Batch experiments were carried out to study the performances of three kinds of nitrification sludge of seeding sludge (S1) and nitrification sludge (S2 and S3) taken from a bioreactor run with inorganic or organic ammonia containing wastewater for a long time. The performances of seeding sludge (S1) were set as control, and the nitrification sludge (S2) showed a higher ammonia oxidation rate, a larger half saturation constant, a stronger tolerance to nitrite, a higher nitrite oxidation rate and an average nitrite accumulation of (63.58±4.19)%. The produced nitrite could be further oxidized into nitrate. The nitrification sludge (S3) had a lower ammonia oxidation rate, a smaller half saturation constant, a weaker tolerance to nitrite, a lower nitrite oxidation rate and an average nitrite accumulation of (92.17±2.67)%. The produced nitrite concentration came to stable because it could not been oxidized into nitrate. The ratio of maximum specific ammonia oxidation rate to half saturation constant (Rma/KSa) showed that the activity of nitrite bacteria in both nitrification sludge S2 and S3 was increased.
