[Control of shortcut nitrification in SBBR with adequate oxygen supply].

At the high level of dissolved oxygen (DO) in sequencing batch biofilm reactor (SBBR), the approach and mechanism for realizing shortcut nitrification were researched. Landfill leachate was used as handling of object, the mainly environment parameters of the reactor were controlled as follow: DO 5 mg/L, pH 7.0, temperature 25 degrees C, adopted all drainage mode and 12-hour cycle influent. Through mathematical derivation and modeling analysis, determined free ammonia (FA), CO2 and HNO2 as the direct control factors, whereas the influent cycle time was the indirect one, shortcut nitrification was achieved effectively in SBBR. When the volume load of ammonia (NH4(+) -N) was 0.52 kg/(m3 x d) and NaHCO3 was 1.5 mg/L in the reactor, the shortcut nitrification effect was apparent as NH4(+) -N conversion rate was 89% and NO2(-) -N accumulation rate achieved 83% at the same time. With adequate oxygen supply, the key factors of achieving NO2(-) -N accumulation is FA concentration, and as the carbon source of ammonia-oxidizing bacteria, CO2 can upgrade the reactor performance further.