Effects of Ammonia Loading on Nitrification in a Biological Fluidized Bed Reactor

초록

The effect of ammonia loading on nitrification, especially on nitrite build-up, in an activated carbon fluidized bed reactor was investigated by increasing the ammonia loading rate stepwise from 0.1 to 7.5 kg NH4-N/m3-day. Although effluent nitrite concentration and nitrification efficiency fluctuated at the loading rate above 1.8 kg NH4-N/m3-day, an average nitrification efficiency of 87% was achieved. Nitrite build-up began at the ammonia loading rate of 1.8 kg NH4-N/m3-day, at which the free ammonia concentration was estimated to be above 1 mg/L. During the nitrite build-up, the ratio of influent NH4-N concentration to the DO of the reactor mixed liquor was measured to be above 100. Considering the advantages of nitritation/denitrification, a fluidized bed reactor could be an effective means for biological nitrification of wastewaters with high ammonia concentration.