AAO工艺活性污泥-生物膜复合系统脱氮增效机制研究

Synergistic mechanism research of nitrogen removal by AAO process biofilm-coupled activated sludge system

采用AAO中试反应器处理低C/N(<5)城市污水,在已成功启动短程硝化反硝化(PND)的工况下,向好氧区投加鲍尔环改性生物填料,以研究活性污泥-生物膜复合系统在AAO工艺中的脱氮增效机制。结果表明,活性污泥-生物膜复合系统可在40d左右稳定成型,膜上负载生物量最终稳定在39.51mg/g(以VSS/填料计);系统好氧区亚硝氮积累率(NAR)和同步硝化反硝化效率(SND)由挂膜初期的61.57%和21.57%增至活性污泥-生物膜复合系统稳定成型期的67.48%和46.28%,生物膜通过促进PND和SND这两种脱氮途径,使系统出水NH3-N和TN浓度分别降至0.67和6.48mg/L,对系统脱氮增效作用显著;通过16SrRNA扩增测序分析发现第60d生物膜中微生物的优势菌门为Proteobacteria,其相对丰度为75.28%,主要的氨氧化菌(AOB)菌属为Nitrosomanas(1.28%)和Nitrosococcus(1.54%),同时典型反硝化作用的微生物菌属占比显著(33.71%),并且在生物膜中存在少量Anammox菌群(Anammoxoglobus,0.57%),测序结果与反应器宏观表现吻合。

A pilot-scale AAO reactor was used to treat low C/N(<5) municipal sewage. The synergistic mechanism of nitrogen removal by biofilm-coupled activated sludge system in AAO process were investigated. The results indicated that biofilm-coupled activated sludge system could be formed stably at 40 d, and the biomass on the membrane is finally stabilized at 39.51 mg/g(VSS/carrier). By promoting the two denitrification pathways of PND and SND, the concentration of NH3-N and TN in effluent was reduced to 0.67 and 6.48 mg/L, respectively, which had significant synergistic effect on nitrogen removal. Through the analysis of 16 S rRNA amplification and sequencing, it was found that the dominant phylum of microorganisms in the 60 th day biofilm was Proteobacteria(relative abundance was 75.28%), and the dominant genus of AOB were Nitrosomanas(1.28%) and Nitrosococcus(1.54%). Meanwhile, the relative abundance of typical denitrification bacterial at genus level accounted for a significant proportion(33.71%). The results of sequencing were consistent with the macroscopic performance of the reactor.