A two-sludge system combined anaerobic/anoxic/oxic with moving bed biofilm reactor (A2/O-MBBR) was used to treat real domestic wastewater. By adding sodium acetate to adjust influent carbonitrogen ratio (C/N), the transformation and utilization and metabolic pathways of organic matter in the system were investigated. When the influent C/N ratio varied from 3.11 to 6.09, the system all achieved efficient COD removal with the maximum removal of 83.85%. However, from the perspective of VFA and PHAs transformation, the influent C/N ratio should not exceed 5.42. Additionally, the material balance analysis of carbon also revealed that when the influent C/N ratio was below 5.42, COD removal percentage in the A 2/O reactor was up to 70.10% and that in the MBBR reactor only accounted for 4.32%~5.89%, where the efficient utilization of carbon source was the key to improve microbial community optimization and enhance denitrification and phosphorus removals under the condition of low C/N ratio. The results of dissolved carbon source component distribution and three-dimensional fluorescence properties manifested that proteins and polysaccharides transformed although COD changed gently along the reactor, in which proteins-like substance was the dominant.%采用厌氧/缺氧/好氧与移动床生物膜反应器(A2/O-MBBR)组成的双污泥系统处理实际生活污水,通过投加乙酸钠调节进水碳氮比(C/N),考察系统中有机物的转化利用和代谢途径.试验结果表明:当进水C/N在3.11~6.09范围内波动时,系统均可实现COD的高效去除,最大去除率可达83.85%;但是从VFA和PHAs的转化利用角度,进水C/N不宜超过5.42.此外,碳平衡分析结果也表明,当进水C/N小于5.42时,A2/O反应器去除的COD百分比最高可达70.10%,MBBR反应器氧化的COD仅占4.32%~5.89%,低C/N条件下碳源的高效利用是促进菌群优化以及提高脱氮除磷效率的关键所在.溶解性碳源组分分布及三维荧光特性的结果显示,尽管系统沿程 COD 浓度变化不大,但蛋白质和多糖之间存在着转化,且类蛋白物质占主导地位.
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