Biological Treatment of Ammonium-Rich Wastewater with the Partial Nitrification and Anaerobic Ammonium Oxidation

The aim of the investigation was to evaluate the nitrogen removal efficiency by using the combined partial nitrification and anaerobic ammonium oxidation (anammox) process for high-strength ammonium synthetic wastewater. The partial nitrification and anaerobic ammonium oxidation reactors were inoculate with domesticated sludge and operated respectively during the startup period. Subsequently, they were combined for stable operation when the partial nitrification effluent was suitable for being the influent of the anaerobic ammonium oxidation. The startup period was about 40 days. The experimental results of the nitrogen removal performance during the startup and the stable operation periods indicate that over 90% of the inlet nitrogen load to the combined reactors was removed. With the influent concentrations of 360 - 400mg NH₄⁺-N /L, the mean NH₄⁺-N, NO₂^--N and TN concentrations of the combined process effluent were 2.7mg/L, 0.51mg/L and 55.9mg/L, respectively. And their mean removal efficiencies were 93.7%, 96.2% and 84.6%, correspondingly.