智能化曝气控制A/O工艺活性污泥特性演化对内源反硝化脱氮的作用机制

将新型智能化曝气控制系统（automatic oxygen supply device，AOSD）应用于A/O工艺中，对比分析AOSD系统曝气模式控制下的A/O工艺（I-A/O）与常规曝气模式A/O工艺（C-A/O）对活性污泥驯化作用、微生物菌群的分布影响，深入探讨I-A/O活性污泥特性演化对内源反硝化脱氮的作用机制.结果表明I-A/O系统出水NH₄⁺-N、NO₂^--N出现一定积累效应，活性污泥在驯化过程中表现为更为显著的微膨胀，在外源碳素充盈状况下能更充分地将污泥混合液中的溶解性COD（SCOD）富集，将其转化为糖原（Gly），并在外源碳素供应匮乏的状况下激发内源反硝化脱氮反应，内源反硝化速率（EDNR）平均可达0.83 mg·（L·h）^-1，超过C-A/O水平.通过Illumina HiSeq高通量测序技术对两系统污泥微生物群落结构解析：两系统污泥微生物群落多样性评估区别不明显，而I-A/O污泥中Candidate division TM7大量增殖是构成其丝状菌污泥微膨胀、Gly贮存能力提高的优势功能菌.AOSD的供氧模式使活性污泥特性与微生物群落在适应新环境上发生了特异性变化，好氧异养菌代谢活性下降，内源反硝化脱氮途径的强化使I-A/O实现了一种总体低氧需求的动态平衡状态.

Mechanism of Action of Activated Sludge Properties in Nitrogen Removal by Endogenous Denitrification Through an Intelligent Aeration-controlled A/O Process

In order to evaluate the mechanism of action of activated sludge properties in nitrogen removal by endogenous denitrification (henceforth EDNR), a new kind of automatic oxygen supply device(AOSD), was applied to the A/O process. The domestication effect of the aeration mode on the activated sludge properties and microbial communities was investigated under the intelligent aeration-controlled A/O process (I-A/O)and the continuous aeration A/O process (C-A/O). The results demonstrated that the effluent NH₄⁺-N and NO₂^--N components showed obvious accumulation efficiencies and activated sludge generated conspicuous limited bulking in the I-A/O process. Domesticated sludge in the I-A/O process was able to enrich more SCOD to transfer into the polymeric substances as Gly, under a rich exogenous carbon supply state, and stimulated nitrogen removal by endogenous denitrifying under a scarce exogenous carbon supply state. The EDNR rate went up to 0.83 mg·(L·h)^-1 in the I-A/O process, which was more than that achieved by the C-A/O process. The microbial communities in the two processes were evaluated by the Illumina HiSeq high-throughput sequencing technology. The results showed that there was no obvious difference in the sludge microbial community diversity between the two processes, but the Candidate division TM7 proliferated in the I-A/O process, and become the abundant taxa to prompt limited filamentous sludge bulking and Gly storage capability enhancement. The oxygen supply mode of AOSD made the activated sludge properties and microbial communities to be screened selectively in the new environment, aerobic heterotrophic bacterial activity to decline, and endogenous denitrifying action to strengthen, which made the I-A/O process implement a kind of dynamic balanced state that limited the DO demand.