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Archived Theses
Kağıt ve plastik atıkların pirolizinde yaşam döngüsü değerlendirmesi
Rapid economic development and industrialization, coupled with a growing global population, have led to an unprecedented surge in waste generation, threatening both environmental and human health. Conventional waste management techniques struggle to process cellulose- and polymer-based composite label wastes due to their intricate structures in recycling operations. However, pyrolysis—a thermochemical process—can convert such non-recyclable wastes into energy and valuable chemical products, aligning with the principles of the circular economy. Cellulose, predominantly carbon, plays a critical role in biofuel production, while polymers, such as polyolefins and polystyrene, yield high-calorific-value products like hydrocarbon oils and syngas. These outputs, including syngas, LNG, and pyrolytic oil serve as carbon-neutral energy alternatives to fossil fuels, enhancing energy security and sustainability in industrial applications. This study evaluates the pyrolysis of label waste (85% cellulose and 15% polymers) using life cycle assessment (LCA) methodology. Leveraging experimental data from ITU Synthetic Fuels and Chemicals Technology Center (ITU-SENTEK), alongside market research and literature, the environmental performance of pyrolysis was compared with incineration in two scenarios. The findings revealed elevated Marine Aquatic Ecotoxicity Potential in the current scenario due to high electricity consumption, whereas the alternative scenario showed increased Global Warming Potential due to surplus CO₂ emissions from gas engines. Despite these challenges, pyrolysis presents a sustainable solution for energy recovery from label waste, contributing to waste management policies and the transition to a circular economy. These insights underscore its potential to promote sustainability and reduce reliance on fossil fuels in line with circular economy.
İkincil arıtma atıksuyunda kalan farmasötiklerin granüler aktif karbon adsorpsiyonuyla giderimi
This study investigates the removal of four pharmaceuticals: acetaminophen (ACT), carbamazepine (CBZ), erythromycin (ERY) and sulfamethoxazole (SMX) by granular activated carbon (GAC). Firstly, sorption and biodegradation potential of these pharmaceuticals was studied and removal mechanisms (primary, secondary, cometabolic substrate, etc.) were investigated. After that, adsorption experiments were carried out in batch reactors to obtain isotherm constants. Then, the removal of pharmaceuticals was examined in rapid small-scale continuous-flow GAC columns. The results were compared with outputs of a model called AdDesign. Results showed that sorption of these pharmaceuticals was very low and they were biodegraded by activated sludge to some extent. ACT was highly biodegradable, whereas CBZ was the least biodegraded pharmaceutical. Adsorption experiments showed that the affinity of pharmaceuticals to adsorb onto GAC was higher when they were the only pharmaceutical, but when they were in the mixture the affinities were lower that indicated there was a competition between them. On the other hand, adsorption of the bulk organics present in secondary effluent on GAC was very low. Small column tests showed that there was no full breakthrough of either of the pharmaceuticals in the experimental period because of the low initial concentrations. In the presence of background organic matter, higher concentrations of pharmaceuticals were observed in the effluent which indicated a competition between the pharmaceuticals and the background organic matter. Through the use of the AdDesign model the column performance could be studied in a longer term and the full breakthrough of pharmaceuticals could be demonstrated under various conditions.
Ölümcül sıcak hava dalgalarına karşı akıllı şehirlerin hazırlanma olanakları
Due to the anthropogenic climate crisis, extreme heatwave events in Türkiye are expected to increase significantly. This study employs the Holiday Climate Index (HCI) in conjunction with HUMIDEX to assess Türkiye's future climatic comfort. For this purpose, the outputs of the MPI-ESM-MR global climate model (GCM) were downscaled to 50 km using the RegCM4.4 regional climate model. Subsequently, HCI and HUMIDEX values for the summer and spring seasons were computed for two future periods, 2021–2050 and 2070–2099, with respect to the reference period of 1971–2000 under two scenarios, RCP4.5 and RCP8.5. The findings revealed alarming increases in extreme heat events accompanied by dangerous HUMIDEX risks. To investigate further, this study further analyzed future extreme heatwaves using temperature-related extreme indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI). Outputs from two GCMs, MPI-ESM-MR and HadGEM2-ES, were downscaled to 50 km with RegCM4.4, and the indices were computed for 2071–2100 relative to 1971–2000 under RCP4.5 and RCP8.5. The results indicate that future heatwaves will be so severe and prolonged that they could lead to significant fatalities without smart precautions. This study finds the most promising solution in air-conditioned facilities, such as libraries, shopping malls, gyms which can function as cooling centers and accommodate solar panel installations on their rooftops to provide a safeguard in the event of a power outage.
Derı̇ endüstrı̇sı̇ atıksuları: Polı̇mer bazlı hı̇brı̇t malzemelerı̇n koagülasyon-flokülasyon ve çamur azaltmadakı̇ performansı
Leather industry effluents are among the most challenging wastewater types, requiring treatment strategies that provide high pollutant removal with reduced chemical use and environmental impact. This study develops hybrid coagulants by combining inorganic coagulants with organic polymers such as polyDADMAC and polyamine, supported by PAM as a flocculation aid. Sixteen hybrid formulations were screened under six treatment scenarios (M1–M6) using twenty-two real wastewater samples collected during high- and low-activity periods at the Çorlu Organized Industrial Zone WWTP, one of Türkiye's tannery wastewater centers. The best-performing formulations were optimized and compared with the conventional 40% alum process, focusing on COD, TOC, TSS, heavy metals, and sludge characteristics. Phase-based jar tests enabled separate evaluation of liquid and solid phases, allowing more precise performance interpretation and mass balance assessment. Environmental performance was examined using an entropy-weighted TOPSIS approach incorporating sludge management, long-term robustness, chemical burden, and treatment efficiency. Biodegradability of the organic polymers was additionally evaluated using U.S. EPA BIOWIN predictions to assess their environmental persistence. Overall, hybrid coagulants significantly reduced dosage requirements and sludge production while maintaining high removal efficiencies even at natural pH. Although the polymers showed limited biodegradability, their low dosing minimized long-term concerns. The findings position hybrid coagulants as a technically effective and environmentally conscious alternative to conventional coagulation and highlight the importance of future research supported by life cycle assessments of polymer systems. The study also suggests that comparable or improved performance may be achieved with more biodegradable materials and broader testing across different industrial wastewater types.
Karbonsuzlaşmaya geçiş ve kirliliğin önlenmesi ı̇lkeleri doğrultusunda gazlı içecek ambalajları için plastik (PET) ve cam şişeler ve alüminyum tenekelerin karşılaştırmalı yaşam döngüsü değerlendirmesi
Packaging materials have numerous applications in our daily lives and in industry. One of them is soft drink packaging products. Both in Turkey (locally) and the EU, packaging-related regulations, directives, and policies have been updated in accordance with circular economy and the EU Green Deal principles. Although LCA is associated with the cradle-to-grave approach, when considering this concept under the circular economy approach, the cradle-to-cradle approach can also be adopted. Therefore, Sustainable Consumption and Production (SDG 12) is a point that needs to be related to Life Cycle Assessment (LCA). The primary objective of this study is to assess the environmental outcomes associated with decarbonization, reuse, recycling, and recycled content targets by conducting a Life Cycle Assessment (LCA) across various scenarios for soft drink packaging of PET, glass, and aluminum. During scenario development, relatable actions were taken together with the EU Green Deal, circular economy, and Paris Agreement targets. Initially, only for the pre-consumer stage, 2020 was set as the baseline scenario, i.e., for the production of the selected materials, less renewable energy and no recycled content were considered. With the increasing share of renewable electricity, 2035 and 2053 were targeted to improve both the pre-consumer stage by applying electrified systems and recycled content, and the post-consumer stage by supporting reuse and recycling. In the context of the selected impact categories, the thesis concluded that for the pre-consumer stage of each product, the use of recycled content, electrified processes and renewable electricity have favorable aspects under proper conditions. Attention must be paid to the necessary efficiency and redesign points in renewable electricity generation and electrification process. In the post-consumer stage, the reuse process (especially for glass) can be promoted in terms of primary resource savings and energy efficiency by improving water consumption in the washing (also applied in recycling) processes. While the reuse stage for PET sounds more environmentally friendly but needs to be considered in the context of health concerns and product durability during consumption, but as well as the aluminum, recycling for PET must be supported compared to their remanufacturing.
Doğaya atfedilen değerler, doğayla bağ, çevre dostu davranış ve esenlik: İstanbul'daki kent parkları ziyaretçileri üzerine bir vaka çalışması
Urban greenspaces play an important role not only for biodiversity conservation, but also for the well-being of urban residents. Recent empirical studies focused therefore on the interplay between nature connectedness, individual well-being and pro-environmental behavior. Yet, most studies so far have used student samples from high-income countries, where conservation and environmental policies are relatively well-established. The present study aims to test the impacts of plural values for nature (intrinsic, instrumental, relational), nature connectedness, ecological knowledge, eco-anxiety, environmental concern, on pro-environmental behavior (PEB) and subjective well-being in a relatively understudied middle-income developing country context with participants from a policy relevant urban greenspace field setting. To do this, face-to-face surveys with 112 participants were conducted in two popular urban greenspaces of Istanbul, Emirgan Grove and Hacıosman Atatürk Urban Forest. Findings suggest that relational values constitute an empirically distinct category of values highly significant for urban park visitors, and mediated by nature connectedness, they can predict PEB and subjective well-being significantly. Moreover, ecosystem-based ecological knowledge (recognition of local plant and animal species) was found to be a positive correlate of PEB, while environmental concern emerged as a potential predictor of subjective well-being. Overall, the study suggests relational values and connectedness to nature as two important leverage points for enhancing sustainable behavior and human well-being in urban contexts that could be targeted by biodiversity policy, education and urban design for reinforcing cycles of increased care and responsibility for nature and improved life satisfaction.
Gelişmekte olan ülkelerde karbon yakalama, kullanma ve depolama teknolojilerinin benimsenmesinde karşilaşilan zorluklarin ve dikkat edilmesi gereken hususlarin incelenmesi: Türkiye örneği
This thesis examines the complex and often ambiguous landscape of Carbon Capture, Utilization, and Storage (CCUS) technologies in developing nations, amidst the pressing need to accommodate increasing material and energy demand within the decarbonization imperatives put forward by the Paris Agreement. By focusing on Türkiye as a case study, due to its reliance on emission-intensive production and strong trade ties with developed (more particulary European) countries, this thesis aims to bridge knowledge gaps and offer insights into the feasibility and strategic integration of CCUS into national climate and technology policies. By drawing upon the existing literature and insights from national and international experts, it concludes that, while CCUS is not a silver-bullet technology for all greenhouse gas (GHG) mitigation, it holds significant potential as a targeted approach for hard-to-abate sectors such as cement, chemicals, and iron and steel, predominantly found in developing economies, and that successful CCUS integration requires tailored strategies accounting for diverse social, economic, technological, and environmental factors, emphasizing that there's no one-size-fits-all approach. A key finding is the significant deployment disparity between developed and developing countries due to challenges in access to capital, knowledge gaps, and the absence of regulatory frameworks, calling for strengthened international climate policy focused on technology transfer, capacity building, and climate finance, tailored to the specific contexts of developing nations. For Türkiye, integrating CCUS into its net-zero strategies necessitates revised climate and energy policies built on clear governance structures to accelerate CCUS adoption, especially in industrial decarbonization rather than power generation.
Türkiye'de bölgesel kalkınma ajanslarının çevre yönetişimindeki rolü üzerine bir değerlendirme: Trakya Bölgesi üzerine bir vaka çalışması
Over past decades, policies shaped solely for the purpose of development have failed to address the level of environmental problems reached and the scope they impact. These problems, seen on each and every scale and affecting every dimension of life, have raised the need for governance that can produce multi-level and multi-dimensional response. Environmental governance, which centers on multi-actor, multi-level and sustainability-focused approaches, has emerged as key response to these accelerating environmental challenges. This framework that is increasingly finding its mark on the global agenda, has also begun to acquire greater importance in Türkiye. Through the accession process to the EU, Regional Development Agencies (RDAs) were established to ensure balanced, participatory, and sustainable development at regional level was introduced in 2006 in Türkiye. In this context, this thesis examines the extent to which environmental governance perspectives are integrated into the RDA model in Türkiye, a country that has a long-lasting centralized decision-making and economic-growth focused approach. To present more grounded findings, this study conducts its analyses through the case study of Thrace Development Agency. The study covers the period 2014–2023 in line with the Thrace Regional Plan and uses content analysis and supporting interviews to present findings on issues that pose challenges and limitations in this integration. The study's findings indicate that, although the regional development agency model in Türkiye appears broadly compatible in concept, there are various issues requiring changes and improvements in terms of integrating environmental governance perspectives into practice more effectively.
Marmara Denizi'nde müsilajın politik ekolojisi: Nilüfer Çayı üzerine bir vaka analizi
This thesis examines the vulnerability of the Marmara Sea ecosystem to pollution and mucilage outbreaks, with a particular focus on the Nilüfer Creek, one of the major contributors to the ecosystem degradation in Marmara Sea. Using a political ecology framework, the study critically assesses existing regulations, preventive measures, and industrialization and urbanization processes to highlight the complex interconnections and interactions between different local, regional and national stakeholders. By using a multi-method approach that includes stakeholder mapping, institutional analysis, document review and targeted interviews, this study aims to comprehensively document the complex relations surrounding the Nilüfer Creek in Bursa. The thesis aims to not only contribute to a nuanced understanding of the linkages between the Nilüfer Creek and mucilage occurrences but also provide insights to improve sustainable water management practices in general. This study underscores the need for integrated governance and community engagement in addressing the complex intertwining of ecological, political and technological factors affecting water resources, especially around the Marmara Sea.
Türkiye'de süt üretiminin politik ekolojisi: Değişen pratikler, kırsal geçim kaynakları ve süt hayvanları
This thesis examines the transformation of dairy farming in Türkiye through a political ecology and multispecies justice lens, focusing on how intensification is framed, governed, and implemented. It argues that dairy intensification cannot be understood as a purely technical or inevitable response to production needs, but as the outcome of a historically shaped governance trajectory that prioritizes growth and efficiency. Empirically, the thesis combines close reading of policy and planning documents, sectoral reports, and statistical series with field material from a major sectoral event in Bursa and semi-structured interviews with the officials from the Ministry of Agriculture and Forestry in Istanbul. The analysis identifies two interconnected hegemonic discourses shaping dairy governance. The first is that milk production must expand and animals must become more "efficient" through yield increases, breed transformation, and reproductive and herd-management technologies. The second is that farmers must become more efficient by scaling up, specializing, formalizing, and integrating into industrial value chains, while small-scale farmers are framed as backward and inefficient. A key finding is the tension between official insistence that Türkiye "needs" more milk and the simultaneous portrayal of the country as already self-sufficient and a leading producer. Read together, these narratives suggest that the push for "more" milk reflects a political-economic commitment to growth as a default policy orientation. The thesis concludes that dairy intensification in Türkiye functions as a multispecies political project with uneven consequences for rural livelihoods and dairy animals.