||Anoxic ammonium oxidation (ANAMMOX) is biochemical process based on the theory of autotrophic nitrogen removal through nitrite to nitrogen gas. Unlike heterotrophic denitrification requiring adding extra organic carbon sources, the process of ANAMMOX can remove ammonia to nitrogen gas from wastewaters characterized by a low content of organic materials.To reach the purpose, in this study a vertical-flow constructed wetland(VFCW) system with deep depth and high HRT was used. The VFCW system was installed with gravels and filled with some anaerobic sludge for ANAMMOX bacteria growth in the system.|
The three VFCW systems were all filled with gravels(20-40 mm in diam) as media, and controlled by three different conditions: anaerobic sludge seeding and with vegetation(Phragmites), anaerobic sludge seeding without vegetation, and without both seeding and vegetation, respetively. Artificial wastewater, with NH3 levels(50 mg N/L) and hydralic retention time (HRT) was controlled as 1 day for all three systems. The experimental results showed that nitrite was found in higher amounts than nitrate in depth of 20cm of the system, while nitrite was decreased down in large amounts with low dissolved oxygen (DO) of 0.5mg/L found in 40cm depth of same system, which was meant that ANAMMOX might occur in this area learned by nitrite removal through Anammox bacteria probably. It was inferred that for the VFCW systems used in this study, ANAMMOX occurred obviously in the areas of 40cm depth. For further study throuth the bio-technique of qPCR, the results exhibited that Anammox bacteria indeed existed in the VFCW systems of this study.