大量的研究证明，污水中的氮是导致水体富营养化的主要原因之一。常规的污水处理技术主要去除有机物和悬浮固体，对氮的去处效率较低。许多国家对排放污水中的氮含量都做了限定，并要求污水处理厂达到除氮的要求。
A large number of studies have proved that nitrogen in sewage is one of the main causes of water eutrophication. Conventional wastewater treatment technologies mainly remove organic matter and suspended solids, but the removal efficiency of nitrogen is low. Many countries have limited the nitrogen content in the sewage, and require the sewage treatment plant to meet the requirements of nitrogen removal.
污水脱氮的技术可分为物理法、化学法和生物法。相对而言，生物脱氮技术投资少、运行操作简单、产生的二次污染物较易被处理，因此生物脱氮方法被广泛应用。
The technology of wastewater denitrification can be divided into physical method, chemical method and biological method. Relatively speaking, biological nitrogen removal technology has the advantages of less investment, simple operation and easy treatment of secondary pollutants, so biological nitrogen removal method is widely used.
活性污泥法脱氮
Nitrogen removal by activated sludge process
活性污泥法脱氮的原理是通过创造好氧和缺氧条件，经过硝化和反硝化两个步骤、利用硝化菌和反硝化菌等一些专性菌实现氮形式的转化。基本方法有具有多级污泥回流系统的传统生物脱氮方法和只有一个污泥回流系统的单级生物脱氮方法。单级生物脱氮法可认为是对传统生物脱氮法的改进，有A/O法、Bardenpho工艺等多种形式，氧化沟，SBR法等具有脱氮功能的工艺也属于单级生物脱氮系统。
The principle of nitrogen removal by activated sludge process is to create aerobic and anoxic conditions, through two steps of nitrification and denitrification, and use some specific bacteria such as nitrifying bacteria and denitrifying bacteria to realize the transformation of nitrogen form. The basic methods include the traditional biological denitrification method with multi-stage sludge return system and the single-stage biological denitrification method with only one sludge return system. The single-stage biological nitrogen removal process can be considered as an improvement on the traditional biological nitrogen removal process, including a / O process, bardenpho process and other forms. The oxidation ditch, SBR process and other processes with nitrogen removal function also belong to the single-stage biological nitrogen removal system.
1.传统生物脱氮工艺
1. Traditional biological nitrogen removal process
传统的生物脱氮流程是三级活性污泥系统，在此流程中，含碳有机物的氧化和含氮有机物的氮化、氨氮的硝化及硝酸盐的反硝化分别在三个构筑物内进行，并维持各自独立的污泥回流系统。曝气池和硝化池均要进行曝气维持好氧状态，反硝化池则要维持缺氧状态，不进行曝气，只采用缓速搅拌使污泥处于悬浮状态并与污水保持良好的混合，反硝化所需碳源采用外加甲醇/葡萄糖的方法。
The traditional biological nitrogen removal process is a three-stage activated sludge system. In this process, the oxidation of carbonaceous organic matter, nitrification of nitrogenous organic matter, nitrification of ammonia nitrogen and denitrification of nitrate are carried out in three structures respectively, and independent sludge return systems are maintained. Both aeration tank and nitrification tank should be aerated to maintain aerobic state, while denitrification tank should maintain anoxic state without aeration. Only slow stirring is used to make sludge in suspension state and keep good mixing with sewage. The carbon source for denitrification is methanol / glucose.
这种流程的优点是好氧菌、硝化菌和反硝化菌分别生长在不同的构筑物内，并可维持各自适宜的生长环境，所以反应速度快，可以得到相当好的BOD5，去除效果和脱氮效果。另外，不同性质的污泥分别在不同的沉淀池中得到沉淀分离，而且拥有各自独立的污泥回流系统，所以运行的灵活性和适应性较好。其缺点是流程长、构筑物多，外加甲醇/葡萄糖为碳源使运行费用较高，出水中往往会残留一定量的甲醇/葡萄糖。
The advantage of this process is that aerobic bacteria, nitrifying bacteria and denitrifying bacteria grow in different structures respectively, and can maintain their own suitable growth environment, so the reaction speed is fast, and good BOD5 removal effect and nitrogen removal effect can be obtained. In addition, different types of sludge are separated in different sedimentation tanks, and have their own independent sludge return system, so the operation flexibility and adaptability are better. Its disadvantages are long process, many structures, and high operation cost due to the addition of methanol / glucose as carbon source. A certain amount of methanol / glucose is often retained in the effluent.
2. Bardenpho工艺
2. Bardenpho process
Bardenpho工艺由两个缺氧/好氧（A/O)工艺串联而成，共有四个反应池，因此有时也称为四段Bardenpho工艺，其工艺流程见下图。
Bardenpho process is composed of two anoxic / aerobic (A / O) processes in series, with a total of four reaction tanks, so it is sometimes called four stage bardenpho process, and its process flow is shown in the figure below.
在一级A/O工艺中，回流混合液中的硝酸盐氮在反硝化菌的作用下利用原污水中的含碳有机物作为碳源在一缺氧池中进行反硝化反应，反硝化后的出水进入一好氧池后，含碳有机物被氧化，含氮有机物实现氨化和氨氮的硝化作用，同时在一缺氧池反硝化产生的N2在一好氧池经曝气吹脱释放出去。
In the primary A / O process, the nitrate nitrogen in the reflux mixture is denitrified in an anoxic tank by using the carbonaceous organic matter in the original sewage as the carbon source under the action of denitrifying bacteria. After the denitrified effluent enters an aerobic tank, the carbonaceous organic matter is oxidized, and the carbonaceous organic matter realizes ammoniation and nitrification of ammonia nitrogen. At the same time, the nitrogen produced by denitrification in an anoxic tank is oxidized in an anoxic tank The aerobic tank is released by aeration.
在二级A/O工艺中，由一好氧池而来的混合液进人二缺氧池后，反硝化菌利用混合液中的内源代谢物质进一步进行反硝化，反硝化产生的N2在二好氧池经曝气吹脱释放出去，改善污泥的沉淀性能，同时内源代谢产生的氨氮也可以在二好氧池得到硝化。
In the two-stage A / O process, after the mixed liquor from the first aerobic tank enters the second anoxic tank, denitrifying bacteria use the endogenous metabolites in the mixed liquor for further denitrification. The N2 produced by denitrification is released by aeration in the second aerobic tank to improve the sedimentation performance of sludge. At the same time, the ammonia nitrogen produced by endogenous metabolism can also be nitrified in the second aerobic tank.
Bardenpho具有两次反硝化过程，脱氮效率可以高达90%-95%。
Bardenpho has two denitrification processes, and the denitrification efficiency can reach 90% - 95%.
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2021-01-29
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