Start-up and operation of partial nitrification in a sequencing batch reactor

The rapid start-up and operation of a sequencing batch reactor for partial nitrification were investigated to treat high ammonium wastewater.The reactor was inoculated with nitrifying sludge and the partial nitrification realized by using complete autotrophic bacteria.The experimental results showed that for dissolved oxygen 0.5 mg/L and free ammonia concentrations 11.8~49.1 mg/L,the start-up could be completed within 13 days.The pH and dissolved oxygen concentrations were varied to monitor the effect on the ammonium oxidation process with stable partial nitrification maintained for 101 cycles.The NH~~+_4-N removal efficiency was 82.6%,NO~~-_2-N accumulation rate reached 97.2% and the maximum NH~~+_4-N removal loading was 0.97 kg/(m~3·d).The partial nitrification was stable for long-term operation with complete autotrophic bacteria in the reactor.