micronucleus assays were performed to study at which one of the four phases in V79d-MZ cell cycle, the cells were most vulnerable to the effects of two selected chlorinated hydrocarbons. To carry out this assay the cells were synchronized using 1-2% of DMSO. The same assay was also used to investigate at which phase of the cell cycle, the enzyme CYP2E1 activates trichloroethylene. The phase at which the V79d-MZ cells were most vulnerable to the chemical effects was mitosis (M). Finally an apoptosis assay was used to investigate whether the chlorinated aliphatic hydrocarbons are inducing cell death: apoptosis or necrosis using annexin-V and from this it was found that 1,2-dichloroethylene induced apoptosis.

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Pandey, Dhurba Raj. "Degradation of Select Chlorinated Hydrocarbons by (i) Sulfide-Treated Hydrous Ferric Oxide (HFO) and (ii) Hydroxyl Radicals Produced in the Dark by Oxygenation of Sodium Dithionite-Reduced HFO." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1535462165887662.

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45

Gualandi, Giovanni <1973&gt. "Chlorinated aliphatic and aromatic hydrocarbons biodegradation: bioaugmentation tests in slurry microcosmos and study of the catabolic potential of microbial community in the interface between groundwater and surface water." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/382/1/giovanni_gualandi.pdf.

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Gualandi, Giovanni <1973&gt. "Chlorinated aliphatic and aromatic hydrocarbons biodegradation: bioaugmentation tests in slurry microcosmos and study of the catabolic potential of microbial community in the interface between groundwater and surface water." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/382/.

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Chen, Zhongbing [Verfasser], Heinz [Akademischer Betreuer] Köser, and Otto R. [Akademischer Betreuer] Stein. "Treatment of waters contaminated by volatile organic compounds (chlorinated hydrocarbons, BTEX aromatics etc.) in constructed wetlands : process characterisation and treatment optimization / Zhongbing Chen. Betreuer: Heinz Köser ; Otto R. Stein." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2012. http://d-nb.info/1027991483/34.

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Kele, Benjamin Mark, and b. kele@cqu edu au. "On-site Wastewater Treatment and Reuse Using Recirculatory Evapotranspiration Channels in Regional Queensland." Central Queensland University. Biology, 2005. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20060831.113529.

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The Central Queensland University developed an on-site wastewater treatment and reuse technology. Septic tanks were used for primary treatment and the discharged effluent was then pumped though a series of contained channels. The channels were designed to be a modified evapotranspiration trench; they were comprised of an aggregate layer and a soil layer in which were planted a variety of plants. The aggregate and the soil provided physical filtration, the microorganisms within the effluent, aggregate and soil provided nutrient reuse and transformation and the plants also used the nutrients and reused the treated effluent through evapotranspiration. Any effluent that was not transpired was returned to a holding tank and pumped through the evapotranspiration again. The treatment technology was assessed in relation to its ability to treat effluent in a sustainable manner. The water and soil was examined for concentrations of nutrients, heavy metals, salts, sodium, and organic carbon %. The pH, temperature and number of colony forming units of certain microorganism potential pathogens were also inspected in the soil and the water. The plants grown within the evapotranspiration channels were assessed in regards to their health, water usage, and in some cases potential pathogens on fruit. The infrastructure that was used to construct the wastewater treatment and reuse system was also evaluated in regards to reliability and maintenance. Certain limiting factors, in particular sodicity and salinity were identified, but the trial was successful and a sustainable form of on-site wastewater treatment and reuse technology was developed.

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Röhrs, Joachim. "Untersuchungen zur Elektrochemischen Bodensanierung für die Stoffklasse der hochsiedenden aliphatischen Chlorkohlenwasserstoffe." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1075380665109-52551.

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Die elektrokinetische Bodensanierung nutzt Transporteffekte aus, die entstehen, wenn ein elektrisches Feld an einen Bodenkörper angelegt wird. Die Sanierungsmethode versagt bei immobilen Schadstoffen. Allerdings scheint unter bestimmten Bedingungen ein im Boden induzierter Abbau der Schadstoffe möglich. Dafür müssen so genannte "Mikroleiter" und Redox-Systeme im Boden vorhanden sein. Hierzu werden theoretische Modelle vorgestellt. An einem konkreten Beispiel (mit aliphatischen Chlorkohlenwasserstoffen kontaminierter Boden) wurde getestet, ob direkt im Boden ein Abbau der Schadstoffe mit der Technik der elektrochemischen Bodensanierung erzielt werden kann. Die Analyse der CKW wurde per GC-MS durchgeführt. Theoretisch ist ein reduktiver Abbau oder eine Dechlorierung durch Eliminierungsreaktionen möglich. Die Ergebnisse der Laborversuche (Einwaage 100-3.000 g) erbrachten unter Einhaltung bestimmter Faktoren einen erfolgreichen Abbau der CKW. Bei ständiger Bewässerung des Bodens und einer Feldstärke von mindestens 600 V/m konnte ein Abbau festgestellt werden. Die Erhöhung des Chlorid-Gehaltes im Abwasser zeigt die erfolgreiche Abbaureaktion an. Potentielle Abbauprodukte mit weniger Chlor-Atomen im Molekülaufbau konnten nachgewiesen werden. Diese Stoffe lassen sich mit den ursprünglichen Kontaminationssubstanzen verknüpfen. Da eine Migration der Schadstoffe im elektrischen Feld nicht beobachtet wurde, wird eine im Boden induzierte Abbaureaktion angenommen. In Bodenzonen mit hohem pH-Wert (Eliminierung) und in Kathodennähe (Reduktion) waren die stärksten Abbauraten zu verzeichnen. Bei Versuchen ohne ständige Bewässerung war der CKW-Abbau schwach. Die Widerstände stiegen stark an. Ein Versuch in einem Container (Einwaage Boden: ca. 2 t) erbrachte nur einen punktuellen Abbau der CKW. Die Struktur des Originalbodens verhinderte den Aufbau eines homogenen elektrischen Feldes. In einem Fassversuch (Einwaage Boden: ca. 33 kg) wurden die Versuchsbedingungen modifiziert. Anlagerungen an allen Elektroden verhinderten eine ausreichend hohe effektive Feldstärke im Bodenkörper. Sanierungseffekte fanden nur lokal begrenzt statt. Im Vergleich von Labor zu Großversuchen zeigte sich, dass die eingetragene Ladungsmenge eine entscheidende Rolle spielt.

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Wang, Bo. "Degradation of Halogenated Hydrocarbons by Zero-Valent Magnesium andCopper/Magnesium Bimetallic Reductant, & Characterization of Poly- andPerfluoroalkyl Substances in Treated Wastewater Reclaimed for Direct Potable Reuse." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1568048522860247.

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Dissertations / Theses on the topic 'Chlorinated hydrocarbons'

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