延时厌氧调控DPAOs内碳源转化实现反硝化除磷

Controlling the internal carbon source conversion of DPAOs by delayed anaerobic to achieve denitrification and phosphorus removal

采用SBR反应器,以模拟市政污水为进水基质,在富集PAOs后采用厌氧/缺氧/好氧运行方式富集DPAOs,探讨延长厌氧时间过程中DPAOs内碳源利用、脱氮除磷效果及富集程度.结果表明:厌氧时间由50min延长至70和90min,DPAOs内碳源的储量及利用率增加,延时厌氧条件的改进使DPAOs富集程度增加.厌氧90min COD和TP的平均去除率分别为91.54%和94.6%,DPAOs/PAOs及DPAOs对内碳源贡献率达69.4%和60.1%,继续延长厌氧时间至110和130min后,DPAOs内碳源的储量降低系统除磷效率下降,厌氧130min TP平均去除率、DPAOs/PAOs及DPAOs对内碳源贡献率分别降至84.6%、50.2%和36.4%.延时厌氧运行过程中,LB-EPS含量变化较小,内碳源储量的改变对TB-EPS影响较大.微生物群落结构分析表明,系统内优势菌门为拟杆菌门(Bacteroidetes)、变形菌门(Proteobacteria)和绿弯菌门(Chloroflexi).厌氧90min时以Dechloromonas、Candidatus_Accumulibacter为代表的DPAOs是系统内优势微生物(相对丰度由接种污泥1.44%、2.12%增至15.58%、5.86%);厌氧130min时DPAOs丰度减少,以Candidatus_Competibacter为代表的DGAOs明显增多(相对丰度由厌氧90min的3.29%增至16.16%),导致系统除磷性能下降.

This study evaluated the delay anaerobic process using an SBR reactor with simulated municipal wastewater as the influent substrate.After enrichment of PAOs,anaerobic/anoxic/aerobic operation was used to enrich DPAOs,and the internal carbon source utilization,nitrogen and phosphorus removal efficiency,and enrichment degree of DPAOs during the extension of anaerobic time were investigated.The results showed that the anaerobic time was extended from 50min to 70min and 90min,leading to an increase in the carbon source storage and utilization rate of DPAOs.The improvement of delayed anaerobic conditions resulted in an increase in the enrichment of DPAOs.The average removal rates of COD and TP during anaerobic time of 90min were 91.54%and 94.6%,respectively.DPAOs/PAOs and DPAOs contribution to internal carbon sources reached 69.4%and 60.1%,respectively.After extending the anaerobic time to 110min and 130min,the storage of internal carbon sources in DPAOs and the phosphorus removal efficiency of the system decreased.The average removal rate of TP during anaerobic time of 130min,DPAOs/PAOs and DPAOs contribution to internal carbon sources decreased to 84.6%,50.2%and 36.4%,respectively.During the delayed anaerobic operation,the change in LB-EPS content was relatively small,and the change in internal carbon source storage had a significant impact on TB-EPS.Analysis of microbial community structure showed that the dominant phyla in the system are Bacteroidetes,Proteobacteria and Chloroflexi.DPAOs represented by Dechloromonas and Candidatus_Accumulibacter during anaerobic treatment for 90min were the dominant microorganisms in the system(relative abundance increased from 1.44%and 2.12%of inoculated sludge to 15.58%and 5.86%).When anaerobic time was extended for 130min,the abundance of DPAOs decreased,while DGAOs represented by Candidatus_Competibacter significantly increased(relative abundance increased from 3.29%in anaerobic time of 90min to 16.16%),leading to a decrease in phosphorus removal performance of the system.