游离亚硝酸抑制硝化杆菌属(Nitrobacter)活性动力学研究

Inhibitory kinetics of free nitrous acid on Nitrobacter

为探究游离亚硝酸(FNA)对亚硝酸盐氧化细菌中硝化杆菌属(Nitrobacter)活性抑制动力学影响,采用序批式活性污泥(SBR)反应器,在通过改变系统进水FNA浓度达到富集Nitrobacter基础上,以富含Nitrobacter污泥为对象(宏基因组物种注释和丰度分析显示上Nitrobacter占细菌总数40.3%),基于批次试验,考察不同FNA浓度梯度下亚硝酸盐氧化过程比亚硝态氮氧化速率(SNiOR)变化规律,进而拟合FNA抑制Nitrobacter活性抑制动力学模型,并进行统计学分析.结果表明,当FNA≤0.1mg/L时,随着FNA浓度升高,SNiOR迅速升高.当FNA>0.1mg/L时,SNiOR随着FNA浓度升高而降低.尤其当FNA浓度高于0.7mg/L时,SNiOR始终维持在0gN/(gVSS·d),表明Nitrobacter活性统被完全抑制.统计学分析结果显示相对于Haldane、Aiba、Edwards-1#、Edwards-2#、Luong抑制动力学模型,Han-Levenspiel模型最适合描述FNA对Nitrobacter活性的抑制影响.其统计学常数:残差平方和(RSS)为0.02、可决系数(R^2)为0.90、拟合方程的方差检验统计量F值为78.1、可信度P值为3.29×10^(-12),其动力学常数值分别为:最大比亚硝态氮氧化速率(r_(max))为1.57gN/(gVSS·d);半饱和常数(K_S)为0.01mg/L;临界抑制常数(Sm)为0.66mg/L.

A sequencing batch reactor(SBR)was operated in this study to investigate the inhibitory kinetics of free nitrous acid(FNA)on Nitrobacter.At the beginning of the experiment,FNA concentration in influent was changed to enrich Nitrobacter.Then,the sludge of enrichment Nitrobacter was employed to study the variation law of the specific nitrite oxidation rate(SNiOR)during nitrite oxidation process of batch tests.Meanwhile,metagenomic species annotation and abundance analysis showed that Nitrobacter accounted for 40.3%of the total bacterial population.Furthermore,kinetic model of FNA inhibition on Nitrobacter activity was fitted for statistical analysis.The results showed that the SNiOR increased rapidly with the increase of FNA concentration when≤0.1·mg/L while decreased with the increase of FNA concentration as FNA>0.1mg/L.In particular,the SNiOR was maintained at 0gN/(gVSS·d)when FNA concentration was higher than 0.7mg/L,implying that Nitrobacter activity was completely inhibited.Statistical analysis results showed that compared to Haldane,Aiba,Edwards-1#,Edwards-2#and Luong inhibition kinetics models,Han-Levenspiel model was the most suitable one for describing the inhibitory effect of FNA on Nitrobacter activity.The statistical constants,e.g.,residual square sum(RSS)correlation coefficient(R2),F value of the analysis of variance and confidence degree(P)was 0.02,0.90,78.1and 3.29×10-12,respectively.The dynamic constant values,e.g.,maximum specific nitrite oxidation rate(rmax),half saturation constant(KS)and critical inhibition constant(Sm)was 1.57gN/(gVSS·d),0.01mg/L and 0.66mg/L,respectively.