Influence of sludge type, MLSS, and substrate ratio on stable implementation of ANAMMOX

As the nitrogen concentration in the sewage flowing into the sewage treatment plant and water system increases, the degree of negative influence, such as eutrophication, decrease in dissolved oxygen and toxicity to the aquatic ecosystem increases. As the nitrogen concentration in sewage increases, a biological nitrogen removal process for high nitrogen concentration is attracting attention, and research is being conducted in various fields. The nitrification-denitrification process at a low carbon-to‑nitrogen ratio is not cost effective because of aeration and external carbon source supplement. Accordingly, an economic improvement of biological nitrogen removal process is required and economical and efficient anaerobic ammonium oxidation (ANAMMOX) process has been proposed. This study analyze operation factors for a stable ANAMMOX process. ANAMMOX reactor was operated to evaluate the appropriate ratio or concentration for each operation factor, such as seeding sludge, mixed liquor suspended solids (MLSS), substrate ratio. In seeding sludge, 3 sludges have a high proportion of ANAMMOX bacteria and are suitable for process implementation. In MLSS, it was challenging to secure the stability of the ANAMMOX process at 4000 mg/L over. In substrate ratio, the ammonia nitrogen and total nitrogen removal efficiency were increased when the nitrite to ammonia ratio was increased. Consequently, the results of this study could be used as basic data for the ANAMMOX process in high nitrogen concentration wastewater and mainstream.