求翻译：请输入您需要翻译的文本！本文从大理洱海周边的江尾、上关、桃源码头、长久村的小水沟以及小溪取得30个水样，通过一系列步骤，从中筛得几种菌，测定其总氮和氨氮含量，得出其脱氮效率。是什么意思？

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This article from Dali er Hai River around the tail, NACA), Taoyuan pier village, long the small ditch and creek made a 30 water samples, and through a series of steps, from which you can sift a few types of bacteria, and determine their total nitrogen and ammonia content, and concluded that the den

This article from the Dali Erhai peripheral river tail, on the pass, the haven wharf, the long-time village small drainage as well as the rill obtains 30 water samples, through a series of steps, sieves several kind of fungi, determines its total nitrogen and the ammonia nitrogen content, obtains it

This article from the surrounding River of erhai Lake in Dali, Terminal, long off, Taoyuan village on a small ditch and stream water samples obtained 30, through a series of steps, from which the screen several bacteria, determination of the total nitrogen and ammonia nitrogen content, its nitrogen

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