NaCl盐度对氨氧化细菌活性的影响及动力学特性

含盐废水的硝化过程常常出现亚硝酸盐积累,NaCl盐度对氨氧化菌(AOB)活性的影响与动力学特性并不清楚.采用高浓度氨氮污水富集培养AOB,并成功实现短程硝化.对富含AOB的污泥进行荧光原位杂交技术(FISH)分析表明AOB占细菌总数比例为(55±7)%.污泥的最大比氨氧化速率为(0.92±0.13)gN/(gVSS·d).用此污泥考察了NaCl盐度对AOB活性的影响,并测定了10g/L时AOB的动力学参数(KNH3、Ko).试验结果表明,与盐度为0g/L时的AOB活性相比,盐度为15g/L时的AOB活性降低了37%;盐度为30g/L时降低了85%.盐度为10g/L时,AOB的最大比氨氧化速率为(0.62 ± 0.03)gN/(gVSS·d),底物半饱和常数KNH3值为(7.62 ± 0.13)mg/L,氧的半饱和常数Ko值为(0.39 ± 0.04)mg/L,其中KNH3测定值高于ASM2模型推荐值.NaCl盐度对AOB的抑制降低了最大比氨氧化速率,对底物(NH4+-N)传递存在影响.

Effect of NaCl salinity on activity of ammonia-oxidizing bacteria and kinetic characterization

Nitrite accumulation was always observed in the saline wastewater nitrification process, but the effect of NaCl salinity on ammonia-oxidizing bacteria (AOB) activity and kinetic characterization has not been clear. In this study, AOB was enriched in a lab-scale SBR system with high concentration of ammonium wastewater, and the partial nitrification was successfully achieved. The fluorescence in situ hybridization (FISH) analysis showed that AOB accounted for (55 ± 7)% of total bacteria. The maximum specific ammonia oxidation rate was (0.92 ± 0.13)gN/(gVSS·d). The effect of NaCl salinity on AOB activity was investigated using this mixed culture. The kinetic parameters of AOB (KNH3、Ko) were also measured under NaCl salinity of 10g/L. Results showed that compared with NaCl salinity 0g/L, the activity of AOB decreased 37% under NaCl salinity of 15g/L and decreased 85% under NaCl salinity of 30g/L. When salinity was 10g/L, the maximum ammonia oxidation rate was (0.62 ± 0.03)gN(gVSS·d), the half-saturation constant for ammonia (KNH3) was (7.62±0.13)mg/L, the half-saturation constant for oxygen (Ko) was (0.39±0.04)mg/L. The KNH3 value was higher than recommended value of ASM2model. NaCl salinity could reduce maximum specific ammonia oxidation rate, and also affects the substrate (ammonia) affinity of AOB.