Fast start-up of ANAMMOX reactor: Operational strategy and some characteristics as indicators of reactor performance

Fast start-up of anaerobic ammonium oxidation (ANAMMOX) reactor was investigated by inoculating the mixed sludge from a partial nitritation reactor and a low loaded ANAMMOX reactor. At room temperatures (24–30 °C) and without taking deoxygenated measures for preparing the influent, nitrogen removal rate (NRR) up to 2.0 kg/m3/d on day 35 and 6.2 kg/m3/d on day 91 was achieved, indicating successful rapid start-up of ANAMMOX reactor. Dissolved oxygen (DO) concentration of 0.30 mg/L inside the reactor did not impair the ANAMMOX performance, suggesting that there is no need to take deoxygenated measures for preparing the ANAMMOX influent. The pH, conductivity, effluent nitrate nitrogen concentration and sludge color were simple indicators of ANAMMOX performance.