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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

Analysis Of The Heterogeneity Scale Effects On Pump And Treat Aquifer Remediation Design

Gungor Demirci, Gamze 01 May 2009 (has links) (PDF)
The effect of heterogeneity correlation scale (&amp / #61548 / ) of hydraulic conductivity (K), equilibrium distribution coefficient (Kd) and mass transfer rate (&amp / #61537 / ) on the design and cost of the P&amp / T remediation system for different heterogeneity levels (defined by the variance (&amp / #963 / 2lnK)) and parameter distributions under the rate-limited sorption conditions was evaluated in this study. In addition, the impacts of initial amount of contaminant mass and plume configuration on the remediation design and cost were explored. The effects of different K heterogeneity and remediation design conditions on the length of remediation period, the influence of &amp / #61548 / anisotropy of K, correlation between K and Kd, and Kd and &amp / #61537 / , and the fraction of equilibrium sorption sites (f) on the pump-and-treat (P&amp / T) design and cost were the other studied subjects. In this study, simulation-optimization approach, in which a groundwater flow and contaminant transport simulation model was linked with a genetic algorithm (GA) library, was used. Results showed that not only the amount of PCE mass initially present in the aquifer was important in terms of P&amp / T design, cost and remediation time, but also the location and size of the high and low K regions defined by &amp / #955 / lnK as well as the magnitudes of K represented by geometric mean and &amp / #963 / 2lnK were influential. It was also found that P&amp / T designs utilizing higher numbers of wells with lower pumping rates may be more robust predicting the time-to-compliance compared to a single well with higher pumping rate for aquifers heterogeneous in K. Homogenous Kd assumption might cause serious error in both the design and the cost of remediation. The magnitude of this error may change depending on the spatial distribution of K and Kd, &amp / #955 / lnKd, &amp / #963 / 2lnKd and &amp / #963 / 2lnK. The effect of heterogeneity in &amp / #61537 / on the design and cost of remediation may or may not be significant depending on K, Kd and &amp / #61537 / distributions, &amp / #61548 / ln&amp / #61537 / and &amp / #963 / 2ln&amp / #61537 / . Increased amount of kinetically sorbed mass defined by decreased f value resulted in more costly remediation.
82

Dark Fermentative Bio-hydrogen Production From Sugar-beet Processing Wastes

Ozkan, Leyla 01 August 2009 (has links) (PDF)
In this study, bio-hydrogen generation potential of sugar-beet processing wastes (sugar-beet processing wastewater and beet-pulp) through dark fermentation was investigated. For this purpose, four different experimental set-ups were used. In the first set-up, sugar-beet processing wastewater was used along with four different cultures to investigate the effect of culture type on bio-hydrogen production. In addition, unseeded reactor was prepared to investigate bio-hydrogen production potential of indigenous microorganisms. The highest bio-hydrogen production yield (87.7 mL H2/g COD) was observed in the unseeded reactor. In the second set-up, beet-pulp was compared with sugar-beet processing wastewater in terms of bio-hydrogen generation potentials at an initial COD level of 4.5 g/L. In the third set-up, bio-hydrogen productivities of only beet-pulp and co-digestion of beet-pulp and sugar-beet processing wastewater at high COD values were investigated. The results of third set-up revealed that the reactor fed by 20 g/L COD beet-pulp provided the highest bio-hydrogen production yield (95.6 mL H2 /g COD). Finally, in the fourth set-up, the effects of five different pretreatment methods on solubilization of beet-pulp were investigated. Then, three out of five pretreatment methods were chosen to compare the corresponding bio-hydrogen productivities. Maximum bio-hydrogen production yield (115.6 mL H2/g COD) was observed in reactor which contained alkaline pretreated beet-pulp. Based on the results obtained in this study, it is postulated that, bio-hydrogen production from sugar-beet processing wastes by dark fermentation can not only enable waste minimization but also contribute to sustainability via valuable bio-based product formation from wastes, namely bio-hydrogen.
83

Application Of Two Receptor Models For The Investigation Of Sites Contaminated With Polychlorinated Biphenyls: Positive Matrix Factorization And Chemical Mass Balance

Demircioglu, Filiz 01 June 2010 (has links) (PDF)
This study examines the application of two receptor models, namely Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB), on the investigation of sites contaminated with PCBs. Both models are typically used for apportionment of pollution sources in atmospheric pollution studies, however have gained popularity in the last decade on the investigation of PCBs in soil/sediments. The aim of the study is four-fold / (i) to identify the status of PCB pollution in Lake Eymir area via sampling and analysis of PCBs in collected soil/sediment samples, (ii) to modify the CMB model software in terms of efficiency and user-friendliness (iii) to apply the CMB model to Lake Eymir area PCB data for apportionment of the sources as well as to gather preliminary information regarding degradation of PCBs by considering the history of pollution in the area (iv) to explore the use of PMF for both source apportionment and investigation of fate of PCBs in the environment via use of Monte-Carlo simulated artificial data sets. Total PCB concentrations (Aroclor based) were found to be in the range of below detection limit to 76.3 ng/g dw with a median of. 1.7 ng/g dw for samples collected from the channel between Lake Mogan and Lake Eymir. Application of the CMB model yield contribution of highly chlorinated PCB mixtures (Aroclor 1254 and Aroclor 1260 / typically used in transformers) as sources. The modified CMB model software provided user more efficient and user friendly working environment. Two uncertainty equations, developed and existing in literature, were found to be effective for better resolution of sources by the PMF model.
84

Development Of Risk Based Soil Quality Standards For Turkey

Ipek, Hatice Meltem 01 March 2011 (has links) (PDF)
Soil quality standards (SQSs) are one of the most important elements of management system for contaminated sites. In order to manage risks associated with soil contamination, risk based SQSs are used worldwide. However, in Turkey, the Soil Pollution Control Regulation in force was focusing mainly on the use of stabilized sludge on soil and was including standards for a limited number of parameters, mainly metals and some organic chemicals. Thus, existing SQSs were far away from providing common criteria for assessment of the soil quality. In this study, the aim was to develop human health risk based SQSs for Turkey. For derivation of risk based SQSs, the conceptual framework and technical infrastructure were established. SQSs were derived for 151 chemical substances and for three different land use types by incorporating generic site characteristics for Turkey. Since SQSs are highly sensitive to site conditions and chemical-specific data used in calculations, a Microsoft Excel based exposure model was developed as a technical tool. This tool serves for calculation of generic and site-specific SQSs and maintenance of the currency of the standards by allowing periodic update of data used in calculations. Besides, a hydrogeologic database was developed to provide information on the general soil and hydrogeologic characteristics that are used in derivation of SQSs. This database is ultimately, expected to serve for development of conceptual site models, sampling strategies, and derivation of dilution factors during risk assessment studies. As a result, this study presents a general perspective and approach for derivation of human health risk based SQSs. It is believed that the developed conceptual and technical infrastructure will contribute to contaminated site management and risk assessment studies conducted by the regulatory authorities and the other stakeholders in Turkey.
85

Treatability And Toxicity Of Nonylphenol Compounds In Anaerobic Batch Reactors

Bozkurt, Hande 01 December 2011 (has links) (PDF)
Nonylphenol (NP) and its ethoxylates are used in formulation of pesticides and detergents, production of personal care products and many industrial sectors such as textile, metal plating, plastic, paper and energy. They are also used in the formulation of household cleaning agents. Industrial uses in the production line make up 55% of the total use / whereas industrial and domestic cleaning processes constitute 30 and 15%, respectively. Since they are widely used in industry and households, NP compounds enter the environment mainly by industrial and municipal wastewater treatment plant effluents. NP is considered strongly toxic and has adverse effects even with short term exposures. Moreover, with its similarities to natural hormones, NP and its ethoxylates are considered as endocrine disrupter compounds. In studies conducted with human cells, chicken embryo, trout and mice eostrogen receptors, positive responses were observed. Due to their lipophilic and hydrophobic characteristics they accumulate in cells, tissues and organic materials such as sludge. For these reasons, fate of NP and its v ethoxylates in wastewater treatment plants and in sludge treatment processes gained importance. Nonylphenol polyethoxylates (NPnEO) are degraded in microbial media and lose their ethoxylates to nonylphenol diethoxylate (NP2EO), nonylphenol monoethoxylate (NP1EO) and NP. Moreover, nonyl phenoxycarboxylic acids (NPnEC) can be formed during some of these reactions. Because the first degradation reactions are fast, concerns and studies are focused mainly on NP2EO, NP1EO, NP, NP1EC and NP2EC. Even though these general degradation information is available, studies on sludge are very rare. In this study, treatability and toxicity of NP2EO in anaerobic batch reactors is investigated. First, with the use of Anaerobic Toxicity Assay (ATA) test, toxic doses of NP2EO which was added to the reactor as the parent component, were determined. Moreover, the degradation of these chemicals were studied in larger scale batch anaerobic digesters. The aim of this part was to observe the degradation patterns and products. Throughout the study the fate of NP and its ethoxylates was followed in aqueous and solid phases by the use of Gas Chromatography / Mass Spectrometry system (GC/MS). ATA tests showed that NP2EO was not toxic to anaerobic microorganisms at the doses investigated in this study. It was rather stimulating and caused an increase in methane production in the reactors. On the other hand the spiked NP2EO&rsquo / s at 0.5 and 2.5 mg/L concentration were completely degraded in the larger scale batch reactors. At the same time, an increase in the concentrations of NP and NP1EO was observed which supported the fact that NP2EO was degraded into NP1EO and NP under anaerobic conditions. Abiotic degradation was not observed.
86

Modeling Anaerobic Dechlorination Of Polychlorinated Biphenyls

Demirtepe, Hale 01 February 2012 (has links) (PDF)
This study aims to investigate the fate of polychlorinated biphenyls (PCBs) in sediments via using an anaerobic dechlorination model (ADM). PCBs are ubiquitous environmental pollutants, accumulated mostly in aquatic sediments. Significant attention was placed on the anaerobic dechlorination of PCBs since this process leads to the conversion of highly-chlorinated biphenyls to lower chlorinated ones, resulting in less toxic and more biodegradable congeners. An ADM was developed previously for the identification and quantification of anaerobic dechlorination pathways. In the present study, this model was improved and applied to laboratory and environmental sediment PCB data from Baltimore Harbor (BH), Maryland, USA, where PCB contamination has been recorded. The laboratory PCB data was from a 500 day microcosm study conducted with BH sediments which was used to validate the model, as well as to gather information on dominant dechlorination pathways affecting the sediments. ADM predicted the laboratory PCB data almost perfectly and subsequently very well predicted the environmental sediment PCB profiles. A complete identification and quantification of the anaerobic dechlorination pathways occurring in the BH sediments is achieved with this study for the first time. The significant similarity between the sediment sample PCB profiles and the model predicted profiles reveals that the BH sediments have undergone anaerobic dechlorination via a combination of previously identified dechlorination activities (N, P, M) with selective pathways. Model findings are consistent with microbial analysis of the sediments. Better understanding of anaerobic dechlorination mechanisms should aid in predicting natural attenuation of PCBs or developing bioremediation strategies for contaminated sites.
87

Environmental Risk Assessment and Leachate Evolution at the Ekebyboda Landfill Site, Uppland, Sweden. / Miljöriskbedömning och lakvattenutvecklingvid Ekebyboda deponi, Uppland, Sverige

Fors, Jonas January 2015 (has links)
Ekebyboda is a closed landfill north west of Uppsala where the leachate water was studied to evaluate the status of the landfill for, the Uppsala environmental office. Leachate water has been measured continually for different parameters, during the period 1959-2007. The landfill differs from other landfills because of its mixed content of domestic and industrial waste. Close to the investigated area is a small number of residents with private water wells which enhances the importance of the investigation of the landfill. In this thesis, the period 1990 -2007 is the investigated with an additional measurement during 2014. Precipitation data is compared with leachate water composition, to evaluate correlations between leachate water and precipitation. Correlation between leachate water, and precipitation also gave an indication of the status of the cover on the landfill during, 2014. Due to the problematic history of Ekebyboda the aim of the thesis is to evaluate the status of the landfill and do a risk classification according to MIFO, which is a classification system for polluted sites from the Swedish Environmental Protection Agency. Measurements were made in four wells in the spring of 2014. These results showed a decline in eight analysed parameters and increase or stagnant trend for pH, NO3- + NO2 and SO42-. Most of the parameters have large fluctuations during the period. A field investigation is also show a non-functional culvert system with stagnant water and indications of water running in the direction of the residential area due to malfunctioning pumps. The stagnant water and problematic culvert system raised concerns for the quality of the datasets. The data analysis shows that the correlation between precipitation and leachate water was non-existent and the second covering of the landfill has reduced the amount of infiltrating water. Analysis of the leachate water and problematic management of leachate water were two major causes for a high risk classification. The MIFO classification of this landfill was set as one which is the highest possible which mainly was due to a possible risk for contamination for private water wells. / Ekebyboda är en nedlagd deponi nordväst om Uppsala vars lakvatten studeras för att utvärdera deponins tillstånd på uppdrag av Miljökontoret i Uppsala. Lakvattenkvalitén från deponin har kontinuerligt blivit mätt under perioden, 1959-2007. Deponin skiljer sig från andra deponier främst på grund av sitt blandade innehåll av både hushållsavfall och industriavfall. Deponin stängdes 1970 och täcktes över i två omgångar först 1970 och senare även 1994. Ekebyboda har under den aktiva fasen orsakat en rad olika problem så som förorenade brunnar och vattendrag samt åkrar inom närliggande område. I när-heten av det undersökta området finns ett mindre antal privata hushåll med egna dricksvattenbrunnar vilket är en förhöjande faktor till att deponin undersöks. Uppsatsen fokuserar på åren 1990-2007 med en ytterligare mätning under 2014 som ligger till grund för utvärderingen av deponins rådande tillstånd. Lakvattensammansättningsmätningar under denna tidsperiod jämförs med nederbörden för att utvärdera hur stor inverkan nederbörden har på lakvatten sammansättning och uppmätta ämnen i det. Korrelationer mellan lakvattensammansättning och nederbörd gav även en indikation om deponins tillstånd idag. På grund av deponins problematiska historia ska detta området studerats men även riskklassificera enligt Naturvårdsverkets MIFO modell. MIFO står för Metod för Inventering av Förorenade Områden och är en mall för att riskklassificera förorenade områden. Fältprovtagning visade även ett ickefungerande kulvertsystem för transport av lakvatten. Stillastående vatten och problematiska lakvatten kulvertar ledde till att datasetets kvalité ifrågasätts. Korrelationen mellan nederbörden och lakvattenkvalitén var låg och en andra täckning av deponin minskade mängd infiltrerat vatten. Analysen av lakvattnet sammansättning och problematisk hantering av lakvatten var ytterligare två anledning för en hög risk-klassificering av deponin. För den fyrskaliga klassificeringen som metoden består av fick Ekebyboda den högsta riskklassificeringen som mestadels beror på en viss risk för spridning av lakvatten till när-liggande privata brunnar. Mätserien är en generell nedåtgående trend där ett flertal näringsämnen m.m. har minskat i koncentration samt att mängden infiltrerat vatten i deponin har minskat i mängd.
88

Mining Booms and Busts: New Evidence on the Consequences of Mining in the U.S.

Matheis, Michael Roy January 2015 (has links)
The extraction of natural resources can lead to higher incomes and standards of living for local areas, but resource exploitation, a lack of broad economic development, and an excess amount of environmental pollution can come with this activity. This dissertation analyzes the short and long run economic, public health, and demographic consequences of economic development via natural resources. It expands upon the current non-renewable resource extraction, "resource curse," and local community health literatures by using county data for the entire U.S. spanning over a century, capturing both short and long run impacts over various time periods, on net-migration, mortality, natality, local economic activity, and environmental impacts. What drove coal production in the U.S. during the twentieth century? How effective were the operators at predicting and responding to changes in price? Did coal mining industries provide broad economic benefits to local communities in non-mining sectors? Did the impacts differ over time? Has natural resource extraction activity caused mortality in the area to increase? To answer these questions I collected, compiled, and digitized a long run panel database of county level mining activity, mortality, natality, and pollution spanning the entire U.S. The dissertation identifies the short and long run net effects of natural resource extraction activity with time-varying measures, and an IV approach that isolates changes in local mining activity independent of local conditions and outcomes. The dissertation shows that coal producers responded to variation in prices, and were aware and responded to past price behavior. Chapter 3 shows increased levels of coal production had positive net impacts on county population and manufacturing employment over an initial ten year span, then became negative over the subsequent decade. This provides evidence that the existence of a "resource curse" on local manufacturing is a long run phenomena. Chapter 4 shows that extraction activity increased infant and total mortality, had no impact on contemporaneous total cancer mortality, and may be driven by areas where coal mining was historically prevalent. Past and present mining activity is strongly related to local pollution, supporting the idea that increasing local environmental pollution increases mortality.
89

Maybe Baby? : Reproductive Behaviour, Fertility Intentions, and Family Policies in Post-communist Countries, with a Special Focus on Ukraine

Wesolowski, Katharina January 2015 (has links)
This thesis studies different aspects of reproductive behaviour on the international, national, and local levels in post-communist countries. The main focus is Ukraine, where fertility rates are very low and the population is in severe decline. The studies contribute new knowledge about the applicability of a family policy typology developed on the basis of Western countries’ experience for post-communist countries, and about the influence of family policies on fertility levels in these countries. Moreover, the studies investigate whether and how macro-level influences impact on individuals’ reproductive behaviour. Four articles are included in the thesis: Family policies in Ukraine and Russia in comparative perspective analyses the institutional set-up of family policies in both countries and compares the findings to 31 other countries. The results show that Ukrainian family policies support a male-breadwinner type of family, while the benefit levels of Russian family policies are low, compelling families to rely on relatives or the childcare market. Family policies and fertility - Examining the link between family policy institutions and fertility rates in 33 countries 1995-2010 comparatively explores whether family policies have an effect on fertility rates across the case-countries. Pooled time-series regression analysis demonstrates that gender-egalitarian family policies are connected to higher fertility rates, but that this effect is smaller at higher rates of female labour force participation. To have or not to have a child? Perceived constraints on childbearing in a lowest-low fertility context investigates the influence of the perception of postmodern values, childcare availability and environmental pollution on individuals’ fertility intentions in a city in Eastern Ukraine. It is shown that women who already have a child perceive environmental pollution as a constraint on their fertility intentions. Prevalence and correlates of the use of contraceptive methods by women in Ukraine in 1999 and 2007 examines changes in the prevalence and the correlates of the use of contraceptive methods. The use of modern contraceptive methods increased during the period and the use of traditional methods decreased, while the overall prevalence did not change. Higher exposure to messages about family planning in the media is correlated with the use of modern contraceptive methods.
90

A Modelling Study For The Health Risk Posed By Nuclear Power Plant In Bulgaria At Different Parts Of Turkey

Unver, Ozge 01 December 2003 (has links) (PDF)
In this study, following a severe accident at Kozloduy nuclear plant in Bulgaria how Turkey would be affected was investigated. The severe accident refers to core meltdown accident with catastrophic failure of containment. The model used is HySPLIT model developed in America. The worst day was predicted considering deposition of radionuclides. For initial runs, accidental release of I-131 and Cs-137 radionuclides was modeled for each day of year 2000 to find the worst day, seen to result from release beginning on April 7th 2000. After modeling release of all radionuclides for the worst day, radiation dose at different receptors, 12 most populated cities over Turkey has been calculated via different pathways. Late effects, fatal cancer, non-fatal cancer and hereditary risks, has been investigated for these receptors. The mostly affected part of Turkey was Marmara region and fatal cancer risk therein was 7x10-2 %. The collective health risk throughout Turkey was approximately 20 600 people. The same approach was then applied for investigating health risk of proposed nuclear reactor at Akkuyu, Turkey. In this case, the worst day was resulted from release beginning on 21st of February 2000. The worst affected part was the narrow strip in Central Anatolia extending to the north-eastern cost and fatal cancer risk in this region was 3.4x10-1 %. The collective health risk over Turkey was approximately 30 600 people. The results showed that Kozloduy nuclear plant has dominating effect throughout Turkey, but proposed Akkuyu reactor affects very limited region.

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