This study investigated soluble organic nitrogen (sON) activity in batch reactors mimicking nitrifying moving bed biofilm reactors (MBBRs). This work was divided into two objectives focusing on the production and degradation of sON, respectively. For the first objective, a synthetic feed that did not contribute any organic nitrogen was used and results indicated that irrespective of the presence of influent organic carbon (0 versus 400 mg COD/L) in the reactors, sON was contributed by the biofilm during nitrification. Although net production of sON was observed, both production and ammonification coexisted which regulated the sON concentration. For the second objective, actual wastewater was fed to the reactors to investigate sON degradation under different carbon to nitrogen (C/N) ratios. A higher concentration of sON was biodegraded in the reactor when fed with influent containing a lower C/N ratio. Overall results suggested that organic carbon bioavailability and/or ammonia concentration influenced the production and ammonification of sON. This study is the first to explore the sON activity by MBBR biofilm and findings from this work could extend the knowledge on the fixed film process with respect to sON activity to regulate and optimize reactor operation in meeting stringent total nitrogen discharge limits.

这项研究调查了模拟硝化移动床生物膜反应器（MBBR）的间歇式反应器中的可溶性有机氮（sON）活性。这项工作分为两个目标，分别侧重于sON的产生和降解。对于第一个目标，使用不贡献任何有机氮的合成饲料，结果表明，无论是否存在进水有机碳（0对400 在反应器中，SON是硝化过程中生物膜的贡献。尽管观察到sON的净产生，但是调节sON浓度的产生和氨化并存。为了第二个目标，将实际废水进料到反应器中，以研究在不同碳氮比（C / N）下sON的降解。当进料含较低C / N比的进水时，反应器中较高浓度的sON会被生物降解。总体结果表明，有机碳的生物利用度和/或氨浓度会影响sON的产生和氨化。