Shortcut Nitrification and Denitrification in MBBR controlled by Inhibitor

Abstract

Multi-factor influence on shortcut nitrification in MBBR when dosing methanoic acid-hydrazine2 was studied in this paper. The results showed that, when the influent ammonia was 30 mg/L and pH was 7.5∼8.5, the average nitrite accumulation rate of the reactor without inhibitor (reactor one) and the reactor dosing methanoic acid-hydrazine2 (reactor two) were respectively 80.2% and 98.5%. When the influent ammonia increased to 50 mg/L, the average nitrite accumulation rate of the reactor one and reactor two were respectively 81.0% and 96.1%. When pH decreased to 6.5∼7.0 and other condition unchanged, the average nitrite accumulation rate of reactor one and reactor two were respectively 69.3% and 95.7%. When the pH of the two reactors was 7.5∼8.5 and gradually increase the influent ammonia to 300 mg/L, the average nitrite accumulation rate of reactor one and reactor two were respectively 87.7% and 98.3%. When temperature was 12∼15 °C, the average nitrite accumulation rate of reactor one and reactor two were respectively 72.4% and 96.9%. From the experimental results, we can see that the realization of shortcut nitrification was the result of multi-factor interaction, the change of each factor affects the realization of shortcut nitrification. However, by adding methanoic acid-hydrazine2 combined inhibitor in the reactor could reduce the effect on nitrite accumulation when parameters changed in the system and maintain the relatively stable shortcut nitrification.