Development of anammox and AOB biofilm on honeycomb plastic media for application in partial nitritation-anammox reactor

The purpose of this research was to cultivate anammox and ammonium-oxidizing bacteria (AOB) and analyze the performance of nitrogen removal using honeycomb plastic media in two reactors intended for use in a single partial nitrite-anammox reactor. Substrate was continuously supplied to the reactors, containing ammonium and nitrite of 180 mg-N/L for anammox and ammonium 180-500 mg-N/L for partial nitritation at HRT 12 hours. The reactors were operated until anammox and AOB biofilm growth in the media within 64 and 37 days, respectively. The reactors’ performance was calculated based on ammonium conversion efficiency (ACE), nitrogen removal efficiency (NRE), and nitrogen removal rate (NRR). The anammox process can be directly initiated, achieving ACE, NRE, and NRR of 65.24%, 51.69%, and 0.10 kg-N/m³·d, respectively. Similarly, partial nitritation was successfully achieved faster with ACE and ΔNO2 --N/ΔNH4 +-N ratio of 51.14% and 0.6. Developing anammox bacteria and AOB using honeycomb plastic media could be a fast-startup strategy for single-stage nitritation-anammox reactors in wastewater nitrogen removal.