Ototrofik denitrifikasyon, sülfat ındirgeme ve sülfür oksidasyonu sıralı sistemi ile yeraltı sularından nitratın ve sülfatın birlikte giderimi
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Tarih
2023
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Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Ülkemizde yeraltı sularında gözlemlenen en yaygın kirletici nitrat olup TS266'da belirtilen değerlerin 5–10 kat üzerinde nitrat gözlenmektedir. Tamamlanan tez daha önce tez danışmanının tamamlamış olduğu 113Y023 ve 117Y014 nolu projelerin nitrat ile ilgili kısımları için bir devam niteliği taşımaktadır. Bu bağlamda kükürt bazlı denitrifikasyonla yüksek nitrat giderimi sağlanırken çıkış suyundaki sülfat yine biyolojik bir proses ile kükürt formunda sistem sınırları dışına çıkarılmıştır. Bu amaçla iki adet yukarı akışlı kolon reaktör kurulmuş olup bir reaktörde kükürt bazlı denitrifikasyon gerçekleştirilirken diğer reaktörde ise etanol bazlı sülfat indirgeme gerçekleştirilmiştir. Bu reaktörlerin sıralı bağlanıp sülfat indirgeme reaktöründen denitrifikasyon reaktörüne yapılan geri devirle de kükürt bazlı denitrifikasyon kükürt/sülfür bazlı olarak işletilmiştir. Yapılan geri devir ile aynı zamanda sülfat indirgeme reaktöründe üretilen alkalinite, denitrifikasyon reaktöründe kullanılmıştır. Sülfat indirgeme reaktörü çıkışından bir kısım çıkış suyu geri devir ile denitrifikasyon reaktörüne gönderilirken diğer kalan kısım ise sınırlı miktarda havalandırma ile kısmi oksidasyona tabi tutularak sülfürün kükürt formunda çökelek oluşturması sağlanmıştır. Çalışmada 100 mg NO3--N/L kükürt/sülfür bazlı denitrifikasyon ile indirgenmiştir. Teorik olarak kükürt bazlı denitrifikasyonda 754 mg/L sülfat oluşması beklenirken sistemin (1) sülfür bazlı olarak işletilmesi ve (2) sistemede bir sülfat indirgeme ve kısmi oksidasyon ile sülfürün kükürt olarak sistemi terk etmesinin sağlanması nedeni ile çıkış suyunda sülfat konsantrasyonu TS 266'da belirtilen seviyenin altında tutulmuştur. Test edilen son periyotta 100 mg NO3--N/L yanında 500 mg/L'de sülfat giriş suyuna eklenmiş ve çıkış suyunda nitrat tamamen giderilirken sülfat konsantrasyonu 25.2±28.9 mg/L seviyesinde tutulmuştur. Hem sülfatın hem de nitratın biyolojik olarak sistem sınırları dışına çıkarılması açısından bu tez bir ilktir.
Nitrate is the most common pollutant observed in groundwater in our country, and observed 5-10 times higher than the levels specified in TS266. The completed thesis is a continuation of the nitrate-related parts of the projects 113Y023 and 117Y014, which were previously completed by the thesis advisor. In this context, while high nitrate removal is achieved with sulfur-based denitrification, the sulfate in the effluent is removed from the system boundaries in the form of elemental sulfur with a biological process. For this purpose, two up-flow column reactors were established and sulfur-based denitrification was carried out in one reactor and ethanol-based sulfate reduction was carried out in the other reactor. Sulfur-based denitrification was operated on a sulfur/sulfide-based by sequentially connecting these reactors and recycling from the sulfate reduction reactor effluent to the denitrification reactor. The alkalinity produced in the sulfate reducing reactor was used in the denitrification reactor. While some of the effluent from the reducing reactor effluent was recycled to the denitrification reactor, the remaining portion was subjected to partial oxidation with limited aeration, allowing the sulfide to precipitate in the form of elemental sulfur. In the thesis, 100 mg of NO3--N/L was reduced by sulfur/sulfide-based denitrification. While theoretically 754 mg/L sulfate is expected to form in elemental sulfur-based denitrification, the sulfate concentration in the effluent was below the level specified in TS 266 due to the fact that (1) the system is operated on a sulfur basis and (2) a sulfate reduction and partial oxidation in the system allows the sulfur to leave the system as sulfur. In the last period tested, besides 100 mg NO3--N/L, 500 mg/L sulfate was added to the system feed. Nitrate was completely removed from the effluent, while the sulfate concentration was kept at 25.2±28.9 mg/L. This thesis is a first in terms of removing both sulfate and nitrate out of the system boundaries biologically.
Nitrate is the most common pollutant observed in groundwater in our country, and observed 5-10 times higher than the levels specified in TS266. The completed thesis is a continuation of the nitrate-related parts of the projects 113Y023 and 117Y014, which were previously completed by the thesis advisor. In this context, while high nitrate removal is achieved with sulfur-based denitrification, the sulfate in the effluent is removed from the system boundaries in the form of elemental sulfur with a biological process. For this purpose, two up-flow column reactors were established and sulfur-based denitrification was carried out in one reactor and ethanol-based sulfate reduction was carried out in the other reactor. Sulfur-based denitrification was operated on a sulfur/sulfide-based by sequentially connecting these reactors and recycling from the sulfate reduction reactor effluent to the denitrification reactor. The alkalinity produced in the sulfate reducing reactor was used in the denitrification reactor. While some of the effluent from the reducing reactor effluent was recycled to the denitrification reactor, the remaining portion was subjected to partial oxidation with limited aeration, allowing the sulfide to precipitate in the form of elemental sulfur. In the thesis, 100 mg of NO3--N/L was reduced by sulfur/sulfide-based denitrification. While theoretically 754 mg/L sulfate is expected to form in elemental sulfur-based denitrification, the sulfate concentration in the effluent was below the level specified in TS 266 due to the fact that (1) the system is operated on a sulfur basis and (2) a sulfate reduction and partial oxidation in the system allows the sulfur to leave the system as sulfur. In the last period tested, besides 100 mg NO3--N/L, 500 mg/L sulfate was added to the system feed. Nitrate was completely removed from the effluent, while the sulfate concentration was kept at 25.2±28.9 mg/L. This thesis is a first in terms of removing both sulfate and nitrate out of the system boundaries biologically.
