A2/O-BCO系统中碳源类型对反硝化除磷及菌群结构的影响

采用厌氧/缺氧/好氧-生物接触氧化(A²/O - BCO)工艺处理低碳氮(C/N)比污水, 考察单因素碳源(阶段Ⅰ: 乙酸钠; 阶段Ⅱ: 乙酸钠+丙酸钠; 阶段Ⅲ: 丙酸钠)对有机物去除以及同步脱氮除磷的影响, 并重点探究乙酸钠、丙酸钠混合碳源条件下内碳源(PHA、Gly)的转化利用以及反硝化除磷(DPR)机理, 同时通过高通量测序对比了不同阶段微生物菌群结构的演变规律.结果表明: 混合碳源提高了有机物、氮、磷的同步去除效率, 厌氧段内碳源转化量为226mg/h, 释磷量高达30.58mg/L, DPR效率稳定在90%以上; 批次试验表明反硝化聚磷菌(DPAOs)占聚磷菌(PAOs)的比例为72.42%, 基本实现了DPAOs的富集; 高通量测序结果表明混合碳源更有利于形成独特的OTUs菌群, PAOs(包括Accumulibacter和Acinetobacter)和DPAOs (包括Dechloromonas和Pseudomonas)总量高达29.13%(> 16.18%(阶段Ⅲ) > 14.34%(阶段Ⅰ)), 有效促进了碳源的高效利用以及反硝化除磷效率; BCO反应器中氨氧化菌(AOB, 包括Nitrosomonas和Nitrosomonadaceae)和亚硝酸盐氧化菌(NOB, 以Nitrospira为主)总量从3.89%(N1)增加到23.09%(N2)、37.23%(N3), 为反硝化除磷提供充足的电子受体; 此外, 建立了基于碳源高效利用的运行调控策略, 以期为A²/O - BCO工艺的推广应用提供理论参考.

Effect of carbon source types on denitrifying phosphorus removal and microbial community in the A2/O - BCO process

The anaerobic/anoxic/aerobic-biological contact oxidation (A²/O-BCO) process was used (1) to treat low carbon/nitrogen ratio (C/N) wastewater, (2) to monitor the effect of single factor of carbon source (Phase Ⅰ: sodium acetate; Phase Ⅱ: Sodium acetate + sodium propionate; Phase Ⅲ: sodium propionate) on organic matter, and (3) to investigate the simultaneous nitrogen and phosphorus removals were investigated. The research explored the transformation and utilization of internal carbon sources (PHA and Gly) and the mechanism of denitrifying phosphorus removal (DPR) under the mixed carbon source conditions of sodium acetate and sodium propionate. Meanwhile, the evolution rules of microbial community structure at different phases were compared through high-throughput sequencing. The results showed that the mixed carbon source improved the simultaneous removal efficiency of organic matter, nitrogen and phosphorus, and the transformation amount of internal carbon source was 226mg/h with the phosphorus release amount of 30.58mg/L in the anaerobic section, and the DPR efficiency was above 90%. The batch test showed that the proportion of denitrifying phosphorous accumulating bacteria (DPAOs) to phosphorous accumulating bacteria (PAOs) was 72.42%, which basically realized the enrichment of DPAOs. The results of high-throughput sequencing showed that the mixed carbon sources were more conducive to the formation of unique OTUs bacterial genus, and the total amount of PAOs (including Accumulibacter and Acinetobacter) and DPAOs (including Dechloromonas and Pseudomonas) was up to 29.13%(> 16.18%(Phase Ⅲ) > 14.34%(Phase Ⅰ)), thus efficiently promoting the utilization of carbon source and efficiently denitrifying phosphorus removal. In the BCO reactor, the total amount of ammonia-oxidizing bacteria (AOB, including Nitrosomonas and Nitrosomonadaceae) and nitrite-oxidizing bacteria (NOB, mainly Nitrospira) increased from 3.89%(N1) to 23.09%(N2) and 37.23%(N3), which provided sufficient electron receptors for denitrifying phosphorus removal. In addition, the operation regulation strategy based on the efficient utilization of carbon source was established, in order to provide theoretical reference for the application of A²/O-BCO process.