Hareketli yataklı reaktörlerde antienflamatuvar yapıdaki mikro kirleticilerin gideriminin araştırılması
Investigation of the removal of anti-inflammatory micropollutants in moving bed reactors
Yazar: BERKAY UÇAN
Danışman: PROF. DR. HAYRETTİN GÜÇLÜ İNSEL
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Çevre Mühendisliği Ana Bilim Dalı / Çevre Bilimleri, Mühendisliği ve Yönetimi Bilim Dalı
Derece: Yüksek Lisans, 2024
Konu: Çevre Mühendisliği = Environmental Engineering

Özet:
Dünyadaki nüfus artışı, sanayinin gelişimi ve kimyasalların üretimi ve tüketimi, çevre kirliliğine sebep olmaktadır. Bu sebeplerin meydana getirdiği sorunlardan biri temiz su kaynaklarının azalmasıdır. Eğer su tüketiminde dikkatli olunmazsa temiz su ihtiyacının artacağı ve dünya nüfusunun %60'ının su kıtlığı ile karşı karşıya geleceği öngörülmektedir. Bu sebeple gelecek yıllarda suyun ıslahı ve yeniden kullanımı kaçınılmazdır. Dolayısıyla atık suların iyileştirilmesi için atık sulara karışan kirleticilere göre arıtma yöntemlerinin geliştirilmesi gerekmektedir. Atık sulardaki bu kirleticilerden biri de mikrokirleticilerdir. Mikrokirleticiler, doğa ve insan yaşamına toksik ve istenmeyen etkileriyle yaşam kalitesini düşüren mikro boyutlu kirletici maddelerdir. Bu mikrokirleticilerden, steroid yapıya sahip olmayan antienflamatuar farmasötiklerin atıksu arıtma tesislerinde giderilmesi için çalışılmaktadır. Bu kirleticilerin atıksu arıtma tesisinde ne kadarının arıtıldığı bilinmediğinden dolayı doğaya karıştığı konsantrasyon ilgi konusudur.
Bahsedilen mikrokirleticilerin çevreye verdiği zararı en aza indirebilmek için literatürde çeşitli arıtma yöntemleri bulunmaktadır. Atık su arıtımında biyolojik arıtma prosesleri oldukça önemlidir. Genellikle kullanılan prosesler, askıda büyüyen sistemler (Aktif çamur prosesleri v.b.) ve biyofilm sistemler (Damlatmalı filtreler v.b.) şeklinde ikiye ayrılır. Günümüzde arıtma etkinliğini ve verimliliği artırmak için iki sistemin iyi özellikleri bir araya getirilerek hibrit sistemler üzerine yapılan çalışmalarda önemli artış gözlemlenmektedir. 
Hibrit sistemlerden biri, Hareketli Yataklı Biyofilm Reaktörlerde (MBBR) mikrokirleticilerin giderimi sürecidir. Bu MBBR süreci Norveç'de 1980'lerin sonlarında, Norveçli Kaldnes şirketi tarafından geliştirilmiştir.
MBBR; performansı, etkin oluşu, maliyeti, kompakt ve kullanım kolaylığı ile halen geliştirilen bir süreçtir. Tez çalışması kapsamında, ilk bölümde atık sulardaki mikrokirleticiler ve onların zararları ile birlikte, bu kirleticilerin giderimini sağlayan arıtma prosesleri üzerine literatür incelemesi verilmiştir. Ayrıca tezin amacı ve hipotez bu bölümde verilmiştir. İkinci bölümde, mikrokirleticiler ve Hareketli Yataklı Reaktörler hakkında bilgi verilmiştir. Üçüncü bölümde MBBR de mikrokirleticilerin giderimi için materyal ve metot ile birlikte deneysel çalışma verildikten sonra sırasıyla sonuçlar ve değerlendirme bölümleri ile sonlandırılmıştır.
Deneysel çalışmada, antienflamatuvar yapıdaki mikrokirleticilerden; Naproksen, ketoprofen, diklofenak, indometasin, ibuprofen ve mefenamik asit ilaç gruplarını ele alınmıştır. Sentetik evsel atıksu ile beslenen, evsel atıksu arıtma tesisi giriş atık suyu konsantrasyon oranları baz alınıp, deney laboratuvar ölçekli ardışık kesikli reaktörde (AKR) yürütülmüştür. MBBR sürecinde, mikrokirleticilerin gideriminin incelenmesi amacıyla kontrol ve mikrokirletici ilaveli hibrit reaktörlerin kurulumunda 6 L çalışma hacmindeki laboratuvar ölçekli silindirik cam reaktörler kullanılmış; sistemler 10 gün çamur yaşında ve 20±2°C sabit sıcaklıkta işletilmiştir. Hibrit reaktörler kurulurken dolgu malzemesi olarak aquaflex marka dolgu malzemesi kullanılmış ve %30 dolgu malzemesi oranında işletilmiştir. Reaktörler evsel atıksu eşdeğeri pepton karışımı sentetik atıksu ile beslenmiştir. Sistemler 2 çevrim olarak işletilmiş ve her çevrimde 150 mg/L KOİ eşdeğerinde substrat ve azot içeriği 60 mg/L olarak beslenmiştir. Kontrol reaktörü 217 gün mikrokirletici ilaveli hibrit reaktörü 150 gün süresince işletilmiştir. Kontrol ve mikrokirletici ilaveli hibrit reaktörlerin AKM, UAKM konsantrasyonları sırasıyla yaklaşık 1050 mg AKM/L ve 935 mg AKM/L; 798 mg UAKM/L ve 837 mg UAKM/L olarak ölçülmüştür. UAKM/AKM oranı ise sırasıyla 0,79 ve 0,88 olarak hesaplanmıştır. Her iki reaktörde de çözünmüş çıkış KOİ değeri 30 mg/L'nin altındadır. Amonyak azotu konsantrasyonu aklimasyon dönemi sonrası çıkış suyunda 8 mg N/L'nin altında ölçülmüştür. Elde edilen sonuçlar antienflamatuvar yapıdaki mikrokirleticilerin (İbuprofen, naproksen, ketoprofen, indometasin, mefenamik asit ve diklofenak) organik maddenin biyolojik olarak parçalamasında ve nitrifikasyon prosesi üzerinde kronik inhibisyon etkisinin olmadığını göstermiştir. Ayrıca, 400 mg/L KOİ eşdeğerinde konsantrasyonu ile beslenen hibrit sistemler için deneysel çalışma yapılmış ve sonuçlar çizelge ve şekillerle sunulmuştur.

Abstract:
The acceleration of population growth, the advancement of industrialization, and the increase in the production and consumption of chemicals contribute to environmental pollution. These developments have significant impacts on the environment, with one of the most pressing issues being the decreased access to clean water sources. The rising demand for water and the inadequacy of existing resources could lead to significant water scarcity in the future. This situation indicates that approximately 60% of the world's population could face water scarcity. Therefore, water reclamation and reuse will become a critical necessity in the coming years. To improve water quality, it is essential to develop wastewater treatment methods. In wastewater treatment processes, it is important to thoroughly examine and effectively remove the pollutants mixed into the water. One of these pollutants in wastewater is micropollutants. Micropollutants are micro-sized contaminants that reduce the quality of life with their toxic and undesirable effects on nature and human health. Micropollutants generally originate from various industrial processes, pharmaceuticals, and personal care products. They can persist in nature for a long time and contaminate water sources. Since these pollutants cannot be completely removed by treatment systems, they accumulate in the environment and can have adverse effects on ecosystems. Efforts are being made to remove these micropollutants, specifically non-steroidal anti-inflammatory pharmaceuticals, in wastewater treatment plants. The concentration of these micropollutants in nature is a matter of interest, since it is currently not known how much of these pollutants are treated in the wastewater treatment plants. 
There are various treatment methods in the literature to minimize the damage caused by the mentioned micropollutants to the environment. Biological treatment processes are highly important in wastewater treatment. Commonly used processes are divided as suspended growth systems (Activated sludge processes, etc.) and biofilm systems (trickling filters, etc.). Nowadays, a significant increase is observed in the studies on hybrid systems which is aimed to combine useful features of both systems in order to increase treatment efficiency and productivity. These systems often integrate features of both suspended growth and biofilm systems, leading to enhanced removal rates of micropollutants and better overall water quality. Hybrid reactors, such as Moving Bed Biofilm Reactors (MBBRs), are particularly notable for their ability to achieve high treatment efficiency while maintaining relatively compact reactor sizes. This has significant implications for both existing wastewater treatment facilities and future designs, especially in areas facing severe water scarcity. Continued research into optimizing these hybrid systems, understanding their operational parameters, and evaluating their long-term effectiveness is crucial for addressing the challenges of micropollutant removal and ensuring sustainable water management practices. MBBR process was developed in Norway by the Norwegian company Kaldnes in the late 1980s and early 1990s. In this system, carrier particles specifically designed to form biofilm move freely within the wastewater. These carriers accelerate the biological treatment process by providing a large surface area for the growth of microorganisms MBBR is a process that is still being improved with its performance, effectiveness, cost, compactness and ease of use. 
The aim of this study is to investigate the treatability of anti-inflammatory micro-pollutants in wastewater in hybrid treatment systems operating for carbon removal and nitrification, and to determine the appropriate operating conditions to improve the hybrid system performance for micro-pollutant removal. The main objectives are; (I) to investigate the fate of micropollutants in hybrid reactors operated under different COD loadings, (II) to evaluate the removal of micropollutants in hybrid systems in comparison with conventional systems. The drug groups naproxen, ketoprofen, diclofenac, indomethacin, ibuprofen and mefenamic acids among anti-inflammatory micropollutants were examined in this study. The experiment was carried out in a laboratory-scale sequence batch reactor (SBR) fed with synthetic domestic wastewater.
Two laboratory-scale cylindrical glass reactors with a working volume of 6 L were used in the setup of control and micropollutant-added control and hybrid reactors, in order to examine the removal of micropollutants with 150 and 400 mg COD/L feeding conditions). The systems were operated at a sludge age of 10 days and a constant temperature of 20±2°C. While establishing the hybrid reactors (MBBR), aquaflex brand was selected and was operated at a rate of 30%. The control reactors were operated for 217 days, and the hybrid reactor with micropollutants was operated for 150 days. 10 µg/L for naproxen and ibuprofen and 1 µg/L for mefenamic acid, ketoprofen, diclofenac and indomethacin were used for acclimation in the micropollutant-added reactors.
The reactors were operated in two cycles, and in each cycle, a substrate equivalent to 150 mg COD/L and a nitrogen content of 30 mg N/L. The suspended solid and volatile suspended solid concentrations of the control and micropollutant-added hybrid reactors were approximately 1050 mg SS/L and 935 mg SS/L, respectively; It was measured as 798 mg VSS/L and 837 mg VSS/L. VSS/SS ratio was calculated as 0.79 and 0.88, respectively. The dissolved effluent COD value in both reactors is below 30 mg/L. Ammonia nitrogen concentration was measured below 8 mg/L NH4-N in the effluent.
Other reactor was operated in two cycles, and in each cycle, a substrate equivalent to 400 mg COD/L, only. For 400 mg COD/L systems, the suspended solid and volatile suspended solid concentrations of the control and micropollutant-added hybrid reactors were approximately 3550 mg SS/L and 4555 mg SS/L, respectively; It was measured as 2670 mg VSS/L and 3545 mg VSS/L. VSS/SS ratio was calculated as 0.75 and 0.78, respectively. The dissolved effluent COD value in both reactors is below 50 mg/L.
Carbon removal was successfully achieved in laboratory scale moving bed biofilm reactors (MBBR) fed with two different COD concentrations. In terms of nitrification process, both the system with low COD (150 mg COD/L) and the system with high COD (400 mg COD/L) were successful. In the 400 mg/L COD control reactor, the average effluent nitrite and nitrate nitrogen concentrations were 5.8 mg N/L and 45.8 mg N/L, respectively. In the reactor with MK addition, effluent nitrite nitrogen and nitrate nitrogen concentrations were measured as 5.4 mg N/L and 45.3 mg N/L, respectively. In the control reactor containing 150 mg COD/L, effluent nitrite and nitrate concentrations were 3.3 mg N/L and 44.7 mg N/L, respectively. In the reactor with MK addition, effluent nitrite and nitrate concentrations were <0.1 mg/L and 45.7 mg/L, respectively. It can be said that the addition of micropollutants has no negative effect on the nitrification process at the micropollutant mixture concentrations used in the study. It was observed that micro-pollutants except diclofenac had high removal efficiencies in moving bed biofilm reactors operated at laboratory scale. Diclofenac removal was achieved in the range of 54-69%.
In the control and MK-added hybrid reactors, the biomass accumulated on the carrier since the installation of the reactor was regularly monitored in the samples taken at regular intervals. For 400 mg COD/L reactor, while the biomass retention on the carrier was not visible in the first month, it was observed that there was a visible biomass retention afterwards. After the 62nd day, the solids measured as 49 mg increased over time and reached an average of 358 mg after the 209th day. From day 209, MK was started to be added to the control reactor and continued to be operated until 365 days. Since there were 190 carriers in total in the reactor, it can be said that approximately 68 g of biomass was retained on the carriers. In addition to the suspended solids value in the hybrid reactor, it was understood that there was 11350 mg/L of biomass retained on the carriers. For 150 mg COD/L reactor, after day 62, the solids measured as 3.03 mg increased over time and reached an average of 43.8 mg after day 209. From day 209, MK was started to be added to the control reactor and continued to be operated until 365 days. Since there were 190 carriers in total in the reactor, it can be said that approximately 7.77 g of biomass was retained on the carriers. It was understood that in addition to the suspended solids value in the hybrid reactor, there was 1295 mg/L of biomass retained on the carriers. These values are very low compared to the system with 400 mg/L COD feed.
The obtained results showed that anti-inflammatory micropollutants (Ibuprofen, naproxen, ketoprofen, indomethacin, mefenamic acid and diclofenac) for selected concentrations did not have a chronic inhibitory effect on the biodegradation of organic matter and the nitrification process.