摘要：本论文主要概括了现阶段各种污水处理工艺，并以宜兴市宜兴镇清源污水处理厂为例，分析了其污水处理工艺，在其污水处理工艺中进水、水解池、生化池、二沉池、絮凝反应池、及出水阶段采样，采用Skalar流动分析仪检测水样中NO2--N、NO3--N、NH4+-N、TDN（total digestible nutrients）、TN（total nutrients）的含量，在各种形态氮含量变化的基础上对污水处理工艺过程中氮的形态的变化提出分析结论。宜兴市清源污水处理厂出水氨氮占总氮比由74.63%降为0.87%，硝态氮占总氮比由1.80%升为67.68%，此工艺氮素转化主要是将氨氮转化为硝态氮，并不是完全将氮素从污水中去除。出水中颗粒态氮占总氮比从19.25%降为5.88%，颗粒态氮部分被沉降，部分被分解转化。氨氮降低量最大的阶段为生化池处理。目前我国污水处理中氨氮、总氮含量很明确，现在虽有人提出对氧化态的氮提出排放标准，但目前并没有明确实行标准，过量的氧化态氮如硝态氮也是引起水体富营养化的重要因素，应当对此提出明确的排放标准。

关键词：污水处理工艺；城镇污水处理；氮的形态

Abstract:This paper mainly summarizes various wastewater processing technologies at the present time, taking Qingyuan Wastewater Treatment Plant in Yixing for example. Samples are taken from the suction sump, the hydrolysis tank, the biochemical tank, the secondary sedimentation tank, the flocculation reaction tank and the process of water exiting, and the contents of NO2--N, NO3--N, NH4+-N, TDN, TN are examined by Skalar flow analyzer. Finally the conclusion of analyzing the morphological change of nitrogen is drawn on the basis of changes of the content of various nitrogen forms. The percentage of ammonia nitrogen in the final effluent of Qingyuan Wastewater Treatment Plant in Yixing decreases from 74.63% to 0.87% while that of nitrate nitrogen rises from 1.80% to 67.68%, which means that nitrogen transformation process is mainly about changing ammonia nitrogen to nitrate nitrogen instead of entirely removing nitrogen from the wastewater. The percentage of particulate nitrogen in the other hand decreases from 19.25% to 5.88%, which indicates that some of the particulate nitrogen are settled and the rest of them are decomposed and then transformed. The biggest decrease of ammonia nitrogen takes place during the biochemical tank treatment. Although the emission standard of nitrogen oxide has been raised recently, there is still no clear implementation of the standard. However, the contents of ammonia nitrogen and the total nitrogen in the wastewater treatments in China are now very clear. The emission standard should be proposed definitely because excessive nitrogen oxide such as nitrate nitrogen could cause water eutrophication.

Key word: wastewater processing technology; wastewater treatment in urban area; nitrogen forms