SPNED-PR系统内PAOs-GAOs的竞争关系及其氮磷去除特性

The competitive relationships of PAOs-GAOs in simultaneous partial nitrification-endogenous denitrification and phosphorous removal(SPNED-PR) systems and their nutrient removal characteristics

为研究同步短程硝化内源反硝化除磷(SPNED-PR)系统的脱氮除磷特性及系统内聚磷菌(PAOs)和聚糖菌(GAOs)在氮磷去除的贡献和竞争关系,本研究以实际低C/N比(4左右)生活污水为处理对象,考察了不同浓度的溶解氧(DO)(0.5~2.0mg/L)、NO2--N(4.7~39.9mg/L)和NO3--N(5.0~40.0mg/L)对延时厌氧(150min)/低氧(180min,溶解氧0.5~0.7mg/L)运行的SPNED-PR系统氮磷去除特性和底物转化特性的影响.结果表明,DO浓度均不影响PAOs和GAOs的好氧代谢活性,且两者之间几乎不存在DO竞争.不同NO2--N浓度条件下,GAOs较PAOs更具竞争优势,NO2--N主要是通过GAOs去除的(约占58%);且GAOs所具有的高内源反硝化活性和亚硝耐受力,减弱了高NO2--N浓度(26.2~39.9mg/L)对PAOs反硝化吸磷的抑制,保证了系统的脱氮除磷性能.不同NO3--N浓度条件下,PAOs较GAOs处于竞争优势,其在NO3--N去除中的贡献比例达61.2%.此外,SPNED-PR系统的PURDO>PURnitrate>PURnitrite,PAOs对DO的优先利用保证了低氧条件下系统的高效除磷,且GAOs的内源短程反硝化特性保证了系统的高效脱氮.

In order to analyze the nitrogen(N)and phosphorus(P)removal characteristics of simultaneous partial nitrification-endogenous denitrification and phosphorus removal(SPNED-PR)systems and to elucidate the contribution and competitive relationships between phosphorus and glycogen accumulating organisms(PAOs and GAOs)in the nutrient removal,an extended anaerobic(150min)/low aerobic(180min,dissolved oxygen(DO)concentration for 0.5~0.7mg/L)operated sequencing batch reactor(SBR)fed with domestic wastewater(C/N:around 4)was studied by investigating the effects of different DO(0.5~2.0mg/L),nitrite(4.7~39.9mg/L)and nitrate(5.0~40.0mg/L)concentrations on the nutrient removal and intracellular carbons transformation.Results showed that DO had barely effects on the aerobic metabolisms of both PAOs and GAOs,and almost no PAOs-GAOs competition was detected at various DO concentrations.GAOs had a competitive advantage over PAOs at the presence of nitrite,and nitrite was mainly removed by GAOs(about 58%);GAOs had a greater tolerance to nitrite than PAOs,which alleviated the nitrite inhibition on PAOs at high nitrite concentrations(26.2~39.9mg/L)and assured the nutrient removal in the SPNED-PR system.PAOs had a competitive advantage over GAOs when nitrate was present,and it contributed to about 61.2%of total nitrate removal.Additionally,PAOs preferred to utilize DO over nitrite and nitrate for P uptake(PURDO>PURnitrate>PURnitrite),which assured the efficient P removal at low aerobic conditions.Highly active GAOs ensured the efficient N removal in the SPNED-PR system via endogenous nitrite denitrification.