硫自养反硝化过程中含硫副产物产生规律及微生物群落结构的空间分布

为探究硫自养反硝化过程中含硫副产物的产生规律，建立了上流式硫自养固定床生物反应器，考察HRT（水力停留时间）对水中NO₃--N去除的影响，运用零级和1/2级反应动力学模型对NO₃--N还原过程进行拟合，通过测定与理论计算分析含硫副产物的产生趋势及规律，利用高通量测序技术（high-throughput sequencing）测定微生物群落结构空间分布特征.结果表明:①当进水NO₃--N浓度为（30.45±0.38）mg/L，HRT为4和1 h时，NO₃--N去除率达到98%以上.硫自养反硝化过程符合1/2级反应动力学模型，1/2K_1/2V（1/2级反应动力学速率常数）为5.69 mg1/2/（L1/2·h）.②出水SO₄2-的产生量接近理论值，S2-在反应器中部出现微量的积累，在出水口处浓度进一步降低（< 0.5 mg/L）.③HRT的缩短改变了反应器内部微生物群落α多样性的变化规律；Proteobacteria成为了最主要的优势菌群，各阶段所占比例均大于59%，Sulfurimonas为最常见的反硝化菌，在HRT为1 h时，反应器中部其丰度达到36%，成为反应器中的优势菌属；Desulfurella为SRB（硫酸盐还原菌），其丰度的增加与反应器内部S2-的积累一致.研究显示，硫自养反硝化过程中产生的SO₄2-与理论值接近，S2-产生量沿反应器高度方向呈现先增加后降低的趋势，微生物群落结构分布情况与反应器高度有关. 

Production Rule of Sulfur By-Products in Sulfur Autotrophic Denitrification and Microbial Community Special Distribution Analysis

Sulfur-autotrophic reduction of nitrate from water by up-flow packed bed reactor was investigated to explore the generation regularity of sulfur by-products. The effect of hydraulic retention time (HRT) on NO₃--N removal was examed. The NO₃--N removal kinetics was fitted with the zero-order and half-order kinetics models. The generation trend of sulfur by-products was analyzed by experimental results and theoretical calculation. High-throughput sequencing was used to reveal the microbial community spatial distribution. The results showed that:(1) The removal efficiency was more than 98% when NO₃--N was at (30.45±0.38)mg/L in the influent and HRT shortened from 4 h to 1 h. Half-order kinetics model fits the experimental data well with 1/2K_1/2V at 5.69 mg1/2/(L1/2·h); (2) The SO₄2- production in the effluent was in line with the theoretical value. Trace of S2- was accumulated in the reactor and further decreased in the effluent (< 0.5 mg/L); (3) The shortened HRT changed the α-biodiversity of the microbial community. Proteobacteria was the dominant bacteria, and its proportion in each stage was greater than 59%. Sulfurimonas was the most common denitrifying bacterium and its abundance at 1 h was 36%, then became the dominant species. The increase of sulfate-reducing bacterium (Desulfurella) abundance was consistent with the accumulation of S2-. The SO₄2- concentration in the effluent was in good agreement with the theoretical value, and the S2- concentration displayed the tendency of rising up with the reactor height and then decreasing in the effluent. The distribution of microbial community structure was related to reactor height.