进水C/N对富集聚磷菌的SNDPR系统脱氮除磷的影响

为了解富集聚磷菌(PAOs)的同步硝化反硝化除磷(SNDPR)系统的脱氮除磷特性,采用延时厌氧(180min)/低氧(溶解氧0.5~1.0mg/L)运行的SBR反应器,以实际生活污水为处理对象, 通过投加固态乙酸钠调节进水C/N值(约为11,8,4,3),考察其对系统脱氮除磷特性及同步硝化反硝化(SND)脱氮率的影响.结果表明:C/N对系统的除磷性能没有影响,出水PO43--P浓度均稳定在0.3mg/L左右,这是由于系统内聚磷菌(PAOs)含量高,且在低氧段可同时发生好氧吸磷与反硝化吸磷.随着C/N的增大,出水NH4+-N浓度升高,C/N下降时,出水NO3--N浓度升高.此外,随着C/N的减小,厌氧段反硝化所消耗的COD占进水COD的比例增大,SND可利用的内碳源-PHAs储存量减少,但PHV的利用率增加;当C/N为4~8时,SND现象最明显,SND脱氮率达50.8%,而其它C/N条件下,SND脱氮率都有相应程度的减弱.C/N为8时,系统出水综合指标最好,TN去除率高达80.8%.

Effect of influent C/N ratio on simultaneous nitrification-denitrification and phosphorus removal (SNDPR) enriched with phosphorus accumulating organisms (PAOs)

This study focused on the elucidation of the mechanisms of nitrogen and phosphorus removal in simultaneous nitrification-denitrification and phosphorus removal (SNDPR) systems enriched with phosphorus accumulating organisms (PAOs). An extended anaerobic (aeration duraction: 180min)/low aerobic (dissolved oxygen: 0.5~1.0mg/L) sequencing batch reactor (SBR) fed with domestic wastewater was studied for SND (simultaneous nitrification-denitrification) efficiency of SNDPR under different C/N ratios (3, 4, 8, and 11) adjusted by adding sodium acetate into the domestic waster. The experimental results showed that the phosphorus removal efficiency was not affected by influent C/N ratios with an effluent PO43--P concentration lower than 0.3mg/L, which might be caused by the enriched PAOs capable of achieving a simultaneous aerobic phosphorus uptake and denitrifying phosphorus uptake at the low aerobic phase. In contrast, effluent NH4+-N concentration increased with the C/N ratio and the effluent NO3--N concentration increased with the decrease of C/N ratio. The consumption of chemical oxygen demand (COD) for exogenous denitrification increased with the decease in C/N ratio. The storage capacity of PHAs (poly-hydroxyalkanoates) for SND was reduced, but its utilization of PHV (Volatile fatty acids) was increased. SND efficiency reach the peak value of 50.8% at the C/N ratio of 4~8, and total nitrogen (TN) removal efficiency reached 80.8% at the C/N ratio of 8.