Pilot ölçekli bir yapay sulakalan sisteminin arıtma performansının incelenmesi

Özet

Bu çalışmada, pilot ölçekli yapay sulakalan sistemlerinin farklı hidrolik yük (30, 50, 70, 80 ve 120 L $m^{-2} gun^{-1}$) etkisi altındaki amonyum ve nitrat azotu giderim kapasiteleri incelenmiştir. Farklı cinste köklü (Canna, Cyperus, Typhia spp., Phragmites spp., Juncus, Poaceae, Paspalum ve Iris), batık (Elodea, Egeria ve Valisneria) ve yüzücü (Pistia, Salvina ve Lemna) bataklık bitkileri kullanılarak bitkilerin giderim üzerine etkileri ortaya konulmuştur. Yüzeyaltı akışlı (YAAS) ve serbest yüzey akışlı (SYAS) sulakalan sistemlerinin $NH_4^+-N$ ve $NO_3^--N$ arıtma verimleri sırayla; %73 ve %57, %37 ve %58 olarak bulunmuştur. Nitrifikasyon hız sabitleri 0.898 gün-1 (YAAS), 0.541 gün-1 (SYAS) ve denitrifikasyon hız sabitleri 0.486 gün-1 (YAAS), 0.502 $gun^{-1}$ (SYAS) olarak bulunmuştur. Çalışma sonunda elde edilen verilerle birinci dereceden piston akım modeline ve çoklu regresyon ilişkilerine dayanılarak tahmini çıkış değerleri elde edilmiştir. Sonuç olarak çıkış konsantrasyonlarının tahmininde çoklu regresyon modelle daha iyi sonuçlar alınmıştır.

Abstract

In this study, the pilot-scale constructed wetland systems were examined for their capacity to remove ammonium and nitrate nitrogen under different hydraulic loading rates (30, 50, 70, 80 and 120 L $m^{-2} d^-1$) . The effects of the plant species on the removal were investigated by using emergent (Canna, Cyperus, Typhia spp., Phragmites spp., Juncus, Poaceae, Paspalum and Iris), submerged (Elodea, Egeria and Valisneria) and floating (Pistia, Salvina and Lemna) marsh plants at different conditions. The average annual $NH_4^+-N$ and $NO_3^--N$ treatment efficiencies in SSF and FWS wetlands are 73% and 57%, 37% and 58%, respectively. The SSF systems demonstrated better performance for the removal of NH4-N when compared with the FWS systems. The average $NH_4-N$ and $NO_3^--N$ treatment efficiencies in the serial system are approximately 89% and 73%, respectively. These results showed that the serial system enhances nitrogen removal. Nitrification and denitrification removal rate constants (k20) in SSF and FWS sytems have found as 0.898 $d^{-1}$ and 0.541 $d^{-1}$, 0.486 $d^{-1}$ and 0.502 $d^{-1}$ respectively. Two types of the models (first- order plug flow and multiple regression) were tried to estimate the system performances. Regression models for the wetland systems were found to provide better predictions of effluent concentrations than first-order plug flow models. These results show that the first-order plug flow model clearly estimates slightly higher or lower values than observed when compared to the other model. This is the case because the transformations of nitrogen in constructed wetlands are a very complicated and dynamic process and many factors (for example, ammonia volatilisation and plant uptake) directly or indirectly affect the system's treatment performance. Based on this fact, basic kinetic models must be re-worked to include these factors.