LEE- Çevre Bilimleri Mühendisliği ve Yönetimi Lisansüstü Programı

Bu topluluk için Kalıcı Uri

http://hdl.handle.net/11527/19235

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Anaerobic processing of and nutrient recovery from source separated human urine

(Graduate School, 2019-06-12) Taher, Mustafa ; Baykal Beler, Bilsen ; 501151728 ; Çevre Bilimleri Mühendisliği ve Yönetim

Due to the increase in world population which is around 7.7 billion in early 2019 and it was estimated to increase to 9.0 billion by 2050, the stress on the available resources of water, food, energy, etc. increases as well. This enormous increase in world population will put the mankind under a critical challenge related to resource security. Part of the Millennium Development Goals as well as Sustainable Development Goals are to reduce the degradation and provide a sustainable environment that the current and next generation can live in with an adequate and healthy resources to insure the prosperity of mankind. To meet the increasing needs for resources, the needs for solutions to overcome resource depletion had been increased too, and alternative resources must be found beside those that exists to maintain permanence and sustainability of these resources. It was assessed that the need for food, water and energy will show an increase of 35, 40 and 50% respectively, owning to that increasing demand of the increased number in world population by 2030 which will be 8.3 billion. Ecological Sanitation or shortly named ECOSAN is a new management concept for domestic wastewater that based on separation at source of generation. According to ECOSAN approach, domestic wastewater can be divided into three streams as grey water (all wastewater generated in household except that one originating from toilets), yellow water (human urine) and brown water (mainly feces and flush water). Human urine is known as a nutrient rich solution, and highly saline with quite considerable amount of organic matter. Human urine consist of 80% nitrogen, over 50% of phosphorus and potassium. Separation of human urine from the rest of the domestic wastewater will enable closing the nutrient loops in domestic wastewater. Several pieces in the literature studied the possibility of recovering nutrient from source separated human urine using different processes. Struvite precipitation, stripping absorption and ion exchange/adsorption are among the available processes studied in the literature. Ion exchange is one of these processes that showed a remarkable recovery of nitrogen, phosphorus and potassium from source separated urine. The studies about the organic matter fate in source separated human urine after employing ion exchange for removal/recovery of nutrients was not reported yet in the literature. This work is aiming to investigate the removal of organic matter from the liquid residue of ion exchange process using fixed bed clinoptilolite columns by suggesting the use of anaerobic process. Different configurations based on the combination between ion exchange and anaerobic processes was investigated to achieve the best results of concurrent nutrient and energy recovery. Part of the investigation is the adaptation of anaerobic granular sludge that was brought form confectionery wastewater treatment plant to a highly saline solution like urine. Natural fresh and mainly stored urine were used in this work. This work investigated the possibilities of ammonium release from anaerobic processes and its effect on the selection of the experiment configurations. Fixed bed clinoptilolite column was used for ion exchange process and Expanded Granular Sludge Bed (EGSB) reactor was used for anaerobic process. Human urine was collected from separation system the separates urine from men's toilet at the Department of Environmental Engineering in Istanbul Technical University. The results revealed that the adaptation of anaerobic granular sludge was successful under very diluted fresh urine solution in the feeding with COD removal efficiency of 75%. While under higher fresh urine concentration in the feeding the COD removal reduced to reach 40% with 65% fresh urine. The release of ammonium was monitored at the adaptation with fresh urine and it was observed that the percent of release was not appreciable with maximum of 6% release only. The poor performance of anaerobic sludge adaptation using fresh urine as its feeding solution was attributed to the increased level of ammonium and salinity. Urine was stored to increase the amount of ammonium as urea in human urine will hydrolyze during storage. The results from urine storage were in line with previous studies specifically in terms of nutrient concentration, pH and electrical conductivity. During this work a considerable reduction of COD concentration was observed through long storage period of about 4 months that counted for almost 65% of COD reduction from its initial state. This observation was not reported by any of the previous studies used natural stored human urine. COD reduction through storage has an important impact on anaerobic processes as the amount of organic matter in the feed is expected to be lower. On the other hand, the reduced COD concentration will be beneficial for protection of the environment. After hydrolysis was completed, clinoptilolite was used to concentrate nutrients from the stored urine through ion exchange process. The results from this stage was in line with previous studies used ion exchange to remove and recover nutrients from human urine. 80% removal of ammonium from liquid phase was obtained with 99% and 70% of removal for phosphorus and potassium, respectively. It was observed that COD was removed during ion exchange process with a removal efficiency of 25 – 35%. This observation has an influence on the use of anaerobic processing for removing organic matter from the liquid residue of ion exchange process, in which lesser amount of organic matter will be present in the feeding solution. Stored urine in which nutrients had been removed then was used as a feeding for the EGSB reactor. COD removal efficiency was ranged between 60 – 85%. Under 50% stored urine in the feeding solution COD removal was observed to be the best with 85%. Regarding the use of 100% stored urine in the feeding the removal efficiency was reduced to 60%. Through these stages the salinity level had a major impact on COD removal efficiency. The quality of the EGSB reactors with stored urine as a feeding solution was evaluated for the sack of environmental protection in case the effluent was discharged without further treatment. The results revealed that the effluent of EGSB was still has a considerable amount of nutrients and COD, thus ion exchange employed with stage wise manner and variable initial loadings. The results of the stage wise operation aid to reduce ammonium, phosphorus and COD considerably that the discharge of the effluent to sewer may be possible. About biogas production up on COD removal from human urine, the results were theoretically appreciable and observable with gas counter. Methane was evolved with a range of 0.3 – 0.8 l CH4/day that corresponds to 0.19 – 0.5 l CH4/ l of urine. The effect of salinity on COD removal using anaerobic process was investigated also in this work. Synthetic solution was used to simulate stored urine that was subjected to single stage ion exchange. Synthetic urine was used to create a controlled condition regarding salinity. The results of this experiment indicated that salinity had a considerable negative impact on anaerobic process at high level like 32000 µS/cm. COD removal efficiencies were ranged between 40 – 90% with salinity level between 32000 – 10000 µS/cm. This work suggest that more effort should focus on adjusting the recommended salinity inhibition threshold in the literature. This work shows that the combination between ion exchange and anaerobic processes is possible and nutrients recovery with organic matter removal is achievable, but factors like adaptation, dilution, storage period, best operational conditions, inhibition from salinity and ammonium must be taken in consideration. This study recommends the combination of ion exchange and anaerobic process in the manner that nutrients will be removed at the first place with single stage ion exchange followed by anaerobic processes, then stage wise operation of ion exchange to improve the effluent quality form environmental protection. Recovery experiment were conducted under two different contact times, 5 and 300 min in an attempt to mimic two different irrigation type. The results revealed that most of the nitrogen and phosphorus could be recovered from the clinoptilolite surface. The results were in line with previous studies. COD was not recovered from the clinoptilolite surface. Potassium was recovered with a very limited percentage which is in contrast to previous research that reported no potassium recovery at all. Plant experiments conducted to show the effectiveness of nutrient enriched clinoptilolite as a fertilizer using pepper and tomato. The results showed that clinoptilolite had a considerable performance as a n alternative fertilizer compared to synthetic fertilizer that was tested in the same experiment. Plant height, texture and no of fruits that indicate possible fruits in clinoptilolite pots were higher than that one of synthetic fertilizer.
Anaerobic treatment of soapstock splitting wastewater

(Graduate School, 2022) Sertgümeç, Simge ; Altınbaş, Mahmut ; 847782 ; Environmental Sciences, Engineering and Management Programme

In the developing world, the needs of the people are also increasing due to the rapidly increasing population. Nutrition comes at the beginning of these needs. In order to meet the increasing nutritional need on a global scale, edible oil production continues every day. Edible oil can generally be made of vegetable origin or animal origin. However, a very large part of the oil produced worldwide consists of vegetable oils produced from oilseeds. Many different kinds of oilseeds are grown in many different countries around the world. In order to obtain vegetable oils from oil seeds, an extraction process must be carried out. And, undesirable substances in the raw vegetable oil as a result of the extraction process must be removed by a couple of processes. Substances in raw vegetable oil that must be removed are generally free fatty acids, vitamins, antioxidants, alcohol, waxy substances, etc. Refining is carried out in order to remove such unwanted substances from the raw oil. In the neutralization step of the refining process, an alkaline environment is created by caustic and thus soapy waxy substances are formed. In this way, the free fatty acids in the raw oil are removed and converted into this soapy by-product called soapstock. Soapstock contains oil due to its structure and for this reason, it is a valuable by-product. The soapstock splitting method with sulfuric acid is applied for the production of acid oil. In this process, sulfuric acid and soapstock are brought together in a high-temperature boiler and the acid oil is recovered as the upper phase. Also, the remaining phase is wastewater. In this thesis, the performance of anaerobic treatment of carbon removal from soapstock splitting wastewater was investigated. For this purpose, a wastewater sample was obtained from the soapstock recycling facility of an edible oil production factory in the Marmara Region of Turkey. Detailed characterization of wastewater was carried out. Sludge from an anaerobic digester of a yeast production industry, digestate, and fresh manure was used as inoculum. Anaerobic reactors were designed as a semi-batch continuous system and operated in a constant temperature room under mesophilic conditions (37°C). The reactors were generally operated to examine the effect of different pH values and different inoculum, different volumetric loading rates, FeCl3 dosages. In the first part of the experimental study, different pH and inoculums were setup to observe best COD removal efficiencies. In the second experimental set, the reactors were operated at the pH where good efficiency was observed in the first experimental setup, and with the inoculum which was also observed with good efficiency. In this set of experiments, the effect of VLR on COD removal efficiency was investigated. Also, the effect of mixing on the removal efficiency was tested. In the third experimental setup, the amount of FeCl3 added in order to prevent the inhibition caused by the H2S gas formed in the anaerobic environment due to the high sulfate content of the soapstock wastewater was investigated simultaneously with the increasing in VLR. In order to investigate the effect of high daily FeCl3 amount on the efficiency of anaerobic reactors, a fourth experimental reactor was set. In this part, the experiment was carried out by adding three different FeCl3 dosages to different reactors. TS, VS, SS, VSS, sCOD, tCOD, pH, Conductivity, Color, TP, TKN, Ammonia, and Acidity parameters were determined according to standard methods. Sulphate and ion concentrations were measured using an IC device (Dionex, ICS-3000, USA). pH was measured using Thermo-Orion 720 A+ model pH meter and conductivity was measured using a Hach-sensION5 model device. The total COD value of the raw wastewater is approximately 28100 mg/L, and the soluble COD value is 25500 mg/L on average. TS in wastewater is 76500 mg/L on average, of which approximately 45500 mg/L is volatile. In addition, SS in the wastewater is approximately 500 mg/L and VSS is 385 mg/L. Wastewater has a pH of 0.2 and conductivity of 103 mS/cm. The color parameter of the wastewater sample is 3495 PtCo. Wastewater's TP and TKN are 41 mg/L and 2000 mg/L, respectively. In addition, ammonia is 300 mg/L. There is a total acidity of 39150 mg CaCO3/L in wastewater and 26200 mgCaCO3/L of this is mineral acidity. SO42- concentration of the wastewater is 68000 mg/L. The pH values of the different inoculum sludges are 8.58 for the sample from the anaerobic digester of the yeast production industry, 8.30 for the digestate, and 8.25 for the fresh manure, respectively. The TS ratio of the inoculum from the anaerobic digester of the yeast production industry is 10 % and the VS ratio is 0.3 %. Digestate has a TS rate of 13 % and a VS rate of 7 %. On the other hand, the TS ratio of fresh manure is 11 % and the VS ratio is 9 %. Mixed sludge was found to be the best inoculum observed for COD removal in anaerobic reactors. It was also observed that reactors at pH 7 had better COD removal than pH 5. In the optimization study carried out in the first experimental setup, the COD removal efficiency of the reactor group operated with mixed sludge at pH 7 was 67 % and the COD reduced to 8416 mg/L. In the second experimental setup, in the reactors operated at pH 7 and in which mixed sludge was added as inoculum, the highest COD removal (72 %) was realized when the volumetric loading ratio was 4. And, COD reduced to 7288 mg/L. At the end of this period, the COD/SO42- ratio was 0.27. In the third experimental set, when the volumetric loading ratio was 4, the reactor group containing 0.70 g FeCl3 had the highest removal rate with 73 % in terms of COD removal, and the COD reduced to 7009 mg/L. The COD/SO42- ratio was 0.33 for reactors with a FeCl3 dose of 0.7 g/day. In the fourth experimental setup, when the volumetric loading ratio was 4, the reactor group dosed with 0.70 g FeCl3 was the most efficient in terms of COD removal. The COD and SO42- removal efficiencies for this reactor group are 74 % and 73 %, respectively. The COD was 6774 mg/L, and the COD/SO42- ratio was 0.36. The efficiency of the reactor with 0.70 g/day FeCl3 dose was higher than the other reactors in both the periods of volumetric loading rate 2 and 4. Despite having the same initial volumetric loading (volume loading: 2) and the same FeCl3 dosages, lower yield (70 %) were obtained from the reactors in experimental setup 3 and the COD was reduced to 7716 mg/L. To sum up, the COD was reduced to 6774 mg/L in semi-batch continuous reactors using mixed sludge as inoculum by dosing 0.70 g/L/day FeCl3 while VLR was 4 at pH 7, under mesophilic conditions (37°C). 74 % carbon removal at COD/SO42- ratio of 0.36 was a significant achievement under these operating conditions. Considering the 200 mg/L of COD discharge to the receiving water bodies of this wastewater, there is a need of additional steps to satisfied these limits.
Antarktika'daki araştırma istasyonlarının çevresel açıdan değerlendirilmesi

(Lisansüstü Eğitim Enstitüsü, 2022-11-18) Erişmiş, Şeyda Nur ; Arıkan, Osman Atilla ; 501181759 ; Çevre Bilimleri, Mühendisliği ve Yönetimi

Antarktika, Güney Yarım Küre'nin en güneyinde bulunan ve yaklaşık ~14 milyon km² alana sahip Güney Kutbu'nu içeren kıtadır. Güney Kutbu'nda yeryüzünün en soğuk ve en fırtınalı iklimi egemendir. Ortalama sıcaklık yaz aylarında -20 °C'dir. Antarktika'yı ortalama 2 km kalınlığında büyük bir buz katmanı örter. Bu buz kütlesi 24 milyon km³'lük hacmi ile yeryüzündeki bütün buzların %92'sini oluşturmaktadır. 20. yüzyılın sonundan bu yana ortaya çıkan küresel ölçekte çevresel değişikliklerin insan yaşamı için oluşturduğu tehdit, Antarktika'nın el değmemiş çevresini koruma ihtiyacını ve bölgedeki bilimsel araştırmaların önemini arttırmıştır. Antarktika, diğer bölgelerle enerji ve element alışverişi yoluyla küresel iklim sistemini düzenlediğinden iklim değişikliğinin ilk belirtilerini gözlemlemek için benzersiz bir bakış açısı sağlamaktadır. Kutup buzullarında Dünya'nın geçmişinin korunmuş koşulları, mevcut iklim sistemini anlamak ve gelecekteki değişiklikleri daha iyi tahmin etmek için önemli ipuçları vermektedir. Bilimde ilerlemeyi hedefleyen ülkeler Antarktika'da bilimsel programlar yürütmekte, kıtada araştırma istasyonları kurmaktadır. Tüm insanlığın bilimsel çalışmalarına açık olan Antarktika, günümüzde 80'i aşan araştırma istasyonuna (30'dan fazla ülkenin) ev sahipliği yapmaktadır. Antarktika'nın yaz nüfusu yaklaşık 5000 kişidir. Ancak bu, uzun, karanlık ve soğuk kış aylarında 1000 kişiye kadar düşmektedir. Türk bilim insanlarının çok taraflı işbirliği çerçevesinde Antarktika'daki çalışmaları 1960'lı yılların ortalarında başlamıştır. 2017 yılına kadar Türk araştırmacılar, bilimsel çalışmalar yapmak üzere Fransa, İtalya, Almanya, Japonya, Ukrayna, Birleşik Krallık ve Amerika Birleşik Devletleri (ABD) gibi diğer ülkelerin keşif gezilerine katılmışlardır. Türkiye tarafından 2017-2022 yıllarında Türk Antarktika Seferleri gerçekleştirilmiştir. Türkiye, 2019 yılında Antarktika Yarımadası'nın batı kıyısındaki Marguerite Körfezi'nde bulunan Horseshoe Adası'nda 2018-2022 yılları arasında hizmet verecek üç modülden oluşan bir Geçici Bilimsel Araştırma Kampı konuşlandırmıştır. 2021 yılında ise aynı adada Türk Antarktika Araştırma İstasyonu'nun kurulması ile ilgili kapsamlı Çevresel Etki Değerlendirmesi raporu sunulmuştur. Antarktika hem iklim koşulları açısından hem de tüm dünyanın korunması konusunda büyük çaba gösterilen hassas bir bölgedir. Böyle bir bölgede planlanan araştırma istasyonları hem zorlu kış koşullarında inşaat ve işletme açısından, hem de halihazırda dünyanın en el değmemiş doğasının ve canlı türlerinin korunması açısından özel tasarım ve lojistik gibi kapsamlı çalışmaların yapılmasını gerektirmektedir. Özellikle son yıllarda inşa edilen araştırma istasyonları yeni teknolojileri de içerecek şekilde planlanmaktadır. Bu araştırma istasyonlarından elde edilen tecrübeler Antarktika'da yeni kurulacak araştırma istasyonlarının planlanması, inşaatı ve işletmesinde önem taşımaktadır. Bu çalışmada, Antarktika'da yeni kurulacak araştırma istasyonlarının planlanması, inşaatı ve işletmesinde kullanılabilecek veya geliştirilebilecek çevresel açıdan önemli tasarımların ve teknolojilerin ortaya konması amaçlanmıştır. Bu amaçla Antarktika'da faaliyet gösteren nispeten yeni (son 20 yılda planlanan) ve Antarktika'nın farklı noktalarında yer alan yedi ülkenin (Belarus, Çin, Güney Kore, Hindistan, Birleşik Krallık, Belçika, Almanya) araştırma istasyonları tasarım ve yerleşim planı, lojistik, enerji temini, su temini ve atıksu yönetimi, atık yönetimi, yakıt depolama ve çevresel etkilerin değerlendirilmesi konularında incelenmiştir. Ayrıca Antarktika'da kurulması planlanan Türkiye Araştırma İstasyonu için yapılan planlamalar da ortaya konmuştur. Söz konusu araştırma istasyonlarının kapsamlı Çevresel Etki Değerlendirmesi raporları ile bu istasyonlara ait internet sayfaları, bilimsel yayınlar ve videolar incelenmiştir. Çalışma sonuçlarına göre; incelenen araştırma istasyonlarında, mevsimlik veya yıllık konaklamalı, genellikle 20-25 yıllık tasarım ömrü olan, çevreye olan etkisinin azaltılması amacıyla taban alanı düşük, kar nedeniyle genellikle yerden yükseltilmiş, inşaat ve lojistik kolaylığı nedeniyle modüler sistemler kullanılmaktadır. İstasyon inşaatları, çalışmalar için havanın nispeten daha iyi olduğu Antarktika yaz aylarında genellikle iki veya üç yılda tamamlanabilmektedir. İnşaat ve işletme için malzeme ve personel genellikle gemi veya hava yoluyla Antarktika'ya getirilmekte, denizden karaya ulaşım ise mavna veya helikopterle yapılmaktadır. Son yıllarda enerji temininde güneş ve rüzgar gibi yenilenebilir enerji kaynaklarının daha fazla kullanımı ön plandadır. Ancak bu enerjilerin yetmediği durumlarda ve yedek olarak dizel jeneratörler hala enerji temininde yaygın olarak tercih edilmektedir. Planlamalarda ayrıca acil durum enerji ihtiyacı için ilave jeneratörler bulundurulmaktadır. Jeneratörde yakıt olarak genellikle Antarktika dizeli kullanılmakta, yakıtlar geçirimsiz, çift cidarlı, izleme sistemi olan yakıt tanklarında depolanmaktadır. Yakıt sızıntısı ve dökülmelerine karşı Acil Müdahale Planları bulunmaktadır. İncelenen araştırma istasyonlarında su temini için daha çok deniz suyu veya kar/buz eritme kullanılmaktadır. Deniz suyunun arıtımında ters ozmoz tercih edilmektedir. Atıksuların yönetiminde siyah ve gri su ayrımı, geri kazanım ve ileri arıtma uygulanmaktadır. Atık yönetiminde atıkların türlerine göre kaynağında ayrılması, evsel ve tehlikeli atıkların Antarktika dışına çıkarılması yanında, organik evsel atıklar ve çamurların istasyonda yakılması da yapılmaktadır. Çevresel etkilerin belirlenmesi için emisyonlar, gürültü, atıksu deşarjları, atıklar, vb. için hesaplamalar, ölçüm ve modelleme vb. çalışmaları yapılmıştır. Antarktika için geçerli uluslararası kriterler olmadığı için genellikle ulusal standartlar dikkate alınmaktadır. Araştırma istasyonlarının inşaat ve işletme faaliyetlerinin çevresel etkileri olasılık, kapsam, süre ve önemine göre matris halinde verilmiş, ayrıca söz konusu etkileri azaltıcı önlemler ortaya konmuştur. Antarktika'nın doğal ortamını korumak ve faaliyetlerin etkilerini takip etmek için kapsamlı izleme programları planlanmıştır. Kurulması planlanan Türkiye Antarktika Araştırma İstasyonu için, incelenen ülkelerin istasyonlarındaki çevresel iyi uygulama örneklerinin dikkate alındığı, istasyonun inşaat ve işletme aşamasındaki çevresel etkilerinin azaltılmasına yönelik planlamaların yapıldığı değerlendirilmiştir. Bununla birlikte istasyonun faaliyeti öncesinde, önerilen saha ve çevresine yönelik mevcut duruma yönelik verilerin mümkün olduğunca fazla olması planlamaların daha iyi yapılmasına, inşaat ve işletmenin çevresel etkilerinin daha da azaltılmasına imkan verecektir. Bu nedenle sonraki yıllarda yapılacak Antarktika seferlerinde bu çalışmalara yönelik faaliyetlerin planlanması ve daha fazla veri toplanması önem taşımaktadır. Halihazırda Antarktika'da SCAR ve COMNAP gibi uluslararası organizasyonlar bulunmakla birlikte, bunların Antarktika'nın korunmasında yeterli oldukları düşünülmemektedir. Bu nedenle Antarktika'da üssü olan ülkelerin yer aldığı, Birleşmiş Milletler Çevre Programı vb. uluslararası kurumların da olacağı bir Antarktika Yönetim Biriminin oluşturulması önerilmektedir. Bu birim Antarktika için ortak standartlar (emisyon, gürültü, deşarj, vb. için) belirleyebilir ve bağımsız ortam izleme çalışmaları yürütebilir. Ayrıca yapılan izleme çalışmaları verilerinin toplandığı, takip edildiği, şeffaf ve web tabanlı bir yönetim sistemi kurabilir. Denetimin esası olan izlenebilirliğin sağlanması ile uygun olmayan uygulamaların önüne geçilebilir. Ayrıca özellikle son yıllarda ciddi şekilde artan Antarktika'ya turistik seferlerin sınırlandırılması da gerekmektedir.
Applicability of advanced oxidation processes for treatment and recovery of washing machine effluent: On-site application with new washing machine design

(Graduate School, 2023-12-14) Kılıç, Levent ; Hancı Ölmez, Tuğba ; 501201719 ; Environmental Science and Engineering

Water scarcity has become one of the most important problems that society must overcome. The effect of climate change with the addition of increased freshwater consumption stands as one of the major problems related to water scarcity. There has been a great increase in domestic-based wastewater generation over a couple of decades. Among the sources of domestic type wastewater, washing machines play a significant role in freshwater consumption, which corresponds to 80-100 liters per working cycle. In this study, it is aimed to perform a feasibility study of various types of Advanced Oxidation Processes (AOPs) to treat laundry wastewater originating from washing machines by reducing organic pollutant load, along with the elimination of dye stuff and surfactant content that was released from textile fibers. Wastewater characterization from different stages of wastewater discharge was analyzed and AOPs including O3, H2O2, O3/H2O2, O3/UV, H2O2/UV, and O3/H2O2/UV were applied to determine the most efficient AOPs. Experimental tests were carried out in labaratory-scale photoreactor with 3liter capacity and lamp of 41 W power. Specific volumes of wastewater was fed to system along with determined ozone (O3) and hydrogen peroxide (H2O2) concentrations respectively. Treatment applications were carried out for 2 hours and samples are taken at regular time intervals to analyze treatment efficiency. Results showed that photolytic oxidation differed significantly from sole chemical oxidation. Among O3/UV, H2O2/UV and O3/H2O2/UV methods, H2O2/UV yielded the best chemical oxygen demand (COD) and methylene blue active substance (MBAS) reduction rates among other methods. An additional set of the design of experiments (DOEs) is performed to analyze the effect of parameters that effect treatment efficiency such as type of detergent used (liquid or powder), effect of microfiber filtration and H2O2 concentration used. Results of DOEs show that COD and MBAS content of wastewater discharge during the rinsing stage of the washing cycle could be reduced by up to 95% and 98%, respectively under optimum conditions of wastewater originated by liquid detergent, the case of microfiber filtration and higher H2O2 concentrations. Another aspect of treatment was analyzed as microorganism growth on stored wastewater since it is known that wastewaters having organic content is expected to be suitable for microorganism growth. Microorganism counts were done by taking water samples at first, fourth and seventh days to see the trend of microorganims growth. Microorganisms count results showed that the rate of microorganism growth is greatly reduced in AOP-applied wastewater when compared to raw wastewater. Based on the outcomes, it is concluded that AOPs with fiber filtration can be effective in reducing organic pollutant load, as well as discoloration and providing hygiene. UV absorbances were analyzed in water samples to see the degradation of dye stuff in laundry wastewater, since it is important to eliminate all of dying components due to the fact that they may cause additional staning on white garmets during next washing cycle. UV absorbance results showed that dye stuff released from textile textures can be effectively eliminated by the application of additional filtration. AOPs treated wastewater also was analyzed using whiteness index to see the potential stainnig cause by treated wastewater. Staining results were satisfactory, meaning to significant staining was observed on white garments, which means that treated laundry wastewater can be recycled inside the washing machine and can be used during the next washing cycle without compromising the cleaning performance of the washing machine. As a result, AOP treatment and recycleing of laundry rinsing wastewater may enable to lower the water consumption and provide more sustainable washing machine operation designs.
Applicability of sulfate radical based advanced oxidation processes for drinking water treatment

(Graduate School, 2022-06-01) Dilsizoğlu, Nergis ; Hancı Ölmez, Tuğba ; 501181726 ; Environmental Science, Engineering and Management

The presence of organic matter in water is the most important factor affecting water quality. The effects of organic matter on conventional drinking water treatment plants have been investigated by researchers for many years. Organic matter in water cause undesirable problems in many cases such as color, taste and odor problem in drinking water systems, changing of microbiological quality negatively, necessity of additional treatment units etc. For this reason, organic matter removal is becoming more and more important day by day. The purpose of this study mainly supported by experimental works is investigation of the applicability of sulfate radical (SO4•−) based photochemical advanced oxidation processes (persulfate/UV-C and peroxymonosulfate/UV-C) in order to provide effective treatment (mineralization) of organic carbon that naturally found in raw water. In the first part of the thesis, experimental studies were conducted to examine the effects of the initial oxidant concentration on the process efficiency. The principles of application of the processes were determined on the basis of selected variables, considering the total organic carbon (TOC) removal efficiencies, residual oxidant concentration and alteration of UV254. The applicability of PS and PMS oxidants for TOC removal were compared by applying PS/UV-C and PMS/UV-C processes. In the second step of the study, it was aimed to determine the changing particle sizes during oxidation applications. Accordingly, PSD analyzes were performed on the raw water and the effluent sample of PS/UV-C and PMS/UV-C treatment processes. Therefore, treatment efficiency of each particle size was determined during oxidation processes. In raw water that come from a drinking water treatment plant with an original TOC concentration of approximately 5 mg/L, at the original pH of the solution (̴ 8.3) and an initial PS and PMS concentration of 0.1-1.0 mM range has been studied in order to specify the effect of initial concentration of oxidant on the mineralization processes. TOC, PS, pH and UV254 measurements are realized in the samples taken from specific time intervals (initial, 15th, 30th, 60th minute) during the reaction. According to the experimental studies, it was observed that organic carbon was effectively removed (55% and 64%) during the reaction time (60 minutes) by using both of PS/UV-C and PMS/UV-C photochemical advanced oxidation processes at an initial oxidant concentration of 1.0 mM and at pH 8.3. In addition, these results were confirmed by PSD analysis of raw and treated water by using PS/UV-C and PMS/UV-C processes. In sum, it was concluded that sulphate radical-based photochemical advanced oxidation processes can effectively remove organic carbon in natural waters under appropriate reaction conditions.
Application 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 Management

Aerobic 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.
Application of different strategies to improve anaerobic digestion for organic fraction of municipal solid waste

(Graduate School, 2024-06-24) Kabakcı, Yağmur ; Arıkan, Osman Atilla ; Üçtuğ, Fehmi Görkem ; 501152707 ; Environmental Sciences, Engineering and Management

Municipal Solid Waste (MSW) management is a worldwide issue with significant effects on public health, community welfare, environmental sustainability, and economic progress which includes items like packaging, food scraps, newspapers, and more, coming from homes, businesses, and industries. Effective MSW management is vital for sustainable urban development, emphasizing waste segregation, recycling, and treatment to minimize landfill reliance and harness waste-to-energy technologies. Tailoring waste management systems to local contexts is crucial, considering factors like waste composition and financial resources. From this perspective, this thesis focused on the characterization of MSW and increasing biogas production by applying different pretreatment strategies to organic fraction of MSW (OFMSW). Due to increasing population worldwide, it is essential to understand the MSW characteristics to apply efficient waste management strategies. The organic fraction of MSW (OFMSW) holds potential for energy recovery through anaerobic digestion (AD), offering municipalities economic opportunities besides environmental benefits. In the first study, waste composition and physiochemical of the mechanically separated OFMSW (ms-OFMSW) at a full-scale AD plant in Türkiye was evaluated. ms-OFMSW predominantly comprised of organic matter (76.45 ± 1.71%), alongside recyclable (8.99 ± 1.56%) and non-recyclable (14.56 ± 1.69%) components according to the findings of this study. Environmental assessment was conducted using Environmental Protection Agency's online tool (Recyculator tool) underscored the substantial energy and water savings associated with segregating recyclable materials (metal, glass and plastic) from the waste stream. Moreover, this study highlighted the importance of efficient pre-separation units in enhancing OFMSW digestibility and maximizing environmental benefits. AD is recognized as an effective waste management strategy for different types of waste with the potential to mitigate greenhouse gas emissions (GHGs) while concurrently generating renewable energy. The physicochemical characteristics of OFMSW can significantly influence the AD process's efficiency and biogas production. Hydrolysis, a pivotal step in AD, is often rate-limiting for degradation of waste, particularly for substrates like OFMSW. In the second and third studies, electrohydrolysis and enzyme pretreatment were explored to improve hydrolysis efficiency. Experiments showed that doubling electrohydrolysis treatment time (from 30 minutes to 60 minutes) led to notable improvements in methane production, with a significant reduction in the lag phase. Methane production increased by 3–10% following electrohydrolysis pretreatment, underscoring its potential to expedite the AD process and enhance biogas yields. While in the enzyme pretreatment, anaerobic degradation of organic waste was investigated by employing alpha amylase enzyme which was obtained from Aspergillus oryzae. According to the results, a significant increase in the methane yield and a decrease in the lag phase was observed. Optimum results were obtained with the addition of 0.5 mg of enzyme per g volatile solids (VS) added, highlighting the effectiveness of alpha amylase in enhancing the biodegradability and biogas production of OFMSW. In summary, this thesis sheds light on the importance of understanding and managing OFMSW characteristics to optimize AD efficiency and maximize environmental benefits. Efficient pre-separation units, electrohydrolysis and enzyme pretreatment emerge as promising strategies for enhancing OFMSW digestibility and biogas production in AD processes. However, further research is warranted to fully explore and optimize these approaches for practical implementation on a larger scale. By leveraging these advancements, the waste management sector can move towards more sustainable practices, reducing environmental impact and contributing to the transition to a circular economy.
Application of high-rate activated sludge processes in municipal wastewater treatment

(Graduate School, 2023-05-03) Hamidi, Muhammet Nimet ; Erşahin, Mustafa Evren ; 501191723 ; Environmental Sciences, Engineering and Management

Along with the circular economy and sustainability concepts, energy efficiency and resource recovery have become vital in wastewater treatment plants (WWTPs). Wastewater sludge is no longer considered as a waste to be disposed of but an energy source due to its organic matter. In anaerobic digesters, biogas can be produced from the process (or excess) sludge of WWTPs, which can be used to produce energy. By producing energy from the organic content of the wastewater, achieving energy neutral and/or positive WWTPs gained popularity throughout the world. Activated sludge systems, which biologically remove organic matter, nitrogen, and phosphorus from wastewater, have been widely applied worldwide in the last century. High aeration energy and large area requirements of the conventional activated sludge (CAS) processes led to the development of low-cost wastewater treatment technologies. One of these technologies is two-stage adsorption-bio-oxidation (AB) process. The purposes of A-stage and B-stage are removal of organic matter and nitrogen, respectively. One of the processes applied in A-stage of the AB process is the high-rate activated sludge (HRAS) process. HRAS process is a modificition of CAS process and has around 20 times higher organic loading rate compared to CAS process. Sludge retention time (SRT), hydraulic retention time (HRT), and dissolved oxygen (DO) concentration in the HRAS process are considerably lower than those in CAS process. The HRAS process aims to mineralize the organic matter in wastewater as minimum as possible and to increase carbon capture in the sludge with the biosorption mechanism. By this way, the amount of biogas produced from the excess sludge in anaerobic digesters can be increased. AB process has drawn considerable attention after the 1980s. The first AB process was established in Germany (Krefeld WWTP), which was taken into operation in 1981. Later, several AB processes have been established in Europe. Strass WWTP in Austria is one of the best examples of AB process since it achieves energy positivity. Most of the literature studies on HRAS process and full-scale HRAS process applications have conventional clarifiar. With lamella clarifiers, which have higher settling performance in a smaller footprint than conventional clarifiers, the footprint of the treatment plant can be further reduced. Nitrogen removal efficiency in HRAS process is not as high as the organic matter removal efficiency. For this reason, nitrogen concentration in the effluent of the HRAS process is higher than the effluent of CAS systems. In order to improve the nitrogen removal efficiency, low-cost nitrogen removal processes such as nitritation-denitritation or nitritation-anammox can be used in B-stage after HRAS process. The purpose of this thesis was to investigate the application of HRAS process including a lamella clarifier in municipal wastewater treatment and determine optimum operational conditions. In this study, the effluent of a grit chamber in a full-scale preliminary wastewater treatment plant was fed to a pilot-scale HRAS plant. Since HRT and DO concentrations are two important operational conditions, two HRTs (75 and 50 min) and three DO concentrations (0.2, 0.5, and 0.8 mg/L) were tested. The optimum conditions were determined based on the effluent quality and carbon capture. During the study, the system was operated with a SRT of 0.5 days. In the first part of the study, the optimum HRT was determined, while in the second part of the study the optimum DO concentration of the system was determined. Firstly, the pilot-scale HRAS system was operated with 75 and 50 min HRTs with the same DO concentration of 0.5 mg/L in Stage-1 and Stage-2, respectively. The optimum HRT was determined in terms of higher carbon capture and better effluent quality. Then, at the selected HRT, HRAS system was operated with DO concentrations of 0.2 and 0.8 mg/L in Stage-3 and Stage-4, respectively. It has been observed that Stage-1 (HRT: 75 min; DO: 0.5 mg/L) was the optimum operation condition. Total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4-N), and total phosphorus (TP) removal efficiencies of Stage-1 were 80±5%, 58±3%, 32±6%, 27±7%, and 58±10%, respectively. Based on a mass balance of the HRAS system, it was determined that 41.7% of the influent COD, 34% of the influent TN, and 60% of the influent TP were captured in the sludge in Stage-1. Comparison of different HRT and DO concentrations showed that low HRT and DO concentration increased carbon redirection. The reduction of HRT from 75 min to 50 min decreased COD lost via oxidation, which resulted in an increased biosorption. However, decrease in HRT worsened particulate matter caprute of the clarifier and caused a decrease in effluent quality. Increase in DO concentration caused further oxidation and hydrolysis of particulate matter. As a result, more soluble COD (SCOD) and colloidal COD (CCOD) were observed in the effluent. The extracellular polymeric substances (EPS) in sludge makes flocs come together and increase solid/liquid separation. While the highest EPS production was observed in Stage-1, the lowest EPS production was observed in Stage-3. Low EPS production in Stage-3 was the reason for weak flocs and particulate COD (PCOD) loss through effluent increase. Sludge volume index (SVI) was between 20-30 mL/g throughout the study, showing that HRAS process sludge had good settleability characteristics. Compared to the literature, TSS removal efficiency was quite high in the pilot-scale HRAS process, which may the effect of lamella clarifier. With HRAS process, capturing organic matter to the sludge would positively affect the biogas production in anaerobic digesters enabling energy efficient WWTP operation. Since nitrogen and phosphours are resources for agriculture, the presence of nitrogen and phosphorus in the effluent of HRAS process offers the possibility for use of the effluent for irrigation purposes. However, effluent quality should be improved due to particulate matter in the effluent and micropollutants that are likely to be found in domestic wastewater. Therefore, reuse of the effluent of HRAS process for irrigation purposes should be investigated.
Aralıklı havalandırma optimizasyonuyla konvansiyonel aktif çamur sisteminin ileri biyolojik arıtmaya dönüştürülmesi

(Lisansüstü Eğitim Enstitüsü, 2024-11-04) Özhan, Andaç ; İnsel, Güçlü H. ; 501211702 ; Çevre Bilimleri Mühendisliği ve Yönetimi

Atıksu arıtma tesisleri, sürdürülebilir çevre ve ekosistemlerin korunması açısından kritik bir role sahiptir. Özellikle artan nüfus, sanayileşme ve kentleşme gibi faktörler, atıksuların doğru şekilde arıtılmasını her zamankinden daha önemli hale getirmiştir. Doğrudan alıcı ortamlara deşarj edilen atıksular, su ekosistemlerinde ciddi sorunlara yol açabilir. Örneğin, ötrifikasyon yani su kaynaklarında aşırı alg büyümesi, oksijen seviyesini düşürür ve su ekosistemini tehlikeye atar. Benzer şekilde, müsilaj (deniz salyası) problemi, deniz ekosistemlerini olumsuz etkileyen bir başka önemli sorundur. Bu tür problemlerin temelinde genellikle atıksularla alıcı ortamlara taşınan azot ve fosfor gibi besin maddeleri bulunmaktadır. Bu durumun önüne geçebilmek için, Çevre, Şehircilik ve İklim Değişikliği Bakanlığı, tüm atıksu arıtma tesislerinin azot ve fosfor giderimini sağlayan ileri teknolojilerle donatılmasını önermekte ve bu yönde çalışmalar yürütmektedir. Bu dönüşüm, yalnızca çevresel problemlerin azaltılmasına katkı sağlamakla kalmaz, aynı zamanda sürdürülebilir kalkınma hedeflerine ulaşmada da önemli bir adım olarak kabul edilmektedir. Konvansiyonel aktif çamur sistemleri, 20. yüzyılın başlarında keşfedilmesinden bu yana atıksu arıtma teknolojilerinin temelini oluşturmuştur. Bu sistemler, ilk olarak münferit evlerde kullanılan küçük ölçekli arıtma sistemleri olarak geliştirilmiştir. Ancak zamanla, artan nüfus yoğunluğu ve sanayileşme ile birlikte daha büyük ölçekli, toplu kullanım alanlarına hitap eden atıksu arıtma tesislerine evrilmiştir. Günümüzde aktif çamur sistemleri, hem evsel hem de endüstriyel atıksuların arıtımında yaygın olarak kullanılan en etkili yöntemlerden biri olarak kabul edilmektedir. Bu sistemler, organik kirlilik yükünün azaltılması ve zararlı mikroorganizmaların kontrol altına alınması gibi işlevleriyle, su kalitesinin korunmasına büyük katkı sağlamaktadır. Teknolojideki ilerlemeler sayesinde, konvansiyonel sistemlere biyolojik, kimyasal ve fiziksel arıtma süreçleri entegre edilerek daha verimli ve sürdürülebilir çözümler sunulmaktadır. Bu gelişmeler, çevresel kirliliğin önlenmesinde önemli bir araç haline gelmiştir. Mevcut durumda Türkiye'de büyük ölçekli tesislerin neredeyse tamamı karbon gideriminin yanında besi maddesi giderimi yapan ileri biyolojik atıksu arıtma tesisleri olarak planlanmaktadır. Bu sistemler atıksudaki karbon azot ve fosforun biyolojik olarak giderimini sağlamaktadır. Biyolojik azot fosfor giderimini sağlayan bir çok sistem konfigürasyonu bulunmaktadır. Bu konfigürasyonlara örnek olarak; A2O (Anaerobik/Anoksik-Oksik), 5 kademeli Bardenpho, Johannesburg ve Modifiye UCT (Universty of Capetown) örnekleri verilebilir. Bu tip konfigürasyonlarda nitrat geri devri, çamur geri devir hatları gibi büyük maliyet gerektiren pompa sistemleri bulunmaktadır. Küçük yerleşim bölgeleri ve yazlık bölgelerde dengesiz atıksu miktarları, değişken giriş atıksu konsantrasyonları sebebiyle sürekli ve büyük ölçekli sistemlerin kullanımı tercih edilmemektedir. Büyük ölçekli yatırımlar ile azot fosfor giderimini sağlayacak tasarımlar hem işletmesel olarak problem çıkarmakta, hem de ekonomik olarak mümkün olmamaktadır. Tüm bu nedenler doğrultusunda bu bölgelerde oluşan atıksular modüler ve yalnızca karbon giderimini amaçlayan paket arıtma mantığını benimseyen tesisler ile arıtılmaktadır.
Arıtılabilirlik ve çevresel etkilerin bütünleşik değerlendirmesi

(Lisansüstü Eğitim Enstitüsü, 2022-02-19) Doğan, Kübra ; Babuna Germirli, Fatoş ; Türkmen Atılgan, Burçin ; 501191717 ; Çevre Bilimleri, Mühendisliği ve Yönetimi

Bu çalışmada, su/atıksularda gerçekleştirilen laboratuvar ölçekli arıtılabilirlik çalışmalarının çevresel etkilerinin değerlendirilmesi ve uygulanan farklı yöntemler arasında en uygun olanın saptanması amaçlanmıştır. Laboratuvarda gerçekleşen ileri oksidasyon ve ozonlama yöntemiyle su/atıksu arıtımı işlemlerindeki enerji ve kimyasal yönetimi üzerine yoğunlaşmaktadır. Çevresel etkileri açısından uygun konsantrasyon kimyasal kullanımı ve o konsantrasyona karşılık gelen enerji tüketiminin değerlendirilmesi yapılmaktadır. Laboratuvar ölçekli önceden yapılmış çalışmalarda farklı amaçla gerçekleştirilen su/atıksu arıtımı deneyleri için farklı kimyasallar ve bu kimyasalların farklı konsantrasyonları için enerji tüketiminin potansiyel çevresel etkileri karşılaştırılmıştır. En fazla çevresel etkiye neden olan faktörler tespit edilmeye çalışılarak optimum düzey çevresel etkiye sahip proses seçilmeye çalışılmıştır.
Assessment of persulfate (ps)/uv-c process for drinking water treatment

(Graduate School, 2023) Shahkar, Shahin ; Hancı Ölmez, Tuğba ; 777728 ; Environmental Science, Engineering and Management Programme

In recent years, there has been a significant amount of effort placed on the development of advanced oxidation processes that are based on sulfate radicals. SO4 •− offers several advantages over OH•, including a high redox potential (2.5 - 3.1 V), which is significantly higher than the redox potential of OH• (1.8 -2.7 V), excellent selectivity, and a long half-life (30 to 40 μs). In addition, SO4 •− is capable of successfully reacting with the contaminants of interest across a broad pH range (ranging from 2 to 8). SO4 •− can break down refractory organic contaminants in water, turning them into carbon dioxide, water, inorganic salt, and other molecules with a smaller molecular compounds. Peroxymonosulfate (PMS) and persulfate (PS) can be converted into these radicals via catalytic, radiation, or thermal activation, among other mechanisms. The most significant component that determines water quality is the amount of organic matter that is present in the water. Scientists have spent a significant amount of time and effort looking into the effects that organic matter has on conventional drinking water treatment plants over the many years that have passed. The presence of organic matter in water can lead to a variety of unwanted effects, including changes in the color, taste, and odor of drinking water plants; negative variation in the water's overall microbiological quality; the requirement for the installation of additional treatment units; and so on. As a result of this, the removal of organic matter is becoming an increasingly crucial practice with each passing day. This research focuses primarily on the enhancement of UV-C tertiary treatment using sulfate radical based photochemical Advanced Oxidation Processes (SR-AOPs). This is done in order to treat effectively (mineralize) the organic carbon that is naturally present in raw water, the coagulation-flocculation effluent, the filter effluent and the final effluent. Within the first section of the thesis, experimental research was carried out to investigate the ways in which the initial oxidant concentration influences the effectiveness of the process. Total organic carbon (TOC) removal efficiency, residual oxidant concentration, and UV254 modification were among the data used to establish the procedures' guiding principles. Through the utilization of the PS/UV-C process, a comparison was made on the practicability of using PS oxidant for TOC removal. In terms of determining the effect of initial concentration of oxidant on the mineralization processes, research was conducted using samples that came from a drinking water treatment plant. Each sample had an initial TOC value, and initial value, and the initial PS concentration ranged from 0.1-1.0 mM. The research was conducted in order to determine the effect that initial concentration of oxidant had on the mineralization processes. During the reaction, evaluations of TOC, PS, pH, and UV254 are carried out on samples that have been taken at predefined time intervals (the initial, the 15th minute, the 30th minute, and the 60th minute). As a result of this research, according to the total organic carbon (TOC) removal evaluations, the persulfate/UV-C process is most efficient when used in the raw water coming to the drinking water treatment plant. In conclusion, it was determined that sulphate radical-based photochemical advanced oxidation techniques, when applied to natural or treated waters under the suitable reaction circumstances, are capable of efficiently removing organic carbon.
Atıksu geri kazanımın pişirici cihaz üretimi yapan bir endüstrisinin su ayak izine etkisi

(Lisansüstü Eğitim Enstitüsü, 2022) Uçan, İpek Ceren ; Çokgör, Emine ; 721307 ; Çevre Bilimleri, Mühendisliği ve Yönetimi Bilim Dalı

Bu tez çalışmasında su kullanımı ve kirliliği baz alınarak su ayak izi hesaplama yöntemi sunulmuştur. Bu tez, endüstriyel faaliyetler sonucunda oluşmuş olan suların kendine ait atıksu arıtma tesisindeki su ayak izini incelemektedir. Pişirici ve ısıtıcı cihazların üretim tesisinin atıksu arıtma tesisi kapsamında farklı iki yıla ait su ayak izi hesaplanmış, değerlendirilmiş ve karşılaştırılmıştır. Bu iki ayrı yılda incelenen tesisteki en büyük fark 2018 yılında 2014 yılına nazaran su geri kazanımının yapılmasıdır. Özetle su geri kazanımının ve kazanılan suyun üretimde kullanımının su ayak izine katkısı değerlendirilmiştir.
Avrupa'daki depozito yönetim sistemi uygulamalarının incelenmesi ve zorunlu depozito yönetim sisteminin Türkiye'de uygulanmasına yönelik öneriler

(Lisansüstü Eğitim Enstitüsü, 2024-06-10) Mısır, Aybike ; Arıkan, Osman Atilla ; 501191743 ; Çevre Bilimleri, Mühendisliği ve Yönetimi

Kaynakların giderek azalması, atık miktarının ivmeli bir şekilde artışı, üretim maliyetlerinin artması sebebiyle her geçen gün daha sürdürülebilir üretim ve tüketim modelleri oluşturulmaya başlanmaktadır. Bu model arayışı, yalnızca kaynağa erişim zorluğu veya yüksek maliyetler sebebiyle olmamakta, aynı zamanda iklim değişikliğine karşı mücadele edilmesi, çevrenin ve doğal kaynakların korunması için de bir gereklilik arz etmektedir. Bu noktada özellikle kullanılmış ambalajların ikincil hammadde olarak değerlendirilmeyip diğer atıklarla karıştırıldığı zaman atık niteliği kazandığını vurgulamak gerekmektedir. Bu durumda döngüsel ekonomi prensiplerini benimseyen atık yönetimi ön plana çıkmakta olup, bu yönetim modeli ürünün üretiminden tüketimine ve nihayetinde atık oluşumuna kadar olan sürecinin mümkün olduğunca kapalı bir döngü olarak kalmasını amaçlamaktadır. Bu sayede atığın aynı ürünün üretimine hammadde olarak geri dönmesi hedeflenmektedir. Bu yaklaşım, kullanılmış ambalajların kaynağında temiz bir şekilde ayrıştırılıp toplanmasıyla mümkündür. Kullanılmış ambalajlar, diğer atıklarla karışmadan temiz bir şekilde toplandığında ekonomik değerini korur ve üretim sürecine tekrar kazandırılarak kaynak olarak kullanılabilir. Döngüsel ekonomi modeli, gün geçtikçe daha fazla öne çıkarken, mevcut koşullar, tüketim alışkanları ve bir dizi diğer nedenlerden dolayı döngüsel bir modele geçiş zor olabilmektedir. Hammadde çıkarımındaki artışın döngüsellik düzeyini azalttığı vurgulanmakta olup, küresel ekonominin döngüsellik oranının 2018'de %9,1'den 2020'de %8,6'ya gerilediği ve 2023'te daha da azalarak %7,2 seviyelerine düştüğü gözlemlenmektedir. Yine de ülkelerin döngüselliğe geçiş konusunda her geçen gün daha fazla aksiyon aldıkları yadsınamaz bir gerçektir. Ülkemizde 2021 yılında yayınlanan Yeşil Mutabakat Eylem Planı, ülkemize özgü Döngüsel Ekonomi Eylem Planı'nın hazırlanacağına dair bir hedef belirtmektedir. Ayrıca, plan içerisinde iklim değişikliği, karbon düzenlemesi, sürdürülebilir tarım, akıllı ulaşım ve yeşil finansman gibi konulara da vurgu yapılmıştır. Yeşil Mutabakat Eylem Planı kapsamında 2022 yılında yayınlanan Yeşil Mutabakat Çalışma Grubu Yıllık Faaliyet Raporu'nda, iklim değişikliği ile mücadele çerçevesinde İklim Kanunu taslağı hazırlandığı ve bu taslak ile iklim değişikliği ile mücadele için gerekli planlama ve uygulama araçlarının yasal dayanağının oluşturulduğu vurgulanmıştır. Bu rapor, ülkedeki yeşil ve sürdürülebilir girişimlere dair detaylı bilgiler içermektedir. 2021 yılı Ekim ayında Paris Anlaşması'nın onaylanmasıyla, ülkemizde iklim değişikliği ile mücadele stratejilerine kararlılıkla yaklaşıldığı ve gerekli aksiyonların hızlı bir şekilde alınacağı ifade edilmiştir. Paris Anlaşması, iklim değişikliği ile mücadele konusunda önemli bir dönemeçtir ve iklim değişikliğine dirençli kalkınma doğrultusunda finans akışlarının oluşturulmasına yönelik hedefler içermektedir. Ülkemizde döngüsel ekonomiye geçiş konusunda ulusal ölçekte atılan en önemli adımlardan biri Zorunlu Depozito Yönetim Sistemine geçişe karar verilmesidir. Bu doğrultuda gerekli mevzuat altyapısı oluşturulmuş olup, sistemin denetlenebilir, iyileştirilebilir ve sürdürülebilir bir şekilde uygulanması için Türkiye Çevre Ajansı kurulmuştur. Türkiye Çevre Ajansı'nın Depozito Yönetim Sistemine ilişkin sorumlulukları haricinde çevrenin iyileştirilmesi, kamuoyunda çevreye dair duyarlılık oluşturulması, geri kazanılabilir ürünlerin ülke ekonomisine kazandırılması, sıfır atık yönetim sisteminin uygulanmasına katkı sağlanması gibi alanlarda da sorumlulukları bulunmaktadır. Zorunlu Depozito Yönetim Sistemi kapsamında, ambalaj atıkları içinde çevre kirliliğini yaratan en görünür atıklardan biri olan içecek ambalajları kapalı döngü bir sistemde yönetilmiş olacaktır. Sahiller, denizler, park ve bahçeler başta olmak üzere bu atıklara baktığımız her yerde rastlamak mümkündür. Üstelik hızlı tüketim ürünleri grubunda yer alan içecekler, günlük yaşamın her yerinde sıklıkla tüketilmekte olduğundan bu ürünlerin atık haline gelen ambalajlarının da etkin ve verimli bir şekilde yönetilmesinin zorunluluk olduğu düşünülmektedir. Sıfır Atık Yönetimi anlayışıyla önemi daha da vurgulanan kaynağında ayrı toplama uygulamalarıyla, ambalajların kaynak olarak değerlendirilmesi sağlanmakta olup, içecek ambalajları özelinde gerek temiz toplanma gerekse yüksek geri dönüşüm hedeflerine ulaşma noktasında depozito yönetim sistemi ön plana çıkmaktadır. Günümüzde Avrupa'da 14 ülkede depozito yönetim sistemi bulunmaktadır. Depozito yönetim sistemi farklı ülkelerde üç yönetişim modeli üzerinden kurgulanmıştır: Kamu tarafından yürütülen sistem, piyasaya sürenlerin ağırlıkta olduğu, ilgili diğer sektör paydaşlarının da dahil olduğu kar amacı gütmeyen kuruluşlar tarafından yürütülen sistem (Genişletilmiş Üretici Sorumluluğu Modeli) ve kamu ile özel sektörün bir araya gelmesiyle yürütülen sistem. Depozito yönetim sisteminin sürdürülebilir şekilde yönetilmesi için yönetişim modelinin doğru oluşturulması gerekmektedir. Bu noktada yukarıda bahsedilen üç model arasından birbirinin alternatifi olarak değerlendirilebilecek iki model öne çıkmaktadır. Bunlar kar amacı gütmeyen kuruluş modeli ve kamu-özel işbirliği ile kurulan yapı üzerinden kurgulanan modeldir. En iyi kurgulanmış sistemin bile veri takibi olmadan yönetilebilir olması mümkün değildir. Sistem dahilindeki tüm paydaşların, süreçlerin ve verilerin merkezi bir sistem üzerinden izlenebilmesi ve yönetilmesi kritik olup Türkiye Zorunlu Depozito Yönetim Sistemi bu konuda da ön plana çıkmaktadır. Ülkemizde tüm sistem merkezi bir veri tabanı üzerinden yürütülmek üzere kurugulanmıştır. Bunun yanı sıra sistemi aldatmaya yönelik girişimlerin önlenmesi için tercih edilen güvenlik yöntemlerinden olan ve kapsam dahilindeki ambalajları etiketleme ve işaretlemede kullanılan özel mürekkep, ülkemiz uygulamasında tercih edilmiştir. Avrupa genelinde sistemi uygulayan ülkelerde toplama oranı ortalama olarak yaklaşık %90 seviyelerine kadar ulaşmış olup en az toplama oranı ise %70 seviyelerindedir. Sistemin ana prensibi tüketicilerden ürün fiyatına ek olarak belirli bir depozito bedeli alınması ve oluşturulan iade noktalarına getirilen depozitolu boş ambalaj başına söz konusu depozito bedelinin tüketiciye iade edilmesidir. Sistem kapsamındaki ürün ve ambalaj grupları, depozitolu ambalajların işaretlenmesi, sistemin uygulama esaslarına ilişkin düzenlemeler ülkeden ülkeye farklılık göstermektedir. Döngüsel ekonomi, sürdürülebilir atık yönetimi, iklim değişikliği konularında dünyadaki gelişmelerin yakından takip edildiği ülkemizde, zorunlu depozito yönetim sistemine geçişe dair yasal düzenlemeye 2018 yılında 2872 sayılı Çevre Kanunu'nda yer verilmiştir. Sistemin sürdürülebilir bir şekilde hayata geçirilmesi için 2020 yılında kurulan ve Sistem Yöneticisi olarak görevlendirilen Türkiye Çevre Ajansı Türkiye'de Zorunlu Depozito Yönetim Sistemi'nin kurulmasına dair çalışmalara hızla başlamıştır. Zorunlu Depozito Yönetim Sistemine geçiş çalışmaları 2022 Ocak ayı itibariyle başlatılmış olup sistemin altyapısının kurulmasına ilişkin süreçler devam etmektedir. Sistemin tüm ülkede zorunlu hale getirilmesinden önce sahada uygulama örneklerinin görülmesi, vatandaşın sisteme dair bilgilendirilmesi ve farkındalığının artırılması için hayata geçirilmesi planlanmış pilot ölçekte uygulamalar, halihazırda Ankara'nın Kızılcahamam İlçesi'nde ve Çevre, Şehircilik ve İklim Değişikliği Bakanlığı'nın ana hizmet binasında yapılmaktadır. Bu uygulamaların giderek yaygınlaştırılması hedeflenmektedir. Zorunlu Depozito Yönetim Sistemi'ne ilişkin düzenlemelere Türkiye Çevre Ajansı tarafından yayımlanan Zorunlu Depozito Yönetim Sistemi Uygulamalarına İlişkin Usul ve Esaslar'da yer verilmiştir. Zorunlu Depozito Yönetim Sistemi, iki ana operasyon üzerinden yönetilecek şekilde tasarlanmıştır. İlk aşama, Depozito Bilgi Yönetim Sistemi'nin kurulumu ve işletilmesini içermekte olup, bu aşamada kapsamdaki ambalajların özel mürekkep operasyonlarıyla etiketlenmesi ve işaretlenmesi gerçekleştirilmektedir. İkinci aşama ise depozitolu boş ambalajlar için iade noktalarının oluşturulmasını, tüketiciden iade alınan ambalajların işlemlerini ve bu ambalajların doğrulanarak geri kazanım tesislerine taşınmasını içermektedir. Birinci faza dair çalışmaların büyük ölçüde tamamlanmış olup depozito logolu ürünler piyasada yer almaya başlamıştır. İkinci faz kapsamında olan ve tüketicilerden depozitolu boş ambalajların alınacağı iade noktalarının oluşturulması ve işletilmesini kapsayan çalışmaların da devam ettiği bilinmektedir. Ülkemizde, zorunlu depozito yönetim sistemi sayesinde elde edilmesi öngörülen çevresel ve ekonomik faydalara dair hesaplamalar yapılmıştır. Ekonomik fayda; Yerel yönetimlerin atık bertaraf maliyetindeki azalma kaynaklı fayda; Materyalin ekonomik değerinin artması kaynaklı fayda; Denizlerdeki plastik kirliliğinin azalması kaynaklı fayda; Birincil hammadde yerine geri dönüştürülmüş malzeme kullanılması ile kaynak tasarrufu; Ürünlerin üretiminde geri dönüştürülmüş malzeme kullanılması ile enerji tasarrufu olmak üzere beş başlık halinde incelenmiştir. Hesaplamalar neticesinde Zorunlu Depozito Yönetim Sistemi çerçevesinde %90 toplama hedefine ulaşıldığında, yıllık ortalama 183,4 milyon EUR ekonomik faydanın elde edileceği ve ambalajların geri dönüşümü sayesinde yıllık olarak 351.000 ton CO2 eşdeğerinde emisyon azaltımı sağlanacağı sonucuna ulaşılmıştır. Bu hesaplamada yer alan parasal değerlere ek olarak, çevre temizliği, atık ithalatında azalma gibi bu çalışmada hesaplanmayan diğer faydalar da düşünüldüğünde, sistemin ülkemize çevresel ve ekonomik anlamda büyük katkı sağlayacağı açıkça görülmektedir.
Calculation of nitrous oxide emissions of municipal wastewater treatment plants under dynamic loads with simulation models

(Graduate School, 2024-07-11) Nalbanto, Hüseyin ; İnsel, H. Güçlü ; 501211712 ; Environmental Sciences, Engineering and Management

In recent years, the urgent need to address environmental pollution has highlighted the importance of effective wastewater treatment processes. Municipal wastewater treatment plants (WWTPs) are complex systems where numerous biochemical processes are employed to remove pollutants from wastewater before it is released into natural bodies of water. The increasing global focus on environmental sustainability mandates these facilities to operate under stringent regulatory frameworks to minimize their ecological footprint, particularly concerning greenhouse gas (GHG) emissions. Among the various GHGs, nitrous oxide (N2O) is of significant concern due to its potent global warming potential, which surpasses that of carbon dioxide by nearly 300 times. Traditional methods of wastewater treatment are often not equipped to handle the dynamic nature of influent streams, which can vary dramatically in composition due to a variety of factors including seasonal variations, industrial discharges, and climatic conditions. This variability can hinder the efficiency of biological processes like nitrification and denitrification, which are crucial for the removal of nitrogenous compounds, consequently increasing the emissions of N2O. This thesis introduces an approach using simulation models to predict and mitigate N2O emissions in municipal WWTPs under dynamic loading conditions. The study utilizes the Sumo software to simulate the operations of a WWTP based in the Marmara Region, Turkey. By incorporating real-time data and simulating various operational scenarios, this research aims to understand the impacts of fluctuating influent characteristics on the efficacy of N2O emission reduction. The objectives of this thesis are to calibrate and validate a simulation model that can accurately forecast the behavior of N2O emissions under variable loading conditions; and to propose operational adjustments and system optimizations that can significantly reduce the emission of N2O. Modeling and simulation results successfully demonstrated the dynamic behavior of N2O emissions in response to fluctuating wastewater characteristics, emphasizing that dynamic loading conditions can significantly influence N2O emissions. Peak emissions were closely associated with transient peaks in influent loads. It was crucial for understanding how different operational conditions and varying influent characteristics impact GHG emissions from wastewater treatment processes. The study observed that OD-1, primarily operating under anoxic conditions, demonstrated a lower N2O emission rate compared to the others. This is attributed to its limited oxygen availability, which is less conducive to the formation of N2O. In contrast, OD-2, which alternates between anoxic and aerobic conditions via controlled aeration, showed a slightly higher rate of N2O emissions. This reactor's operational flexibility helps mitigate emissions but still presents challenges in maintaining low emission levels during transitions between anoxic and aerobic conditions. OD-3 and OD-4, consistently operated under aerobic conditions, recorded the highest N2O emissions among the four reactors. The consistent aeration in these reactors supports aerobic processes that are necessary for efficient breakdown of organic matter; however, it also facilitates conditions that favor N2O production. The study points out that the operational design of OD-3 and OD-4, while effective for organic removal, does not optimize the control of N2O emissions. The findings indicate a clear relationship between the operational mode of each reactor and its N2O emissions, underscoring the importance of reactor configuration and management in controlling greenhouse gas emissions from WWTPs. Considering the information obtained from the simulation studies, it can be said that it is necessary of optimizing operational parameters like aeration rates and internal recycling flows to mitigate conditions conducive to N2O production. The study suggests that flexible operational strategies that can be adjusted in real-time based on the loading conditions are essential for reducing N2O emissions effectively. Furthermore, the thesis recommends the exploration and adoption of advanced nitrogen removal technologies, such as Anammox, which could potentially reduce N2O emissions further. This comprehensive analysis not only addresses the challenges of managing N2O emissions but also promotes the critical role of innovative operational strategies and ongoing research in advancing environmental management practices.
Calculation of the carbon footprint of valex vegetable tannin product used as an alternative chemical in the tanning process in the leather industry and reduction proposals

(Graduate School, 2024-06-11) Yaşar, Serdar ; İnsel, Hayrettin Güçlü ; 501211729 ; Environmental Sciences Engineering and Management

The primary objective of this thesis is to calculate the carbon footprint of the Valex vegetable tannin product, used as an alternative chemical in the leather tanning process, and to propose reduction strategies. The study focuses on analyzing the production processes of Valex in the Aegean Region of Turkey, specifically Manisa, and aims to quantify the carbon dioxide equivalent (CO2e) greenhouse gas emissions. The carbon footprint calculation is grounded in the GHG Protocol and the ISO 14064- 1 and ISO 14067 standards. The scope of this research includes examining the importance of the leather industry, identifying the sources of greenhouse gas emissions within the industry, and evaluating the environmental impact of the Valex vegetable tannin product compared to traditional tanning agents. The study highlights the significant contribution of the leather industry to global greenhouse gas emissions and emphasizes the need for sustainable practices. To achieve its objectives, the study meticulously analyzes the production stages of Valex, from raw material collection to the final product. This includes the collection and transportation of acorns, their processing into tannin, and the emissions generated at each stage. By identifying the major contributors to the carbon footprint, the study proposes strategies to reduce emissions, such as optimizing energy consumption and exploring alternative fuels. The findings of this thesis aim to provide insights into the environmental impacts of the Valex vegetable tannin product and offer recommendations for reducing the carbon footprint of the leather industry. By comparing Valex with other materials, the study seeks to understand its advantages and suggest improvements for more sustainable leather production practices. In conclusion, this research contributes to the literature by evaluating the environmental performance of Valex vegetable tannin and proposing methods to mitigate its impact. The results are intended to serve as a reference for future studies and practical applications, promoting more sustainable and eco-friendly practices in the leather industry.
Comparative evaluation of sustainable sound absorption materials using TOPSİS method

(Graduate School, 2022-05-17) Alkraidi, Buroog Basil Nader ; Dülekgürgen, Ebru ; 501181711 ; Environmental Science, Engineering and Management

This study intends to determine, evaluate and compare new, local and sustainable sound absorptive materials for their possible use in indoors acoustic panel production. The materials selected for this study are recycled textile, tea waste and corn husk. Recycled textile is proposed for its high availability in Turkey since textile industry is very active in the region and tons of pre-consumer (production offcuts) and post-consumer (used clothes) textile wastes are sent to landfill every year. Using recycled textile in producing acoustic panels may not only assist with providing an alternative solution to remediating the noise pollution problem but may also contribute to reducing solid wastes. Additionally, its porous structure is a great quality for the aim of sound absorption. Tea waste and corn husk are proposed as food wastes and agricultural wastes, respectively, as raw materials for acoustic panel production. In additional to being locally available, they possess promising acoustics characteristic that make them promising candidates for the sustainable acoustic panel production industry. Additionally, there is a fourth material, namely fiberglass, that has been selected for the aim of comparison of the herein proposed new, sustainable raw material alternatives with the commercially available conventional materials widely used in acoustic panel production. To select the best sound absorbing material among different alternatives, it is important to use a decision-making tool for the aim of a comprehensive comparison. Such tools help with making the decision based on a number of selected criteria, which might be chosen by the users in accordance with their preference. Within the framework of this study, TOPSIS was selected as the decision-making tool in order to choose the best sound absorbing material among the studied alternatives.
Comparison between membrane bioreactor and hybrid membrane bioreactor (IFAS MBR) systems: A pilot scale study

(Graduate School, 2024-11-07) Demirbilekli, Muhammed Ahmet ; Koyuncu, İsmail ; 501211723 ; Environmental Science, Engineering and Management

With the increasing global demand for water treatment, there has been rising interest in innovative treatment methods that offer compact designs, cost-effectiveness, and high-quality water output. Membrane technologies have emerged as a leading solution in this domain and are increasingly being adopted in place of conventional systems, especially in domestic wastewater treatment facilities. Membrane Bioreactor (MBR) systems, due to their economic feasibility and ease of operation, have become a key focus of research in the field. Membrane Bioreactor (MBR) systems are a cutting-edge process that integrates biological wastewater treatment with advanced membrane filtration, offering a highly efficient solution for both domestic and industrial wastewater treatment. In MBR systems, biological degradation of organic matter occurs through the activated sludge process, while solid-liquid separation is achieved using a membrane. This obviates the need for secondary settling tanks, which are a standard component of traditional wastewater treatment facilities. Fine pores of membrane, typically in the microfiltration or ultrafiltration range, allow for high-quality effluent with low turbidity and nearly complete removal of suspended solids and pathogens. MBR systems are particularly valued for their ability to operate with higher biomass concentrations, resulting in smaller footprint requirements and improved treatment performance. Today, it has become necessary to revise conventional wastewater treatment plants to ensure nitrogen and phosphorus removal and to achieve treatment efficiency levels that allow for wastewater reuse in water-intensive industries. To meet these demands, new technologies must be employed, and wherever possible, local resources should be utilized in the design of facilities and selection of equipment. In doing so, the environmental sector can reduce dependency on foreign technologies. The Integrated Fixed Film Activated Sludge (IFAS) system represents a relatively recent advancement in wastewater treatment technology, providing several benefits compared to conventional activated sludge systems. In IFAS systems, a growth medium is introduced into the activated sludge tank to facilitate biomass development and enhance the overall treatment process. This medium can either be fixed or free-moving. The technology is relatively recent and can be implemented either as an upgrade to existing facilities or as part of new construction projects. IFAS integrates advantages of traditional activated sludge and biofilm technologies within a single reactor, providing performance improvements of up to 40% without requiring additional aeration tanks. The media in IFAS system provides an increased surface area to support greater biomass accumulation and enhances microbial growth, increasing sludge retention time and treatment efficiency. This thesis presents a comparative analysis of the operational performance of two wastewater treatment systems: a Membrane Bioreactor (MBR) and a Hybrid Membrane Bioreactor known as the Integrated Fixed Film Activated Sludge Membrane Bioreactor (IFAS MBR). The two systems were operated simultaneously parallel under identical conditions using real wastewater from the Istanbul Technical University's Ayazaga Campus. The aim of the study was to assess the treatment efficiencies, operational stability, and membrane fouling behaviors of both systems in handling municipal wastewater at SRT 5 days.
Concentrate treatment via membrane distillation/crystallization method

(Graduate School, 2023-08-23) Salmanlı Mutlu, Öykü ; Koyuncu, İsmail ; Wiesner, Mark R. ; 501152708 ; Environmental Sciences and Engineering

Boron is an important semimetal element that is found in water, soil and rocks. Boron is widely used in a variety of industries such as glass, semi-conductors, detergents, cosmetics, drugs and fertilizer. Boron is also an essential nutrient for animals, plants and humans that needs to be found in dietary intake. Although it is beneficial the excessive amount of boron can lead to some health problems for humans and growth problems or death for plants. The boron content in wastewater is increasing due to the increasing industrial activities. Boron can also be found naturally from rocks, salt deposits or rainfalls and approximately 75% of the boron reserves of the world are found in Turkey. In the second chapter of this thesis study a literature review was prepared comprehensively. Boron removal and recovery techniques were reviewed. The increasing demand for clean water resources makes boron removal from water resources much more important. However, the removal is not enough alone in the aspect of sustainability. The removal and recovery techniques both conventional methods like precipitation, adsorption, coagulation, ion exchange and membrane processes are examined to juxtapose the states of the science in these two related—and increasingly important—processes. In the third chapter, the optimization studies of the membrane distillation process used in the thesis study were conducted. 2 different MD configurations, 3 different vacuum pressures, 6 different membranes and 3 different feed water were used to determine the optimum conditions. VAGMD had the higher fluxes since vacuum assistance enhanced fluxes while decreasing specific energy consumption. The boron content in permeate waters was lower than the 0.5 mg/L. In the fourth chapter hydrophobic and superhydrophobic membrane production methods were investigated. Different fabrication techniques as phase inversion and electrospinning were utilized while coating was applied to modify commercial and fabricated membranes. Different coagulation bath mediums for phase inversion method, nanoparticle additives and different coating solutions were compared. It was possible to obtain a superhydrophobic membrane that has a contact angle of 153. A novel hydrophobic blend membrane was fabricated to use in VAGMD within the scope of the fifth chapter. NaCl, synthetic boron solution and real RO concentrate supplied from the boron mining area were tested. A fluoro-containing benzoxazine monomer (Bz) was blended with our base polymer PVDF. The cross-linking of Bz is provided by thermal curing. According to the results, the BisF-Bz membrane showed higher hydrophobicity, more durability and physical stability compared to the pristine membrane. Boron rejection was highest for the BisF-Bz blended and two times thermally cured nanofiber membrane. In chapter six VAGMDC system was utilized to remove and recover boron from the concentrate stream. The concentrate problem is the main drawback of membrane processes so needs additional treatment and management. To address this problem VAGMDC system was tested. Synthetic boron solution was used to optimize process conditions such as concentration, pH and membrane type. Real RO concentrate was tested in the following experiments. Flux values, boron concentration and boron rejections, SEM-EDS analysis and XRF analysis for obtained crystals were conducted. The results showed that VGMDC could be successfully used for the removal and recovery of boron. The pilot scale VAGMDC system was tested in the scope of chapter seven. Different recovery ratios and operating modes were tested. Highly boron-contented raw river water and RO concentrate of that water were fed to the pilot scale MD system. Conductivity, flow rate and vacuum pressure were observed during the experiments. Boron, arsenic, hardness and conductivity removals were analyzed and determined. After VAGMD operation crystallization was applied to the obtained concentrate. 43.9% B2O3 contented crystals could be obtained. In conclusion, the relatively new VAGMDC process is an effective method for boron removal and recovery.
Coupling ozone with GAC, AIX and biochar: Removal of pharmaceuticals from the biologically treated wastewater and fate of their transformation products

(Graduate School, 2024-09-24) Kutlu Fakıoğlu, Malhun ; Öztürk, İzzet ; 501172707 ; Environmental Science, Engineering and Management

In order to prevent water pollution in the water bodies, there has been a rising interest in improving cost-efficient quaternary treatment technologies to efficiently remove pharmaceuticals from the effluents of wastewater treatment plants. Various methods, including physical, biological, and chemical processes, are being utilized to eliminate organic micropollutants (OMPs) which include pharmaceuticals and persistent pollutants such as per- and polyfluoroalkyl substances (PFAS). Among these advanced techniques, ozonation and activated carbon adsorption are currently suggested as the most feasible options for substantially decreasing pharmaceutical concentrations in the wastewaters. Carbon-based materials such as activated carbon are notably effective adsorbents used for removing pharmaceuticals. Likewise, ozone is a highly potent oxidizing agent capable of oxidizing micropollutants directly via O3 itself or indirectly through the generation of hydroxyl radicals. However, after ozonation, instead of being mineralized, compounds can be converted into other substances known as transformation products, which may pose greater toxicity than the original compound. Additionally, the reaction between bromide and ozone produces bromate which is a toxic and carcinogenic by-product. To mitigate potential adverse effects from ozonation, it is often recommended to implement post-treatments such as biological or adsorptive systems like granular activated carbon (GAC) to eliminate potential transformation products and by-products. When combined with activated carbon adsorption, ozonation acts as an additional method for removing compounds that are resistant to adsorption. Crucially, activated carbon, with its extensive specific surface area and high concentration of functional groups, has demonstrated its ability to eliminate transformation products and by-products that may be generated during ozonation. While the effectiveness of the O3-GAC pairing is well-documented in literature, less attention has been given to combinations like ozonation with anion exchange (AIX) or other potentially more sustainable sorption materials such as biochar. The O3-AIX combination is particularly intriguing for this study, as many wastewater treatment plants, including the WWTP that provided wastewater for this research, are grappling with the challenge of removing PFAS. The treated wastewater from the aforementioned WWTP is released into the Fyrisån River, which flows into Ekoln Lake, Mälaren Lake, and eventually to the Baltic Sea. Fyrisån River also contributes to replenishing a groundwater source used for the city's drinking water. Consequently, the conventionally treated wastewater, containing untreated micropollutants, is discharged into a river that ultimately serves as a drinking water source. Thus, this study aims to simulate a potential combined advanced treatment step for the wastewater treatment plant. This research is particularly noteworthy as it not only provides guidance for implementing advanced techniques to remove micropollutants in full-scale wastewater treatment plants, but also investigates the fate of transformation products within three different combined systems: ozone and granular activated carbon filtration, ozone and ion exchange, and ozone and biochar. The objective of this thesis was both to examine the effectiveness of removing 24 selected pharmaceuticals and to monitor the fate of 7 of their metabolites, including oxidation transformation products. This investigation utilized a combination of processes, namely O3-GAC, O3-biochar (with two different types of biochar), and O3-AIX, in laboratory-scale experiments using actual effluent from a full-scale WWTP. The entire system was operated with three different O3 dosages, each maintained continuously for two weeks. Various sorption filters, including two types of biochar (one derived from forest biomass and the other from sewage sludge), reactivated GAC, and an AIX resin, were assessed. The evaluation of results focused not only on micropollutant removal but also on the generation of transformation products and by-products. 23 out of the 24 pharmaceuticals examined were detected in the effluent wastewater collected from the Kungsängsverket WWTP in total. The findings revealed that concentrations of sertraline, trimethoprim, fluconazole, atenolol, and sulfamethoxazole were below 500 ng/L, whereas the average concentrations of venlafaxine, desvenlafaxine, fexofenadine, bicalutamide, and lamotrigine were above 5,000 ng/L. According to the study findings, the average removal of selected pharmaceuticals varied between 8.8% and 97% with an O3 dosage of 0.28 g O3/g DOC, while it ranged from 86% to 99% for higher O3 dosages (0.96 and 2.17 g O3/g DOC). Pharmaceuticals such as fluconazole, atenolol, metoprolol, and tramadol exhibited relatively lower removal rates (9-15%) with the specific O3 dosage of 0.28 g O3/g DOC compared to furosemide, propranolol, clindamycin, and clarithromycin, which showed high removal rates (>90%). Tertiary amines like cetirizine and fexofenadine, known for their high reactivity with ozone, achieved removal rates of 79% and 89%, respectively, via 0.28 g O3/g DOC in this study. Furthermore, highly reactive compounds such as carbamazepine, diclofenac, sulfamethoxazole, and trimethoprim were removed by 70%, 85%, 70%, and 88%, respectively, with 0.28 g O3/g DOC, consistent with existing literature. Conversely, fluconazole exhibited a removal rate of 9% with an O3 dosage of 0.28 g O3/g DOC, while atenolol had an average removal rate of 15%. Among all materials tested, GAC emerged as the top-performing sorbent, effectively removing nearly all compounds below the limit of quantification (LOQ) even after continuous operation for two weeks (BV=864). The potential efficacy of biochar 2 for pharmaceutical removal, which was derived from sewage sludge, was particularly significant for the overall sustainability of the WWTP. Although biochar 1 exhibited better performance than biochar 2, both sorption materials showed decreased sorption capacity over the two-week period (BV=864) for most target compounds, including carbamazepine, fexofenadine, tramadol, fluconazole, sulfamethoxazole, and erythromycin. By the end of the continuous two-week operation, biochar 1 achieved removal rates ranging between 30% and 89% (mean 68%), while biochar 2 removed selected compounds at rates of 8.5% to 82% (mean 38%). Conversely, AIX that has been included for PFAS removal, demonstrated lower removal rates as expected after two weeks compared to biochars 1 and 2, ranging between 2% and 55% (average: 20%) for positive removal rates (BV= 3,264). Based on the findings, GAC exhibited the highest performance when paired with ozone (>99%), followed by biochar 1. Generally, the combination of ozone with biochar 1 proved to be more effective (mean=91%, range: 42-99%) than with biochar 2 (mean=79%, range: 29-99%). As anticipated, the combination of ozone with AIX yielded the lowest removal rates for pharmaceuticals (mean=58%, range: 6-98%). Based on the findings, six out of seven metabolites were identified in samples both pre- and post-ozonation. The results suggested that while the concentrations of certain metabolites decreased during ozonation, some metabolites, including oxidation transformation products like citalopram N-oxide, exhibited an increase over the two weeks of continuous operation. On average, citalopram concentration decreased by 81%, whereas the concentration of citalopram N-oxide increased by 19% with an O3 dosage of 0.28 g O3/g DOC. With the system operating at 2.17 g O3/g DOC, citalopram's average removal reached the LOQ, while the increase in citalopram N-oxide exceeded to 33%. Furthermore, all detected metabolites were eliminated to below the LOQ using GAC after two weeks of operation. Concentrations of most metabolites exhibited a linear decrease over time for biochar 1 and biochar 2, while for AIX, concentrations of certain metabolites increased over time. During all three O3 dosages (0.28, 0.96, and 2.17 g O3/g DOC), bromate concentrations remained below 5 µg/L. At the lower O3 dosage of 0.28 g O3/g DOC, the bromide concentration in the utilized WWTP effluent was 1.03 mg/L, whereas at the higher O3 dosages of 0.96 and 2.17 g O3/g DOC, the bromide concentrations were 0.52 and <0.50 mg/L, respectively. This variation resulted in an inability to assess the potential formation of bromate. Removal of DOC via different O3 dosages ranged from 19% to 26%, while GAC removed over 90% of DOC under all operational conditions. Conversely, AIX only removed less than 10% of initial DOC across all operational conditions, while in all cases, biochar 1 and biochar 2 removed within the range of 18-23% and 5-10%, respectively. In summary, ozonation exhibited high removal efficiency of pharmaceuticals and their metabolites at higher O3 dosages (>0.96 g O3/g DOC), while at lower O3 dosages (0.28 g O3/g DOC), a post-treatment became necessary for effective pharmaceutical removal. However, higher O3 dosages entail increased operational costs and pose a risk of transformation product formation. Therefore, employing combined systems for pharmaceutical and metabolites elimination is suggested as a preferable alternative to sole reliance on ozonation as the advanced treatment method. Comparative analysis of different post-treatment filter sorbents indicated that GAC yielded the most favorable results for pharmaceutical and metabolite removal. Conversely, the adsorption capacities of two distinct biochar types diminished over the continuous two-week operation, whereas GAC's performance remained consistent throughout. Biochar 1 outperformed biochar 2 in terms of pharmaceutical removal. AIX exhibited the lowest removal efficiencies, suggesting it may not suffice as a polishing step for ozonation when simultaneous removal of pharmaceuticals and PFAS is targeted. Overall, the combination of O3 with GAC demonstrated the most effective performance for pharmaceutical removal. Biochar holds promise as a more sustainable substitute for GAC, as it can be sourced from renewable materials like wood. However, there is a need for ongoing development to better understand the efficacy of combined O3-filter systems, with a focus on considering long-term operation. Before scaling up to a full-scale WWTP, conducting a life cycle assessment and feasibility analysis would be prudent steps to take.
Critical 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 Management

In 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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