Department of Civil Engineering, University of Manitoba, Canada.
Chemosphere. 2012 Jun;88(2):188-95. doi: 10.1016/j.chemosphere.2012.02.085. Epub 2012 Apr 6.
Using a bench scale moving bed bioreactor (MBBR), the effect of free ammonia (FA, NH(3), the un-ionized form of ammonium NH(4)(+)) concentration on anoxic ammonium oxidation (anammox) was evaluated based on the volumetric nitrogen removal rate (NRR). Although, a detailed microbial analysis was not conducted, the major NRR observed was assumed to be by anammox, based on the nitrogen conversion ratios of nitrite to ammonium and nitrate to ammonium. Since the concentration of free ammonia as a proportion of the total ammonia concentration is pH-dependent, the impact of changing the operating pH from 6.9 to 8.2, was investigated under constant nitrogen loading conditions during continuous reactor operation. Furthermore, the effect of sudden nitrogen load changes was investigated under constant pH conditions. Batch tests were conducted to determine the immediate response of the anammox consortium to shifts in pH and FA concentrations. It was found that FA was inhibiting NRR at concentrations exceeding 2 mg N L(-1). In the pH range 7-8, the decrease in anammox activity was independent of pH and related only to the concentration of FA. Nitrite concentrations of up to 120 mg N L(-1) did not negatively affect NRR for up to 3.5 h. It was concluded that a stable NRR in a moving bed biofilm reactor depended on maintaining FA concentrations below 2 mg N L(-1) when the pH was maintained between 7 and 8.
使用批式移动床生物膜反应器（MBBR），根据体积氮去除率（NRR）评估了游离氨（FA，NH3，未离解形式的铵 NH4(+)）浓度对缺氧氨氧化（anammox）的影响。虽然没有进行详细的微生物分析，但根据亚硝酸盐与氨和硝酸盐与氨的氮转化比，假设主要的 NRR 是通过 anammox 实现的。由于游离氨浓度与总氨浓度的比例取决于 pH 值，因此在连续反应器运行期间，在恒定氮负荷条件下，研究了操作 pH 值从 6.9 升高到 8.2 的影响。此外，还研究了在恒定 pH 值条件下突然氮负荷变化的影响。分批试验用于确定 anammox 生物群落在 pH 和 FA 浓度变化时的即时响应。结果发现，FA 的浓度超过 2 mg N L(-1)时会抑制 NRR。在 pH 值为 7-8 的范围内，anammox 活性的下降与 pH 值无关，仅与 FA 的浓度有关。亚硝酸盐浓度高达 120 mg N L(-1)时，在长达 3.5 小时的时间内不会对 NRR 产生负面影响。因此，当 pH 值维持在 7 到 8 之间时，移动床生物膜反应器中稳定的 NRR 取决于将 FA 浓度保持在 2 mg N L(-1)以下。
