厌氧氨氧化颗粒污泥内部原位生物活性与N_(2)O产生特性

In situ biological activity and N2O production characteristics inside Anammox granular sludge

以厌氧氨氧化颗粒为对象,利用NH_(4)^(+)、NO_(2)^(−)、NO_(3)^(−)和N_(2)O微电极测定了浓度连续分布,并建立微生物原位活性与N_(2)O产生之间的关系.结果表明,NH_(4)^(+)和NO_(2)^(−)同步消耗的厌氧氨氧化活性区分布在颗粒的表层区域(0~1500μm),其中200~400μm活性最高;当NH_(4)^(+)-N浓度为14mg/L(c(NH_(4)^(+)):c(NO_(2)^(−))=1:1.2)时,NH_(4)^(+)-N和NO_(2)^(−)-N最大净体积消耗速率分别为1.19与1.65mg/(cm^(3)⋅h).反硝化活性主要分布在1500~2500μm的深层区域,当采用NO_(2)^(−)-N或NO_(3)^(−)-N为单一基质(NO_(x)^(−)-N=14mg/L)时,最大N_(2)O生成速率分别为0.37和0.19mg/(cm^(3)⋅h).N_(2)O的生成主要在深层反硝化区域,且随pH值由8.5降至7.0,产生速率增加了28.16倍,达到0.35mg/(cm^(3)⋅h).高通量测序发现,颗粒中除厌氧氨氧化细菌(Candidatus Kuenenia)外,具有反硝化功能的细菌(Truepera、Limnobacter、Ignavibacterium和Anaerolineaceae)和氨氧化细菌(Nitrosomonas)也被检出.综上,厌氧氨氧化活性主要分布在表层区域,N_(2)O主要产生于深层的反硝化活性区,可能的作用者为反硝化菌.

The concentrations of ammonium,nitrite,nitrate and N_(2)O were determined inside Anammox granules using microelectrodes,and the relationship between in situ biological activity and N_(2)O production was established.The results showed that the Anammox activity with simultaneous consumption of ammonium and nitrite was distributed in the surface layer of the granule(0~1500μm),with the maximum activity at 200~400μm.When the concentration of ammoonium was 14mg/L(c(NH_(4)^(+)):c(NO_(2)^(−))=1:1.2),the maximum ammonium and nitrite consumption rates were 1.19 and 1.65mg/cm^(3)/h,respectively.The denitrifying activity was mainly distributed in the deep layer of 1500 to 2500μm.When nitrite or nitrate was used as the only substrate(NO_(x)^(−)-N=14mg/L),the maximum N_(2)O production rates were 0.37 and 0.19 mg/(cm^(3)⋅h),respectively.N_(2)O was mainly produced in the deep layer of the granule,and the production rate increased 28.16 times with the decrease of pH from 8.5 to 7.0,reaching 0.35mg/(cm^(3)⋅h).Anammox bacteria(Candidatus Kuenenia),denitrifying bacteria(Truepera,Limnobacter,Ignavibacterium and Anaerolineaceae)and ammonia oxidizing bacteria(Nitrosomonas)were also detected by high-throughput sequencing.In conclusion,Anammox activity was mainly distributed in the surface layer,while N_(2)O was mainly generated in the deep denitrifying active layer.Therefore,N_(2)O was mainly produced by denitrifying bacteria.