LEE- Çevre Bilimleri Mühendisliği ve Yönetimi Lisansüstü Programı
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ÖgeApplication of different strategies to improve aerobic granular sludge process performance for treatment of municipal wastewater(Graduate School, 2022-09-29) Koşar, Şadiye ; Erşahin, Mustafa Evren ; 501162714 ; Environmental Sciences, Engineering and ManagementAerobic granular sludge (AGS) process is an energy-efficient alternative biological wastewater treatment process to the conventional activated sludge (CAS) process which requires high energy and big space. In CAS systems, flocs sized above 0.2 mm are referred as granule. So far flocs and granules could be easily differentiated by size clustering as well as their capabilities of removal for organic matter and nutrients. Surface of the granule has porous morphology, and this allows the substrate penetration and as well as oxygen diffusion into the inner layers of the granule. The diffusion of oxygen is somehow can be a limiting factor for the simultaneous carbon and nutrient removal due to structure of the granule. In many cases, granule has a compact and dense structure that limits the oxygen transfer to the inner core layers of the granule which improves the denitrification and allows better phosphorus (P) removal within the granule. Whereas in some situations, granules have amorphous structure which do not improve any core inside the granule so affects the removal of substrate. Aerobic granules are heavier than flocs formed in waste sludge, so they settle faster, and this improves the settleability of the sludge which further allows to operate in one reactor. For this reason, large sedimentation tanks are not required in AGS systems. Since aerobic, anoxic and anaerobic biological activities take place inside the granule, AGS process offers 25-75% less space and consumes 20-50% less energy compared to conventional activated sludge plants. Nitrification takes place on the surface of the granule during aeration phase and denitrification occurs in the inner layers of the granule under anoxic conditions. P removal is maintained by polyphosphate accumulating organisms (PAOs) that are located in the core part of the granule. PAOs and denitrifiers which are responsible for the denitrification are both heterotrophic organisms and compete for the carbon sources as substrate. For this reason, it is important to have sufficient amount of organic matter for nitrogen (N) and P removal. Since PAOs are located in the inner layer of the granule they are only capable of using organic that are in dissolved form. In municipal wastewater, organic matter is particulate and dissolved forms. Particulate matter reduces N and P removal up to 40% and 46% respectively. Particulate organic matter is turned into dissolved form in the presence of extracellular polymeric substances (EPS) which are hydrolyzing them further. Hydrolysis ends up in anaerobic phase when the attached particulate matter on the surface of the granules hydrolyzed and it is uptaken by PAOs and denitrifiers. If dissolved organic matter cannot be consumed by these species, then it would be consumed by the aerobic heterotrophic bacteria on the surface of the granule which further causes filamentous microorganisms' overgrowth. This leads to amorphous structure and disintegration of the granule. In this thesis, the treatability municipal wastewater by AGS process was investigated under different circumstances. Four separate studies were conducted within the scope of this study. In the first study, two different sludge were comparatively investigated as inoculum: (a) waste activated sludge (WAS) taken from the return activated sludge line of an advanced biological wastewater treatment plant (WWTP), (b) WAS taken from the return activated sludge line of a pilot scale high-rate activated sludge (HRAS) system. This study was conducted in two stages: AGS system was seeded with the WAS taken from the return activated sludge line of an advanced biological wastewater treatment plant in the first stage; in the second stage, AGS system was seeded with the mixture of WAS taken from the return activated sludge line of an advanced biological WWTP and WAS of pilot scale HRAS process as volume in proportion of 1:1. This study was performed to reveal the contribution of microorganisms found in the flocculent sludge to the granulation process. Since HRAS process sludge has high settleability and the mixture of WAS with HRAS process as inoculum was expected to enhance the settling properties of granular sludge as well as achieving good treatment performance. Although at the start-up period sludge wash-out occurred and mainly fluffy waste sludge wasted, HRAS process sludge settles faster, and it remained in the reactor. So, in this case especially denitrifiers were mostly washed out of the system which deteriorated system performance compared to the AGS system operated solely with WAS. At the end of this study, WAS waste sludge was chosen as seed sludge for the further studies to obtain aerobic granulation based upon AGS system treatment performance. In the second study, WAS taken from the return activated sludge line of an advanced biological WWTP was used as seed sludge. Study was conducted in two stages: (a) AGS system was fed directly with the synthetic municipal wastewater, (b) AGS system was fed with the pre-settled synthetic municipal wastewater (30 min of settling) to simulate pre-sedimentation tanks in the full-scale wastewater treatment plants (WWTPs). With pre-settling application, it was proposed that particulate matter would settle so mainly dissolved organic matter could be introduced to the AGS system. Since AGS system is anaerobically fed, this would improve the nutrient removal by allowing the uptake of organic matter easily by PAOs and denitrifiers. It was shown that up to 60% of particulate matter was removed by settling and as a result carbon/nitrogen (C/N) ratio decreased 20% lead deterioration of the AGS system treatment performance. It was apparent that a combination of pre-sedimentation in AGS process didn't improve the system. In the third study, AGS system was operated in three different stages continuously following each other without having different start-up periods: (a) AGS system was fed directly with raw municipal wastewater, (b) AGS system was fed with the pilot scale HRAS system's effluent (treated wastewater), (c) AGS system was fed with the mixture these two flows: raw municipal wastewater (20%) and HRAS process effluent (80%). Waste sludge taken from the return activated sludge line of an advanced biological wastewater treatment plant was used as inoculum. Firstly, aerobic granulation was maintained by introducing municipal wastewater than HRAS process effluent fed to the system and AGS system performance was followed thoroughly. It was shown that the granule stability remained somehow same, but AGS system performance was affected by decreased C/N ratio. AGS system was fed with the mixture the raw municipal wastewater and HRAS process effluent to improve the system performance. As a result, AGS system performance was improved with the increase in C/N ratio (20% increase compared to feeding with only HRAS process effluent). Thus, HRAS process integration with AGS process was found to be energy efficient configuration. Both systems comparably occupy less space than conventional treatment systems and their integration will definitely improve the effluent quality. In the fourth study, digestibility of AGS which was obtained from the third study was compared to the WAS taken from the return activated sludge line of an advanced biological wastewater treatment plant. It is known that AGS process sludge has low digestibility than WAS. Thus, ultrasonication was applied to improve the solubilization of organic matter for increasing sludge digestibility. Since aerobic granules are clusters of microorganisms that are attached together, they are bigger in size and more compact than WAS flocs. Therefore, relying on their physical differences, it was assumed that ultrasonication would enhance digestibility of the AGS. It was shown that ultrasonication as pre-treatment method led to solubilization for both sludge sources in terms of volatile fatty acids (VFAs), protein and carbohydrates besides causing decrease in particle size. A direct relation found between the release of organic compounds, ammonium, phosphorus and heavy metals with the increase in ultrasonication intensity. Overall results obtained from this thesis showed a comprehensive approach to treat municipal wastewater by AGS process while improving the treatment performance by focusing on inoculum source as well as feeding strategy. Besides, sludge from AGS process was evaluated in terms of soluble products release by applying ultrasonication process compared to the WAS. This thesis would enhance the knowledge on AGS technology in terms of seeding and feeding regimes beneath giving clues for full-scale AGS process applications.
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ÖgeCritical evaluation for nitrogen removal performance of a stereotype activated sludge system under dynamic process conditions(Graduate School, 2021-12-28) Bodur, Minel ; İnsel, Güçlü Hayrettin ; 501181724 ; Environmental Sciences Engineering and ManagementIn recent years, with the increasing population and the effects of global warming, the design, construction, and operation of domestic and urban wastewater treatment plants are carried out considering the treatment steps that provide nutrient removal. The most suitable treatment alternative to remove nutrients from wastewater in terms of applicability and cost are determined to be Biological Nutrient Removal processes. Because of the need for biological nutrient removal, stress caused by the nutrients and organic matter on receiving water environments are reduced and active sludge systems gain more and more attention moving forward. As widely known, highly complex biological reactions occur in activated sludge systems and although stable state conditions are generally used to simplify design calculations, active sludge systems operate under dynamic conditions. This indicates that input wastewater characterization as well as the inlet flow, various environmental factors (temperature, precipitation, etc.) and operating conditions vary depending on time. Therefore, various modeling tools are used to understand the treatment system more efficiently. With the modelling tools, it is possible to comprehend system dynamics and determine the rehabilitation, refurbishment and expansion requirements of existing treatment plants, while for the new plants, plant design can be optimized considering modeling outputs. Additionally, data from pilot-scale reactors can be evaluated through models and used to predict full-scale plant performance. To reflect the actual conditions at wastewater treatment plants, process simulators which provide guidance on determining the design principles of wastewater treatment plants, creating automation scenarios, choosing equipment, and evaluating process performance for both wastewater and sludge units, are used. The main purpose of this thesis is to evaluate the use of oxidation ditch reactors in series in terms of nitrification and denitrification processes and to model the actual behavior of an Oxidation Ditch (OD) system operated by following the pre-denitrification principles using input wastewater data collected from an urban wastewater treatment plant in the Marmara Region (Istanbul, Turkey) under dynamic conditions. Sumo software was used to model and simulate the wastewater treatment plant under dynamic conditions and the treatment efficiency of the plant in terms of nitrogen removal was examined. This thesis mainly focuses on nitrogen removal under dynamic conditions in a municipal wastewater treatment plant that employs four oxidation ditches located upstream of Bio-P tanks and operated in series. Although simultaneous nitriding denitrification principles apply to plant configuration due to oxidation ditches, the treatment plant is operated as a conventional active sludge system and considers pre-denitrification principles, which the first oxidation ditch is operated under anoxic conditions. The second oxidation ditch in the plant is operated under anoxic and aerobic conditions by controlling the diffusers (on/off), while the remaining two oxidation ditches are continuously aerated by the diffusers located at the bottom of the tanks and operated under aerobic conditions. In this context, a dynamic simulation was carried out using Sumo software for the entire oxidation ditch system. Bio-P tanks and final sedimentation tanks were included in the model to ensure system integrity, but only the nitrogen removal efficiency of oxidation ditch reactors was examined within the scope of this thesis. Modeling and simulation results confirmed that the minimum nitrate production rate occurred in the first oxidation ditch due to lack of aerobic environment. It was also examined that the nitrate recirculated from the fourth oxidation ditch to the first oxidation ditch was consumed within this first reactor. Hence, transfer of recirculated nitrate to the second reactor does not occur. Additionally, it was confirmed by the modelling studies that nitrate is consumed within the first reactor only at rates of the recirculated nitrate. Even if the second OD reactor is operated under anoxic conditions to provide denitrification for the recirculated nitrate, the volume of the first oxidation ditch cannot be used efficiently, because the recirculated nitrate from the fourth OD to the first OD is very low due to simultaneous nitrification denitrification occurs in the remaining reactors. In addition, results confirmed that the highest nitrate consumption rate was achieved within the first reactor, while this is followed by the second, third and fourth reactors, respectively. Nitrate production and utilization rates were determined through model outputs, which were very close in the second oxidation ditch due to operating conditions and creating both anoxic and aerobic zones, while in the third and fourth reactors, the difference between these rates increases due to decreased anoxic volume. Considering the information obtained from the modeling studies, it can be stated that the system is divided into two parts as the first oxidation ditch reactor and the remaining tanks (OD-2, OD-3 and OD-4). This is because nitrate can be removed from wastewater in OD-1 reactor only at a rate and an amount of the recirculated nitrate, which is determined to be low due to simultaneous nitrification denitrification occurred within the remaining OD reactors. Hence, the first oxidation ditch reactor volume, operated under anoxic conditions to provide denitrification, is not used effectively, and does not fit for purpose. Therefore, it was recommended that the optimization of the system could be achieved by operating four oxidation ditches in parallel with the principles of simultaneous denitrification nitrification. In addition, it is envisaged that this will also provide flexibility to plant operators in case of maintenance works etc., and the treatment system can be operated without interruption even if one of the tanks is out of operation. It may also be beneficial to select simpler and more efficient treatment systems for the plant configurations to prevent such treatment complications in the future.
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ÖgeÇamur çürütücü çıkış suyunda pilot ölçekli kısmi nitrifikasyon prosesinin modellenmesi(Lisansüstü Eğitim Enstitüsü, 2021-11-15) Hallaç, Esra ; İnsel, H. Güçlü ; 501181717 ; Çevre Bilimleri Mühendisliği ve Yönetimi Programı ; Environmental Sciences Engineering and ManagementAzot, doğada bulunan tüm canlıların yaşamları için gereken bir besin maddesidir. Azot, azot çevrimi adı verilen döngü ile doğada devamlı olarak form değiştirmekte ve farklı ekosistemlerde transfer olmaktadır. Ekolojik zincir ile doğada taşınım ve dönüşüm içinde bulunan azot; insan nüfusunun ve faaliyetlerinin artması ile dengeli döngüsünün dışına çıkar. Bu durum için, doğanın kendini temizleme ve yenileme kapasitesinin üzerinde bir yüke maruz kalması denebilir. Kendini temizleme kapasitesi üzerinde kirliliğe maruz kalan doğayı korumak için çeşitli arıtma yöntemlerinin geliştirilmesi ve uygulanması kaçınılmazdır. Azot, çoğunlukla biyolojik yöntemlerle arıtmaya tabi tutulur. Fiziksel ve kimyasal proseslerle giderimi mümkün olmakla birlikte, tasarım ve işletme kolaylığı ile düşük maliyet gerekliliği sebebiyle yaygın olarak biyolojik arıtma tercih edilmektedir. Azotun biyolojik arıtımında konvansiyonel yöntem, doğada da yer alan nitrifikasyon-denitrifikasyon prosesidir. Atıksuların, nitrifikasyon ve denitrifikasyon prosesini içeren klasik aktif çamur sistemi ile arıtıldığı arıtma tesisleri ülkemizde ve dünyada oldukça yaygındır. Bu sistemde atık su bünyesindeki kirleticiler, aktif çamur olarak nitelendirilen mikroorganizmalar tarafından besin ve enerji kaynağı olarak kullanılmak suretiyle atık sudan uzaklaştırılırlar. Mikroorganizmalarla atık suyun kontak halinde olduğu proses tanklarını (havalı / havasız), arıtılmış olan suyun mikroorganizmalardan ayrıldığı çöktürme havuzları takip eder. Klasik aktif çamur sisteminin yatırım maliyeti düşük, işletimi nispeten kolay ve çıkış suyu iyi kalitededir. Ancak günümüzde arıtılmış suyun alıcı ortama deşarj kriterlerinde daha sıkı limitler gelmektedir. Diğer yandan enerji verimliliği daha yüksek sistemlerle ilgili arayış ve bu sistemlere rağbet artmaktadır. Hem prosesteki havalandırma ihtiyacı, hem de sistemde oluşan fazla aktif çamurun bertarafı klasik aktif çamur sisteminin önemli bir dezavantajıdır. Aktif çamur sisteminin sahip olduğu avantajlardan faydalanmak ve dezavantajlarını azaltmak için yenilikçi prosesler geliştirilmektedir. Yenilikçi proseslerden biri olan Anammox'la azot gideriminde klasik aktif çamur sistemine göre daha az çamur oluşur. Reaksiyon oksijensiz ortamda gerçekleştiğinden havalandırma ihtiyacı yoktur. Ayrıca elektron alıcının da vericinin de azotlu bileşen olduğu proseste karbon ihtiyacı olmadığı gibi, karbon kaynaklı sera gazı da oluşmamaktadır. Anammox prosesi öncesinde uygulanan kısmi nitrifikasyon prosesi, amonyumun sırası ile nitrit ve nitrata yükseltgendiği nitrifikasyon prosesini nitrit oluşumu aşamasında durdurma esasına dayanmaktadır. Kısmi olarak gerçekleştirilen bu nitrifikasyon işleminin çıktıları amonyum ve nitrittir. Amonyum ve nitrit arasında elekton alışverişinin gerçekleştiği Anammox prosesinin çıktısı ise azot gazıdır. Kısmi nitrifikasyon, tam nitrifikasyona göre daha az oksijen, dolayısıyla daha az havalandırma maliyeti gerektirir, arıtma çamuru üretimi düşüktür. Özellikle azot yükünün fazla olduğu sistemlerde fizibildir. Bu çalışma, İstanbul'da bulunan bir evsel atıksu arıtma tesisinin yan akım suyunda azot giderimini Anammox prosesi ile gerçekleştiren bir pilot tesisin kısmi nitrifikasyon prosesini konu edinmektedir. Kısmi nitrifikasyonun gerçekleştiği reaktör, anaerobik çürütücülerin ortalama 800-1000 mg/L amonyum azotu konsantrasyonuna sahip çıkış suyu ile beslenmektedir. Sistemde giriş suyundaki amonyumunun yarısının nitrite dönüştürülmesi ve kısmi nitrifikasyon çıkış suyunun Anammox reaktörüne beslenmesi hedeflenmiştir. Reaktörün 651 günlük işletilme süreci, bu süreçte işletme parametrelerinde yapılan değişiklikler, elde edilen sonuçlar bu çalışmada yer almaktadır. Bazı işletme parametreleri kontrollü olarak değişmiş, bazıları ise sistemsel aksaklıkların sonucu olarak değişmiştir. Her iki durumun da sonuçlara etkisi, amonyum giderimi ve nitrit ile nitrat azotlarının oluşumu üzerinden ortaya konmuştur. Dönemsel olarak farklılıklar göstermekle birlikte, kısmi nitrifikasyon reaktöründe ortalama olarak giriş amonyumunun % 60'ı nitrite dönüşmüştür. Çalışmada yaşanan işletme problemlerine de yer verilmiştir. İşletme tecrübeleri, online ölçüm enstrumanlarının kritik öneme sahip olduğunu göstermiştir. Özellikle online amonyum ölçümü ve buna bağlı olarak reaktöre amonyum dozajının sağlanması kısmi nitrifikasyon prosesinin temel gerekliliklerini sağlamak açısından önemlidir. Çalışma kapsamında ayrıca, işletme ve laboratuvar analiz verileri ile yapılan dinamik modelleme yer almaktadır. Modelleme, SUMO 2019 (Nyons, Fransa) programı kullanarak yapılmıştır. Modelleme sonuçlarında özellikle amonyum oksidasyonunda tesis verileriyle uyumlu sonuçlar elde edilmiştir. Modelleme çalışmasının çıktısı prosesin kinetik parametreleri olmuştur. Kinetik parametreler, sistemin tasarımı ve işletme performansının tespiti açısından önemlidir. Bu çalışmada yer alan kısmi nitrifikasyon prosesinin ana aktörü olan amonyum oksitleyici bakterin çoğalma hızı (μAOB) 1,0 gün-1, sistemde yer alan ve baskılanan nitrit oksitleyicilerin çoğalma hızı (μNOB) 0,5 gün-1 olarak bulunmuştur. Elde edilen değerler literatürle uyum içerisindedir.
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ÖgeDegradation of industrial micropollutants with sulfate radical–based advanced oxidation processes(Lisansüstü Eğitim Enstitüsü, 2021) Montazeri, Bahareh ; Arslan Alaton, İdil ; 693111 ; Çevre MühendisliğiOccurrence of micropollutants in wastewaters from the industries poses a serious threat to the environment and many of these contaminants are recalcitrant and/or toxic and/or biologically non-degradable. Therefore, the major concern is to treat the wastewater before being discharge into the environment. Among all these industrial micropollutants, in particular 3,5-dichlorophenol (3,5-DCP) from chlorophenols (CPs), 2,4-dichloroaniline (2,4-DCA) from chloroanilines (CAs) and iprodione (IPR) from hydantoins, have been drawn specific attention due to their commercial importance as raw materials, potential toxicity and refractory nature. 3,5-DCP is directly released to the aquatic environment through various waste streams such as wood pulp bleaching processes. 2,4-DCA is extensively used in manufacturing of pigments, optical brighteners and pharmaceutical agents. IPR as a fungicide is used to prevent gray mold on crops; however, its usage has been banned recently by the European Food Safety Authority. Considering the wide spread usage of the above-mentioned micropollutants and their incomplete removal in conventional industrial and urban wastewater treatment plants; they may end up in the aquatic environment, becoming threats to wildlife. Sulfate radicals (SO4●-)-based advanced oxidation processes (AOPs) have demonstrated that they have the potential to be efficiently applied in removing many organic pollutants from wastewater. In the first part of this study, three persulfate (PS)-mediated AOPs including one homogenous photochemical oxidation processes; ultraviolet-C (UV-C)-activated PS oxidation process (UV-C/PS), and two heterogeneous catalytic oxidation processes; zero-valent iron-activated persulfate oxidation process (ZVI/PS) and zero-valent aluminum-activated persulfate oxidation process (ZVA/PS) were employed in order to investigate the three micropollutants removal in distilled water (DW) and examine the influence of initial PS concentration (0.00 mM-1.00 mM) and pH on the treatment performances. UV-C/PS treatment of 3,5-DCP for all studied PS concentrations resulted in complete 3,5-DCP removal and the 3,5-DCP degradation rate increased by increasing the initial PS concentration which can be explained by an increase in the steady-state concentration of SO4●- generation in reaction solution. Increasing the initial pH to values more than 7.5, resulted in rapid 3,5-DCP degradation. Maximum 3,5-DCP removal efficiency was as 59% by 120 min ZVI/PS (PS=1.00 mM; pH=5.0); however, complete 3,5-DCP removal was obtained by decreasing pH to more acidic value after 20 min ZVI/PS (PS=0.50 mM; pH=3.0) treatment. ZVA/PS could not provide complete 3,5-DCP removal after 120 min treatment such that for the highest tried PS concentration.(1.00 mM; pH=3.0) resulted in only 31% 3,5-DCP removal. 2,4-DCA degradation by UV-C/PS, at all studied initial PS concentrations and pH values resulted in complete pollutant removal. PS activation with ZVI resulted in complete 2,4-DCA removal for initial PS concentration exceeding 0.50 mM such that after 80 min ZVI/PS (PS=0.75 mM; pH=5.0) treatment, complete 2,4-DCA was obtained; however, the required time to achieve complete 2,4-DCA with initial PS of 1.00 mM was longer (100 min) most probably as a result of SO4●- scavenging reaction with excess PS and/or ferrous ion. The highest 2,4-DCA removal (47%) by 120 min ZVA/PS (pH=3.0) treatment was obtained with initial PS concentration of 0.25 mM, below or beyond which the 2,4-DCA removal decreased. 2,4-DCA removal by 120 min ZVA/PS (PS=0.50 mM) treatment increased remarkably from 20% to 89% , when pH decreased from 3.0 to 1.5 suggesting that more acidic pH facilitated effective removal of 2,4-DCA due to ZVA corrosion. Complete IPR removal was achieved by UV-C/PS at all studied initial PS concentrations such that even with low PS (0.03 mM), complete IPR was obtained in 20 min. Increasing initial PS concentration in the range of 0.01 mM to 1.00 mM led to higher SO4●- concentrations and consequently faster IPR degradation rates. Alkaline hydrolysis of IPR was observed at initial pH of 9.0 and 11.0 during UV-C/PS treatment; however, complex pH effect on IPR degradation rate was observed at neutral and acidic pH values. ZVI/PS (pH=5.0) treatment of IPR, demonstrated that increasing initial PS concentration to more than 0.50 mM, appreciably improved ZVI/PS treatment of IPR. ZVA/PS was an efficient treatment only in IPR degradation such that even low PS concentrations (0.10 mM and 0.25 mM) with initial pH of 3.0 resulted in almost 80% IPR removal after 120 min treatment and for higher PS concentrations, complete IPR was obtained. In both heterogeneous treatments of all three model industrial micropollutants acidic pH values showed a better performance. Those oxidation processes from treatability of the micropollutants in DW resulted in complete micropollutant removal, were investigated under selected PS and pH conditions to correlate each micropollutant removal with chloride ion (Cl-) release, metal ion release, dissolved organic carbon (DOC) removal and PS consumption. Experiments conducted in DW indicated that for all three model industrial micropollutants, complete removals were achieved by UV-C/PS accompanied with dechlorination and appreciable mineralizations. 3,5-DCP was completely degraded by UV-C/PS (PS=0.30 mM; pH=6.3) treatment in 40 min accompanied with 95% DOC removal that was achieved after 120 min treatment. Maximum Cl- concentrations of 3.91 mg/L was obtained after 120 min UV-C/PS treatment of 3,5-DCP corresponding to practically 90% of the highest possible theoretical Cl- release of 4.35 mg/L. Practically complete 2,4-DCA removal was achieved after 10 min UV-C/PS (PS=1.00 mM; pH=6.0); however, with the progress of the treatment, dechlorination and DOC removal were proceeded such that 93% DOC removal and Cl- concentration of 3.64 mg/L were obtained after 40 min treatment. Beyond this treatment time, both DOC removal and dechlorination were practically stopped and remained constant probably due to PS depletion. IPR degradation was accompanied with rapid dechlorination and PS consumption. UV-C/PS (PS=0.30 mM; pH=6.2) treatment was also effective in IPR mineralization; 78% DOC was removed after 120 min treatment and maximum Cl- concentrations of 1.50 mg/L was obtained at the end of the reaction. For all three studied industrial micropollutants, complete/near-complete removals were achieved by ZVI/PS accompanied with iron (Fe) release; however, their mineralizations were partially (21%-50% DOC removal) after 120 min treatment. ZVA/PS was only effective in IPR removal; however poor mineralization was obtained after 120 min treatment. Treatability of the selected micropollutants was also examined in a synthetic tertiary treated urban wastewater (SWW) during the studied treatments due to the fact that the presence of different water constituents in the reaction solution may inhibit the oxidation performance. Experimental results of three model industrial pollutants by the selected treatments (UV-C/PS and ZVI/PS) in SWW, revealed complete micropollutant removals; however, their mineralizations were partially and different compared to DW. UV-C/PS treatment of 3,5-DCP in DW that exhibited appreciable mineralization of 3,5-DCP, demonstrated worse treatment performance compared to ZVI/PS when applied in SWW (26% DOC removal and 41% DOC removal in SWW after 120 min treatment by UV-C/PS and ZVI/PS, respectively). Partial mineralizations of 2,4-DCA in SWW by 120 min UV-C/PS and ZVI/PS treatments were obtained as 57% and 35% DOC removals, respectively which were lower compared to DW revealing performance of both treatments decreased in complex medium. The experiments in DW exhibited the superior performance of the UV-C/PS for IPR mineralization (78% DOC removal after 120 min); however, the oxidation performance of UV-C/PS in SWW decreased appreciably and resulted in 24% DOC removal after 120 min. 40% DOC removal after 120 min was observed with ZVI/PS being the most efficient process in SWW. UV-C/PS treatment of all three selected micropollutants, was most negatively affected when apply in SWW most probably due to UV-C light absorption of SWW constituents hindering effective absorption by the target pollutant. Vibrio fischeri (V. fischeri) and Pseudokirchneriella subcapitata (P. subcapitata) were employed as the organism tests to assess changes in acute toxicity during application of the studied treatments. Responses of the two mentioned test organisms were rather different; higher inhibition rates were observed on P. subcapitata than V. fischeri. While the percent relative inhibition of the original 3,5-DCP on P. subcapitata was almost 20%, the inhibitory effect increased after 80 min UV-C/PS treatment reaching to 47%. After 80 min ZVI/PS treatment of 3,5-DCP, the percent relative inhibition of treated samples on P. subcapitata did not change appreciably. The percent relative inhibition of the original 2,4-DCA on P. subcapitata was in the range of 20%-28%; however, the inhibitory effect increased and reached 72% after 120 min UV-C/PS treatment. The percent relative inhibition of original IPR samples on P. subcapitata was obtained as <10%; however, it reached 56% and 39% after 120 min UV-C/PS and ZVI/PS, respectively. During the application of selected treatments in DW, the genotoxicity of original micropollutants and their AOPs-treated samples were explored using a mutant strain of Salmonella typhimurium TA 1535; however, no significant genotoxic effect was observed. At the final stage of this study, the type and nature of possible evolved degradation products during the selected treatments of three model industrial pollutants in DW were examined by ion chromatography, liquid chromatography and mass spectrometry analysis in order to gain a deeper insight into the formed radical reactions with the target pollutants. Hydroquinone, acetic acid and Cl- could be detected and quantified in the reaction solution during UV-C/PS and ZVI/PS treatments of 3,5-DCP. Aniline and acetic acid formations were evidenced during UV-C/PS treatment of 2,4-DCA accompanied with dechlorination; however only acetic acid was identified during ZVI/PS. LC analysis confirmed the formation of 2,4-DCA, hydroquinone, acetic acid and formic acids as the major aromatic and aliphatic degradation products of IPR during UV-C/PS while hydroquinone, lactic acid and acetic acid was evidenced for ZVI/PS treatment of IPR.
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ÖgeDöngüsel ekonomi yaklaşımıyla kullanım ömrü dolan seramik membranların iç ortam havasından co2 giderimi için yeniden kullanımı(Lisansüstü Eğitim Enstitüsü, 2021-07-16) Karataş, Elçim ; İmer, Derya Yüksel ; 501181745 ; Çevre Mühendisliği ; Environmental EngineeringSürdürülebilirlik konusu son yıllarda küresel olarak ön plana çıkmış ve başta Avrupa Birliğindeki ülkeler olmak üzere birçok ülke bu konuyu ele almaya başlamıştır. Sürdürülebilirlik kavramı, çevresel bir yaklaşımla doğal kaynak tüketimini azaltmaya odaklanırken, aynı zamanda kaynakları tasarruflu kullanmayı hedeflemektedir. Bu bağlamda, döngüsel ekonomi ve sürdürülebilirlik ayrılmaz bir şekilde bağlantılıdır. Son zamanlarda, membran proseslerinin birçok alanda kullanımının artması buna karşın hızlı kirlenme problemi nedeniyle membranların sık değişim gerekliliği ve atık oluşturma potansiyeli bu alanda kullanım ömrünü tamamlamış membranların yeniden kullanımı, atık membranlardan enerji geri kazanımı veya başka bir membran türüne dönüştürme ve yeniden kullanma (örneğin, ultrafiltrasyon veya nanofiltrasyon olarak ters osmoz membranlarının kullanılması) ile ilgili çalışmalara ihtiyaç artmaktadır. Membranlar son yıllarda su ve atıksu arıtımı ve madde geri kazanımı alanında oldukça fazla kullanılmaktadır. Ortalama verimli kullanım ömürleri ve değişim periyotları düşünüldüğünde çok ciddi bir atık yüküne sahiptir. Bu alanda sürdürülebilirlik çözümü için bilim ve teknoloji çerçevesinde yeni yaklaşımlar ortaya koymak gelecek için çok ciddi bir adımdır. Yapılan çalışmaların büyük bir çoğunluğu TO polimerik membranların döngüsel ekonomi yaklaşmıyla UF veya NF olarak tekrar kullanımını içermektedir. Polimerik membranların ömrünün yeni membran üretim stratejileri ve modül tasarımları ile en az 6 yıl, seramik membranların ise çok fazla çalışma olmamasına rağmen ömrünün 20 yıla yakın olduğu belirtilmektedir. Seramik membranların veya filtrelerin yeniden kullanımı veya geri kazanımı ile ilgili çalışmaları araştırdığımızda şu anda literatürde veya endüstriyel uygulamada bununla ilgili bir çalışmaya rastlanmamış ve kabul görmüş sistematik bir yaklaşımdan bahsedilmemiştir. Genel olarak seramik atıklarının tekrar değerlendirilmesi ile ilgili literatürde yer edinmesine rağmen seramik membranların tekrar kullanımı ile ilgili bir çalışma mevcut değildir. Tez kapsamında endüstriyel atıksu arıtımında kullanılmış ve ekonomik ömrünü tamamlamış seramik membranların CO2 gideriminde kullanılabilirliğini incelemek, bu amaçla membran temas reaktör dizayn etmek ve işletmek ve böylelikle döngüsel ekonomi yaklaşımını membranların yeniden kullanımı için uygulayarak ön bir çalışma niteliğinde ortaya koymaktır. Tez çalışmasının amacı son yıllarda kullanımı gittikçe artan membran proseslerin temel malzemesi olan membranların faydalı kullanımları sonrası ekonomiye yeniden kazandırılması için yöntemler geliştirmektir. Bu bağlamda membran temas reaktörün CO2 giderimde verimliğini değerlendirebilmek amacıyla kullanılan sıvı absorbentin (NaOH çözeltisi) CO2 tutma kapasitesinin farklı NaOH konsantrasyonlarında ve farklı sıvı ve gaz sirkülasyon debisinde test edilerek optimum koşulu belirlemek amaçlanmıştır.
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ÖgeDynamic membranes in aerobic membrane bioreactor systems for municipal wastewater treatment(Graduate School, 2021-06-08) Işık, Onur ; Demir, İbrahim ; Özgün, Hale ; 501142704 ; Environmental Sciences Engineering and Management ; Çevre Bilimleri Mühendisliği ve YönetimiThe amount of municipal wastewater produced around the world is expected to increase parallel to the increase in population. Therefore, the treatment of municipal wastewater is very crucial for public health. Conventional activated sludge systems have been used for the treatment of municipal wastewater for a long time. Due to limited area availability and stringent discharge standards in most cases, compact treatment systems enabling high effluent quality have become attractive recently. Membrane bioreactor (MBR) technology is a good alternative to conventional activated sludge systems. There are several advantages of MBR technology over conventional biological treatment systems. Low footprint and high permeate quality can be considered as the most distinguishing features of the MBRs. Due to the retention of high suspended solids concentration in the bioreactor, smaller reactor volume and low sludge production can be achieved by the MBR process. However, some constraints have been observed during the operation of MBRs including membrane fouling and membrane costs. Dynamic membrane (DM) technology is a promising solution for problems encountered during the operation of MBRs for wastewater treatment. Membranes can be substituted with coarse-pore filters made of low-cost materials such as meshes or fabrics in dynamic membrane applications for cake (DM) layer formation. DM is a secondary layer formed on a low-coast porous support material. DM layer acts like a Microfiltration (MF) or Ultrafiltration (UF) membrane and keeps the sludge particles inside the bioreactor providing high permeate quality. Besides, physical cleaning, without using chemical reagents, may be enough for cleaning in dynamic membrane bioreactors (DMBRs), thus, the operational costs can be reduced. Flat sheet submerged module configurations were mostly used for aerobic DMBR studies for municipal wastewater treatment in the literature. Also, few studies used tubular modules in DMBRs. However, no studies reported using hollow fiber modules in the literature. The main aim of this thesis was to investigate the applicability of hollow fiber DM for municipal wastewater treatment in an aerobic DMBR. This thesis was conducted in 6 Stages. In stage 1, a hollow fiber polyester fabric support material was used for DM formation and compared with a commercial hollow fiber UF membrane. The system was fed with medium strength synthetic municipal wastewater to keep the characteristics of the wastewater same, and to evaluate the treatment and filtration performances of both membranes clearly. Morphological analyses were also carried out for DM and UF surfaces. The system was operated continuously at a flux of 5 L/m2·h for 85 days. High chemical oxygen demand (COD) removal efficiency and total suspended solids (TSS) rejection were achieved by the DM. Transmembrane pressure (TMP) of the DM was higher in comparison to the UF membrane, which was related to the formation of the cake layer in DM. In Stage 2, impact of support material type on DMBR performance was investigated for municipal wastewater treatment. A hollow fiber polyester support material was compared with a glass fiber support material in terms of treatment and filtration performances. Medium strength synthetic municipal wastewater was used for a stable feed characteristics. Similar treatment performances were obtained with each membrane achieving high removal efficiencies for COD(>97%) and TSS (>99%) parameters. Higher TMP was observed for glass fiber material in comparison to polyester material. Based on morphological analyses, dynamic layers formed on both support materials had similar compositions, organic and inorganic materials. A homogeneous layer was formed on a polyester support material, while fine particles were deposited between the filaments of glass fiber support material, which caused clogging. In Stage 3, a hollow fiber polyester fabric support material was used for DM formation for raw municipal wastewater treatment. The wastewater had average COD concentration of 413 mg/L, sCOD concentration of 208 mg/L and TSS concentration of 259 mg/L. Treatment and filtration performances were evaluated. High treatment performance was obtained in the permeate achieving over 93% of COD removal efficiency and low TSS concentration (<10 mg/L) in the permeate. The average TMP value was observed as around 598 mbar after the system reached stable conditions. In Stage 4, effect of different TSS concentrations on the DM layer was evaluated in terms of biological treatment and filtration performances. Hollow fiber polyester support material was used for DM layer formation. Treatment and filtration performances of the DMBR were investigated at two different TSS concentrations (5 g/L; 10 g/L). The DMBR was operated at a flux of 18 L/m2·h at each condition. High treatment performance and permeate quality were achieved at each sludge concentration. However, a shift to a relatively higher range in particle size distribution of permeate was observed at high sludge concentration. Furthermore, higher TMP was observed at the sludge concentration of 10 g/L, resulting in a rapid clogging. Overall, results indicated that selection of the optimum sludge concentration played a significant role in achieving homogeneous and stable DM layer in DMBRs. In stage 5, hollow fiber polyester support material was used for DM formation and compared with a commercial UF membrane in terms of micropollutant and heavy metal treatment performance from raw municipal wastewater, also biological treatment and filtration performances were evaluated. The removal of different micropollutants; sulfamethoxazole, ciprofloxacin, trimethoprim, caffeine and acetaminophen, was assessed for both membranes. The membranes were operated at a flux of 10 L/m2·h. High TSS (>99%) and COD (> 91%) removal efficiencies were achieved with both membranes. Similar high removal efficiencies of micropollutants (>68.3->99.7%) were achieved with both membranes. DM was operated at higher TMP compared to UF membrane, since DM layer was formed on the support material. Morphological analyses were conducted for both membranes to get insight to the DM layers which accumulated on the membranes. In Stage 6, effect of using different inoculum on DMBRs performance was investigated. Excess sludge from HRAS and conventional activated sludge system retuned activated sludge were used as inoculums. Conventional UF membrane was used in parallel with a dynamic membrane (DM) in the same reactor to be operated at the same conditions. Both sludges were characterized to understand the changes during the operational period. Biological treatment and filtration performances of both membranes were investigated. High TSS (>99%) and COD (> 86%) removal efficiencies were achieved with both membranes for both inoculum sludge. Because of the inoculum sludge characteristics, lower TMP values were observed for DM at Phase-2. Morphological analys (ESEM measurement) was conducted to understand the effect of different inoculum on the sludge cake on the surface of the membranes.
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ÖgeEnvironmental life cycle assessment of zinc phosphating chemicals(Institute of Science and Technology, 2020-07) Sezginer, Halide İlayda ; Germirli Babuna, Fatoş ; 629363 ; Çevre Bilimleri, Mühendisliği ve Yönetimi Bilim DalıThe industrialization has gained importance with the rapidly increasing world population. Over time, productions have evolved from physical strength to machine power, and have diversified in terms of quality and quantity. With the need for more production, industrialization has started to be mentioned with the environmental problems that it causes. In the period from the industrial revolution to the present day, sustainability has become a subject that is closely followed by everyone, especially in the last period. Increasing social sensitivity has started to reveal the necessity of making necessary improvements in new projects or existing production systems with product life cycle analyses. The product lifecycle is a common method that provides to evaluate product or service the environmental impacts that each of the stages of raw material extraction, production, use, disposal, and all other stages have over the duration. The rapid disappearance of natural resources and the increase of environmental impacts arising from industry in nature caused the developed countries to increase their product life analysis studies and take necessary measures.
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ÖgeFabrication of thin film nanocomposite pressure retarded osmosis (PRO) membranes using cellulose nanocrystal (CNC) and evaluation of performances in the processes(Graduate School, 2021-02-02) Paşaoğlu, Mehmet Emin ; Koyuncu, İsmail ; 659118 ; Environmental EngineeringNowadays, owing to quick world population growth and abrupt economy, high water demands desire innovative technologies in order to ensure clean and safe water with lower energy use. Severe environmental emissions arising by the consumption of fossil fuels often needs us to build energy harvesting technology which are environmentally sustainable. As an advanced technology, osmotic membrane processes consisting of forward and pressure-retarded osmosis, are conceived to be conspicuous technologies for the treatment, recycling and reuse of wastewaters and the harvesting of salinity gradient energy which is called "Blue Energy". Nevertheless, forward osmosis (FO) and pressure retarded osmosis (PRO) are at the level of growth yet. It is difficult piece of work to fabricate osmotic membranes obtaine high water permeability and perfect ion retention. The ideal osmotic membrane candidate can be a thin film composite membrane satisfy the conditions which has high water permeation and as soon as low reverse salt flux ratio. Furthermore, for the membrane to endure relatively high hydraulic pressures in PRO systems, certain mechanical properties are vital. Thankfully, membranes that are fabricated with electrospinning method have an excellent capability to overcome all specifications of the perfect support layer in consequence of porous structure characteristics and simplicity with that nanomaterials may be integrated to enhance the nanofibers mechanical strength. Apart from this, interfacial polymerization (IP) may be accomplished to electrospun nanofiber membrane to achieve a very thin selective polyamide coating. TFN membranes may show tremendous potential in osmotically driven membrane processes after integrating nano additives into their support layer. The aim of this thesis to carry out and design a comprehensive study on the development of reinforced pressure retarded osmosis membranes. Specifically, this thesis presents the development of novel nanofiber supported thin film composite membranes with high water permeability and excellent selectivity for solvents, while showing an excellent mechanical strength for PRO processes. Interfacial polymerization reactions were used to construct very thin polyamide selective layer on the support, and electrospinning process was used to fabricate a number of support layers. Initially, we investigated the potential to use flat sheet electrospun polyacrylonitrile nanofibers as support support layer to fabricate PRO membranes. Polyamide TFCs were successfully applied on five different substrate containing 0,1,2,5,10% crystal nanocellulose (CNC) in 16% PAN polymer solution. PRO membranes successfully fabricated via tailor-made flat sheet fabrication unit. It is concluded that PAN and CNC generated a complete mixture according to SEM, FTIR, DMA & contact angle analysis findings.The addition of CNC improved the mechanical strength of PAN support layers which is the main phenomenon in PRO applications. The newly developed membrane can achieve a higher PRO water flux of 300 LMH, using a 1 M NaCl draw solution and deionized water feed solution. The corresponding salt flux is only 1.5 gMH. The reverse flux selectivity represented by the ratio of water flux to reverse salt flux (Jw/Js) was able to be kept as high as 200 L/g for PRO operation. Following the success of flat-sheet TFN PRO membrane fabrication, improvements need to be done to increase packing density of fabricated final membrane modules. In this point, we used a novel technique to fabricate tubular membranes for PRO applications. The newly fabricated membrane achieves a higher PRO water flux of 405.38 LMH with using a 1 M NaCl and a DI as feed water. The corresponding salt flux is found as 2.10 gMH which is higher than flat sheet membranes. The selectivity of the reversed flux represented by the ratio of the water flow to the reversed salt flux (Jw/ Js) was able to be kept as high as 193.03 L/g for PRO operation.As far as we know, the performance of the work developed membrane in this study has shown better performance than all PRO membranes reported in the literature previously.
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ÖgeGeri dönüştürülmüş agrega kullanımının çevresel etkilerinin yaşam döngüsü değerlendirme (YDD) yöntemi ile değerlendirmesi(Lisansüstü Eğitim Enstitüsü, 2022-11-03) Babalık, Özge ; İskender, Fatma Gülen ; Baş, Bilge ; 501171753 ; Çevre Bilimleri, Mühendisliği ve YönetimiDünya çapında yaşanan hızlı kentleşme ve kentsel dönüşüm ile birlikte, inşaat ve yıkım atıklarının (İYA) oluşumu hızlı bir artış ile önemli miktarlara ulaşmıştır. Bu artış nedeniyle gelişmiş ve gelişmekte olan ülkeler, çevresel baskı altına girmiştir. İYA'da bulunan beton, tuğla, alçı, ahşap, cam, metaller, plastik, solventler, asbest ve hafriyat toprağı da dahil olmak üzere çoğu geri dönüştürülebilinir özellikte olup ham madde kullanım olarak yüksek kaynak değerine sahiptir. Özellikle, İYA'dan elde edilen agregalar yol, drenaj ve diğer inşaat çalışmalarında yeniden kullanılarak değerlendirilmektedir. 2008/98/EC Atık Çerçeve Direktifi, 2020 yılına kadar İYA'nın %70'inin geri dönüştürülmesini hedefleyerek İYA ve geri dönüştürülmüş malzemelerin doğru yönetimini amaçlamaktadır. Sürdürülebilir inşaat sektörü için doğal kaynakların kullanımı azaltmak amacıyla, geri dönüştürülmüş agreganın (GA) inşaat projelerinde kullanılması gündeme gelmiştir. Bu çalışmada doğal agrega (DA) ile üretilen normal beton (NB) ve GA içeren geri dönüştürülmüş agregalı betonun (GDAB) çevresel etkileri karşılaştırılmalı olarak değerlendirilmiştir. Bu amaçla, Yaşam Döngüsü Değerlendirmesi (YDD) yöntemi kullanılmıştır. Çalışmanın çevresel etki değerlendirme modellemesi GaBi ve 4.3 yazılımı ile yazılımın "profesyonel database" veritabanı kullanılmış, etki değerlendirmesi CML 2001 yöntemiyle belirlenmiştir. YDD dört aşamadan oluşmaktadır. Yöntemin ilk aşamasında çalışmanın amacı ve kapsamı belirlenmiştir. Bu çalışmanın amacı, bir inşaat molozundan elde edilen geri dönüştürülmüş agreganın beton üretiminde kullanılmasının potansiyel çevresel etkilerinin araştrılması ve ayrıca NB üretimi ile karşılaştırmalı olarak değerlendirilmesidir. Modellemede, %50 GA içeriğine sahip GDAB için inşaat yıkımı sonucu oluşan molozun geri dönüşüm tesisinden kırma işlemine ardındanda beton santralinde beton üretimini kapsarken, %100 DA'lı NB oluşturmak için bir taş ocağından başlanarak kırma tesisinde kırma işlemi sonrası beton santralindeki beton üretim aşamalarına kadar olan işlemleri içermektedir. Bu çalışmada iki betonun basınç dayanımları incelendiğinde, fonksiyonel birim, C40-C50 aralığında 1 m³ NB ve C40-C50 aralığında 1 m3 GDAB olarak seçilmiştir. İkinci aşama olan envanter analizinde çalışma sistemindeki enerji, su hammadde kullanımı gibi girdi ve çıktılar hesaplanmaktadır. Envanter analizinde belirlenen girdi ve çıktılar, etki analizi aşamasında çevresel değerler üzerindeki etkileri değerlendirilmektedir. Üçüncü aşamada, bu çalışmanın çevresel etki değerlendirme için etki kategorileri seçilmektedir. Seçilen etki kategorileri; Abiyotik element tüketim potansiyeli (AETP), abiyotik fosil tüketim potansiyeli (ATPf), asidifikasyon potansiyeli (AP), fotokimyasal ozon oluşum potansiyeli (FOOP), ozon tabakası tükenme potansiyeli (OTTP), küresel ısınma potansiyeli (KIP), ötrofikasyon potansiyeli (ÖP), tatlı su canlılarına ekotoksitite potansiyeli (TCETP) ve karasal ekotoksisite potansiyeli (KETP)'dir. YDD'nin son aşaması olan yorumlama aşamasında iki farklı beton türünün çevresel etkileri yorumlanmış ve benzer YDD çalışmalar ile kıyaslanmaktadır. Elde edilen sonuçlar 1m3 GDAB üretiminin AETP'i 0,000415 kg Sb eşd., ATPf'i 1440 MJ, AP'i 0,516 kg SO₂ eşd., ÖP'i 0,29 kg PO₄ eşd., TCETP'i 0,472 kg DCB eşd., KIP'i 292 kg CO₂ eşd., OTTP'i 0,0000000217 kg CFC₁₁ eşd., FOOP'i 0,0526 kg C₂H₄ eşd., KETP'i ise 0,643 kg DCB eşd. olduğu görülmektedir. 1m3 NB üretiminin AETP'i 0,000427 kg Sb eşd., ATPf'i 520 MJ, AP'i 0,584 kg SO₂ eşd., ÖP'i 0,289 kg PO₄ eşd., TCETP'i 0,505 kg DCB eşd., KIP'i 300 kg CO₂ eşd., OTTP'i 0,0000000263 kg CFC₁₁ eşd., FOOP'i 0,0569 kg C₂H₄ eşd., KETP'i ise 0,703 kg DCB eşd. olduğu görülmektedir. GDAB üretiminin, ÖP etki kategorisi dışında NB üretimine göre çevresel etkisi daha az olduğu tespit edilmiştir. GDAB üretiminin ÖP etki kategorisi değeri, NB üretiminin ÖP etki kategorisi değerinden büyük olmasının sebebi GDAB üretiminde kullanılan süper akışkanlaştırıcı miktarının daha fazla olmasıdır. Bu çalışmada YDD değerlendirmesine ek olarak, maliyet analizi yapılmaktadır. 1 m³ NB ve GDAB üretiminin maliyet miktarı sırasıyla, 462,74 TL ve 474,427 TL'dir. 1 m³ GDAB üretimi 11,68 TL fark ile daha maliyetli olduğu tespit edilmektedir. Bunun nedeni GDAB üretiminde kullanılan doğal agreganın (agrega no:2) üretim ve taşıma maliyetidir.
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ÖgeGri suyun ozon, perokson ve kimyasal destekli ön arıtma prosesleri ile arıtılması(Lisansüstü Eğitim Enstitüsü, 2023) Karahan, Beyza Nur ; Ergün, Hale ; 809087 ; Çevre Bilimleri, Mühendisliği ve Yönetimi Bilim DalıGünümüzdeki dünya nüfusunun yirminci yüzyıl ortalarındaki nüfusa göre üç kat daha fazla olduğu bilinmektedir. 1950 yılından bugüne kadar artarak büyüyen dünya nüfusu 2023 yılı itibariyle 8 milyara ulaşmıştır. 2059 yılına kadar dünya nüfusunun 10 milyarın üstüne çıkması öngörülmektedir. Hızla artan dünya nüfusu insanların temiz su kaynaklarına ulaşmasını günden güne zorlaştırmaktadır. İklim değişikliği ile yaşanan son kuraklıklar yaşam için ciddi bir tehdit oluşturmuş ve dünya çapında su kıtlığı yaşayan ülkelerin sayısı artmıştır. Bu durum sonucunda alternatif su kaynağı arayışı başlamıştır. Arıtılmış su geri kazanımı bu bağlamda alternatif su kaynağı olarak değerlendirilmektedir. Evsel atıksuların tek bir akım halinde toplandığı geleneksel atıksu toplama sistemleri yerine akım ayrımı prensibi ile çalışan güncel uygulamalar gün geçtikçe yaygınlaşmaktadır. Sürdürülebilir su kullanımı, alternatif kaynak arayışında ve doğal kaynakların kontrollü kullanılmasında etkin rol oynayan bir uygulamadır. Ekolojik evsel atıksu yönetimi (ECOSAN), evsel atıksuların farklı bileşenlerinin ayrık akımlar halinde toplanmasını önermektedir. Bu sistemle birlikte atıksuların değerli bir kaynak olarak kullanımı ve bunun neticesinde sürdürülebilir su kullanımı sağlanabilmektedir. ECOSAN prensibinde evsel atıksular iki veya üç bileşene ayrılarak toplanabilmektedir. Evsel atıksuyun üç akım halinde ayrı toplanması durumunda atıksu bileşenleri; gri su, sarı su ve kahverengi sudur. Gri su, evsel atıksuların tuvalet suları dışında kalan banyolardan, duşlardan, el yıkama lavabolarından, mutfak lavabolarından, çamaşır ve bulaşık makinelerinden gelen kısmı olarak tanımlanmaktadır. Gri sular evsel atıksuların %75'lik kısmını oluşturmaktadır. Gri su, yüksek hacim potansiyeli ve kirlilik yükünün geleneksel evsel atıksulara oranla daha düşük olması sebebiyle değerli bir yenilenebilir su kaynağıdır. Kirlilik yükünün az olması sebebiyle geleneksel evsel atıksulara göre gri suların arıtılması daha kolaydır. Gri su arıtma süreçleri; arıtılmış su geri kazanımı için düzenleyici standartları sağlamalı ve organik bileşikler ile patojenlerin giderimi açısından etkili olmalıdır. Gri su arıtımı ve geri kazanımı için; doğal arıtma sistemleri, filtrasyon gibi fiziksel arıtma sistemleri, kimyasal ve biyolojik süreçler dahil olmak üzere çeşitli teknolojiler uygulanmaktadır. Bu arıtma prosesleri ile sulama ve tuvalet sifon suyu gibi içilebilir olmayan gri suyun geri kazanımına yönelik düzenleme ve gerekliliklerin yerine getirilmesi amaçlanmaktadır. Bu çalışma kapsamında, 1000 kişi kapasiteli ve günlük ortalama debisi 40-50 m3/gün aralığında olan bir otelden temin edilen gri suyun arıtımı incelenmiştir.
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ÖgeInvestigation of SO2 pollution from coal-fired and geothermal power plants using high resolution satellite retrievals(Graduate School, 2022-01-10) Değer, Sümeyye Sena ; Kaynak, Burçak ; 501191733 ; Environmental Sciences Engineering and Management ; Çevre Bilimleri Mühendisliği ve YönetimiAir pollution, which emerged with the increasing industrialization after the industrial revolution, has become an important problem in Turkey, as in many parts of the world, due to its negative effects on human health and the environment. Air pollution causes serious health problems such as asthma, allergies, lung cancer, heart diseases, skin and eye damage and even death, as well as environmental problems such as acid rain, dust formation, turbidity and fog. In addition, air pollutants have direct and indirect effects on the climate. Known as one of the criteria and common pollutants, sulfur dioxide (SO2) originates primarily from large point sources such as power plants, volcanoes, smelters and oil and gas industries, or from residential heating with coal. Since Turkey has a significant share with 2 % of the current world reserves, it follows a coal-oriented energy policy. However, since the existing domestic lignite in Turkey has a low calorific value, it is generally used in power plants, and domestic lignite, which has a higher sulfur content than other types of coal, causes a high amount of SO2 pollution. Especially due to the high SO2 pollution levels and its negative effects on the environment and human health, the determination and monitoring of SO2 pollution in the region, like other air pollutants, plays an important role. Although air quality measurement stations (AQMSs), which are a common and old method for monitoring air pollutants, capture the diurnal changes with hourly measurements in their located region, they may be insufficient to understand the distribution of pollution especially in large areas, since they are located in certain regions and in limited numbers. In addition, the meteorological factors and land characteristics in the region where they are located, also have an effect on the ground-based measurements. On the other hand, the remote sensing technology, which was developed for the detection of air pollutants in the 1980s, facilitates the determination of the distribution of air pollutants globally and the detection of air pollution sources with its gradually developing spatial resolution and wide coverage area. The adventure of remote sensing, which started with the detection of the SO2 plumes originating from the El Chicón volcanic eruption with the Total Ozone Mapping Spectrometer (TOMS) instrument in the 1982, continued to develop with measurement of tropospheric SO2 with the Global Ozone Monitoring Experiment (GOME) instrument in the following years. With the changing and developing spatial resolution and global coverage in the following years, Atmospheric Infrared Sounder (AIRS) and the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instruments started to measure atmospheric air pollutants in 2002, Ozone Monitoring Instrument (OMI) in 2004, and GOME-2 and Infrared Atmospheric Sounding Interferometer (IASI) in 2006, and Ozone Mapping and Profiler Suite (OMPS) in 2011, respectively. The TROPOspheric Monitoring Instrument (TROPOMI), which finally started its measurements in 2019, has a higher spatial resolution of 5.5 km × 7 km compared to previous instruments such as GOME (320 km × 40 km), SCIAMACHY (60 km×30 km) and OMI (13×). In this thesis, SO2 Level 2 retrievals from the TROPOMI instrument on the Sentinel-5 platform, which is launched by European Space Agency (ESA) in October 2017, are used to monitor two-year (2019-2020) SO2 pollution in and around Turkey and determine its spatial and temporal distribution. First of all, TROPOMI SO2 Level 2 retrievals from National Aeronautics and Space Administration (NASA) Goddard Earth Sciences Data and Information Services Center (GES DISC) were processed using Phyton programming language and filtered according to the quality criteria in the TROPOMI Readme file. Spatial average was calculated with a grid resolution of 1 km × 1 km and the SO2 data were spatially matched with the grids to calculate the average monthly gridded SO2 column concentrations. Using different oversampling diameters, the 10 km radius oversampling method was applied, where the best distribution was observed for SO2 retrievals. In order to represent the pollution levels of coal-fired power plants (CPPs) and geothermal power plants (GPPs), SO2 retrievals at a distance of 10 km from the locations of CPPs were selected. Monthly statistics for SO2 retrievals were calculated using the Rstudio programming language, and then the data opened in the ArcGIS software program was visualized and average SO2 maps of Turkey for 2019-2020 were created. Emission inventory and ground measurements were used for comparisons. After the hourly ground-based measurements were selected according to the TROPOMI transit time, their daily and monthly averages are calculated. The energy production of power plants was examined using EPIAS electricity data. The impact of regional conditions was evaluated using meteorology and land use throughout all investigations. Considering the SO2 pollution in and around Turkey, hot spots are generally associated with CPPs. In October 2020, when the cleanest and highest signals was seen, the highest SO2 levels in Turkey were detected in the provinces of Kahramanmaraş and Muğla. The highest SO2 pollution in the region was observed in 10 of 18 months around Afşin Elbistan Power Plants. Following Kahramanmaraş, the SO2 pollution is at a remarkable level in Muğla, where there are three large-capacity CPPs. In addition, high SO2 pollution from CPPs was detected in Şırnak and Sivas provinces, and Aydın, Kocaeli, Malatya provinces where minor hotspots were observed, were also investigated. It has been determined that large-capacity GPPs in Aydın may also be an indirect source of SO2. High SO2 concentrations from CPPs have been observed in Turkey's district countries, Bulgaria, Iraq and Syria. The performance of AQMSs and the TROPOMI instrument were investigated by comparing the ground-based measurements where pollution is intense and the satellite retrievals around 10 km of AQMSs. Firstly, the daily SO2 ground-based measurements, satellite retrievals around the power plants and total electricity production variations of the CPPs that were temporarily closed with the decision taken on 31 December 2019 were examined and the current situation in the 2019-2020 period, the effect of the temporary shut down, the change in SO2 levels during reopening period has been investigated. Satellite retrievals often show similar changes with total electricity production, while ground-based measurements were insufficient to capture the variations. Especially the missing data at ground-based measurements and the limited number of satellite retrievals in winter months make comparisons difficult. For the selected large-capacity CPPs, the individual correlations are higher when SO2 and NO2 are compared to electricity generation, as well as high correlations between NO2 and SO2 (R2=0.62-0.96). The highest correlation between satellite SO2 retrievals and electricity production for Afşin Elbistan Power Plants with R2=0.84. SO2 pollution levels in Afşin Elbistan Power Plant, where the highest signals are observed, were investigated considering land use and meteorological factors. Ground-based measurements and meteorological factors show that the pollution in Kahramanmaraş is more intense in autumn and winter and is transported to south every season. Monthly gridded average SO2 retrievals show high concentrations (>2 DU) around the power plants in summer and autumn months. The correlation between electricity production and satellite SO2 retrievals is higher with R2=0.84 on a monthly basis than the daily correlation (R2=0.45). In the comparison made by subtracting the winter months due to limited number of SO2 retrievals, the correlation between satellite retrievals around the power plant and satellite retrievals around the AQMS (R2=0.86) is higher than the correlation between satellite retrievals around the power plant and ground measurements (R2=0.20). However, there is a low correlation (R2=0.20) between satellite retrievals and ground-based measurements around the AQMS. Similarly, the effect of three power plants in Muğla, where high signals were observed, on SO2 concentrations, the relationship between ground-based measurements, satellite retrievals and total electricity production were investigated. When ground-based measurements and meteorological factors were examined, it was seen that the intense pollution in Muğla transported to the southeast in the summer and autumn months, and to the northwest in the winter and spring months. Monthly gridded average SO2 retrievals show high concentrations (>2 DU) in the region in November, July and April 2020. While the pollution is generally distributed around the three CPPs, the AQMS can only detect the pollution originating from Yatağan Power Plant in summer and autumn months due to the land characteristics and location. Contrary to Afşin Elbistan Power Plants, correlations are low for three power plants in Muğla, but Yatağan Power Plant has the highest correlation (R2=0.27) between them. Similarly, for Muğla, the correlation between satellite retrievals 10 km around the power plant and satellite retrievals around the AQMS (R2=0.54) was found to be higher than the correlation between satellite retrievals around the power plant and ground-based measurements (R2=018). There is a low correlation (R2=0.27) between satellite retrievals and ground-based measurements around AQMS. In order to improve the ground-based measurements, it should be located close to the power plants, taking into account the wind and land characteristics. Finally, the contribution of GPPs to SO2 pollution is investigated, starting from the province of Aydın, where small hot spots are seen. The monthly average gridded SO2 distributions clearly show the pollution around GPPs especially in April, May and November months. Daily time series of satellite SO2 retrievals around the power plant also prove the contribution of geothermals to SO2 pollution with high SO2 concentrations in April 2019, May 2019, April 2020 and November 2020. In May 2019, the maximum concentrations were determined as 5.39 DU for Efeler, 3.45 DU for Ken-3, 2.54 DU for Mis-3 and 4.85 DU for Alaşehir. Concentration above 0.5 DU is observed in Ken-3 GPP with a capacity of 25 MWe in 34%, and with 165 MWe in Kızıldere GPP only in 20% of the days.
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ÖgeInvestigation of the change of NO2 pollution during the pandemic period using satellite retrievals in Marmara region(Graduate School, 2022-01-10) Ceker, Ali Osman ; Kaynak, Burak ; 501191703 ; Environmental Sciences Engineering and Management ; Çevre Bilimleri Mühendisliği ve YönetimiAir pollution has been a great problem during the history of mankind with its effects on human health and the environment. Among the major air pollutants, nitrogen oxides (NOx=NO+NO2) are still an issue with significant emissions, and their contribution especially on urban areas to ozone (O3) and secondary particulate matter formation. Satellite-based measurements have been used for monitoring of the air pollutants for obtaining information on the global distribution of these pollutants in the last decade, and their performance was increased in terms of both resolution and data reliability. In addition to being a leading country in Europe and Asia with its increasing industry and population, Turkey is struggling with air pollution with high ambient levels. Past studies showed that air pollution reaches dangerous concentrations, especially in city centers. This thesis aims to analyze the NO2 pollution in the Marmara Region, which is the most populated and developed Region of Turkey, with the help of satellite retrievals and ground-based measurements. The effect of human activities and restrictions on NO2 during the pandemic period, which is the study time interval, was also examined, and the study showed the effects of urbanization, industrialization, increasing human population, and the NO2 pollution of these parameters. A deductive approach was used in the study and Turkey, Marmara Region, and Istanbul province were examined in terms of NO2 pollution with detailed analyses, respectively. With this aspect of the study, both the high-resolution data technology of the TROPOMI instrument and the technology of measuring large areas were used. These measurements were supported by the ground-based measurements, the relationship between them was examined and the differences were interpreted. TROPOMI is an instrument onboard ESA's Sentinel-5. TROPOMI NO2 retrievals obtained from ESA were processed, and gridded monthly NO2 tropospheric columns were calculated to a uniform spatial distribution. In this thesis, both satellite and ground-based measurements were investigated for two years: 2019 and 2020. Differences between the examined periods were analyzed and the effect of restrictions during the pandemic period and different urban indicators (such as traffic density or natural gas usage for domestic heating) on NO2 pollution was examined. Ground-based measurements were also used for Marmara Region, which are located in provinces of Istanbul, Kocaeli, Bursa, Canakkale, Balikesir, Sakarya, Tekirdag, Yalova, Edirne, Bilecik and Kırklareli. Ground-based measurements were selected according to the overpass time (around local time 13:00) of TROPOMI. Also, the Marmara Region, which is the study area, was divided into 1×1 km2 grids and satellite retrievals were selected only for the grids which have urban residences and 1 km around them for further comparison with ground-based measurements. All the data used in the study were eliminated according to the measurement criteria determined by the ESA, the days deemed invalid for comparison (with less than 75% data) were eliminated, and the data obtained as a result of the process were processed and/or visualized with programming and mapping programs, and possible errors were analyzed and interpreted. Firstly, national NO2 pollution levels over Turkey were examined. As a result of the examinations performed using satellite retrievals, Marmara was found to be the most polluted Region of Turkey in terms of NO2 pollution. The most polluted provinces are Istanbul, Kocaeli, Ankara, and Izmir, and for Marmara Region, those are Istanbul, Kocaeli, Bursa, and Yalova, respectively. It was found that the winter months have noticeably higher values than the summer months of 2019 and 2020 possibly because of domestic heating in period and meteorological factors, and the most polluted month is November 2019 for all of Turkey. In addition, it has been observed that NO2 pollution in various cities in Turkey, especially in Mugla, during the summer months is equivalent to and sometimes higher than, the crowded provinces due to point sources such as thermal power plants. When an analysis was made based on districts with the clustering method using monthly averaged measurements, it was seen that the districts of the provinces with dense vehicles and populations such as Istanbul were included in the same cluster. In addition, it has been observed that the central districts of cities with less population have close pollution and show the same seasonal variation. When the same clustering method was performed using ground-based measurements and satellite retrievals separately, it was seen that the ground-based measurements did not show seasonality, and many Regions were found to have high NO2 pollution levels whereas satellite retrievals were clustered as less polluted. As a result of the correlation analysis performed using satellite retrievals and ground-based measurements, it was observed that Ground-based measurements of the Marmara Region were not correlated with satellite retrievals. They were measuring lower signals than satellite retrievals in the time intervals when the data was not missing. Especially the low correlation values of the stations in the densely populated areas have revealed that the difference in the NO2 pollution measurements of the Region is high and that improvements should be made. With the statistical analyses performed, it was observed that the highest rate of change was observed in the Istanbul Region and the NO2 pollution decreased by 60% for March, April, November, and December months compared to the previous year. When comparing the same months of 2019 and 2020 throughout Turkey decrease rates were found to be decreased in direct proportion as the population and industrialization rates of cities, while increases were seen in some eastern provinces of Turkey such as Mugla and Aydin. It is thought that the most important reason for these increases, which are intense in the winter period, is the decrease of seasonal temperatures. Both satellite retrievals and ground-based measurements showed elevated concentrations of NO2 in and around highly populated areas. When the pollution changes of the Marmara Region were examined during the COVID-19 pandemic, the effects of human behavior on pollution were observed, especially in the days of full restriction and in the associated months. Districts grouped by clustering method, from districts with dense industry to districts with high population, were interpreted with the help of these groups and examined in terms of both provincial and urban status during the pandemic period. The study has shown that situations such as domestic heating, a change in the number of vehicles, and the closure of some businesses have caused a visible effect on NO2 pollution. During the study period, a comparison was made between the pre-pandemic period and the pandemic period for the densely populated cities of Marmara provinces. As a result of the comparison, a decrease in NO2 pollution was observed in the districts, especially in November and December 2020 (weekend curfew period) compared to November and December 2019. As a result of the calculations, the decrease between 10-20% is proportional to the population. Lastly, urban indicators and NO2 pollution in Istanbul were also examined in detail for 2019. As a result of the correlations made with indicators such as population, natural gas use, socio-economic status of the districts, a high correlation was found between NO2 pollution and population and natural gas use (R = 0.81 and 0.83 respectively), and a moderate correlation between socio-economic score (R = 0.35). The fact that the strong relationship between urban indicators and NO2 pollution is high in mega cities such as Istanbul results in taking precautions, and making more detailed analyses. As shown in the thesis, Istanbul is the largest province in the whole of Europe in terms of population, urbanization, and traffic, and the study showed the NO2 pollution that the people of Istanbul are exposed to in daily life under these conditions, district by district. In addition, in this section, the correlation between ground-based measurement and satellite retrievals in Istanbul were examined, and it was understood that the Ground-based measurements had lower levels than satellite retrievals in many districts. These low levels, especially in regions with high population and vehicle traffic, were attributed to the non-representativeness of the ground-based measurements. As a result of the study, the highest NO2 values in Istanbul were found as 6.44×1015 molecules/cm2 (Gungoren) and 94.12 μg/m3 (Aksaray) annual average on a monthly basis satellite retrievals and ground stations, respectively. The results showed the extent of NO2 pollution in Istanbul, proved to be directly related to urban factors, and created an initial analysis for future studies to be repeated in more detail for the future years. In conclusion, this thesis showed TROPOMI can detect temporal variation of NO2 pollution over different districts, and the impact of COVID-19 pandemic restrictions over Turkey, specifically in Marmara Region. The results also gave important information about the evaluation and status of ground-based measurements, the relationship between urban indicators and NO2 pollution, and the changing NO2 pollution during the pandemic period. The thesis also showed that NO2 pollution in dense urban areas decreased during the pandemic period with the help of satellite retrievals. The study examined important points in this respect and prepared a basis for future studies and it explained, interpreted, and discussed the seasonal distribution of pollution and the effects of the districts with statistical analyses and spatial distribution of NO2. This thesis is the first study in terms of applied Region, high-resolution satellite retrievals, and time interval.
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Ögeİç ortam havasından eş zamanlı partikül madde ve toluen giderimi için nanolif ve aktif karbon içeren filtre sisteminin geliştirilmesi(Lisansüstü Eğitim Enstitüsü, 2022-01-26) Yavaş Erdem, Melike ; İmer, Derya Yüksel ; 501191720 ; Çevre Bilimleri Mühendisliği ve Yönetimi ; Environmental Sciences Engineering and ManagementGünümüzde insanlar zamanlarının %80-90 gibi büyük bir kısmını iç ortamlarda geçirmektedir ve bu nedenle tren, uçak, hastane, restoran, ev ve ofis gibi sıklıkla bulunduğumuz iç ortamların hava kalitesi önemli çalışma konusu haline gelmiştir. İç ortamlarda soluduğumuz hava, en az dış ortamda soluduğumuz hava kadar sağlığımızı etkilemektedir. Özellikle modern binalarda yapılan izolasyon sistemleri taze hava sirkülasyonunu azaltmakta ve bu durum iç ortam havası kirleticilerine olan maruziyeti arttırmaktadır. İç ortamlarda geçirilen zamanın, insan sayısının ve kirletici kaynakların artması ile ''Hasta Bina Sendromu'' ve ''Bina Bağlantılı Hastalık'' gibi bazı sağlık sorunları da ortaya çıkabilmektedir. Bunların yanı sıra iç ortam havası kirleticilerinden partikül maddelerin (PM) ve uçucu organik bileşiklerin (UOB) varlığı solunum yolu hastalıklarına neden olmaktadır. İç ortam havasındaki partikül maddelerin birçok kaynağı bulunmaktadır. Yapılan çalışmalarda iç ortamdaki partikül madde ve uçucu organik bileşik konsantrasyonlarının dış ortamdaki partikül madde ve uçucu organik bileşik konsantrasyonları ile paralellik gösterdiği, ayrıca iç ortamlarda kullanılan birçok malzeme, teçhizat ve ekipmanın da kirletici madde kaynağı olabileceği görülmektedir. Günümüzde yaşanan COVID-19 pandemi salgınında en önemli ve en büyük bulaş yolu olarak görülen kaynak ise canlılardır. Ciddi solunum yolu enfeksiyonlarından ölüme kadar sebebiyet verebilen SARS-CoV-2 koronavirüsü de aynı zamanda yaklaşık 0,065 – 0,125 µm boyutları arasında ince tanecik grubunda yer alan bir partikül maddedir. Aynı zamanda bazı uçucu organik bileşikler de kimyasal yapılarından, buhar basınçlarından ve kaynama noktalarından dolayı bulunulan iç ortamlarda solunabilmektedir. Uçucu organik bileşikler, solunum yolu hastalıklarına ek olarak aynı zamanda nörolojik toksisite, göz ve boğaz tahrişi gibi sağlık etkilerine de neden olabilmektedir. İç ortamdaki partikül maddelerin ve uçucu organik bileşiklerin gideriminde en etkili yöntemlerden biri olarak görülen filtrasyon teknolojisi adsorpsiyon, oksidasyon ya da her iki mekanizmanın da kullanılması ile işlevselleştirilebilmektedir. Bu tezin de temel çıkış noktası, iç ortam havasında farklı boyutlarda bulunabilen partikül maddelerin, polimer yapılarının nanolif filtrelere entegrasyonu ile adsorpsiyon özelliği kazandırılarak filtrasyon teknolojisi yardımı ile gideriminin sağlanmasıdır. Böylece elektroeğirme yöntemi ile üretilen nanolif hava filtreleri ve aktif karbon kullanılarak yetersiz iç ortam hava kalitesinin iyileştirilmesine yönelik bir çözüm olarak tasarlanmıştır. Tez kapsamında nanolif filtreler üretilirken literatürde poliamid 6 (Naylon 6, PA6) polimeri ile ilgili nanolif hava filtrelerin geliştirilmesine yönelik çalışmaların verimlerinin yüksek olması hem de yüksek dayanım ve fiber oluşturma özelliği sunması nedeniyle ağırlıkça %18 oranında PA6 polimeri kullanılmıştır. Havada bulunan partikül maddelerin filtrasyon mekanizması ile fiber yüzeylerine adsorpsiyonunu sağlayarak kirleticilerin giderimi hedeflenmiştir. PA6 nanolif filtreler, iki farklı mesh (büyük gözenekli) filtre destek tabaka üzerine ve 15-30-45 dakikalık farklı üretim sürelerinde üretilerek filtrelerin hem yapısal karakterizasyonu hem de performanslarına bakılmıştır. Üretilen PA6 nanolif filtreler filtrasyon cihazına yerleştirilerek reaktör sistemi içerisinde PM1,0 ve PM2,5 boyutları için partikül madde giderim etkinliklerine bakılmıştır. Üretilen nanolif filtrelerin en yüksek PM1,0 giderimi %93, PM2,5 için %94 giderim verimi sergilediği görülmüştür. Bir diğer aşamada farklı adsorbentler denenerek aralarında en iyi UOB giderim performansı gösteren adsorbent belirlenmiştir. Kullanılan klinoptilolit, bentonit, aktif karbon, selüloz nanofibril (CNF), silika jel, polivinil alkol (PVA) adsorbentlerinden aktif karbonun %97,03 giderim verimi ile en iyi performansı sergilediği görülmüştür. Filtre sistemine farklı oranlarda aktif karbon adsorbenti yerleştirilerek uçucu organik bileşik olarak kullanılan toluen kirleticisinin reaktör ortamında giderimi incelenmiştir. Kullanılan cihazın kapasitesine bağlı olarak ve ön denemelere göre 3 ve 5 gram aktif karbon adsorbenti ile toluen giderimleri izlenmiş ve %98'in üzerinde giderim verimi olduğu görülmüştür. Eş zamanlı partikül madde giderimi ve toluen adsorpsiyonu optimum şartlarda hem reaktör hem de gerçek oda ortamında gerçekleştirilmiştir. Böylece en iyi partikül madde giderimi ve toluen adsorpsiyonu sağlayan PA6 nanolif filtre ve aktif karbon oranı kullanılarak optimum koşullarda eş zamanlı giderim sağlanabilmiştir. Eş zamanlı giderimde, seçilen nanolif filtre ve 3 gr aktif karbon kullanıldığında PM1,0 giderimi %97,83, PM2,5 giderimi %97,37 ve 5 gr aktif karbon kullanıldığında PM1,0 giderimi %97,51 ve PM2,5 giderimi %98,95 olarak bulunmuştur. Gerçekleştirilen çalışmalar sonucunda seçilen nanolif filtre ve 3 gr aktif karbon adsorbenti ile gerçek oda koşullarında ölçümler gerçekleştirilmiştir. Farklı kompozisyonlarda üretilen nanolif filtrelerin karakterizasyonu için SEM analizi ile fiber çapları ve yüzey morfolojileri belirlenmiştir, nanolif fiber çaplarının 147 ile 167 nm arasında değiştiği görülmüştür. Nanolif filtrelerin performanslarını belirlemek için ise standart yöntemler ile hava geçirgenliği ve su buharı geçişi deneyleri yapılmıştır. Deneysel çalışmalar sonucunda farklı destek tabakaları ve nanolif filtre üretim süreleri ile üretilen filtrelere uçucu organik madde tutunum özelliği kazandırılarak iç ortam hava kalitesinin iyileştirilmesine yönelik partikül madde ve toluen giderimi için filtre malzemeleri geliştirilmiştir.
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Ögeİstanbul'da ulaştırma sektörünün iklim değişikliğine etkisinin belirlenmesi(Lisansüstü Eğitim Enstitüsü, 2021-09-16) Güzel Doğan, Tuğba ; Alp, Kadir ; 501142712 ; Çevre Bilimleri Mühendisliği ve Yönetimiİklim değişikliği, günümüzde küresel ölçekteki en önemli problemlerden biri haline gelmiştir. İklim değişikliğinin temel sebebi olarak gösterilen küresel ısınma ise, atmosferde bulunan sera gazları (CO2, CH4, N2O, HFCs, PFCs ve SF6) tarafından dünyadan yansıtılan ışınların tutulması sonucu yerkürenin ısınması şeklinde tanımlanmaktadır. Sanayileşme öncesi dönemden bu yana, küresel ortalama yüzey sıcaklığı 1°C artış göstermiştir. Ayrıca, insan faaliyetleri günümüzdeki atmosferik CO2 konsantrasyonunu sanayi devrimi öncesi seviyenin neredeyse %50 üzerine çıkarmıştır. İklim değişikliğinin olumsuz etkilerine karşı küresel düzeyde çözüm bulunabilmesi amacıyla çeşitli adımlar atılmaktadır. Bu doğrultuda, 2015 yılında 21. Taraflar Konferansı'nda kabul edilen ve küresel ısınmanın sanayi öncesi seviyelere kıyasla 2°C'nin çok altında, tercihen 1,5°C ile sınırlandırılmasını hedefleyen Paris Anlaşması küresel emisyonların en az % 55'ini oluşturan 55 ülkenin onayı ile 4 Kasım 2016'da yürürlüğe girmiştir. Tarihi Paris Anlaşması'nın kabul edildiği COP21 öncesinde ülkeler, kendi yerel koşulları ve yeteneklerini dikkate alarak hazırladıkları sera gazı emisyonlarını azaltma isteklerini BMİDÇS Sekreteryası'na iletmiştir. Niyet Edilen Ulusal Olarak Belirlenmiş Katkı olarak nitelendirilen bu iyi niyet beyanını ülkemiz 30 Eylül 2015 tarihinde Sekreterya'ya iletmiş olup, sera gazı emisyonlarında 2030 yılında artıştan %21 oranında azaltım katkısı hedeflemiştir. Bu kapsamda, ulaştırma sektörü sera gazı salımına katkıda bulunan önemli bileşenlerden birini oluşturmaktadır. Ülkemizde ulaştırma sektörü birincil enerji tüketimi 27,7 milyon TEP ile sektörel tüketimler arasında sanayi tüketiminden sonra ikinci sırada yer almaktadır. Ulaştırma sektörü birincil enerji tüketiminin yaklaşık %93'ünü karayolları oluşturmaktadır. Sera gazı salımına katkıda bulunan motorlu kara taşıtı sayısı ülkemizde gün geçtikçe artmaktadır. Türkiye'nin 2019 yılı motorlu kara taşıtı sayısı yaklaşık 23,2 milyon olup, bu değerin 4,2 milyonu İstanbul'daki araç sayısıdır. 5.461 km2 ile ülke yüzölçümünün yalnızca %0,7'sini oluşturan İstanbul, küçük bir il olmasna rağmen nüfus ve ekonomik çıktı açısından ulusal olarak baskın bir rol oynamaktadır. İstanbul, 15,52 milyon nufusu ve 15.285 ABD Dolar kişi başı gayri safi yurtiçi hasıla (GSYİH) değeri ile Türkiye'nin en büyük ve en gelişmiş metropol şehridir. Ayrıca, 2987 kişi/km2 nüfus yoğunluğu ile zirvede yer almaktadır. İstanbul'da şehir içi ulaşım karayolu, raylı sistem ve denizyolu ile sağlanmaktadır. İstanbul Boğazı şehir içi ulaşımda olduğu kadar uluslararası ulaşımda da önemli bir rol oynamaktadır. İstanbul'un Anadolu ve Avrupa Yakası'nda toplamda 2 adet havalimanı bulunmaktadır. Bu doğrultuda, bu çalışma kapsamında İstanbul'da ulaştırma sektörünün iklim değişikliğine olan etkisinin incelenmesi amaçlanmıştır. Türkiye'de trafik yoğunluğunun en fazla olduğu şehirlerinden biri olan İstanbul için ulaştırma sektörü kaynaklı sera gazı emisyonlarının mevcut durum için hesaplanması, ileriye yönelik sera gazı emisyonu projeksiyonlarının yapılması ve farklı senaryolar altında gelecekte sera gazı emisyonları üzerinde ne gibi etkiler olacağının değerlendirmesi yapılmıştır. Tez çalışması kapsamında TIMES (The Integrated MARKAL-EFOM System) Modeli kullanılmıştır.
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ÖgeKüçüksu atıksu ön arıtma tesisi ileri arıtma alternatiflerinin değerlendirilmesi(Lisansüstü Eğitim Enstitüsü, 2023) Karataş, Fatma Nur ; Özgün Karahan , Özlem ; 790936 ; Çevre Mühendisliği Ana Bilim DalıSınırlı bir kaynak olan su, nüfüs artışıyla birlikte artan kentleşme ve endüstrileşme sonucu, hızla tüketilmektedir. Bu tüketimle birlikte atıksuların doğrudan doğal ortamlara verilmesi çeşitli sağlık ve çevre problemlerine yol açmaktadır. Mevcut su kaynaklarının korunması için kirlenmelerinin önüne geçilmesi ve verimli bir şekilde kullanılması gerekmektedir. Dahası atıksuların arıtılıp su kaynaklarına deşarj edilmesinin önüne geçilerek, yeniden kazanılması gerekmektedir. İstanbul gibi kentleşmenin yüksek olduğu bir şehirde klasik arıtma sistemleri için gerekli olan alan ihtiyacı karşılanamamaktadır. Bu nedenle atıksuların aerobik granüler çamur ve membran biyoreaktör gibi daha az alan ihtiyacı olan yöntemlerle arıtılıp hatta geri kazanılması su kaynaklarının geleceği açısından önem arz etmektedir. Bu kapsamda Küçüksu Atıksu Ön Arıtma Tesisi detaylıca tanıtılarak evsel atıksuların arıtıldığı klasik sistemler açıklanmış ve bu sistemlere alternatif olan prosesler araştırılmıştır. Aerobik granüler çamur prosesi, özellikleri, granül oluşumu ve mekanizması, bunları etkileyen faktörler açısından araştırılmış ve dünyada uygulanan tam ölçekli çalışmalardan örnekler sunulmuştur. Küçüksu Atıksu Ön Arıtma Tesisi'ne gelen atıksuyun, aerobik granüler çamur prosesine göre tasarımı yapılmıştır. Tesis için gerekli olan alan ihtiyacının 11.520 m2 olduğu ve bu ihtiyacın tesisin yanında bulunan 37410 m2'lik alandan karşılanabileceği görülmüştür. Membran biyoreaktörler hakkında türleri, konfigürasyonları, membran türleri ve sistemleri hakkında bilgiler verilmiş ve avantaj ve dezavantajları araştırılmıştır. Tam ölçekli işletilen membran biyoreaktörler örnek olarak sunulmuştur. Günlük debi ve kirletici parametrelerine göre Küçüksu Atıksu Ön Arıtma Tesisi'ne gelen atıksuyun tasarımı yapılmıştır. Tesis için gerekli olan alan ihtiyacının 21.500 m2 olduğu ve gerekli olan alan ihtiyacının tesisin yanında bulunan alandan karşılanabileceği görülmüştür. Alan ihtiyacı ile birlikte iyi kalitede çıkış suyunun membran sistemlerle elde edilebileceği görülmüştür. Dahası laboratuvar ölçekli entegre sistem çalışmalarından örnekler verilmiştir ve bu entegre sistemlerin atıksuların yeniden kullanılabilmesi açısından önemli olduğu ve proseslerin verimini arttırdığı görülmüştür. Sonuç olarak, bu tez kapsamında Küçüksu Atıksu Ön Arıtma Tesisi için uygun olan proses olarak Aerobik Granüler Çamur ve Membran Biyoreaktör prosesleri belirlenmiştir. Bu proseslere göre tasarımları ve değerlendirilmeleri yapılmıştır.
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ÖgeNitrogen removal and microbial community shift in oxic-settling-anoxic sludge reduction process( 2020) Karlikanovaite Balıkçı, Agne ; Yağcı, Nevin ; 618662 ; Çevre Mühendisliği ; Environmental BiotechnologyNitrifikasyon ve biyolojik azot giderme mekanizmalarını içeren sürekli araştırma çalışmalarıyla aktif çamur işleminin performansı arttırıldı. Ancak, uygulanan bu işlemden kaynaklanan aktif çamurun rutin israfı nedeniyle, sürekli olarak fazla biyokütle üretimi olmaktadır, bu da daha fazla arıtma ihtiyacıyla beraber çamurun uygun bir bölgeye atılmasını veya yakılmasını gerektirdiğinden dolayı fazla çamurun arıtımı ve imha edilmesi hala zorlayıcıdır. Fazla çamurun arıtılması ve imha edilmesi, toplam işletme maliyetinin % 25-65'ini oluşturmaktadır. Bu nedenle, aşırı çamur üretimini en aza indirmek için stratejilerin uygulanması hem çevresel hem de ekonomik açıdan ideal bir çözüm olabilir. Şimdiye kadar çamurun en aza indirilmesi için yaygın olarak Anaerobik sindirim kullanılsa da, üretilen aşırı çamur hacminin dünya çapında hala artması, biyolojik atık su arıtma proseslerinde aşırı çamur üretimini azaltmak için daha yeni, daha umut verici stratejiler ve yöntemlerin keşfedilmesi gerekmektedir. Literatürdeki mevcut bilgiler ve bu alanlardaki uzmanlıkların ışığında, nitrojen giderimi ve çamuru en aza indirgemek için uygun işlem alternatiflerinin belirlenmesi ve çamur üretimini azaltmak adına anaerobik/anoksik yan akım reaktörleriyle besin giderimi için modifiye edilmiş alternatif işlemlerin uygulanması gibi seçenekler mümkün olabilir. Literatüre göre, OSA sürecinin avantajlarına ek olarak, OSA arıtma performansını en üst düzeye çıkarmak için operasyonel ve tasarım parametrelerini belirlemek hala büyük bir ihtiyaçtır; Daha da önemlisi, OSA süreci ile ilgili çalışmaların çoğunda sentetik atık su kullanıldı, bu çalışmanın orijinal tarafı, gerçek evsel atık su kullanılarak yapılmış olmasıdır. Bu özel araştırmada, konular uluslararası bir düzeyde ele alınacaktır, çünkü OSA sürecinin entegrasyonu ile kademeli besleme SBR sistemi toplam azot giderimi açısından oldukça verimlidir, çamur imhası ve arıtımı gerekli olmayacaktır. Yine de, mevcut literatürdeki araştırmacılar arasında çamurun azaltılmasına neden olan kilit mekanizma halen çok tartışmalıdır, bu nedenle ASM1 bu çalışmada OSA sürecinde çamur azaltmaya neden olan mekanizmayı araştırmak için kullanılmıştır. Buna ek olarak mikrobiyal topluluğu değerlendirmek için literatürde ilk kez bakteriyel 16S rRNA gen amplikonları Yeni Nesil Dizileme (NGS) kullanılmıştır. Özet olarak, OSA sistemi ile ilgili multidisipliner bir yaklaşım ve yoğun araştırma gerektiren bir zorluk yaratan birçok darboğaz vardır. Bu çalışmanın amacı, OSA sürecinin uygulanmasından önce ve sonra SBR sistemlerinin performansını göstermektir. Gerçek atık su kullanan OSA sürecindeki bilgi eksikliği, OSA sistemlerinin uygulanmasından sonra toplam azot giderimi, aşırı çamur azaltımı, mikrobiyal topluluk değişikliklerine odaklanan bu çalışmayı güçlü bir şekilde motive etmiştir. Bu çalışma, gerçek atık suyun tam ölçekte arıtılmasında OSA sistemlerinin uygulanmasının daha iyi anlaşılmasına katkıda bulunacaktır. Kentsel atıksu arıtımı sırasındaoluşan fazla çamurun uzaklaştırılması ve besi maddesi giderimi konusunda son yıllarda uygulanan standartların sıkılığı,pekçok atıksu arıtma tesisinin çıkış suyu standartlarını sağlama ve çamuroluşumu konusunda ciddi zorluklarla karşı karşıya kalmasına neden olmuştur. Bu çalışmada, yukarıda belirtilensorunların giderilmesi konusunda gelecek vaad eden bir proses olanoksik-çökeltim-anaerobik (OSA) üzerine odaklanılarak, azot giderimi ve çamur azalmasının birlikte gerçekleştirildiği bir sistemin değerlendirilmesi amaçlamıştır. Yan akım reaktöründe en yüksek çamur azalması iç geri devir oranının %7,7 olduğu durumda %58 olarak gerçekleşmiştir. Diğer sistemlerde ise iç geri devir oranının %5,9 ve 5,0 olması durumlarında bu değer sırasıyla %37 ve %35 olarak elde edilmiştir. Bu doğrultuda, bu sistemlerde, yan akım reaktöründen gelen çamur girişi nedeniyle ana reaktörde gerçekleşen yüksek biyokütle konsantrasyonunun ve çamur bekletme süresinin etkisiyle mikrobiyal ölüm fazının çoğalmaya görece daha yüksek gerçekleştiği düşünülmektedir. Bu sistemlerde, aynı zamanda, yüksek (%85'e kadar) azot giderim verimlerinin gerçekleştiği gözlenmiştir. Buna göre, iç geri devir oranının, literatürde genellikle kullanılan %10 oranı yerine %8 olarak gerçekleştirilmesinin hem çamur azalması hem de azot giderimi açısından, muhtemelen daha düşük maliyetli, bir seçenek olacağı düşünülmektedir. OSA prosesi, biyolojik atıksu arıtımı sırasında kaçınılmaz olarak oluşan, susuzlaştırılıp stabilize edildikten sonra uzaklaştırılması gereken fazlabiyolojik çamur miktarının azaltılmasına yönelik olarak fazla çamur yan akımına anaerobik reaktör ilavesi ile gerçekleştirilmektedir. İlave edilen yan akım anaerobik reaktörde, fazla çamur hattındaki biyolojik çamurun bir kısmı belirli bir süre oksijensiz koşullara maruz bırakıldıktan sonra biyolojik arıtma ünitelerinin girişine biyokütle girdisi olarak verilmektedir. Bu sayede, yan akım reaktöründe kısmi stabilize olan çamur biyolojik ünitelerde besi madde olarak kullanılmak suretiyle özellikle azot giderimi için karbon kaynağı olma potansiyeli taşımaktadır. Aynı zamanda, yan akımda stabilizasyon nedeniyle sistemin çamur yaşı artmakta, dolayısıyla gözlenen dönüşüm oranları düşmektedir. Bunun sonucu olarak da biyolojik sistemde çamur üretimi azalmakta ve uzaklaştırılacak çamur miktarı düşmektedir. Bu çalışmada, çamur azalmasına yönelik olarak geliştirilen OSA sistemi kullanılarak farklı işletme koşullarında çamur azalması oranları ve azot giderimine yoğunlaşılmıştır. Bu sistemlerin aktif çamur modelleri ile modellenmesi ve gerçek sistemlere yönelik modelleme çalışmalarına esas oluşaturacak kinetik katsayı belirleme çalışmaları gerçekleştirilmiştir. Ayrıca, bu sistemlerde farklı işletme şartlarında mikrobiyal topluluğun değişimi ortaya konulmaya çalışılmıştır. Mikrobiyal kinetiğin değerlendirilmesi ve çamur azaltma mekanizmasının daha iyi anlaşılması için bir dizi respirometrik test tasarlanmıştır. Kalibrasyon çalışmasının sonuçlarına göre mikrobiyal ölüm oranının, sistem konfigürasyonuna bağlı olarak, en değişken kinetik parametre olduğu görülmüştür. Bu kinetik katsayının sistemler OSA konfigürasyonunda işetilmeye başlandıktan sonra önemli ölçüde arttığı, buna karşılık -diğer model parametrelerinin neredeyse sabit kaldıkları görülmüştür. Bu durumun, mikrobiyal topluluktaki veya mevcut topluluğun metabolizmasındaki değişimden kaynaklanıyor olabileceği düşünülmektedir. Bu çalışmada işletilen klasik aktif çamur sistemlerinde, yürütülen respirometrik analizler sonucunda, aktif biyokütle oranı% 75 civarında elde edilmişken yan akım reaktöründe bu değer 2 kat daha düşük olarak belirlenmiştir. Sonuç olarak, respirometrik analizlerden elde edilen veriler doğrultusunda, OSA prosesininölüm fazını teşvik ettiği, bunun sonucu olarak reaktördeki biyokütle canlılığını azaldığı ve aşırı çamur azalmasının sağladığı sonucuna varılmıştır. Bu çalışmanın en önemli yönlerinden birisi de gerçek evsel atık su kullanılmasıdır. Literatürdeki çalışmalar sentetik olarak hazırlanmış atıksuların kullanımı ile gerçekleştirilmişken, tüm deneysel çalışma bir atıksu arıtma tesisi kum tutucu çıkışından alınan ham atılsu ile yürütülmüştür. Böylelikle, OSA prosesinin pratik uygulanabilirliği yönünde önemli sonuçlar elde edilebilmiştir. Elde edilen veriler, OSA sistemlerinde çamur azalmasının ve azot gideriminin birlikte gerçekleştirilebilirliğinin mümkün olduğunu göstermiştir. Mikrobiyal topluluğun ölüm fazına yakın çalışması ve biyolojik çamur girdisi nedeniyle biyolojik reaktörde yüksek biyokütle konsantrasyonları elde edilmiş, bu çalışma süresinde sistemden normal biyolojik atıksu arıtma tesislerinde yapılan rutin çamur atma işlemi yapılmamıştır. Yürütülen deneysel çalışmada, kurulan OSA sistemleri farklı değişim oranlarında işletilmiştir. Bu amaçla, biyolojik sistemden yan akım reaktörüne beslenen çamur miktarları değiştirilmiştir. Bu sistemlerde çamur azalması, gözlenen dönüşüm oranları ve azot giderim yüzdeleri belirlenmiştir. Mikrobial topluluk kompozisyonu başlangıç biyolojik çamuru ve farklı işletilmiş OSA sistemlerinden alınan biyolojik çamurlarda belirlenerek sonuçlar karşılaştırılmıştır. Literatürde ilk kez kapsamlı olarak, bu sistemlerde, bakteriyel 16S rRNA gen sekanslama analizi (Yeni Nesil Sekanslama) ile mikrobiyal topluluk profili ortaya konulmuş ve değerlendirilmiştir. Bu çalışmada, çamur azalması oranlarının değerlendirilmesi ve mikrobiyal topluluktaki değişimin ortaya konulması amacıyla farklı iç geri devir oranlarında işletilen sistemlerin gözlenen dönüşüm oranları hesaplanarak, aynı koşullarda işletilen kontrol sistemleri ile karşılaştırılmıştır. Buna göre, en yüksek çamur azalması (%52,1) iç geri devir en yüksek olduğunda elde edilmiştir. 16S rRNA gen amplikon sekans analizi, benzer filogenetik gruplardan, Proteobakteriler, Acidobacteria ve Bacteroidetes türlerinden oluşan bakteri topluluğunun baskın olduğunu göstermiştir. Değişen iç geri devir oranlarına bağlı olarak bu toplulukların baskınlığı da farklılık göstermiştir. OSA sistemlerindeThiothrixtürünün baskın olduğu ve sistemlerde önemli rolü olabileceği görülmüştür. Çamur üretiminin en aza indirilmesinin, Intrasporangiaceae türlerinin baskınlığı ile de ilgili olabileceği elde edilen bulgular arasındadır.
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ÖgeNutrient recovery from source separated human urine and the treatment of the residual urine with anaerobic processing and ion exchange/adsorption(Graduate School, 2022-05-11) Akdağ, Yasemin ; Baykal Beler, Bilsen ; 501181734 ; Environmental Sciences Engineering and ManagementGlobal population is continuously increasing with a predicted increase to 9.7 billion by 2050. On the other hand, resources are facing with extinction. Sustainable food production greatly depends upon fertilizer production, which has nitrogen, phosphorus and potassium as key elements. Nitrogen, which is abundant in the air, is fixated by Haber-Bosch process, which consumes enormous amounts of energy, to be used in the fertilizer production. Phosphorus, which is a vital element, has limited resources, which is distributed unevenly around the world. The current domestic wastewater management, which adopts mixed collection of wastewater, is based on "treat" and "discard". Valuable materials in wastewater cannot be recovered with the current management practices. Therefore, an alternative way is needed to be generated. Segregation of domestic wastewater into different streams at the source of generation is suggested to get benefit from each stream. ECOSAN is an alternative sanitation concept that claims wastewater is not waste to be discarded but a source to be revaluated. Within this context, each stream is separately collected at the source and is processed for the recovery/reuse of valuable materials. ECOSAN is based on the separation of different domestic wastewater streams into three streams as yellow water, grey water and brown water. Yellow water, which is mainly source separated human urine, is a valuable waste stream in terms of macro plant nutrients (N, P, K). Yellow water constitutes only 1 % of conventional domestic wastewater by volume; however, it contains over 80% of nitrogen, over 50% of phosphorus and over 50% of potassium. This rich nutrient content makes urine a potential source of fertilizers. There are two routes to use source separated human urine as fertilizer in agriculture; (i) direct application and (ii) indirect application. Direct application of human urine as fertilizer is based on the collection of human urine, followed by transport (if required), storage of human urine to destruct pathogens and direct application of stored urine onto soil as fertilizer. Indirect use of human urine as fertilizer necessitates processing urine before intended use. Urine is frequently processed to produce urine-based fertilizers through struvite precipitation, ammonia stripping/absorption and ion exchange/adsorption. Nutrient removal/recovery from source separated human urine was widely investigated in literature. After nutrient removal, the residual liquid phase needs to be handled in an appropriate way as it still contains appreciable amounts of organic matter and nutrients. However, studies on the handling of residual urine are scarce. This study aims the investigation of nutrient recovery from source separated human urine by ion exchange/adsorption on one hand, while investigating organic matter and nitrogen removal from the residual urine by anaerobic processing and ion exchange/adsorption. The behavior of organic matter was closely monitored during different phases of the investigation. Within the scope, urine was collected from two urine diverting toilets and a urinal, and then it was stored for the conversion of urea to ammonium, which is the desired form of nitrogen for ion exchange. Ion exchange/adsorption was employed for nutrient removal from stored urine. The residual urine was processed with anerobic processing and second stage ion exchange/adsorption. Anaerobic processing was suggested to reduce organic matter content of the residual urine and to investigate possible production of biogas. Second stage ion exchange/adsorption was employed to reduce organic matter content of the residual urine and to maximize nutrient removal from the residue. The results of this study revealed that storage was a crucial step not only for urea hydrolysis but also for organic matter removal as between 25% to 39% of COD in urine was removed during storage. Through ion exchange/adsorption for nutrient removal/recovery with the initial loading of 15 mg NH4+/g clinoptilolite, 82% of ammonium and 28% of COD were removed from stored urine. The residual urine still contained appreciable amounts of COD and ammonium, and a high level of salinity for which a special care should be taken. During nutrient recovery, 99% of ammonium and 94% of phosphorus were recovered from the surface of nutrient enriched clinoptilolite upon contact with tap water with the contact time of 5 min in 16 days. 63% of ammonium and 100% of phosphorus were recovered with the contact time of 300 min in 35 days. The COD release from the surface was not considerable for both contact times, indicating that organic matter is not released appreciably from the surface of the clinoptilolite upon contact with water. This is beneficial from the standpoint of pollution prevention when nutrient enriched clinoptilolite is applied as fertilizer in agriculture. Anaerobic granular sludge from a confectionery industry was adapted to highly saline human urine using synthetic urine as feed in attempt to control adaptation conditions. During adaptation the effect of salinity and COD concentration on the removal of organic matter were investigated. During adaptation to high salinity levels at constant COD, organic matter removal efficiency was decreased from 90% to 85% when electrical conductivity was gradually increased from 14000 to 32000 µs/cm, indicating that organic matter removal was not considerably affected by salinity. For different COD concentrations at constant salinity, organic matter removal efficiency was decreased from 83% to 53% when COD was reduced from 2000 mg/L to 750 mg/L, indicating that organic matter removal efficiency was greatly affected by COD concentration. The results showed that selection of the treatment process for residual urine was case specific. Anaerobic processing seems to be a better option for organic matter removal in case of higher COD in residual urine. However, second stage ion exchange/adsorption seems to be a better choice for the treatment of residual urine in case of lower COD concentrations. Anaerobic processing has a potential of a calculated biogas production between 0.2 to 0.46 L CH4/L urine. However, not all of this could be collected under the conditions of the experiments in this work. Second stage ion exchange/adsorption, on the other hand, was advantageous in terms of complete removal of ammonium from residual urine. This study showed that the suggested processing layout was applicable for simultaneous recovery of nutrients and treatment of residual urine. For residual urine, process selection should be evaluated based on the conditions of specific cases to be handled.
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ÖgeOptimization of anaerobic membrane bioreactors for sludge treatment(Graduate School, 2023-02-01) Abdelrahman, Amr Mustafa ; Erşahin, Mustafa Evren ; Volcke, Eveline ; 501182702 ; Environmental Sciences, Engineering and ManagementWastewater treatment is an energy intensive process. The energy balance is positively affected by anaerobic sludge digestion, especially primary sludge. The inclusion of a primary clarifier before the biological reactors results in a higher sludge total production compared to the direct treatment of raw wastewater. Conventional anaerobic digesters for sludge treatment are designed as completely mixed reactors operated at long solid retention times (SRTs) for enhanced solids conversion and to maintain the methanogenic activity in the reactor. Consequently, anaerobic digesters are commonly built with large volumes to ensure sufficient reduction of volatile solids (Xu et al., 2011). Anaerobic membrane bioreactor (AnMBR) is a promising alternative to conventional anaerobic digesters for sludge digestion. AnMBRs are operated at long SRTs independent from hydraulic retention time (HRT) by means of physical separation of the membrane. Thus, slow growing methanogenic biomass can be kept longer in the reactor, resulting in enhanced methane production. Moreover, a smaller footprint of the anaerobic reactor can be achieved since the HRT can be controlled by manipulating the flux. To understand the rationale behind the thesis, Chapter 1 presents a brief description about the energy consumption for wastewater treatment and its distribution in the wastewater treatment plant (WWTP). The organic matter removal mechanism in the conventional WWTP is explained. Novel process configurations for organics capture are presented. Anaerobic digestion process and the design parameters of the anaerobic digester are explained as well. The advantages of using AnMBR for sludge treatment are defined. The chapter ends with research gap and an outline of the thesis. The current status and perspectives of the AnMBR technology for sludge treatment are critically reviewed in Chapter 2. It discusses the historical development of the AnMBR for sludge treatment, and factors influencing the AnMBR performance reported in the literature. The operational conditions such as SRT, HRT and temperature have a noticeable effect on the methane production and permeate quality. Volatile fatty acids (VFAs) can be recovered simultaneously during sludge treatment, which can improve the economics of the WWTP. However, there are still problems, such as membrane fouling, which hinder the adoption of AnMBR technology for sludge management, as well as a lack of studies demonstrating the economic benefits of using AnMBRs for sludge treatment. Suggestions for research perspective are given, aiming for overcoming the challenges and for optimization of the AnMBR for sludge treatment. The aim of this thesis was to investigate the applicability of the AnMBR for sludge treatment in the view of energy-positive WWTPs. The objectives of this thesis were met through four different studies. Chapter 3 explains the material used and methods followed during these studies. The results of these studies are explained and disscussed in Chapter 4. In order to maximize organic capture and thus energy recovery from wastewater, novel configurations including an A-stage and CEPT have been proposed as alternatives to primary settling. However, it remains to be investigated to which extent these configurations affect the sludge characteristics, which may affect the economic feasibility of the integrated systems. Therefore, the first study focuses on the effect of these primary treatment methods on sludge characteristics and digestibility, and on plant-wide economics of wastewater treatment. A detailed characterization of sludge obtained from primary settling (primary sludge), A-stage treatment (A-sludge) and CEPT showed significantly different sludge characteristics. The organic compounds in primary sludge consisted mainly of 40% carbohydrates, 23% lipids, and 21% proteins. A-sludge was characterized by a high amount of proteins (40%) and a moderate amount of carbohydrates (23%), and lipids (16%), while in CEPT sludge, organic compounds were mainly 26% proteins, 18% carbohydrates, 18% lignin, and 12% lipids. The biomethane potential test showed that primary sludge and A-sludge had the highest methane yield (347 and 333 mL CH4/g VS, respectively), while methane yield of CEPT sludge was lower(245 mL CH4/g VS). A plant-wide economic evaluation for the three systems, indicated that energy surplus was the highest with CEPT. The inclusion of an A-stage had the lowest positive net energy due to the relatively high energy consumption in aeration. Considering the effluent quality of the three systems, CEPT had the highest benefits, followed by A-stage. Overall, integration of CEPT or A-stage, instead of primary clarification in existing wastewater treatment plants, has the potential to improve the effluent quality and energy recovery. AnMBRs have been applied as compact alternatives for anaerobic digesters for sludge treatment in conventional WWTPs. However, there is no information about the impact of integrating an A-stage, instead of primary clarifier, on sludge digestion in an AnMBR. The second study examines the performance of lab-scale AnMBRs, in terms of treatment and filtration performances, for both digestion of primary sludge and A-sludge. The results showed that anaerobic digestion of A-sludge yielded more methane and improved methanogenic activity in the AnMBR compared to primary sludge. The permeate of the AnMBR fed with A-sludge contained higher nitrogen and phosphorous concentrations due to higher nitrogen and dissolved phosphorous concentrations of A-sludge. No coliforms were detected in the permeates, which showed that from the hygienic point of view, the permeate had the potential to be directly used for irrigation purposes. A higher EPS concentration was observed during the digestion of A-sludge compared to the primary sludge, which accumulated on the surface of the membrane and caused an increase in transmembrane pressure (TMP) and filtration resistance. On a plant-wide level, the integration of an A-stage increased the amount of organic matter (COD) recovered from wastewater in the form of methane gas by about 15% compared to a WWTP configuration with a primary clarifier. Anaerobic digesters are operated at either mesophilic (35°C) or thermophilic (55°C) conditions. In general, it is known that higher amounts of biogas are produced from digesters operated at thermophilic conditions because of higher biochemical reaction rates. However, the specific effect of temperature on AnMBR performance for A-sludge digestion has not yet been assessed. Therefore, the third study evaluates the treatment and filtration performances of lab-scale AnMBR under mesophilic and thermophilic conditions. Higher biogas and VFAs were produced under thermophilic conditions, which were 23% and 47% higher than those under mesophilic one, respectively. Besides, the membrane could be operated at lower TMP under thermophilic conditions. However, taking into account the energy consumption and production, operating the AnMBR under mesophilic conditions would result in a more than three-fold higher net energy production than operating under thermophilic conditions, whereas surplus energy recovery under thermophilic conditions was less than the additional energy consumption. Therefore, despite the advantages of thermophilic conditions, operating AnMBR for sludge digestion under mesophilic conditions has a higher potential to improve the energy balance in the WWTPs. As found during the review (Chapter 2), there is a lack of studies demonstrating the economic benefits of using AnMBRs for sludge treatment in the WWTP. Therefore, the feasibility of the AnMBR for sludge (primary and waste activated sludge) treatment in a conventional WWTP is evaluated in the fourth study, through mathematical modeling and simulation, on unit process and plant-wide levels. The impact of HRT and SRT as control handles on the performance of the AnMBR was assessed. The amount of COD converted into methane could be increased by increasing the SRT or lowering the HRT, the former having a higher positive impact. The nitrogen and phosphorous load in the permeate increased by increasing the SRT or lowering the HRT, while the COD concentration in the permeate was hardly affected. As for the energy balance, increasing the SRT was more efficient than lowering the HRT. Indeed, increasing the SRT caused a significant increase in energy production while lowering the HRT only slightly reduced the energy consumption and did not affect the energy production. On a plant-wide level, the integration of an AnMBR instead of the anaerobic digester decreased the operational costs of the WWTP by 27%, but led to a worse effluent quality. The latter could be remedied by post-treatment of the permeate by struvite recovery and nitrogen removal through partial nitritation/anammox, at the same time further decreasing the operational costs - with 35% compared to a conventional WWTP. Overall, applying AnMBR for sludge treatment combined with post-treatment of the permeate provides effluent quality that meets the EU regulations and implies significant operational cost savings for wastewater treatment. Finally, Chapter 5 summarizes the main findings of the previous chapters and gives perspectives for further research inspired from the thesis.
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ÖgeOrganik atıklardan sürdürülebilir enerji geri kazanımı: Biyolojik ve termal geri kazanım proseslerinin analizi(Lisansüstü Eğitim Enstitüsü, 2022-04-28) Altan, Hasan Suphi ; Sözen, Seval ; 501152712 ; Çevre Bilimleri, Mühendisliği ve YönetimiYürütülen tez çalışması kapsamında farklı kaynaklarda üretilen enerji potansiyeli yüksek olan organik atıklardan, alternatif teknolojiler kullanılarak sürdürülebilir şekilde yenilenebilir enerji geri kazanımının fizibilitesi ortaya konmaktadır. Çalışma kapsamında ele alınan organik karakterdeki evsel katı atıklar, endüstriyel içeriğe sahip olmayan arıtma çamurları, ülke genelinde yaygın olarak yürütülen hayvancılık faaliyetlerinden kaynaklanan atıklar ve ülke genelinde bölgesel olarak majör tarımsal faaliyetler neticesinde açığa çıkan atıkların enerji geri kazanımı ile ülke enerji arz çeşitliliğine ve enerji ekonomisine önemli bir katkı sağlanabileceği tahmin edilmektedir. Çalışmanın temeli kapsamlı bir literatür araştırmasına dayanmaktadır. İlk olarak ülke genelinde enerji üretimine uygun olan katı atık potansiyeli araştırılmış ve evsel katı atıklar, endüstriyel içeriğe sahip olmayan arıtma çamurları, majör hayvancılık faaliyetlerinden kaynaklanan atıklar ve her bir coğrafi bölgede yaygın olan tarım faaliyetlerinden kaynaklanan atıklar için literatür kaynaklı miktar tespiti yapılmıştır. Bir sonraki basamakta ise organik madde muhtevası yüksek olan katı atıkların enerji geri kazanımı için yaygın olarak kullanılan prosesler detaylı araştırılmış ve termal geri kazanım prosesleri kapsamında yakma, gazifikasyon (gazlaştırma), piroliz ve biyolojik enerji geri kazanım prosesleri kapsamında ise anaerobik çürütme (digestion) prosesi simüle edilerek, bu proseslerin modellenmesine yönelik parametreler tespit edilmiştir. Evsel katı atık miktarlarının tespitinde TÜİK verilerinden faydalanılmış, her bir il için yıllara bağlı miktarlar tespit edilmiştir. Evsel/Kentsel atıksu arıtma tesislerinden kaynaklanan arıtma çamurlarının miktarı, TÜİK veri tabanında ilan edilen atıksu arıtma miktarları ile ilişkili olarak hesaplanmıştır. Söz konusu hesaplamada coğrafi bölge özellikleri ve arıtma tesislerinin konfigürasyonları dikkate alınmış ve her bir il için oluşan arıtma çamurlarının miktarı tespit edilmiştir. Hayvancılık faaliyetlerinden kaynaklanan atıkların miktarının tespitinde ise Enerji ve Tabii Kaynaklar Bakanlığı, Yenilenebilir Enerji Genel Müdürlüğü tarafından oluşturulan Biyokütle Potansiyel Atlası veri tabanından faydalanılmıştır. Buna göre çalışma kapsamında ele alınmak üzere büyükbaş, küçükbaş ve kanatlı hayvan yetiştirme faaliyetlerinden kaynaklanan atık miktarları il bazında tespit edilmiştir. Tarım faaliyetlerinden kaynaklanan atıkların tespitinde ise ülke genelinde tarım faaliyetlerinin değişken olması nedeniyle bölgesel yaklaşım ile ilerlenmiştir. Yapılan literatür çalışmasının kaynağını hayvancılık faaliyetlerinden kaynaklanan atıklarda olduğu gibi Biyokütle Potansiyel Atlası oluşturmaktadır. Çalışma genelinde her bir coğrafi bölge için o bölge içerisinde en fazla miktarda üretilen üç farklı atık tipi esas alınmıştır.
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ÖgeProfile of priority substances and toxicity assessments of wastewater treatment plants in Istanbul(Graduate School, 2023-05-31) Birtek, Rahime İclal ; Öztürk, İzzet ; 501122704 ; Environmental Sciences, Engineering and ManagementWastewaters formed due to anthropogenic activities around urban areas pose a threat to aquatic environments. The growth in industrial activity along with the worldwide urban migration, as well as the threat posed by climate change, increase the extent of pollution. The discharge of the treated or untreated wastewaters is reported to cause a threat to their receiving water environments. Conventional wastewater treatment plants (WWTPs) are constructed to minimize the nutrient loads of macropollutants (C, N, and P) entering the receiving water bodies. As, removal of some of the emerging contaminants (ECs) or micropollutants present in wastewaters is found to be incomplete in conventional wastewater treatment processes, traces of those non-biodegradable ECs were reported to be found in the receiving environments. The presence of ECs, even in very low concentrations (pg/L - ng/L) in the water environments could cause adverse effects on humans and the ecosystem. In addition to industrial emissions, domestic discharges along with urban runoffs are main contributors of ECs in WWTPs. Understanding the presence, sources and transport of the micropollutants and ECs in wastewaters is important for assessing their impacts, and hence can help their reduction and management in the receiving environment. Micropollutants that have shown toxic, persistent, bioaccumulative, and ubiquitous properties and have been identified in aquatic environments, are designated as priority substances (PSs) by the EU Water Framework Directive (WFD). EU Member States are required to identify the presence of PSs in surface waters, in order not to exceed threshold levels specified by the Environmental Quality Standards (EQS) dictated by WFD. The Turkish Ministry of Forestry and Water Affairs adopted the aforementioned quality standards for the PSs in surface waters in 2012, and updated them in 2016. Since WWTPs are known to be main point sources of ECs entering the receiving water bodies, investigating the occurrence of PSs in wastewaters of Istanbul has generated valuable information. This thesis aims at understanding the occurrences of PSs in the wastewaters of the megacity of Istanbul as well as assessing WWTP effluents as sources of PSs in receiving environments. The thesis also includes the acute toxicity assessment of the same wastewaters. The scope of the study includes the wastewaters of the seven largest WWTPs, a hospital wastewater and leachate of a landfill treatment plant in Istanbul. The results of the PSs analyses allowed estimation of risks posed by the PSs in the WWTP effluents. Lists were formed to PSs showing sufficient risk (RQ>1), and their inclusions are recommended in the surveillance monitoring programs for the effluents of advanced treatment, as well as mechanical treatment. The regulators undertaking environmental risk assessments in the initiation of monitoring programs for the protection of the Sea of Marmara, Bosphorus and the Black Sea may utilize the findings of this study. Chapter 2 provides general information on the background of the study that is related to the aim and objective of the study. Chapter 3 comprises of information regarding the study area as well as methods on the description of all the experiments conducted through this study, namely analyses of PSs, toxicity analyses and physiochemical analyses. Chapter 4 Results and Discussion, provides information on the results of the experiments conducted through this study (PSs analyses, toxicity analyses and physiochemical analyses), as well as discussion of those results. Chapter 5 provides a summary of the whole thesis. The References section includes the complete bibliography. The Appendix includes tables, figures and pictures.