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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The use of biological methods for the assessment of oil contamination and bioremediation

Bundy, J. G. January 1999 (has links)
There is a concern that concentration-based targets for soil clean-up are arbitrary, and do not necessarily relate to the environmental threat posed by the residual contamination. The development of sensitive, reliable, and ecologically relevant biological tests for oil-polluted soils would address these problems, and form a valuable complement to chemical analysis. Three biological test systems were chosen for examining the impact of oil contamination on soil microbes: (1) lux-marked bacterial biosensors, (2) Biological carbon source utilization profiles, and (3) phospholipid fatty acid (PLFA) community profiles. This allowed the testing of effects at three different levels of ecological complexity: respectively, single species; culturable bacteria; and eubacteria and eukaryotes. The use of specific bioluminescent biosensors (i.e. with lux genes fused to promoters from hydrocarbon degradation pathways) allowed the rapid detection of different hydrocarbon classes. The bacterial biosensors were optimized for the assessment of hydrocarbon compounds. Development of quantitative structure-activity relationships (QSARs) increased understanding of their responses to hydrocarbons and other petroleum-derived compounds. The three biological methods were then used to monitor the nutrient-assisted bioremediation of oil-spiked soils in two separate microcosm experiments: (1) remediation of four crude oils and one refined oil compared using bacterial biosensors, and (2) effects of diesel on three different soil types, and effects of three refined oils on one soil type, assessed using Biolog and PLFA profiling. All three biological test methods were sensitive to the oil contamination levels applied in the microcosm experiments. Individual species (biosensor tests) gave different responses to different oils; however, the community-level responses showed no differences. The microbial communities of the three different soil types could still be distinguished after 14-15 weeks of hydrocarbon contamination. The community response of the contaminated soils had changed from that of the control soils after four weeks of bioremediation, and did not return in similarity to the control over the course of the experiment.
2

Avaliação de novos processos de limpeza para quantificação de pireno em amostra de mexilhão / Evaluation of new cleaning processes for quantification of pyrene in samples of mussels

Priscila Mendonça de Andrade 27 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os hidrocarbonetos policíclicos aromáticos (HPA) constituem um grupo de poluentes ambientais persistentes são moléculas com dois ou mais anéis aromáticos condensados, pouco solúveis em água e estão presentes no ambiente como resultante de processos naturais e também de atividades antrópicas; desta forma, os HPA podem ser encontrados em diversas matrizes ambientais. No presente trabalho foram utilizados mexilhões da região de Búzios, no Estado do Rio de Janeiro. Esse organismo foi selecionado devido à facilidade de acumulação de HPA nos tecidos, decorrente das propriedades hidrofóbicas dos HPA. O presente projeto teve como objetivo estudar um novo material de limpeza capaz de minimizar os compostos interferentes da matriz. Os cartuchos de SPE Florisil 5 g, são convencionalmente usados na limpeza de amostras de organismos, porém para diminuir os custos foram testados outros materiais adsorventes que pudessem ser eficientes na remoção dos interferentes presentes nos tecidos de mexilhão. Sendo assim, na etapa de limpeza conhecida como clean-up, foi estudada a recuperação do pireno após a extração por micro-ondas através de duas abordagens diferentes; a) utilização de cartuchos de SPE comerciais de 5 g de Florisil; b) cartuchos preenchidos com argila comercial K-10 bentonite, simulando os cartuchos comerciais. A recuperação e eficiência dos procedimentos de limpeza foram testadas e comparadas. A clean-up com argila K-10 apresentou uma recuperação de até 77% de pireno, sendo eficiente na remoção de compostos de colesteróis; confirmando a eficiência do material escolhido para a limpeza da amostra. A técnica de Cromatografia Gasosa e detecção por Espectrometria de Massas (GC-MS) foi aplicada para identificação e quantificação do contaminante pireno no extrato finaa / Polycyclic aromatic hydrocarbons (PAH) are a group of persistent environmental pollutants are molecules containing two or more condensed aromatic rings, little soluble in water and are present in the environment as a result of natural processes and human activities; in this way, the HPA can be found in various environmental matrices. In this work we used mussels in Búzios, Rio de Janeiro State. That body was selected due to the ease of accumulation of HPA in the tissues, due to the hydrophobic properties of HPA. This project aimed to study a new cleaning material able to minimize interfering compounds of the array. The 5 g Florisil SPE cartridges, are conventionally used in the cleaning of samples of organisms, however for lower costs have been tested other adsorbent materials which could be effective in the removal of the present in the tissues of mussels interfering. Therefore, in step of cleaning known as clean-up, recovery of pyrene was studied after extraction by microwave through two different approaches; a) use of commercial SPE cartridges 5 g of Florisil; b) cartridges filled with K-10 clay bentonite commercial, simulating the commercial cartridges. Recovery and efficiency of cleaning procedures were tested and compared. The clean-up with K-10 clay presented a recovery of up to 77% of pyrene, being effective in removing compounds of cholesterols; confirming the efficiency of the chosen material for cleaning of the sample. The technique of gas chromatography and detection by mass spectrometry (GC-MS) was applied for identification and quantification of contaminant pyrene in the final extract
3

Avaliação de novos processos de limpeza para quantificação de pireno em amostra de mexilhão / Evaluation of new cleaning processes for quantification of pyrene in samples of mussels

Priscila Mendonça de Andrade 27 February 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os hidrocarbonetos policíclicos aromáticos (HPA) constituem um grupo de poluentes ambientais persistentes são moléculas com dois ou mais anéis aromáticos condensados, pouco solúveis em água e estão presentes no ambiente como resultante de processos naturais e também de atividades antrópicas; desta forma, os HPA podem ser encontrados em diversas matrizes ambientais. No presente trabalho foram utilizados mexilhões da região de Búzios, no Estado do Rio de Janeiro. Esse organismo foi selecionado devido à facilidade de acumulação de HPA nos tecidos, decorrente das propriedades hidrofóbicas dos HPA. O presente projeto teve como objetivo estudar um novo material de limpeza capaz de minimizar os compostos interferentes da matriz. Os cartuchos de SPE Florisil 5 g, são convencionalmente usados na limpeza de amostras de organismos, porém para diminuir os custos foram testados outros materiais adsorventes que pudessem ser eficientes na remoção dos interferentes presentes nos tecidos de mexilhão. Sendo assim, na etapa de limpeza conhecida como clean-up, foi estudada a recuperação do pireno após a extração por micro-ondas através de duas abordagens diferentes; a) utilização de cartuchos de SPE comerciais de 5 g de Florisil; b) cartuchos preenchidos com argila comercial K-10 bentonite, simulando os cartuchos comerciais. A recuperação e eficiência dos procedimentos de limpeza foram testadas e comparadas. A clean-up com argila K-10 apresentou uma recuperação de até 77% de pireno, sendo eficiente na remoção de compostos de colesteróis; confirmando a eficiência do material escolhido para a limpeza da amostra. A técnica de Cromatografia Gasosa e detecção por Espectrometria de Massas (GC-MS) foi aplicada para identificação e quantificação do contaminante pireno no extrato finaa / Polycyclic aromatic hydrocarbons (PAH) are a group of persistent environmental pollutants are molecules containing two or more condensed aromatic rings, little soluble in water and are present in the environment as a result of natural processes and human activities; in this way, the HPA can be found in various environmental matrices. In this work we used mussels in Búzios, Rio de Janeiro State. That body was selected due to the ease of accumulation of HPA in the tissues, due to the hydrophobic properties of HPA. This project aimed to study a new cleaning material able to minimize interfering compounds of the array. The 5 g Florisil SPE cartridges, are conventionally used in the cleaning of samples of organisms, however for lower costs have been tested other adsorbent materials which could be effective in the removal of the present in the tissues of mussels interfering. Therefore, in step of cleaning known as clean-up, recovery of pyrene was studied after extraction by microwave through two different approaches; a) use of commercial SPE cartridges 5 g of Florisil; b) cartridges filled with K-10 clay bentonite commercial, simulating the commercial cartridges. Recovery and efficiency of cleaning procedures were tested and compared. The clean-up with K-10 clay presented a recovery of up to 77% of pyrene, being effective in removing compounds of cholesterols; confirming the efficiency of the chosen material for cleaning of the sample. The technique of gas chromatography and detection by mass spectrometry (GC-MS) was applied for identification and quantification of contaminant pyrene in the final extract
4

none

Chen, Hui-Chu 13 July 2002 (has links)
none
5

Environmental clean-up and property price change

Aronow, Emily January 1999 (has links)
No description available.
6

Fine grained sediment clean-up in a modern urban environment

Villemure, Marlene January 2013 (has links)
Fine grained sediment deposition in urban environments during natural hazard events can impact critical infrastructure and properties (urban terrain) leading to reduced social and economic function and potentially adverse public health effects. Therefore, clean-up of the sediments is required to minimise impacts and restore social and economic functionality as soon as possible. The strategies employed to manage and coordinate the clean-up significantly influence the speed, cost and quality of the clean-up operation. Additionally, the physical properties of the fine grained sediment affects the clean-up, transport, storage and future usage of the sediment. The goals of the research are to assess the resources, time and cost required for fine grained sediment clean-up in an urban environment following a disaster and to determine how the geotechnical properties of sediment will affect urban clean-up strategies. The thesis focuses on the impact of fine grained sediment (<1 mm) deposition from three liquefaction events during the Canterbury earthquake sequence (2010-2011) on residential suburbs and transport networks in Christchurch. It also presents how geotechnical properties of the material may affect clean-up strategies and methods by presenting geotechnical analysis of tephra material from the North Island of New Zealand. Finally, lessons for disaster response planning and decision making for clean-up of sediment in urban environments are presented. A series of semi-structured interviews of key stakeholders supported by relevant academic literature and media reports were used to record the clean-up operation coordination and management and to make a preliminary qualification of the Christchurch liquefaction ejecta clean-up (costs breakdown, time, volume, resources, coordination, planning and priorities). Further analysis of the costs and resources involved for better accuracy was required and so the analysis of Christchurch City Council road management database (RAMM) was done. In order to make a transition from general fine sediment clean-up to specific types of fine disaster sediment clean-up, adequate information about the material properties is required as they will define how the material will be handled, transported and stored. Laboratory analysis of young volcanic tephra from the New Zealand’s North Island was performed to identify their geotechnical properties (density, granulometry, plasticity, composition and angle of repose). The major findings of this research were that emergency planning and the use of the coordinated incident management system (CIMS) system during the emergency were important to facilitate rapid clean-up tasking, management of resources and ultimately recovery from widespread and voluminous liquefaction ejecta deposition in eastern Christchurch. A total estimated cost of approximately $NZ 40 million was calculated for the Christchurch City clean-up following the 2010-2011 Canterbury earthquake sequence with a partial cost of $NZ 12 million for the Southern part of the city, where up to 33% (418 km) of the road network was impacted by liquefaction ejecta and required clearing of the material following the 22 February 2011 earthquake. Over 500,000 tonnes of ejecta has been stockpiled at Burwood landfill for all three liquefaction inducing earthquake events. The average cost per kilometre for the event clean-up was $NZ 5,500/km (4 September 2010), $NZ 11,650/km (22 February 2011) and $NZ 11,185/km (13 June 2011). The duration of clean-up time of residential properties and the road network was approximately two to three months for each of the three liquefaction ejecta events; despite events volumes and spatial distribution of ejecta. Interviews and quantitative analysis of RAMM data revealed that the experience and knowledge gained from the Darfield earthquake (4 September 2010) clean-up increased the efficiency of the following Christchurch earthquake induced liquefaction ejecta clean-up events. Density, particle size, particle shape, clay content and moisture content, are the important geotechnical properties that need to be considered when planning for a clean-up method that incorporates collection, transport and disposal or storage. The geotechnical properties for the tephra samples were analysed to increase preparedness and reaction response of potentially affected North Island cities from possible product from the active volcanoes in their region. The geotechnical results from this study show that volcanic tephra could be used in road or construction material but the properties would have to be further investigated for a New Zealand context. Using fresh volcanic material in road, building or flood control construction requires good understanding of the material properties and precaution during design and construction to extra care, but if well planned, it can be economically beneficial.
7

Flow injection systems for process analytical chemistry

Lukkari, Ingrid January 1995 (has links)
Flow injection systems have great potential for sample handling and analysis in process analytical chemistry. The flexibility and versatility of flow injection manifolds can he utilized in specific applications of sample conditioning and analysis. An overview of various flow injection methods, including flow reversals, double injection, and sequential injection is given, as well as different clean-up methods, such as gas diffusion, solid phase extraction, dialysis, and solvent extraction. Calibration techniques, such as single standard and multivariate calibration are also discussed. In addition, different aspects of process analytical chemistry, in particular sampling and sample handling, are discussed. The papers in this thesis describe a number of flow systems, where gradient-, gas diffusion-, and solid phase extraction- methodologies are applied, all of which have potential use in process analytical chemistry. Paper I is focused on multicomponent analysis of mixtures of organic acids by mathematically extracting information from complex spectra. The selectivity is improved by generating pH-gradients in the flow system. In paper II, the methodology of sensor injection is described and electrochemical and spectroscopic sensors are implemented in a sequential injection system. The method is illustrated by using pH sensors and a glucose electrode. Ammonia and ammonium ions are determined on-line to a bioprocess by gas diffusion in paper III. The benefit of frequent re-calibrations and in-line cleaning sequences are demonstrated. Finally a method for on-line determination of o-diphenols in the kraft process has been developed (paper IV). The o-diphenols are isolated from black liquor samples by solid phase extraction and thereafter transferred to a high performance liquid chromatography system for separation and quantification. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1996, Härtill 4 uppsatser</p> / digitalisering@umu
8

Gasification of biomass : an investigation of key challenges to advance acceptance of the technology

Le, Chien Dinh January 2012 (has links)
Although the general principles of biomass gasification are broadly understood, at a larger scale of operation (e.g. > 200 kg/h) there is a lack of confidence in the translation of the basic scientific concepts into a financially viable operation that satisfies regulatory requirements. Looking in particular at the operation of a down-draft type of gasifier, a number of challenges were identified and studied in greater detail. Gasification experiments were performed on wood and straw pellets in a small scale, 21 mm i.d. quartz-tube reactor. These provided useful insight into what was occurring inside the gasifier, and the complexity and roles of the various reaction zones. In order to perform on-line gas analysis measurements in real time, a method was developed which enabled a quadrupole mass spectrometer (QMS) to be used. This was tested in a laboratory environment, and then used on a commercial pilot-plant gasifier (150 to 250 kg/h). This enabled the composition of the gas to be monitored while the plant was started up, and then operated at various levels of gas flow through the plant. In general the concentrations measured during a stable operation were as follows: CO = 16.0 vol.%, H2 = 11.9 vol.%, CO2 = 15.8 vol.%, N2 = 54.1 vol.%, CH4 = 1.9 vol.%, O2 = 0.3 vol.%. Measurements of O2 concentrations in the gas stream on start-up provide useful information on conditions when a flammable atmosphere could exist in the lines/vessels. To help with the development of suitable gas clean-up strategies, the presence of two key sulphur species, H2S and carbonyl sulphide (COS), was studied in more detail. Experimental measurements were taken on the laboratory reactor (e.g. H2S = 286 ppmv, COS = 28 ppmv for gasification of refuse-derived fuel (RDF) pellets), and the commercial pilot-scale gasifier (e.g. H2S = 332 ppmv, COS = 12 ppmv). This data was also compared with theoretical thermodynamic predictions. The steam gasification of char was also studied in a laboratory 9.5 mm i.d. reactor, and kinetic expressions were determined for RDF-derived char. It was shown that high concentrations of H2 (20 vol.%) and CO (15 vol.%) can be achieved, and the temperature at which reactions were initiated was > 700 ºC, and significant at 900 ºC. Interestingly, the RDF-derived char (at carbon conversion from 10 to 70 %) appears to be more reactive than other biochars reported in the literature. However, at high conversion (> 50 %), its apparent reactivity decreases with carbon conversion, behaving in a similar manner to coal chars.
9

Unravelling the chemistry behind the toxicity of oil refining effluents : from characterisation to treatment

Pinzón-Espinosa, Angela January 2018 (has links)
Adequate wastewater management is a crucial element to achieve water sustainability in the petroleum refining sector, as their operations produce vast quantities of wastewater with potentially harmful contaminants. Treatment technologies are therefore pivotal for stopping these chemicals from entering the environment and protecting receiving environments. However, refining effluents are still linked to serious pollution problems, partly because little progress has been made in determining the causative agents of the observed biological effects, resulting in non-targeted treatment. Here it is shown that naphthenic acids, which have been reported as toxic and recalcitrant, are important components of refining wastewater resulting from the processing of heavy crude oil and that they have a significant contribution to the toxic effects exerted by these effluents. Furthermore, it was found that their chemical stability makes them highly resistant to remediation using Pseudomonas putida and H2O2/Fe-TAML (TetraAmido Macrocyclic Ligands) systems under laboratory conditions, and only sequential aliquots of Fe-TAML catalysts and H2O2 showed to partially degrade naphthenic acids (50 mg/L) within 72 hours. Results suggest that a combinatorial approach of Fe-TAML/H2O2 followed by biodegradation might improve current treatment options, but further optimisation is required for the biological treatment. These results can serve as a starting point for better environmental regulations relevant to oil refining wastewater resulting from heavy crude oil, as naphthenic acids are not currently considered in the effluent guidelines for the refining sector. Furthermore, the degradation of naphthenic acids under mild conditions using Fe-TAML/H2O2 systems indicates that these catalysts hold promise for the remediation of refining wastewater in real-life scenarios.
10

Desenvolvimento de procedimento analítico para a determinação de ácido salicílico em materiais vegetais explorando cromatografia por injeção sequencial / Development of an analytical procedure for the determination of salicylic acid in plant materials exploiting sequential injection chromatography

Barrientos, Marcia Otto 24 July 2015 (has links)
A cromatografia por injeção sequencial com extração em fase sólida (EFS) em linha foi explorada para a determinação de ácido salicílico em amostras vegetais. Uma mini coluna de polietileno, preenchida com sílica funcionalizada C18, foi utilizada para EFS, com tampão fosfato pH 5,2 como eluente. O eluato foi diretamente transferido para a separação cromatográfica em uma coluna monolítica C18, utilizando solução de acetonitrila/tampão acetato pH 4,75 (5:95, v/v) como fase móvel. A detecção foi realizada por fluorescência com excitação em 298 nm e emissão em 406 nm. Os sinais analíticos foram baseados na altura do pico cromatográfico referente ao ácido salicílico em um tempo de retenção de 9.0 min. Os limites de detecção (99,7% de confiança) e quantificação foram estimados em 80 e 240 ?g L-1, respectivamente. A precisão foi estimada através do coeficiente de variação intradia (n = 10) em 0,99% e interdia (3 dias) em 3,6%. A resposta foi linear até 8,0 mg L-1 (r = 0,996). A resolução em relação aos demais componentes da matriz, o número de pratos e a altura equivalente a um prato foram estimados em 6,0; 3980 e 12,6 ?m, respectivamente. Utilizando calibração pelo método das adições de padrão, foram estimadas recuperações entre 74,2 e 96,4% em 4 amostras de folhas de soja. Com estes resultados conclui-se que o procedimento é adequado à determinação de ácido salicílico nos materiais vegetais com a remoção de interferentes em linha, tendo as vantagens de ser um procedimento rápido (ca. 17 min por determinação), limpo (consumo de ca. 320 ?L de acetonitrila por determinação), de custo relativamente baixo, suficientemente sensível e seletivo / Sequential injection cromatography with on-line solid phase extraction (SPE) was explored for the determination of salicylic acid in vegetable samples. A polyethylene column filled with C18-bonded silica was used for SPE, with a phosphate buffer pH 5.2 as eluent. The treated extract was directly sent towards chromatographic separation in a C18 monolithic column with an acetonitrile/acetate buffer solution, pH 4,75 (5:95, v/v) as mobile phase before fluorescence detection (excitation at 298 nm and emission at 406 nm). The analytical signals were based on peak height at the 9.0 min retention time. Limits of detection (99.7% confidence level) and quantification were estimated at 80 and 240 ?g L-1. Precision was estimated through intraday coefficient of variation (n = 10) at 0.99% and interday (3 days) at 3.6 %. A linear response up to 8.0 mg L-1 was estimated (r = 0.996). Resolution, number of plates and the height equivalent to one plate were estimated at 6.0, 3980 and 12,6 ?m, respectively. With calibration by the standard additions method recoveries within 74.2 and 96.4 % were estimated to four soy leaves samples. Thus, the procedure is suitable for the determination of salicylic acid in the extracts with on-line removal of interferences, being a rapid (ca. 17 min per determination), clean (ca. 320 ?L of acetonitrile by determination), inexpensive, and suitably sensitive and selective

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