Ph.D. Theses
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Browsing Ph.D. Theses by Author "Erdinçler, Ayşen."
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Item A simple method for small scale wastewater treatment plants for the thickening of sludges: mesh filter and foam filter(Thesis (Ph.D.)-Bogazici University. Environmental Sciences, 2008., 2008.) Gökyay, Orhan.; Erdinçler, Ayşen.The ultimate disposal of wastewater sludge (biosolids) continues to be one of the most difficult and expensive problems in the field of wastewater engineering. Wastewater treatment plants generate different sludges, like primary settled sludge, waste activated sludge, chemical sludge and anaerobic sludge, according to their operating systems. These excess sludges have to be managed by reducing their volume and stabilizing them before their ultimate disposal. Generally used volume reduction methods are thickening and dewatering that are usually coupled with conditioning. Sludge thickening and dewatering require either a big capital investment or a big surface area. Moreover, most of the mechanical dewatering technologies use polymers to condition the sludge before dewatering. These polymers have high cost rendering the mechanical dewatering uneconomical. Small-scale wastewater treatment facilities play an important role in the aquatic environment in many countries. Although sludge treatment is essential for overall wastewater treatment, it is difficult and non-economical for small-scale treatment plants to use mechanical equipments. Considering these points, there is therefore a need for alternative technologies for high performance and easy to operate small-scale wastewater treatment facilities. In this study, mesh filter and foam filter are used as a liquid-solid separator instead of the conventional equipments like gravity sludge thickener, dissolved air flotation or centrifuge. By this way, it is possible to reduce the water content of the sludge as mechanical devices and make thickening process economical.Item Analysis of CO2 emissions resulting from electricity sector in Turkey by using Boğaziçi University Energy Modeling System (BUEMS) modeling framework(Thesis (Ph.D.) - Bogazici University. Institute of Environmental Sciences, 2022., 2022) Kalkan, Emre.; Erdinçler, Ayşen.Due to factors such as industrialization, increase in population and economic growth electricity demand has shown a significant increase at global scale. This increase has put forward discussions concerning electricity supply security, source diversification and clean electricity generation. Fossil based electricity generation featured the transition to clean generation in this sector. Particularly, towards the goal of the Paris Agreement, policy developments have gained momentum to reach carbon neutral electricity sector by 2050. These developments have been closely monitored by Turkey. The purpose of this thesis is to evaluate long-term results of the CO2 emissions resulting from electricity sector in Turkey by using BUEMS model in line with latest available data and updated policy papers. Total electricity installed capacity, generation portfolio and increase in electricity demand were investigated. In the context of the thesis, a Base scenario was established. The response of the electricity sector under carbon tax and emission restrictions and their effect to CO2 emissions were analyzed. The results of the study showed that tax and emission targets played an important role for CO2 emission reduction. In Base Scenario, Total CO2 emissions exceeded 1,000 Million tons and electricity sector’s contribution was almost 680 Million tons in the year 2057. Among all scenarios the highest decrease was obtained under Peak Emission Scenario. Total emissions reduced to 705 Million tons and emissions from electricity sector decreased by 61% compared to Base Scenario and fell to 244 Million tons in 2057 by means of renewables and nuclear penetration.Item Process modeling and energy optimization of a full scale advanced biological wastewater treatment plant in Istanbul(Thesis (Ph.D.) - Bogazici University. Institute of Environmental Sciences, 2023., 2023) Güneş, Gıyasettin.; Erdinçler, Ayşen.; İnsel, H. Güçlü.When standard design methods are applied directly to projects, they can lead to serious design errors. Due to the low nitrification growth rate in Istanbul, treatment plants generally cannot meet total nitrogen discharge standards. During the study, an innovative treatment process was discovered. The pilot plant with "Biofilm Nitrification - Contact Denitrification System" and the real plant were operated simultaneously and their performances were compared. In the pilot plant, the return sludge was sent to the reactive pre-sedimentation tank and 80% of the organic matter was removed without the use of chemicals. Another advantage of this system is that nitrification in the hybrid system is less affected by inhibition because it occurs in a separate biofilm reactor. Nitrogen removal performance was also improved. Since the organic matter settled in the preliminary clarifier is sent directly to the denitrification tank, it is not exposed to aerobic conditions and therefore there is no loss of organic matter. Sending the organic matter first to nitrogen removal and then to biogas production is another advantage of this process. Modeling studies have shown that a higher amount of biogas can be obtained from anaerobic digestion of this sludge. The hybrid system was found to have lower operating costs (i.e., 9% less air and 39% less energy required for mixing). It also requires 40% less volume than other BNR systems, resulting in significantly lower capital costs. Therefore, the new hybrid configuration was found to be a more efficient and attractive option for treating wastewater. NOTE Keywords: Activated Sludge Model, Moving Bed Biofilm Reactor, Reactive Primary Clarifier, Energy Optimization, Wastewater Treatment.