The effect of outside conditions on anaerobic ammonia oxidation reaction

YANG+Min1　WＡＮＧ+Shu－bo2

【Abstract】Organic carbon， inorganic carbon， temperature， pH and ORP are all to have a certain influence on the anaerobic ammonia oxidation reaction. We can draw some conclusions on the optimum conditions of anaerobic ammonia oxidation reaction. The optimum temperature of the anaerobic ammonia oxidation reaction is 30-35℃. And the optimum pH of the anaerobic ammonia reaction is 7.5-8.3. The presence of organic matters can affect the anaerobic ammonia reaction， and different organic matters have different influence on it. The concentration of the inorganic carbon also exist great influence on the reaction. High inorganic carbon concentration also can inhibit anaerobic ammonia oxidation reaction.

【Key words】The anaerobic ammonia oxidation； Organic matter； Temperature； Inorganic matter

Anaerobic ammonia oxidation reaction is the process of anaerobic ammonium oxidation bacteria which nitrate as electron acceptor transformed the ammonia to N2 under anaerobic conditions. The denitrification efficiency of this reaction is very high， also does not need additional source of organic carbon， so can save a lot of cost， and has the very high economic value. Therefore， in its once found， has attracted extensive attention of scholars.

However， with the numerous advantages of anaerobic ammonia oxidation reaction， it is also have the shortcoming of sensitive to changes in the external environment. So， in this paper， the outside conditions change on the impact of anaerobic ammonia oxidation reaction are summarized， with its provided the reference for the engineering application of anaerobic ammonia oxidation reaction.

1 The effect of organic matter on anaerobic ammonia oxidation reaction

As regard to the effects of organic matter on anaerobic ammonia oxidation reaction， the scholars found there are two main types. One view is that， anaerobic ammonia oxidation bacteria and denitrifying bacteria are competition with each other， in high concentration when the organic matters existence， the reaction will be inhibited in high concentration of organic matter. Another view is that the anaerobic ammonia oxidation bacteria and denitrifying bacteria can use the same organic matter， so as to promote the anaerobic ammonia oxidation reaction.

2 The effect of temperature on anaerobic ammonia oxidation reaction

Temperature is one of the important factors of anaerobic ammonia oxidation reaction， it not only affects the activity of anaerobic ammonia oxidation bacteria， but also directly determines the reaction rate. Researches has shown that the optimum temperature of anaerobic ammonia oxidation reaction is 30-35℃， and the sludge of anaerobic ammonia oxidation rate with temperature changing trend is consistent with the nitration.

In the laboratory experiments， all the reaction temperature are controlled at 35℃ generally， in order to make sure it is in the most appropriate growth environment. But the reality of engineering practice， the temperature of 35℃ are above the outside world need raising temperature can reach， which not only greatly increased the operating costs.

3 The effect of pH and ORP on anaerobic ammonia oxidation reaction

By the chemical equation of anaerobic ammonia oxidation reaction， due to its special substrate reaction relationship， this reaction is a reaction of consumption of H+ actually. Therefore， as the reaction progresses， the pH in anaerobic ammonia oxidation reaction system will be increased accordingly. Research has shown that the optimum pH of anaerobic ammonia oxidation reaction within the range of 7.5 to 8.3. Also， due to the increase of pH will cause increased the concentration of free ammonia（FA） in the system， the higher FA can inhibit anaerobic ammonia oxidation reaction， and therefore in order to make the anaerobic ammonia oxidation reaction system can stable and continuous operation， need to pH control system in the proper range.

4 The effect of inorganic matter on anaerobic ammonia oxidation reaction

The survival of anaerobic ammonia oxidation bacteria needs proper inorganic carbon. The inorganic carbon can not only promote the rapid reproduction of anaerobic ammonia oxidation bacteria growth， but also enhance the anaerobic ammonia oxidation reaction of ammonia nitrogen and nitrate removal. However， when the source of inorganic carbon（IC） of more than a certain concentration， it will have the opposite effect. But when the inorganic carbon concentration is greater than 55.77mg/L， will cause the anaerobic ammonia oxidation reaction rate of decline. [1]

5 Conclusion

Anaerobic ammonia oxidation reaction is very sensitive to the change of the external environment. A slight change will cause the change of anaerobic ammonia oxidation reaction. To minimize the concentration of organic matter in sewage， and the temperature controlled within 30-35℃， pH controlled between 7.5 to 8.3， can effectively promote the smooth progress of anaerobic ammonia oxidation reaction.[2] In addition， inorganic carbon concentration also affect anaerobic ammonia oxidation reaction exists， and need to be controlled in appropriate range. Only the external environment are controlled in a suitable range， can play to its biggest anaerobic ammonia oxidation reaction， greatly improve the reaction rate of anaerobic ammonia oxidation， so as to reduce the ammonia nitrogen and nitrate unit mass of processing cost.

【Reference】

[1]Fu J X， Tong Y， Yu P F， et al. Two-way effect and disinhibition effect of organic matter on Anammox[J].Industrial Water Treatment，2014，34（7）：19-22.（in Chinese）.

[2]Antoniou P， Hamilton J， Koopman B， et al. Effect of temperature and pH on the effective maximum specific growth rate of nitrifying bacteria[J].Water Research， 1990，24（1）：97-101.

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