中文摘要：

回用水管网中的反硝化可以去除水中的硝态氮（或亚硝态氮）及微量的有机质，对于提高回用水水质具有积极意义。以西安市某再生水厂出水为原水，采用4个完全混合式CDC生物膜反应器串联模拟回用水管道，探讨了回用水管道的反硝化现象。连续8个月的运行结果表明，70％的水样通过模拟管道反应器后出现了氮的损失。沿程水质分析、生物膜表面电镜扫描以及反硝化速率测定结果表明，系统具备反硝化所需的碳源条件，且硝化和反硝化是同时发生的；生物膜表面普遍存在通气孔，管道始端的生物膜反硝化速率可达160．08mg NO3^- -N／（h·m^2）。

英文摘要：

Denitrificafion in reclaimed water and trace organic compounds in water, which has distribution system can remove nitrate （or nitrite） positive significance for improving reclaimed water quality. Four modified CDC biofilm reactors were connected in series to simulate a reclaimed water distribution system carrying the finished water from a wastewater treatment and reuse plant located in Xi＇ an. Denitrification in the reclaimed water distribution system was investigated. Results from 8 months of continuous operation showed that nitrogen loss appeared in about 70% of the samples. In addition, analysis of water quality and biofilm along the modified CDC biofilm reactors showed that carbon source for denitrification was attainable and simultaneous nitrification and denitrification could occur. Meanwhile, denitrification pores on the biofilm surface appeared universally, and the denitrification rate of the biofilm reached 160.08mg NO3^--N/（h·m^2 ） at the beginning of the reclaimed water distribution system.