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암모니아 폐수의 부분아질산화에서 최적 운전 pH의 변동 |
배우근, Hammad Khan |
한양대학교 건설환경공학과 |
Variation of Optimum Operational pH in Partial Nitritation |
Wookeun Bae, Hammad Khan |
Department of Civil and Environmental Engineering, Hanyang University |
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Received: February 26, 2016; Revised: March 14, 2016; Accepted: March 25, 2016. Published online: May 31, 2016. |
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ABSTRACT |
Nitrite accumulation is essential for constructing an anammox process. As the pH in the reactor exerts a complicated and strong influence on the reaction rate, we investigated its effects upon treatment of an ammonic wastewater (2,000 mgN/L) through modeling and experiment. The modeling results indicated that the reaction stability is strongly affected by pH, which results in a severe reduction of the ‘stable region’ of operation under alkaline environments. On a coordinate of the total ammonia nitrogen (TAN) concentration vs. pH, the maximal stable reaction rates and the maximal nitrite accumulation potentials could be found on the ‘stability ridge’ that separates the stable region from the unstable region. We achieved a stable and high ammonia oxidation rate (~6 kgN/m3-d) with a nitrite accumulation ratio of ~99% when operated near the ‘stability ridge’. The optimum pH that can be observed in experiments varies with the TAN concentrations utilized, although the intrinsic optimum pH is fixed. The direction of change is that the optimum operational pH falls as the TAN concentration increases, which is in excellent accordance with the observations in the literature. The optimum operational pH for 95% nitritation was predicted to be ~8.0, whereas it was ~7.2 for 55% partial nitritation to produce an anammox feed in our experimental conditions. |
Key Words:
Ammonia, Nitritation, Nitrite Accumulation Potential, Optimum pH, Reaction Stability |
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