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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.
81

Předpovídání směnného kurzu v České republice s použitím nelinárních prahových modelů / Forecasting the Exchange Rate in the Czech Republic Using Non-linear Threshold Models

Žák, Petr January 2017 (has links)
The aim of this thesis is to analyze the performance of nonlinear threshold models in forecasting the exchange rate of Czech koruna against EUR. Data for this study were obtained from Statistical Data Warehouse of European Central Bank (ECB) website, from Czech National Bank (CNB) Board decisions minutes and from the press releases of Governing Council of ECB. The data set was split into two periods - from 1999 until November, 2013 when CNB started to use interventions and from November, 2013 until April, 2016. Models used in the thesis are Self-Exciting Threshold Auto Regressive (SETAR) models with one and two thresholds and two Threshold Auto Regres- sive (TAR) models with different threshold variables - meetings of CNB Board as dummy variable and average volatility over recent periods. The forecasting results indicate that SETAR models did not outperform Random Walk in any period. TAR models offered promising results in the period before interventions and surprisingly failed in the period during interventions. This study supports the general belief of exchange rates being difficult to forecast and that it holds in case of Czech koruna as well. JEL Classification F12, F21, F23 H25, H71, H87 Keywords forecasting, exchange rate, time series, nonlin- earity, SETAR, TAR Author's e-mail zaka.one@gmail.com...
82

The effect of biomass, operating conditions, and gasifier design on the performance of an updraft biomass gasifier

James Rivas, Arthur Mc Carty January 1900 (has links)
Master of Science / Department of Biological and Agricultural Engineering / Wenqiao Yuan / Gasification is an efficient way to produce energy from biomass, which has significant positive impacts on the environment, domestic economy, national energy security, and the society in general. In this study, a lab-scale updraft biomass gasifier was designed, built, and instrumented for stable gasification using low-bulk density biomass. Related accessories, such as a biomass feeder, inlet air temperature controller, air injection nozzle, and tar cracking system, were also developed to enhance gasifier performance. The effect of operation parameters on gasifier performance was studied. Two operational parameters, including air flow rate and feed-air temperature, were studied on three sources of biomass: prairie hay, sorghum biomass, and wood chips. Results showed that higher air flow rate increased tar contents in syngas for all three types. It was also found that different biomasses gave significantly different tar contents, in the order of wood chips>sorghum biomass>prairie hay. Feed-air temperature did not have a significant effect on tar content in syngas except for prairie hay, where higher feed air temperature reduced tar. A statistical model was implemented to study differences on syngas composition. Results showed that different biomasses produced syngas with different high heating value, e.g., wood chips > prairie hay > sorghum biomass. CO composition also showed differences by feed air temperature and biomass, e.g. prairie hay>wood chips>sorghum biomass, but H[subscript]2 did not show significant differences by either biomass type or operating conditions. Moreover, because of the downstream problems caused by tars in syngas such as tar condensation in pipelines, blockage and machinery collapse, an in-situ tar cracking system was developed to remove tars in syngas. The tar cracking device was built in the middle of the gasifier’s combustion using gasification heat to drive the reactions. The in-situ system was found to be very effective in tar removal and syngas enhancement. The highest tar removal of 95% was achieved at 0.3s residence time and 10% nickel loading. This condition also gave the highest syngas HHV increment of 36% (7.33 MJ/m[superscript]3). The effect of gas residence time and Ni loading on tar removal and syngas composition was also studied. Gas residence of 0.2-0.3s and Ni loading of 10% were found appropriate in this study.
83

Investigating the effect of substituting fractions of imported coals with coke oven tar on coke quality: pilot plant study

Makgato, Seshibe Stanford 23 January 2015 (has links)
In this study, coke oven tar addition over a range of 0 – 8 wt.% was evaluated as a possible substitute for imported coals fractions. Coke oven tar used was collected from coke oven tar decanters of the by-products section of the coke making plant. Moisture content in coke oven tar varied depending on the residence time and water carryover from coke oven tar separators to storage tanks. Therefore, various moisture ranges were considered in order to observe its effect on coal blend, carbonization and coke properties. The optimum moisture content in coke oven tar was found to be 3% with a coke oven tar addition of 6 wt.% in the coal blend. At the same coke oven tar addition of 6 wt.% in the coal blend but with 6% moisture content in coke oven tar, coke properties improved, coke yield showed up to 4% decrease. On the other hand, with 1% moisture content in coke oven tar of 6 wt.% in the coal blend, coke yield increased by 1% and low coke properties such as I40 of 42.9 and Stability of 50.3 were achieved. The latter process was characterized by excessive increased in wall pressure and pushing energy. Both wall pressure and pushing energy increase are less desirable due to their detrimental effect on the physical condition of the oven walls. Furthermore, addition of coke oven tar with 1% moisture content to coal blend can be prohibited by its high viscosity. At 3% moisture content in coke oven tar addition of 6 wt.% in the coal blend, coke properties improved. When the amount of coke oven tar was increased to 8 wt.% at the optimum coke oven addition, coke yield was not affected but low CSR of 57.8 against a target of ³60 was achieved as opposed to CSR of 65.4 at 6 wt.%. Also, coke stability of 52.2 at 8 wt.% as opposed to 56.1 at 6 wt.% was achieved. Moreover, the highest I40 of 50.9 was achieved at 6 wt.% whereas with 8 wt.% coke oven tar, I40 of 47.9 was achieved. However, up to 2% decrease in coke yield was observed. Despite this 2% decrease in coke yield, coke oven tar addition is a positive and viable option based upon economic factors (i.e. this reduces the quantity and cost of imported coals and still achieves improved coke quality which result in improved blast furnace operation and better hot metal quality).
84

Fabricação de um sistema para decomposição de naftaleno e tolueno como compostos modeladores de alcatrão por meio da aplicação individual e combinada de plasma e micro-ondas / Fabrication of a system for the decomposition of naphthalene and toluene as tar model compounds by the individual and combined application of plasma and microwave.

Moreira, Lucia Hiromi Higa 08 February 2019 (has links)
Neste trabalho foi apresentado um sistema para decomposição de aerossóis partindo de soluções contendo naftaleno (C10H8) e tolueno (C7H8) diluídos em nitrogênio por meio da aplicação individual e combinada de plasma e micro-ondas. O naftaleno e o tolueno são chamados nesta tese como \"compostos modeladores de alcatrão\" como sugere a literatura. A disposição e geometria das câmaras de plasma e micro-ondas foram estabelecidas por meio do auxílio de simulações fluidodinâmicas empregando o FloEFD V.16 (Mentor Graphics) associado aos modelos sólidos desenhados no Solid Edge ST10 (SIEMENS). Os processos de coleta de resíduos dos compostos modeladores de alcatrão, seja das cinzas, sejam da fração não decomposta foram obtidos de acordo com um protocolo bem estabelecido baseado em estudos descritos na literatura. As concentrações de tolueno e naftaleno foram obtidas utilizando espectrometria de mobilidade iônica com ionização por electrospray (ESI-IMS). Não foram empregados materiais catalisadores. As densidades de energia empregadas ao longo deste trabalho foram 0,73, 1,22 e 1,98 kWh·m-3, sob uma vazão constante de 10 L·min-1 de N2 para concentrações de 3,0 e 5,0 g·m-3 de naftaleno e tolueno. As temperaturas empregadas na decomposição térmica assistida por micro-ondas foram de 845, 960 e 1.016 °C. Para cada uma das densidades de energia, considerando a concentração de 3,0 g·m-3 de naftaleno, as eficiências obtidas por meio do plasma foram de 48,3, 59,6 e 72,2%, enquanto que aplicando micro-ondas foram de 46,2, 57,9 e 68,2%. Por outro lado, considerando a concentração de 5,0 g·m-3, as eficiências foram 31,5, 45,9 e 64,8% para plasma e 26,6, 44,3 e 56,8% empregando a decomposição térmica assistida por micro-ondas, respectivamente. Analogamente, considerando a concentração de 3,0 g·m-3 de tolueno, as eficiências foram de 52,2, 69,9 e 84,5 % por meio de plasma e 49,3, 66,8 e 79,9% por meio de micro-ondas. Finalmente, considerando a concentração de 5,0 g·m-3, as eficiências foram 33,8, 60,7 e 80,7 % empregando plasma e 30,1, 54,1 e 72,9% empregando a decomposição térmica assistida por micro-ondas, respectivamente. Por meio do teste pareado de Wilcoxon, pôde ser afirmado com evidência estatística suficiente a 95% de certeza de que decomposição por plasma foi mais eficiente do que a decomposição térmica assistida por micro-ondas e SiC. / In this work a system for the aerosols decomposition from aerosols containing naphthalene (C10H8) and toluene (C7H8) diluted in nitrogen by means of the individual and combined application of plasma and microwaves was presented. Naphthalene and toluene are referred to in this thesis as \"modeling compounds of tar\" as suggested by the literature. The arrangement and geometry of the plasma and microwave chambers were established with the aid of fluid dynamics simulations using FloEFD V.16 (Mentor Graphics) associated to solid models drawn in Solid Edge ST10 (SIEMENS). The residues collection processes of the tar model compounds, whether from the ashes or from the non-decomposed fraction of the tar model compounds were constructed according to a protocol based on well-established studies presented in the literature. The toluene and naphthalene concentrations were obtained using ion mobility spectrometry with ionization by electrospray (ESI-IMS). No catalyst materials were used. The energy densities employed during this work were 0.73, 1.22 and 1.98 kWh·m-3, under a constant flow rate of 10 L·min-1 of N2 at concentrations of 3.0 and 5.0 g·m-3 of naphthalene and toluene. The temperatures obtained in microwave assisted thermal decomposition were 845, 960 and 1016 °C. For each of the energy densities, considering the concentration of 3.0 g·m-3 of naphthalene, the efficiencies obtained by means of plasma were 48.3, 59.6 and 72.2%, while applying microwave were 46.2, 57.9 and 68.2%. On the other hand, considering the concentration of 5.0 g·m-3, the efficiencies were 31.5, 45.9 and 64.8% for plasma and 26.6, 44.3 and 56.8% using decomposition microwave assisted thermal power, respectively. Similarly, considering the 3.0 g·m-3 concentration of toluene, the efficiencies were 52.2, 69.9 and 84.5% by means of plasma and 49.3, 66.8 and 79.9% by means of microwaves. Finally, considering the concentration of 5.0 g·m-3, efficiencies were 33.8, 60.7 and 80.7% using plasma and 30.1, 54.1 and 72.9% employing assisted thermal decomposition by microwave, respectively. The Wilcoxon paired test was applied and it was stated sufficient statistical evidence with a 95% level of certainty that plasma decomposition was more efficient than microwave and SiC assisted thermal decomposition.
85

Investigação Geofísica do Alto Estrutural de Anhembi - SP / Geophysical research of high structural Anhembi - SP

Francisco de Assis Cavallaro 10 December 2013 (has links)
Nesse trabalho são apresentados os resultados de levantamentos gravimétricos e magnetométricos feitos no Alto Estrutural de Anhembi, SP. Para a área total, foi adotada a escala de semi-detalhe, enquanto que, para a área de ocorrência de geiseritos, os levantamentos foram feitos em escala de detalhe. O Alto Estrutural de Anhembi registra dois eventos geológicos importantes durante a evolução da Bacia Sedimentar do Paraná, ou seja, uma intensa atividade geotermal no final do Permiano que produziu milhares de geiseritos, bem como a migração e o transporte do óleo da Formação Irati armazenados em arenitos da Formação Pirambóia causados pela intrusão de diques e sills associados ao vulcanismo da Formação Serra Geral. Esses reservatórios são agora arenitos asfálticos que afloram na borda da estrutura circular, mostrando que eles estão localizados na base da Formação Pirambóia. O levantamento gravimétrico de semi-detalhe mostra uma anomalia positiva na direção NW-SE superposta ao rio Tietê, que indica uma forte correlação com o Lineamento Tietê. Esta é a prova de que, durante a sedimentação das formações do final do Permiano , havia um alto estrutural separando as formações Serra Alta, Teresina e Rio do Rasto a sul do rio Tietê, da Formação Corumbataí a norte do mesmo rio. Além disso, a anomalia gravimétrica residual também mostra uma feição aproximadamente circular coincidindo com a área de afloramentos da Formação Teresina no centro do Alto Estrutural de Anhembi. O padrão e forma da anomalia gravimétrica residual confirmam que as rochas do embasamento estão dispostas em blocos escalonados resultados do efeito dominó. Na realidade, a estrutura das rochas do embasamento é reproduzida na superfície por falhas e lineamentos. Levantamentos de semi-detalhe não mostram qualquer possível rocha ígnea como fonte de calor sob a área dos geiseritos. Os resultados sugerem que uma possível falha ao longo do córrego do Retiro tenha servido como conduto principal para a água quente vindo do embasamento. A fonte de calor está associada com a deformação dúctil ocorrida no interior da crosta e do manto superior. / In this work results from gravity and magnetic surveys done on Anhembi Structural High, SP, are presented. For whole area a large scale surveying was adopted while for outcropping area of geyserites both gravity and magnetic surveys were done at a small scale. This structural high records two important geological events during the evolution of the Paraná Sedimentary Basin, that is, an intense geothermal activity in Late Permian that produced thousands of geyserites, and migration and transport of oil from the Irati formation trapped into sandstones of the Pirambó ia Formation caused by intrusion of sills and dykes associated with the Serral Geral volcanism. These reservoirs are now tar sand deposits that outcrop in the border of the circular structure showing that they are located in the bottom of the Piramboia Formation. Gravity survey at large scale shows a positive anomaly in NW-SE direction matching the Tietê river which indicates a strong association with Tiet ê Lineament. This is the proof that during sedimentation of Late Permian formations there was a structural high along this lineament separating Serra Alta, Teresina and Rio do Rasto formations occurring southern Tietê river from the Corumbatai formation that occurs only northern this river. Moreover, residual gravity anomaly also shows an approximately circular feature matching the outcropping area of the Teresina formation in the center of the structural high. The pattern and shape of this residual gravity anomaly also confirms that the basement rocks are broken into blocks laying each other such as domino effect. Actually, the structure of t he basement rocks is reproduced on the ground by faults and lineaments. Small scale surveys do not show any possible igneous rock as heat source under the area of geyserites. Results suggest that a possible fault existed along the Retiro river served as the main conduct for hot water coming from the basement. The heat source is associated with ductile deformation occurred under the crust and upper mantle.
86

Investigação Geofísica do Alto Estrutural de Anhembi - SP / Geophysical research of high structural Anhembi - SP

Cavallaro, Francisco de Assis 10 December 2013 (has links)
Nesse trabalho são apresentados os resultados de levantamentos gravimétricos e magnetométricos feitos no Alto Estrutural de Anhembi, SP. Para a área total, foi adotada a escala de semi-detalhe, enquanto que, para a área de ocorrência de geiseritos, os levantamentos foram feitos em escala de detalhe. O Alto Estrutural de Anhembi registra dois eventos geológicos importantes durante a evolução da Bacia Sedimentar do Paraná, ou seja, uma intensa atividade geotermal no final do Permiano que produziu milhares de geiseritos, bem como a migração e o transporte do óleo da Formação Irati armazenados em arenitos da Formação Pirambóia causados pela intrusão de diques e sills associados ao vulcanismo da Formação Serra Geral. Esses reservatórios são agora arenitos asfálticos que afloram na borda da estrutura circular, mostrando que eles estão localizados na base da Formação Pirambóia. O levantamento gravimétrico de semi-detalhe mostra uma anomalia positiva na direção NW-SE superposta ao rio Tietê, que indica uma forte correlação com o Lineamento Tietê. Esta é a prova de que, durante a sedimentação das formações do final do Permiano , havia um alto estrutural separando as formações Serra Alta, Teresina e Rio do Rasto a sul do rio Tietê, da Formação Corumbataí a norte do mesmo rio. Além disso, a anomalia gravimétrica residual também mostra uma feição aproximadamente circular coincidindo com a área de afloramentos da Formação Teresina no centro do Alto Estrutural de Anhembi. O padrão e forma da anomalia gravimétrica residual confirmam que as rochas do embasamento estão dispostas em blocos escalonados resultados do efeito dominó. Na realidade, a estrutura das rochas do embasamento é reproduzida na superfície por falhas e lineamentos. Levantamentos de semi-detalhe não mostram qualquer possível rocha ígnea como fonte de calor sob a área dos geiseritos. Os resultados sugerem que uma possível falha ao longo do córrego do Retiro tenha servido como conduto principal para a água quente vindo do embasamento. A fonte de calor está associada com a deformação dúctil ocorrida no interior da crosta e do manto superior. / In this work results from gravity and magnetic surveys done on Anhembi Structural High, SP, are presented. For whole area a large scale surveying was adopted while for outcropping area of geyserites both gravity and magnetic surveys were done at a small scale. This structural high records two important geological events during the evolution of the Paraná Sedimentary Basin, that is, an intense geothermal activity in Late Permian that produced thousands of geyserites, and migration and transport of oil from the Irati formation trapped into sandstones of the Pirambó ia Formation caused by intrusion of sills and dykes associated with the Serral Geral volcanism. These reservoirs are now tar sand deposits that outcrop in the border of the circular structure showing that they are located in the bottom of the Piramboia Formation. Gravity survey at large scale shows a positive anomaly in NW-SE direction matching the Tietê river which indicates a strong association with Tiet ê Lineament. This is the proof that during sedimentation of Late Permian formations there was a structural high along this lineament separating Serra Alta, Teresina and Rio do Rasto formations occurring southern Tietê river from the Corumbatai formation that occurs only northern this river. Moreover, residual gravity anomaly also shows an approximately circular feature matching the outcropping area of the Teresina formation in the center of the structural high. The pattern and shape of this residual gravity anomaly also confirms that the basement rocks are broken into blocks laying each other such as domino effect. Actually, the structure of t he basement rocks is reproduced on the ground by faults and lineaments. Small scale surveys do not show any possible igneous rock as heat source under the area of geyserites. Results suggest that a possible fault existed along the Retiro river served as the main conduct for hot water coming from the basement. The heat source is associated with ductile deformation occurred under the crust and upper mantle.
87

La création et la répartition de la valeur en droit fiscal international / Value creation and allocation in international tax law

Vergnet, Nicolas 01 December 2018 (has links)
La crise financière de 2008 et l’accroissement considérable de l’endettement public qui en a résulté ont mis au centre des priorités politiques contemporaines la nécessité de veiller à un alignement entre la fiscalité internationale et la création de valeur. Cette contemporanéité de l’enjeu ne doit pas occulter la redondance de ses causes avec celles qui ont présidé à la mise en place des premiers modèles de conventions fiscales bilatérales durant l’entre-deux-guerres sous l’égide de la Société des Nations. L’étude des travaux de l’organisation durant les années 1920 ainsi que de leur reprise par l’OECE puis l’OCDE au cours de la seconde moitié du XXème siècle permet de constater que l’ordre fiscal international actuel repose sur une logique d’alignement de la répartition de la matière taxable avec la géographie de la création de valeur. L’étonnement que suscite cette constatation lorsqu’elle est mise en perspective avec les critiques faites au système fiscal international actuel invite plus que jamais à étudier les rapports qu’entretient ce dernier avec la création de valeur : leurs connexions, leurs déconnexions, et les tentatives de reconnexions dont ils font l’objet. / The 2008 financial crisis and the resulting significant increase in public debt have put the focus of today's political priorities on the need to tax profits in accordance with value creation. The topicality of this issue must not overshadow the striking similarity of its causes with those that led to the drafting of the first model tax treaties in the 1920s under the aegis of the League of Nations. A study of the organisation's work, built on by the OEEC, and the OECD in the second half of the 20th century, shows that the current international tax system already tends to align jurisdiction to tax with value creation. This observation is surprising when put in perspective with the criticisms of the current international tax order. It invites us more than ever to study the relationship between the international tax system and value creation: their connections, their disconnections, and the attempts to reconnect them.
88

Thermochemical and Catalytic Upgrading in a Fuel Context : Peat, Biomass and Alkenes

Hörnell, Christina January 2001 (has links)
No description available.
89

Pyrolysis of biomass. Rapid pyrolysis at high temperature. Slow pyrolysis for active carbon preparation.

Zanzi, Rolando January 2001 (has links)
Pyrolysis of biomass consists of heating solid biomass inthe absence of air to produce solid, liquid and gaseous fuels.In the first part of this thesis rapid pyrolysis of wood(birch) and some agricultural residues (olive waste, sugarcanebagasse and wheat straw in untreated and in pelletized form) athigh temperature (800ºC–1000ºC) is studied ina free fall reactor at pilot scale. These conditions are ofinterest for gasification in fluidized beds. Of main interestare the gas and char yields and compositions as well as thereactivity of the produced char in gasification. A higher temperature and smaller particles increase theheating rate resulting in a decreased char yield. The crackingof the hydrocarbons with an increase of the hydrogen content inthe gaseous product is favoured by a higher temperature and byusing smaller particles. Wood gives more volatiles and lesschar than straw and olive waste. The higher ash content inagricultural residues favours the charring reactions. Charsfrom olive waste and straw are more reactive in gasificationthan chars from birch because of the higher ash content. Thecomposition of the biomass influences the product distribution.Birch and bagasse give more volatiles and less char thanquebracho, straw and olive waste. Longer residence time inrapid pyrolysis increase the time for contact between tar andchar which makes the char less reactive. The secondary charproduced from tar not only covers the primary char but alsoprobably encapsulates the ash and hinders the catalytic effectof the ash. High char reactivity is favoured by conditionswherethe volatiles are rapidly removed from the particle, i.e.high heating rate, high temperature and small particles. The second part of this thesis deals with slow pyrolysis inpresence of steam for preparation of active carbon. Theinfluence of the type of biomass, the type of reactor and thetreatment conditions, mainly temperature and activation time,on the properties and the yield of active carbons are studied.The precursors used in the experiments are birch (wood) anddifferent types of agricultural residues such as sugarcanebagasse, olive waste, miscanthus pellets and straw in untreatedand pelletized form. The results from the pyrolysis of biomass in presence ofsteam are compared with those obtained in inert atmosphere ofnitrogen. The steam contributes to the formation of solidresidues with high surface area and good adsorption capacity.The yield of liquid products increases significantly at theexpense of the gaseous and solid products. Large amount ofsteam result in liquid products consisting predominantly ofwater-soluble polar compounds. In comparison to the stationary fixed bed reactor, therotary reactor increases the production of energy-rich gases atthe expense of liquid products. The raw materials have strong effect on the yields and theproperties of the pyrolysis products. At equal time oftreatment an increase of the temperature results in a decreaseof the yield of solid residue and improvement of the adsorptioncapacity until the highest surface area is reached. Furtherincrease of the temperature decreases the yield of solidproduct without any improvement in the adsorption capacity. Therate of steam flow influences the product distribution. Theyield of liquid products increases while the gas yielddecreases when the steam flow is increased. <b>Keywords</b>: rapid pyrolysis, pyrolysis, wood, agriculturalresidues,biomass, char, tar, gas, char reactivity,gasification, steam, active carbon
90

Miljöteknisk undersökning enligt MIFO : en studie på fastigheten Bodsjölandet 1:14 avseende den nedlagda tjärfabriken i Grötingen

Ed, Maria January 2006 (has links)
During 40 years of industrial production, from the end of the 1890’s until the end of 1930’s, coal and wood distillation products were manufactured in AB Carbo’s tar factory along the River Gimån in Grötingen, in the county of Jämtland, Sweden. In accordance with the Swedish Environmental Protection Agency’s Methods for Inventories of contaminated sites, MIFO, the site in Grötingen has been identified as a potentially contaminated site. In order to determine whether toxic substances pose a threat to human health and ecological systems in the area, there was a need to investigate the presence of contaminants, their levels and potential for migration. Sensitivity and protection value regarding exposure of man and the environment at the site is high, since people live next to the site and River Gimån is a part of the Natura 2000 network. The initial phase of the MIFO method includes a preliminary survey. Information regarding AB Carbo’s activities and production has been obtained by studying map and archive material, as well as by interviews and site inspections. Potential point sources have been identified around the factory forge, storage cellar, distillation building and the wooden channel for the discharge of tar and other condensates into the River Gimån. Guided by the information gathered in MIFO phase 1, a preliminary site investigation was carried out at the site. It included sampling of soil, sediment, groundwater and surface water together with sample analysis of heavy metals and organic pollutants. The result of the analysis shows that very high levels of the contaminants PAH, aromatics and lead are found in both soil and groundwater. The sediment contamination level is high while that of surface water is very low. The distribution of contamination levels among the samples indicates a likely point source close to the distillation building due to very high contamination levels in soil and groundwater close to that point. The point source may represent a larger spillage or dumped waste products. Two of the contaminants present at the site, phenantrene and phenol, were studied by using the model CHEMFLO-2000. The analysis focussed on mobility in unsaturated soils under conditions that prevail at the site in Grötingen. The adsorption of phenantrene is significantly higher in comparison to that of phenol. Comprehensive assessment and risk classification results in risk class 2 for the site in Grötingen, which implies a need for further investigations and measurements. The risk of human exposure could be reduced by removing contaminated soil around the factory forge. Additional studies should focus on finding the location of the point source around the distillation building as well as contaminant migration from the wooden channel and the geographical spreading of heavy metal contamination. / Från slutet av 1890-talet och fram till slutet av 1930-talet tillverkades träkol och trädestillationsprodukter vid AB Carbos kolugnsanläggning i Grötingen, Jämtlands län. En undersökning enligt MIFO-modellen motsvarande fas 1 och fas 2 har genomförts på området med syfte att fastställa vilka föroreningar som förekommer på området, föroreningsnivå, spridningsförutsättningar och sammanfattningsvis bedöma föroreningssituationen på området utifrån de miljö- samt hälsorisker som området ger eller kan ge upphov till. Objektsområdet har hög känslighet och högt skyddsvärde då människor bor permanent alldeles intill objektsområdet samt att det intilliggande vattendraget Gimån ingår i Natura 2000-nätverket. Genom de orienterande studier som genomfördes i MIFO fas 1 har kart- och arkivstudier samt intervjuer resulterat i information om kolugnsanläggningens verksamhet samt tillverkade produkter. På fabriksområdet identifierades potentiella punktkällor vid fabrikens smedja, källare, reningsverk samt vid den träränna varigenom spilltjära släpptes ut till Gimån. Utifrån den information som erhölls i den orienterande fasen genomfördes en riktad provtagning enligt MIFO fas 2 i såväl mark och sediment som grund- och ytvatten. Bedömning av uppmätta föroreningshalter baseras på riktvärden och skattas från mindre allvarliga till mycket allvarliga. Analysresultaten påvisar allvarliga till mycket allvarliga halter av PAH, aromater och bly i jorden och grundvattnet. Andra föroreningar som påvisas i högre halter på området är alifater och koppar. Föroreningsnivån med avseende på PAH i sedimenten bedöms som allvarlig medan analysresultaten från ytvattenprovtagningen påvisar mycket låga föroreningsnivåer. Provtagningsresultaten påvisar ett mycket förorenat grundvattenflöde från reningsverket, där en punktkälla i form av större spill eller nedgrävda förvaringskärl kan vara lokaliserad. Eventuell spridning av föroreningar från trärännan går inte att fastställa då föroreningsspridning även kan ske från det intilliggande området där kolugnar och kondenseringshus har varit lokaliserade. Föroreningarna fenantren och fenol studerades genom modellering i CHEMFLO-2000 med avseende på deras rörlighet i omättad jord under de geohydrologiska förhållanden som råder på objektsområdet i Grötingen. Resultatet visar att fenantren adsorberas i marken i betydligt större grad än fenol. Koncentrationen fenantren i porvattnet minskar nästan lika mycket som den totala koncentrationen fenantren i marken, vilket tyder på att fenantren binds starkt genom adsorbtion i marken. Den samlade riskbedömningen av objektet resulterar i att objektet bedöms tillhöra riskklass 2, vilket innebär att objektet ger upphov till en stor risk för människa och miljön. Fortsatta undersökningar på området i Grötingen bör fokusera på att hitta den punktkälla vid reningsverket som bedöms vara orsaken till de höga föroreningsnivåer som uppmättes i grundvattenrör V1. Den geografiska utbredningen av de ytliga föroreningarna som påträffades där smedjan har stått bör också utredas vidare och eventuellt avlägsna förorenad jord eller vidta åtgärder för att minska exponeringen. Vidare undersökningar bör även klarlägga spridningen från trärännan samt orsakerna till de höga föroreningsnivåer av bly som uppmättes på området.

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