[Approaches of biological nitrogen removal in a single sequencing batch biofilm reactor].

The conventional microorganism techniques and the molecule biological techniques such as PCR and DGGE were utilized to study the approaches of biological nitrogen removal in a single sequencing batch biofilm reactor (SBBR). The main approach of biological nitrogen removal, no less than 65% of the total NH4(+)-N was removed in this approach, was composed of partial nitrification, anaerobic ammonium oxidation and denitrification. The second approach included twain processes such as partial nitrification and denitrification, and the third one was conventional nitrogen removal process (nitrification and denitrification). All approaches accomplished simultaneously or asynchronously. When the approach occurred in the simultaneous way, it performed as nitrogen-loss. The accomplisher of asynchronous way depended on the microbe's different activity between aerated phase and anaerobic phase. First, ammonia was converted to nitrite in the aerated phase when the nitrite bacteria performed high activity, and then anaerobic phase was operated in turn when the denitrifying bacteria and the anammox bacteria eliminated the nitrogen form gases.