Vildan AKGUL, Dilek AKMAN, Yakup CUCİ, Kevser CİRİK

Farklı İşletim Koşulları Altında Tiyosülfat Bazlı Ototrofik ve Miksotrofik Denitrifikasyon Performansının Araştırılması

Bu çalışmanın amacı ototrofik ve miksotrofik denitrifikasyon proses performanslarını etkileyen faktörlerin ardışık kesikli reaktörde araştırılmasıdır. Çalışma verileri ototrofik denitrifikasyon prosesinin karbon içeriği düşük atıksular için gerçek ölçekte uygulanabilirliğine ışık tutmaktadır. Ototrofik denitrifikasyon prosesinde farklı döngü süresi, elektron vericive organik karbon ilavesinin nitrat giderim performansına etkisi sülfat, nitrat, nitrit, ORP ve inorganik karbon parametreleri ile değerlendirilmiştir. Çalışmanın ilk aşamasında farklı döngü sürelerinin (8sa-4sa-2sa) tiyosülfat (S2O3-2) bazlı ototrofik denitrifikasyon prosesine etkisi araştırılmıştır. Daha sonra 2 saatlik optimum döngü süresinde farklı S2O3-2/NO3-oranları (1,5-1,25-1) ile ototrofik denitrifikasyon prosesinin optimizasyon çalışmaları yürütülmüştür. Elde edilen çalışma bulguları göz önünde bulundurulduğunda maksimum %84 nitrat giderim verimi 2 saatlik döngü süresi ve 1,5 S2O3-2/NO3- oranı ile işletilen işletim koşullarından elde edilmiştir. Çalışmanın son aşamasında ise farklı C/N (0,35-0,70-1,05) oranlarının miksotrofik denitrifikasyon performansına etkisi incelenmiştir ve C/N oranın 1,05 olduğu işletim koşulunda nitratın tamamı tüketilirken organik madde kaynağı olarak metanolün artmasıyla nitrat giderim hızının arttığı gözlemlenmiştir.

Anahtar Kelimeler:

Döngü süresi, Miksotrofik denitrifikasyon, S2O3-2/NO3- oranı, Ototrofik denitrifikasyon, Tiyosülfat

Evaluation of Thiosulfate-Based Autotrophic and Mixotrophic Denitrification Performances under Different Operational Conditions

The aim of this study was to investigate the factors affecting the autotrophic and mixotrophic denitrification performances in sequencing batch reactor (SBR). Findings obtained from this study shed light on the full-scale applicability of the autotrophic and mixotrophic denitrification processes in carbon deficient wastewaters. In this study, the effect of cycle time, varying concentrations of electron donor source and the addition of external organic carbon source was evaluated by sulfate, nitrate, nitrite, ORP and inorganic carbon parameters. Firstly, SBR was operated with thiosulfate (S2O32-) based autotrophic denitrification process at different cycle times (8h-4h-2h). Further, autotrophic denitrification process was optimized the under varying S2O32-/NO3- ratios (1.5-1.25-1.0) at the optimum cycle time of 2h. The maximum nitrate removal efficiency of 84% was accomplished at operational conditions containing 2h cycle time and 1.5 S2O32-/NO3- ratio. In the rest of the study,the impact of increasing C/N ratio by methanol supplementation (0.35-0.7-1.05)was evaluated on mixotrophic denitrification performance. It was observed that nitrate was completely consumed at the C/N ratio of 1.05 and nitrate removal rate improved with increasing methanol supplementation as organic carbon source.

Keywords:

Cycle time, Mixotrophic denitrification, S2O3-2/NO3- ratio, Autotrophic denitrification, Thiosulfate,

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