No description available.

Terra mine is an abandoned copper and silver mine in the Northwest Territories, Canada, from which mine tailings were deposited into Ho-Hum Lake, adjacent to the mine’s processing plant. The tailings contain elevated levels of arsenic (As), resulting in As levels exceeding Canadian sediment and water quality guidelines in the lake, and in downstream wetland water and sediment. This field and laboratory study focuses on the microbial ecology, and the reduction and oxidation of As, iron (Fe) and sulphur (S), in the wetland downstream from Ho-Hum Lake. This wetland is proposed as a passive remediation system for removal and storage of As. Using microcosm experiments, the stability of As-bearing sediments was compared in the upper, middle and lowestmost areas of the wetland over a 42-day period. Fresh sediments and sediments amended with a 10 mM acetate solution, both mixed with water, were compared. While no significant geochemical differences were found between acetate-amended and unamended microcosms, formation of inorganic As-S species was higher in amended microcosms, suggesting that micro-organisms were more active in the system because they were not carbon-limited. Formation of methylated-As species increased over time in all samples, including abiotic controls. Bacterial sulphate reduction occurred during the first 10 days of the experiment, perhaps resulting in precipitation of sulphide minerals. X-ray adsorption near edge spectroscopy was used to assess solid-state speciation of As in the sediments and indicated that pre-microcosm sediments from all sites showed high proportions of As(III)-S and As(III)-O speciation. Post-microcosm sediments revealed a 13% increase in the proportion of As(V)-O species, whereas abiotic controls showed only an 8% increase. DNA sequencing in post-microcosm sediments identified As, Fe and S reducing bacteria, and the geochemical patterns of As, Fe and S in the microcosms indicate the bacteria are likely active in the system. Microbial diversity and solid-state speciation of As in the sediments were assessed at varying depths at the microcosm sites, but correlation analysis revealed no significant relationship between As speciation and microbial diversity. A positive correlation between diversity and depth, and a negative relationship between As concentration and diversity, were found, perhaps indicating decreasing contamination with depth in the wetland. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2011-07-03 23:27:44.373

Groundwater parameter analysis, microcosm experiments, and microcosms modeling were undertaken to assess the potential of Monitored Natural Attenuation as a remediation strategy at Site 12 at the Naval Amphibious Base (NAB) Little Creek. Site 12 was contaminated with PCE waste disposed by a former dry cleaning facility. In the groundwater analysis, contaminant characteristics and redox indicators were evaluated to assess the reductive dechlorination potential of Site 12. The results of the groundwater analysis indicated that Site 12 exhibited sulfate-reducing and methanogenic conditions which provide the required environment for reductive dechlorination. However, Site 12 only demonstrated partial reductive dechlorination to cis-1,2-DCE and possible anaerobic oxidation of cis-1,2-DCE and VC to CO₂. Microcosms were designed to further evaluate the extent of microbial degradation of the chlorinated ethenes at Site 12 and to provide concentration versus time data for the estimation of chlorinated ethenes' biodegradation rates. The extent of degradation in the microcosms was consistent with the groundwater data. However, ethene production was not observed and the quantity of TCE measured for two of the microcosms differed substantially when compared to the groundwater data. The microcosm model used SEAM3D to simulate the results of the microcosm experiments (concentration versus time data) to estimate the biodegradation rates of PCE and its daughter products. The SEAM3D reductive dechlorination package, based on Monod kinetics, predicted for the MLS12-Shallow microcosm maximum specific utilization rates for PCE, TCE, cis-1,2-DCE and VC at 0.4, 0.42, 0.05, and 0.25 day⁻¹, respectively and half saturation coefficients for PCE, TCE, cis-1,2-DCE and VC at 0.41, 0.01, 0.07, and 0.02 mg/L, respectively. The results of this study suggest that while the groundwater environment provides the necessary conditions for reductive dechlorination, Site 12 is not an efficient system for reductive dechlorination. This lack of efficiency may stem from sparse microbial populations capable of reducing cis-1,2-DCE or the system may contain levels of PCE which inhibit the further reduction of cis-1,2-DCE. Based on the observed inhibitory relationship between PCE and cis-1,2-DCE and VC production, source removal would reduce the PCE levels and encourage further reductive dechlorination at Site 12. Therefore, the recommended first step for a monitered natural attenuation-based remediation strategy at Site 12 should be source removal. / Master of Science

Remediation of chlorinated ethene contaminated sites presents a problem for the environmental industry. Many innovative technologies exist to remove these chemicals from the subsurface; however, most of these technologies require extensive time and incur significant cost. A technology called bioremediation utilizes microorganisms to break down contaminants such as perchloroethene (PCE), trichloroethene (TCE), dichloroethene (DCE), and vinyl chloride (VC) to non-toxic compounds in a process called reductive dechlorination. Microorganisms that are capable of dechlorination usually require reducing conditions as well as bioavailable hydrogen and carbon sources. Emulsified vegetable oil has emerged as a cost-effective source of degradable organic matter to facilitate reductive dechlorination in the subsurface. Through Æ Ã -oxidation, microorganisms can break down the long chain fatty acids in vegetable oil into smaller fatty acids such as acetate, propionate, and butyrate. The fermentation of the oil provides reduced conditions as well as a slow release of hydrogen and carbon into the subsurface. This study consisted of an evaluation the effectiveness of emulsified vegetable oil in stimulating reductive dechlorination using sixteen laboratory microcosms constructed from soil and groundwater from an aquifer contaminated with TCE located at the Naval Weapons Station in Charleston, South Carolina. Each microcosm was monitored for chloroethenes, volatile fatty acids, long chain fatty acids, and total carbon on a weekly basis. Results show successful fermentation of fatty acids and reduced conditions favorable for dechlorination. / Master of Science

Orientador: Lucia Regina Durrant / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T20:12:21Z (GMT). No. of bitstreams: 1 Dias_FabioGuimaro_D.pdf: 798649 bytes, checksum: c223f07173b848327e30607dc7f3fe6d (MD5) Previous issue date: 2007 / Resumo: Neste trabalho foi formulado um consórcio microbiano para avaliação de seu potencial em degradar petróleo e seus derivados, em microcosmos e meio mínimo de sais. As 43 bactérias testadas na primeira fase do projeto demonstraram alguma propriedade que as classificam como potencialmente degradadoras de hidrocarbonetos. Todavia, as cepas 1, 9, 22, 23 e 36 demonstraram os melhores e mais homogêneos resultados em praticamente todos os parâmetros analisados, sendo estas, portanto, as cinco cepas selecionadas para a formulação do consórcio. As cepas do consórcio propiciaram uma degradação média para todos os hidrocarbonetos testados de 62,65% para cepa 1, 61,12% para a cepa 9, 53,77% para a cepa 22, 57,87% para a cepa 23 e de 44,03% para a cepa 36. Com exceção de alguns HPA¿s degradados por determinadas cepas, a grande maioria não foi totalmente biodegradado, fato que pode ser comprovado pelos baixos valores de EC50, e, com isso, altos valores de toxicidade aguda. No experimento realizado em microcosmo, avaliando-se a evolução de C-CO2 por modelos estatísticos, pode-se concluir que a melhor condição para a maximização desse parâmetro foi na condição do ponto central para a fonte de nitrogênio (0,10 g/100g de solo), ferro (0,0015 g/100g de solo) e inóculo (0,6ml/100 g de solo) e, na condição de +2 para a fonte de fósforo (0,08 g/100g de solo). Com este experimento foram fixadas as condições ótimas para uma melhor evolução de CCO2 em solos contaminados. No mesmo experimento, analisando a degradação dos hidrocarbonetos por cromatografia gasosa, foi obtida uma melhor degradação para o experimento 3 (uréia 0,07 g/100g de solo, fosfato de potássio 0,065 g/100 g de solo, Sulfato de ferro 0,001 g/100 g de solo, e inoculo 0,4 ml/100 g de solo), com uma degradação de 70,74% dos hidrocarbonetos. Nos microcosmos utilizando solo da REPLAN (Refinaria de Paulínia/PETROBRAS), com histórico de contaminação, foi obtida uma melhor degradação para os hidrocarbonetos analisados de 75% quando se utilizou a bioestimulação e de 51,7% quando se utilizou a bioaumentação e bioestimulação juntas. Para os microcosmos utilizando o consórcio liofilizado, foi obtida uma degradação de 57,85% para o liofilizado sem nutriente e, de 67% para o liofilizado com nutriente. As linhagens foram identificadas através da técnica do RNA 16S, como sendo pertencentes a gênero Bacillus, exceto o microrganismo 23, cuja identificação não foi possível através dos resultados obtidos, o consórcio microbiano tem potencial para ser aplicado em áreas contaminadas com petróleo e seus derivados / Abstract: In this work, a microbial consortium was evaluated regarding to its potential to degrade oil and derivatives, using microcosms in salt minimal medium. Forty three bacteria were tested in the first phase of this project to demonstrate some properties that could identify them as potentially degraders of hydrocarbons. The strains 1, 9, 22, 23 and 36 showed the best and homogeneous results in practically all the analyzed parameters, and five strains were selected to be part of the bacterial consortium. These strains had an average degradation of 62.65% for the strain 1; 61.12% for the strain 9; 53.77% for the strain 22; 57.87% for the strain 23; and 44.03% for the strain 36. Some PAHs were not completelly degraded by some strains, and this fact could be proven by the low values of EC50, with production of high values of acute toxicidade. In the microcosm experiments, the C-CO2 evolution was performed using statistical models, which could be concluded that the best condition for the maximization of this parameter was in the central point condition for the nitrogen source (0.10g/100g of soil), iron (0.0015g/100g of soil) and inoculum (0,6ml/100g of ground), using the condition of +2 for the phosphorus source (0.08g/100g of soil). In this experiments could be set an excellent condition for a better evolution of C-CO2 in contaminated soil. In the same experiment, analyzing the degradation of the hydrocarbons in GC-FID, a better degradation was obtained for the experiment 3 (urea 0,07g/100g of soil, potassium fosfate 0.065g/100g of soil, iron sulphate 0.001g/100g of ground, and inoculum of 0.4 ml/100g of soil), reaching hydrocarbons degradation of 70.74%. In the microcosms using the REPLAN (PAULINIA REFINARY/PETROBRAS) soil with previous contamination history, the best degradation of 75% was promoted when bioestimulating, and 51.7% when this soil was bioaugmented with the bacterial consortium and also bioestimulated. For the microcosms using the lyofilizated consortium, a degradation of 57.85% was verifyed without nutrient, and 67% with nutrient. The strains were identified through the RNA 16S sequencing as Bacillus genus, excepting to the strain 23, whose results of sequencing identification was not possible in this time. These results showed that the microbial consortium has a potential application in contaminated areas with oil and derivatives / Doutorado / Doutor em Ciência de Alimentos

Since 1961, a fourold increase in application of fertilizers in the United States has helped to double crop yields. Nutrients not used by crops are often transported to aquatic ecosystems adjacent to agricultural fields. In the Lower Mississippi Alluvial Valley, nutrients enter agricultural drainage ditches and are transported to receiving water bodies, eventually reaching the Gulf of Mexico. The annual occurrence of a hypoxic zone in the Gulf of Mexico is caused by nitrogen loads from the Mississippi River Basin. Objectives of these studies were: (1) evaluate how organic carbon amendments affect nitrate-nitrogen removal in agricultural drainage ditch systems, (2) determine effects of organic carbon amendments and flow rate on nitrate-nitrogen removal in a semi-controlled field setting using experimental drainage ditches, and (3) assess relationships between organic carbon and nitrogen content of overlying water, pore water, and sediments of drainage ditches throughout the Lower Mississippi Alluvial Valley. In laboratory experiments, nitrate-nitrogen removal in dissolved and particulate organic carbon treatments was greater than 90% compared to as low as 60% in control treatments. The optimal carbon-to-nitrogen ratio of organic carbon amendments for efficient nitrate-nitrogen removal was 5:1. Studies in experimental drainage ditches revealed that flow substantially lowered the ability of organic carbon amendments to remove nitrate-nitrogen with a maximum percent nitrate-nitrogen reduction of 31.6% in a dissolved organic carbon treatment, although implementation of low-grade weirs in experimental drainage ditches did result in removal of nitrate nitrogen in all treatments and at all flow rates. Examining the nitrogen and organic carbon contents in agricultural drainage ditches throughout the Lower Mississippi Alluvial Valley revealed that organic carbon content in overlying water, pore water, and sediments is lower than observed in other wetland-like ecosystems and indeed may be limiting denitrification and other nitrogen removal processes. Increasing organic carbon content overall could be achieved by using organic carbon amendments, but this body of research highlights that additional studies are necessary to ensure successful implementation of organic carbon amendments that reach their greatest potential as a management practice to effectively remove nitrate-nitrogen in the realistic settings of agricultural drainage ditches.

No description available.

Doctor of Philosophy / Department of Biochemistry / Lawrence C. Davis / Halogenated organic compounds have had widespread and massive applications in industry, agriculture, and private households, for example, as degreasing solvents, flame retardants and in polymer production. They are released to the environment through both anthropogenic and natural sources. The most common chlorinated solvents present as contaminants include tetrachloroethylene (PCE, perchloroethene), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CT). These chlorinated solvents are problematic because of their health hazards and persistence in the environment, threatening human and environmental health. This contribution provides insight on PCE degradation at laboratory and field scale at a former dry cleaning site in Manhattan, KS. Biostimulation experiments included combinations and concentrations of the following nutrients: soy oil methyl esters (SOME), yeast extract (YE), glucose, lactate, methanol and cheese whey. Bioaugmentation studies used KB-1 bacterial consortium (commercially available culture containing Dehalococcoides). This culture is known to complete the degradation of PCE to a safe end product, ethene. Concentrations of PCE and its degradation intermediates were monitored in the gas phase of the microcosm vials. Biostimulation of the natural ground water and soil microflora did not completely degrade PCE as cis-DCE (c-DCE) accumulated in the sample. Bioaugmented microcosms containing YE and SOME created reducing conditions for KB-1 culture, resulting in ~ 90% dechlorination of PCE to methane and c-DCE. Cheese whey microcosms containing 0.05% cheese whey inhibited the KB-1 culture. This inhibition was due to a drop of pH that inhibited the culture activity. Lower concentrations of cheese whey (e.g. 0.01% to 0.025%) reduced PCE and generated methane in KB-1 augmented microcosms. Based on microcosm results, a pilot bioremediation field study was conducted for a dry cleaning site contaminated with PCE. Ground water flow threatened public water wells located 1.5 miles from the source. Concentrations of PCE in the aquifer was 15 mg/L above the maximum contaminant level of 5 µg/L. Tracer studies with potassium bromide (KBr) were conducted before, during and after the bioremediation study. Nutrient solutions prepared with YE, SOME, lactate and glucose were used for biostimulation and preconditioning of ground water prior to KB-1 injection. Nutrients were provided twice during the pilot study to supplement microbial growth and cheese whey was used. During biostimulation no degradation beyond DCE was evident. The addition of KB-1 reduced PCE and DCE concentrations in the monitoring wells of the pilot study area. Total chlorinated ethene concentrations did not reach background levels 2 years after the last nutrient addition. Tracer results showed that microbial growth decreased ground water velocity during the study, but returned to normal conditions 1 year after the last nutrient addition. In this study we were able to show that native microbial population was not able to degrade PCE to final end products. Therefore, it was necessary to introduce KB-1 culture a long with nutrients to support complete reductive dechlorination of PCE.

Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-07-10T19:17:06Z No. of bitstreams: 1 TESELL_5jul.pdf: 8671551 bytes, checksum: c59b1fb1df38a655609d9a3ce6cd7d50 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-07-13T20:27:02Z (GMT) No. of bitstreams: 1 TESELL_5jul.pdf: 8671551 bytes, checksum: c59b1fb1df38a655609d9a3ce6cd7d50 (MD5) / Made available in DSpace on 2018-07-13T20:37:40Z (GMT). No. of bitstreams: 1 TESELL_5jul.pdf: 8671551 bytes, checksum: c59b1fb1df38a655609d9a3ce6cd7d50 (MD5) Previous issue date: 2018-05-16 / The climate changes associated with the increase of greenhouse gases emissions to the atmosphere stand out as one of the greatest current environmental concerns. Extensive research is being conducted in order to reduce the amount of emissions and their impact on climate. Carbon dioxide (CO2) is the main greenhouse gas contributing to this problem. Therefore, it is increasingly important to find solutions to reduce CO2 levels in the atmosphere. Among the feasible techniques to reduce these emissions is the geological storage, which consists of injecting large amounts of this gas into deep underground geological formations. To be effective, CO2 must be trapped in these deep geological formations for at least several centuries. In this context, monitoring of CO2 leakages and seepages to sensitive environments is a key step in the process. Research on monitoring and verification of CO2 leakages in shallow environments are carried out in large areas prepared for controlled injection and leakage of this gas, this techniques for its detection are hard and expensive. In this sense, this study aims to verify the use of microcosms as a biomonitoring tool to control CO2 leakage by conducting controlled injections of CO2 into continuous flow columns under different experimental conditions. For this, physical, chemical and microbiological analyzes were performed in the soil before, during and after percolation of CO2 in the column. These parameters were also analyzed with in situ soil samples. Based on statistical methods at the end of the study, it was observed that the design of the columns was suitable, however, the chosen parameters were insufficient to determine the influence of CO2 on the proposed test conditions. / As mudan?as clim?ticas associadas ? intensifica??o do efeito estufa est?o entre as maiores preocupa??es ambientais atuais. Muita pesquisa tem sido realizada com o intuito de reduzir o impacto dos gases associados ao efeito estufa, dentre eles o di?xido de carbono (CO2). Devido ? grande contribui??o do CO2 para o aquecimento global, ? cada vez mais importante a realiza??o de estudos que visem a diminui??o de seus n?veis na atmosfera. Entre as t?cnicas vi?veis para conter estas emiss?es est? o armazenamento geol?gico de carbono, que consiste em injetar quantidades significativas deste g?s em forma??es geol?gicas. No entanto, para ser efetiva, o CO2 deve ficar retido nestas forma??es geol?gicas profundas, n?o retornando a superf?cie a longo prazo. Assim, o monitoramento de vazamentos de CO2 ? uma etapa fundamental no processo de armazenamento geol?gico. Estes estudos usualmente s?o realizados em ?reas extensas preparadas para testes controlados de inje??o e vazamento de g?s (geralmente trabalhosos e dispendiosos). Este trabalho teve como objetivo verificar a utiliza??o de microcosmos como ferramenta de biomonitoramento no controle de vazamento de CO2, realizando inje??es controladas de CO2 em colunas de fluxo cont?nuo em diferentes condi??es experimentais. Foram realizadas an?lises f?sico qu?micas e microbiol?gicas no solo antes, durante e ap?s a percola??o de CO2 na coluna. Esses par?metros tamb?m foram comparados com amostras do solo in situ. Com base em m?todos estat?sticos no fim do estudo foi observado que o projeto das colunas foi adequado, no entanto, os par?metros escolhidos foram insuficientes para determinar a influ?ncia do CO2 nas condi??es de ensaio proposta.

Les hydrocarbures aromatiques polycycliques (HAPs) sont des polluants organiques persistants (POP) émis essentiellement par les activités humaines suite à la combustion incomplète de la matière organique (industrie, chauffage, trafic routier...). En raison de leur faible taux de dégradation, de leur toxicité et de leur bioaccumulation, les HAPs font l'objet de plusieurs études d'écotoxicologie. La présente thèse, entreprise dans ce contexte par le biais d'une étude microcosmique se propose d'évaluer l'impact des HAPs sur la microflore et la méiofaune et d'appliquer différentes techniques de bioremédiation (biostimulation, bioaugmentation et combinaison des deux techniques) dans le but de dégrader les HAPs. Nos résultats ont montré que les HAPs sont toxiques aussi bien pour la microflore que pour la méiofaune de la lagune de Bizerte. Sur la microflore, l'effet toxique de ces contaminants s'est manifesté par l'inhibition de l'activité bactérienne à l'interface eau–sédiment et par la modification profonde de la structure des communautés bactériennes. En ce qui concerne la méiofaune, les HAPs ont entrainé une altération de la structure des communautés nématologiques. En effet, nous avons pu caractériser des espèces indicatrices de pollution par les HAPs. Ainsi, l'espèce Spirinia parasitifera dont la densité s'accroît dans tous les microcosmes contaminés par les HAPs paraît être une espèce “opportuniste” à la pollution par les HAPs. Cependant, Oncholaimus campylocercoïdes, fortement dominante dans tous les microcosmes témoins, a diminué de densité dans tous les microcosmes contaminés et a été considérée comme HAP-sensible. En analysant la structure des communautés microbiennes et méiofaunistiques, nous avons observé que la méiofaune joue un rôle structurant dans le maintien d'une communauté microbienne peu sensible aux effets des HAPs. Ce rôle structurant a été moins prononcé dans le cas d'ajout des sels nutritifs par la technique de biostimulation ; technique qui a présenté des effets non significatifs vis-à-vis des communautés nématologiques et a semblé plus efficace dans la minéralisation des HAPs et par conséquent à la réduction de leur effet toxique sur les organismes benthiques. Ces résultats suggèrent que la bioremédiation serait une alternative prometteuse à la dégradation des HAPs. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POP) emitted mainly by human activities due to the incomplete combustion of organic matter (industry, heating, traffic ...). Because of their low rate of degradation, their toxicity and their bioaccumulation, PAHs are main of concern in ecological studies. In this context, the objectives of this thesis were to assess the impact of PAHs on the benthic microflora and meiofauna and apply different techniques of bioremediation (biostimulation, bioaugmentation and combination of both treatments) in order to degrade PAHs, using experimental approach with microcosms.Our results showed that PAHs are toxic for microflora but also for meiofauna of Bizerta lagoon. The toxic effects of these contaminants were demonstrated by the inhibition of bacterial activity in the sediment/water interface and by profound changes in the structure of bacterial communities. PAHs provoked significant changes on meiofaunal community with the selection of nematode species that could be proposed as bioindicators of PAH pollution. Thus, Spirinia parasitifera which significantly (p<0.05) increased in PAH contaminated microcosms, suggesting that it is an "opportunistic» species to PAH pollution. In contrast, Oncholaimus campylocercoïdes, strongly dominant in control microcosms, decreased in PAH contaminated microcosms and seemed to be a ‘‘PAH-sensitive'' species.By analyzing the structure of microbial and meiofaunal community, we observed that the structural role of meiofauna on bacteria community structure was still evident even under PAH contamination despite the toxic effects on meiofauna. However, this structural role of meiofauna disappeared when nutrients were added to the sediment resulting in an almost complete removal of PAHs. Biostimulation seemed to be the most effective bioremediation strategy in the reduction of PAH toxic effects on benthic organisms. Overall, these results suggest that bioremediation using nutrient addition is a promising alternative technique for the degradation of PAHs in coastal polluted environments.