HRT对A/O-BF处理低碳氮比农村生活污水脱氮的影响

通过四组平行小试装置，研究空床水力停留时间(HRT)对缺氧/好氧生物滤池(Anoxic/oxic biofilter，A/O-BF)去除低碳氮比(C/N)农村生活污水中氮的影响；结合高通量测序，研究了不同HRT条件下的脱氮效能和微生物群落变化特征，优选出最佳HRT.结果表明:①缺氧段HRT为6 h的条件下，好氧段HRT为9和10 h时，A/O-BF对NH₄+-N和TN的平均去除率均分别为99%和75%，显著高于HRT为7 h(分别为93%和66%)和8 h(分别为96%和70%)时的情况.②好氧段HRT为9 h的条件下，缺氧段HRT为6 h时，A/O-BF对TN的平均去除率为78%，明显高于HRT为4 h(59%)、稍高于HRT为5 h(74%)和7 h(75%)时的情况.③好氧段HRT为9 h时，其硝化菌属Nitrosomonas和Nitrospira的总丰度占11.42%，明显高于HRT为7 h(4.61%)、8 h(7.39%)和10 h(7.64%)时的情况.④缺氧段HRT为6 h时，其主要的反硝化菌属Denitratisoma占5.83%，明显高于HRT为4 h(0.81%)、5 h(2.90%)和7 h(3.27%)时的情况.研究显示，HRT影响A/O-BF的脱氮效能和微生物群落分布特征，处理低碳氮比(1.4~3.0)农村生活污水时，A/O-BF好氧段和缺氧段的最佳HRT分别为9和6 h. 

Effects of HRT on A/O-BF Nitrogen Removal of Low C/N Rural Domestic Sewage

Four sets of bench-scale anoxic/oxic biofilters (A/O-BF) were set up to study the influence of hydraulic retention time (HRT) on the nitrogen removal from simulated low carbon-to-nitrogen (C/N) ratio rural domestic sewage. Combined with the high-throughput sequencing method, the characteristics of nitrogen removal efficiency and microbial communities were extensively investigated at different HRTs, and the best HRT for the anoxic and oxic column of A/O-BF was recommended. The results were as follows: (1) When the HRT of anoxic column maintained at 6 h, the average NH₄+-N and TN removal efficiency of A/O-BF was 99% and 75% at 9 h and 10 h HRT in the oxic column, which was significantly higher than those at 7 h (93% and 66%) and 8 h (96% and 70%) HRT. (2) When the HRT of the oxic column was 9 h, the TN removal efficiency of A/O-BF was 78% at 6 h HRT in the anoxic column, which was significantly higher than that at 4 h (59%) and slightly higher than that at 5 h (74%) and 7 h (75%) HRT. (3) The total proportion of Nitrosomonas and Nitrospira in the oxic column at 9 h (11.42%) HRT was significantly higher than that at 7 h (4.61%), 8 h (7.39%) and 10 h (7.64%) HRT. The proportion of the major denitrifying bacteria, i.e. Denitratisoma in the anoxic column at 6 h (5.83%) HRT was significantly higher than that at 4 h (0.81%), 5 h (2.90%) and 7 h (3.27%) HRT. (4) The nitrogen removal efficiency and microbial community distribution of A/O-BF were influenced by the HRT, and 9 h and 6 h were the optimum HRT for the oxic and anoxic column of A/O-BF during the treatment of rural domestic sewage with low C/N ratio.