Nitrogen Contribution Rate of Anammox in Different Systems and Its Relationship with Environmental Factors

Abstract

Anammox bacteria can remove ammonium directly, which is different from what was previously believed. This is an important process for the global nitrogen cycle. Anammox bacteria were first identified in sewage treatment systems and were later proven to exist widely in natural ecosystems. To better understand the relationship between the anammox reaction and different systems, and to maintain the stability of the nitrogen cycle, anammox functional microorganisms found in different natural environments were summarized. In addition, anammox nitrogen production rate and the contribution of anammox to nitrogen were discussed under different ecological environments. A literature analysis showed that the contribution rate of nitrogen removal of anammox was the highest in the Terrestrial ecosystem, up to 87.5%. The Terrestrial ecosystem is more likely to form an anoxic or even anaerobic environment conducive to anaerobic ammoxidation. Therefore, the control of DO is an important factor in the activity of anaerobic ammoxidation. Other environmental factors affecting the contribution of anammox to nitrogen removal include temperature, pH, organic matter content, inorganic nitrogen concentration, and salinity. However, the dominant influencing factors of anammox reactions in different ecosystems are evidently different. Therefore, the mechanism of the impact of different environmental factors on the anaerobic ammonia oxidation process is necessary to discuss. This provides a scientific basis for the global nitrogen cycle and is of great significance to improve nitrogen’s biogeochemical cycle in the ecosystem.