雨水管道沉积物中典型无机氮的干期粒径分布

Particle sizes distribution of typical inorganic nitrogen from rainwater pipeline sediments during dry periods

以南京江北新区分流制雨水管道沉积物为研究对象,考察不同粒径沉积物中铵态氮(NH3-N)和硝态氮(NO3^--N)干期分布特征,分析其随干期长度的变化关系,并探讨沉积物理化性质及微生物菌群结构对NH3-N和NO3^--N干期分布的影响.结果表明:粒径≤0.075mm的沉积物中NH3-N占比最高(交通区30.8%,商业区36.7%);交通区粒径≤0.075mm的沉积物中NO3^--N占比最高(33.0%),而商业区粒径0.075~0.15mm沉积物中NO3^--N占比最高(34.4%);干期长度与交通区0.075~0.15mm粒径段的沉积物中NO3^--N含量及商业区粒径≥0.3mm的沉积物中NH3-N含量之间的相关性均最显著;雨水管道沉积物中NH3-N和NO3^--N的干期分布与O-H和N-H等官能团､表面极性和亲水性､微观形貌等有一定关联;交通区雨水管道沉积物中Gemmobacter等反硝化优势菌种(相对丰度总和为20.15%)对NO3^--N干期分布影响更显著.

Separate rainwater pipeline sediments from Jiangbei New District,Nanjing,were selected as research objects,in order to the distribution characteristics for both NH3-N and NO3^--N attached in sediments with different particle sizes during dry periods,the change of the mentioned distribution with the length of dry periods,and the effect of physicochemical properties and microbial flora structure.The results showed that NH3-N contents accounted for the highest proportion in sediments with particle size≤0.075mm(traffic area 30.8%,commercial area 36.7%).The proportion of NO3^--N in sediments with particle size≤0.075mm in the traffic area was the largest(33.0%),while there was the highest(34.4%)in sediments with particle size of 0.075~0.15mm in commercial area.The length of dry periods had the most significant correlation with NO3^--N content in sediments with particle size 0.075~0.15mm in traffic area,as well as NH3-N content in sediments with particle size≥0.3mm in commercial area.The distribution of NH3-N and NO3^--N in rainwater pipeline sediments during dry periods had a certain degree relation with the functional groups(O-H and N-H),surface polarity,hydrophilicity,and micro-morphology.The dominant denitrification bacteria(the total relative abundance was 20.15%)in rainwater pipeline sediments from the traffic area,like Gemmobacter,had the relatively obvious influence on the distribution of NO3^--N during dry periods.