NaCl盐度对氨氧化细菌活性的影响及动力学特性

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

含盐废水的硝化过程常常出现亚硝酸盐积累,Na Cl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)g N/(g VSS·d).用此污泥考察了Na Cl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)g N/(g VSS·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.Na Cl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.

Nitrite accumulation was always observed in the saline wastewater nitrification process,but the effect of Na Cl 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）g N/（g VSS·d）. The effect of Na Cl salinity on AOB activity was investigated using this mixed culture. The kinetic parameters of AOB（KNH3、Ko） were also measured under Na Cl salinity of 10g/L. Results showed that compared with Na Cl salinity 0g/L,the activity of AOB decreased 37% under Na Cl salinity of 15g/L and decreased 85% under Na Cl salinity of 30g/L. When salinity was 10g/L,the maximum ammonia oxidation rate was（0.62 ± 0.03）g N（g VSS·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 ASM2 model. Na Cl salinity could reduce maximum specific ammonia oxidation rate,and also affects the substrate（ammonia） affinity of AOB.