Process of inorganic nitrogen transformation and design of kinetics model in the biological aerated filter reactor

As one of the plug-flow reactors, biological aerated filter (BAF) reactor was divided into four sampling sectors to understand the characteristics of elemental nitrogen transformation during the reaction process, and then the different characteristics of elemental nitrogen transformation caused by different NH3–N loadings, biological quantities and activities in each section were obtained. The results showed that the total transformation ratio in the nitrifying reactor was more than 90% in the absence of any organic carbon resource, at the same time, more than 65% NH3–N in the influent were nitrified at the filter height of 70 cm below under the conditions of the influent runoff 9–19 L/h, the gas–water ratio 4–5:1, the dissolved oxygen 3.0–5.8 mg/L and the NH3–N load 0.28–0.48 kg NH3–N/m3 d. On the base of the Eckenfelder mode, the kinetics equation of the NH3–N transformation along the reactor was Se = S0 exp(−0.0134D/L1.2612).