Thermo-Lability of Nitrifying Activity in Biological Aerated Filter

The effect of temperature on nitrification in a two-stage BAF system used for the treatment of ammonia-rich river water was investigated. The rapid increase of water temperature in spring induced a decrease of the ammonia removal efficiency. However, when the water temperatures were equal to or above 5?℃, there was no sign of adverse effect of temperature rise on nitrification. The short-term temperature effects on the activity of nitrifying biofilm acclimated to very cold temperature (about 0.5?℃) and to moderate temperature (15?℃) were also investigated. The results indicated the former activity was seriously affected by the increase of temperature, but the latter activity was not thermo-labile. The cold-adapted response should be seriously considered to model the temperature effect on nitrification in a BAF system. Temperature effect on nitrification became more profound at lower temperature.