IFAS工艺处理南方低碳源污水的泥膜微生物互作规律分析

针对低碳源条件下污水处理问题，开展了活性污泥和生物膜共生系统（IFAS）的实验研究，讨论了低碳源下泥膜两相微生物的赋存特征和互作规律，明确其生态位和对处理效能的影响，通过实际水厂的中试实验，分析生物膜挂膜特性、泥膜活性和菌群的演替规律，对比在不同活性污泥泥龄调控下的泥膜两相中微生物结构和相互作用.结果表明，在变SRT下，反应器内污泥浓度随着SRT的增大而增加；由于SRT-H中微生物浓度远大于SRT-L，因此SRT-H中泥膜之间的竞争关系较SRT-L更激烈，SRT-H中污染物去除效能较SRT-L更低.低碳源进水条件下，IFAS工艺中污泥活性随SRT增大而降低，当低SRT （5 d）条件下，活性污泥硝化、反硝化、聚磷和吸磷速率较高SRT （25 d）分别增加了122%、88%、34%和44%；而SRT对生物膜活性的影响较小，两种SRT下生物膜硝化活性、反硝化活性相差不大.微生物测序分析表明，IFAS工艺功能菌在泥膜两相间会随着SRT的变化而发生富集转移；SRT-L中，因"播种（seeding）"效应而在泥膜两相间发生富集转移的功能菌主要为unclassified_g__Enterobacteriaceae，SRT-H中则主要是Acinetobacter.同时，通过分析优势功能菌分布，发现活性污泥中脱氮菌和聚磷菌之间也存在一定竞争；在进水有机基质匮乏的条件下，脱氮菌的相对丰度明显高于聚磷菌的相对丰度，表明脱氮菌更能适应低碳源条件，所以能在竞争中占据优势地位，这种优势主要体现为好氧反硝化菌相对丰度的增加；此外，泥相的SRT变化会反作用于膜相，使得生物膜的停留时间相应发生改变，从而改变菌群结构，筛选出不同优势菌属，进一步加大差异.

Analysis of Microbial Interaction Law of Mud Membrane in IFAS Process for Treating Low Carbon Source Sewage in South China

To assess the problem of sewage treatment under the condition of low carbon sources, we carried out a study of activated sludge and a biofilm symbiosis system (IFAS). The occurrence characteristics and interaction law of microorganisms in two phases of sludge membrane under low carbon source conditions were discussed, and their niche and influence on treatment efficiency were clarified. Through a pilot-scale experiment in actual water plants, the biofilm characteristics, sludge membrane activity, and succession law of flora were analyzed, and the microbial structure and interaction in sludge membrane in two phases under the control of different activated sludge ages were compared. The results showed that the sludge concentration in the reactor increased with the increase in SRT under variable SRT. Because the microbial concentration in SRT-H was much higher than that in SRT-L, the competition between mud films in SRT-H was more intense than that in SRT-L, and the pollutant removal efficiency in SRT-H was lower than that in SRT-L. Under the condition of low-carbon feed water, the sludge activity in the IFAS process decreased with the increase in SRT. Under the condition of low SRT(5 d), the nitrification, denitrification, phosphorus accumulation, and phosphorus absorption rate of activated sludge increased by 122%, 88%, 34%, and 44%, respectively, compared with that of high SRT (25 d). However, SRT had little effect on biofilm activity, and there was little difference in nitrification activity and denitrification activity between the two SRTs. Microbial sequencing analysis showed that the functional bacteria of the IFAS process were enriched and transferred with the change in SRT between the two phases of mud membrane. In SRT-L, the functional bacteria that were enriched and transferred between the two phases of mud film owing to the "seeding" effect were mainly unclassified_g__Enterobacteriaceae, whereas in SRT-H, Acinetobacter was mainly used. At the same time, by analyzing the distribution of dominant functional bacteria, it was found that there was some competition between denitrifying bacteria and phosphorus-accumulating bacteria in activated sludge. Under the condition of a lack of organic substrate in the influent, the relative abundance of denitrifying bacteria was obviously higher than that of phosphorus-accumulating bacteria, which indicated that denitrifying bacteria could better adapt to low-carbon source conditions. Thus, they could occupy a dominant competition position, which was mainly reflected in the increase in the relative abundance of aerobic denitrifying bacteria. In addition, the SRT change in the mud phase reacted in the membrane phase, making the residence time of biofilm change correspondingly, thus changing the flora structure, screening out different dominant bacteria genera, and further increasing the difference.