Afşın Yusuf Çetinkaya

In this study, the 2021 emission measurement results of a cement production facility located in Düzce Province were tested against emission concentrations calculated using the facility’s production capacity and process-based emission factor values for the same year, as defined by the Ministry of Environment, Urbanization and Climate Change. The analysis focused on Particulate Matter (PM) and Nitrogen Oxides (NOₓ) parameters, evaluating both theoretical (calculation-based) and practical (measurement-based) concentration values. The primary objective was to compare the agreement between these two approaches. Based on the field measurements conducted under the guidance of the Ministry, the average annual concentrations of PM and NOₓ (NO + NO₂) were 2.64 µg/m³ and 436.64 µg/m³, respectively. In contrast, the calculated values based on the emission factor (EF) with 2021 production data were 13.12 µg/m³ for PM and 157.61 µg/m³ for NOₓ. These discrepancies are influenced by several factors, including operational duration, production capacity during measurement periods, and other activities occurring at the facility. The obtained concentrations of emissions from both methods were then simulated with the AERMOD Air Quality Dispersion Model and using 2021 meteorological data, and spatial map plots of the resulting concentrations were made to observe the impact in the surrounding region.

The European Union is leading the Blue Growth initiative as a strategic approach to increasing economic prosperity in Europe's seas despite today's challenges. Drawing on the EU's Green Growth initiative, Blue Growth extends sustainability principles to marine areas, solidifying commitments to the sustainable management of marine ecosystems and the promotion of technological innovations. This initiative focuses on sectors such as energy, aquaculture, tourism, and biotechnology in coastal and offshore environments. Blue Growth has increased in importance following major events such as Rio+20 and has had a significant impact on ocean and marine resource management practices. In this study, we conduct a comprehensive bibliometric analysis to trace the trajectory of global research on blue growth across science, policy, and the blue economy over the 17 years since the term's inception in 2007. We analyze blue growth using bibliometric techniques. Examining the blue growth literature, identifying key contributors, collaborations, research trends, and gaps. Our analysis covers publication outputs, institutional affiliations, author collaborations, research themes, and alignment with the Sustainable Development Goals (SDGs). Blue growth research is aligned with several Sustainable Development Goals, particularly SDG 14 (Life Below Water) and SDG 15 (Life on Land), highlighting marine conservation and land-sea ecosystem connectivity. Keyword analysis underlines the interdisciplinary nature of blue growth research, highlighting key themes such as the blue economy, aquaculture, and sustainable development. Institutional analysis identifies the University of Exeter and CNR as key contributors, while country-level analysis highlights global collaboration networks. Citation analysis reveals the intellectual structure of blue growth research, with marine biology, oceanography, sustainability science, and climate change among the prominent themes. During the 17-year period from 2007 to 2024, there was a significant increase in publication output, especially from 2013 onwards. Key countries contributing to this research include the UK, US, Germany, Italy and Spain, reflecting extensive global collaboration. The research emphasizes a strong commitment to sustainability, with a heavy emphasis on Environmental Science and Ecology. Alignment with the Sustainable Development Goals (SDGs) emphasizes a focus on marine conservation (SDG 14) and land-sea ecosystem connectivity (SDG 15). Keyword analysis reveals critical themes such as “blue economy,” “aquaculture,” and “sustainable development,” with an emphasis on interdisciplinary approaches. Institutionally, the University of Exeter and CNR stand out among the contributors.

This study presents an innovative approach to sustainable wastewater treatment by integrating electrocoagulation (EC) with solar energy and biogas. The research evaluates the performance of an EC reactor in terms of chemical oxygen demand (COD) removal efficiency under varying current densities, demonstrating enhanced COD removal rates with increased current densities, achieving up to 95.3% at 1500 A/m². Life cycle assessment (LCA) is employed to compare the environmental impacts of different energy sources for powering the EC system. The findings indicate that biogas derived from domestic waste offers a lower environmental impact compared to natural gas, coal, hydro, solar, and wind. The study further explores the potential of solar energy in Turkey, particularly in Istanbul, where high solar radiation could be harnessed. However, the efficiency of photovoltaic (PV) panels is affected by temperature, with an observed efficiency decrease of approximately 0.5% per degree Celsius increase in temperature. Effective cooling strategies are thus essential for optimizing PV performance. The integration of EC with solar energy, powered by biogas, not only enhances wastewater treatment efficiency but also contributes to reduced greenhouse gas emissions and energy costs. This combined approach presents a viable solution for both domestic and industrial wastewater treatment, especially in remote or off-grid areas.

Several methods are used during waste management: landfill, incineration, composting, anaerobic digestion, pyrolysis, and recycling etc. In particular, the use of biogas formed through anaerobic digestion in energy production and the energy obtained through the incineration process is very effective in turning the negative effects of wastes into positive ones. In this study, the effects of three different waste management scenarios were examined from a life cycle perspective. According to the results, scenario1 (landfill and incineration), scenario2 (landfill, incineration, and anaerobic digestion), and scenario3 (landfill, anaerobic digestion, and recycle) produced emissions of 3233.1, 328.8, and -848.9 kg of CO2eq, respectively. Accordingly, and in accordance with the results of the previous studies, it is observed that the landfill application gave the worst environmental result, the incineration and anaerobic digestion applications reduce the environmental effects, and the recycling application provides environmental benefits. It is concluded that the best environmental practice is plastic and metal recycling.

This study presents a thermodynamic and life cycle analysis of a biomass-based integrated energy system, comprising a biomass gasification cycle, a steam Rankine cycle, and an ammonia fluid Organic Rankine cycle. The primary objective of the system is to efficiently convert olive husk, a sustainable biomass source, into electricity and heating. The gasification process generates syngas, which fuels a gas turbine, producing high-temperature exhaust that drives a Rankine cycle. The thermodynamic analysis indicates that the overall system achieves an energy efficiency of 20.85% and an exergy efficiency of 11.70%. The Rankine cycle exhibits an energy efficiency of 23.91%, while the Organic Rankine cycle demonstrates a higher exergy efficiency of 68.87%. Parametric studies reveal that increasing the combustion chamber temperature significantly enhances system efficiency and output, with energy efficiency rising linearly as the temperature increases from 800 °C to 1000 °C. Additionally, the analysis emphasizes the importance of the compressor’s compression ratio on system performance. A life cycle assessment conducted using the ReCiPe methodology evaluates the environmental impact of the system throughout its lifecycle, revealing critical insights into its sustainability. This comprehensive evaluation highlights the potential of utilizing agricultural waste, such as olive husk, to produce renewable energy, thereby supporting environmental sustainability and waste management goals. The findings underscore the viability of the proposed system for enhancing energy production while minimizing environmental impacts, making it a promising solution for renewable energy generation in regions with abundant biomass resources.

The objective of this study is to improve the filtration efficiency of commercially available polyethersulfone (PES) ultrafiltration (UF) membranes, with a specific focus on removing natural organic matter (NOM) and preventing membrane fouling. The modification of UF membranes was accomplished by utilizing chitosan/multi-walled carbon nanotubes (CS/MWCNT-OH) and employing both dip and spin coating techniques. The membrane surface morphologies were evaluated using the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Energy-Dispersive X-ray Spectroscopy (EDX) techniques. Tests were carried out to assess the effectiveness of the membranes in a laboratory-scale system using two primary water sources from Istanbul, specifically the Melen River and Terkos Lake. Total organic carbon (TOC), UV254 absorbance, turbidity, and trihalomethane formation potential (THMFP) were all measured as part of a thorough analysis. The surface morphology investigations verified the effective deposition of MWCNT-OH nanoparticles onto the membrane surface. This was corroborated by the reduction in the water contact angle, showing an improvement in the hydrophilicity of the membrane. The modified membranes demonstrated much higher TOC removal rates compared to the original membranes. Specifically, the removal efficiencies for Melen River and Terkos Lake were 37.14% and 56.86%, respectively. Nevertheless, the alteration of the surface led to a decline in membrane flux as a result of the concurrent drop in pore size. To summarize, the results of this work highlights the considerable capability of surface modification using CS/MWCNT-OH to improve the performance and antifouling characteristics of commercial PES UF membranes.

Slaughterhouse wastewater is one of the most produced industrial wastewater in the world and has a high pollution potential, and this wastewater can cause a high level of polluting effect when it is given directly to river beds or sewage systems. Wastewater contains proteins, fats, carbohydrates in the treatment of blood, skin and feathers, which results in much higher biological oxygen demand (BOD) and chemical oxygen content (COD). The possibility of using ultrafiltration for slaughterhouse wastewater treatment was investigated. The results showed that ultrafiltration can be an efficient purification method. COD and BOD5 remova lefficiency is around 96% and 95%. In addition to these results, the Life Cycle Analysis (LCA) of the ultrafiltration system was also carried out. Accordingly, the effects of ultrafiltration system on human health, ecosystem quality, climate change and resources were calculated as 0,00000046 Disability-Adjusted Life Years (DALY), 0,134 PDFxm2yr, 0,336 kg CO2 eq and 6,937 MJ respectively. As a result of the study, it is thought that slaughterhouse wastewater can be used as irrigation water after passing through the ultrafiltration membrane due to the high content of N and P.