Modeling of Simultaneous Partial Nitrification, Anammox and Denitrification Process In a Single Reactor
One sequencing batch reactor (SBR) seeded with anaerobic granular sludge was started-up to enrich simultaneous partial nitrification and anaerobic ammonia oxidation (Anammox) bacteria. The SBR could be operated successfully through first enriching Anammox bacteria under strictly anaerobic condition during the first stage and then controlling the dissolved oxygen (DO) in the reactor between 0.3 and 0.6 mg/L during the second and third stage, and eventually the maximum total nitrogen removal rate could reach 63.7%. Besides, a dynamic mathematical model including nitrification, Anammox, COD oxidation and denitrification was developed for the simulation of the performance of biological processes. The dynamic mathematical model was extended with two parts: model correction factors of DO, and Haldane kinetics for Anammox. Subsequently, a set of experiments and simulations were carried out to analyze the effects of substrate nitrite and DO on SBR system, and to validate the model. Research results indicated that biological processes could be inhibited by a certain nitrite concentration 20~30mg/L, and high or low DO concentration was not in favor of operation of SBR system. In addition, the simulation results were consistent with the experimental results, which illuminated that the mathematical model was appropriate for the modeling of simultaneous partial nitrification, Anammox and denitrification process in a single reactor, thus it could estimate the impact of specific parameters and predict the efficiency of system.