Control Of Shortcut Nitrification In SBBR With Adequate Oxygen Supply

In the recent years, nitrogen pollution in the water has become more and more serious, which leads to more and more disaster, so people pay more attention to this problem. It's very important to take actions for nitrogen removal. The novel biological treatment technology will significantly improve the level of nitrogen removal. Recently, some new technologies of ammonia removal such as shortcut nitrification has been developed very fast, which provide economic and feasible ways to the treatment of high ammonia wasterwater.This paper explained the harmfulness of nitrogen pollution by giving the example of landfill leachate pollution, and indicated the importance of the new nitrogen removal technology, and simply introduced the research progress and result in these fields at home and abroad. Then, taking shortcut nitrification as the research object, the experiment has been carried out by controlling DO concentration. The feasibility for achieving shortcut nitrification with adequate oxygen supply was discussed and the effective strategy was also explored.Landfill leachate was used as handling of object in the whole experiment,the mainly environment parameters of the reactor were controlled as follow:DO 5mg/L,pH 7.0,temperature 25℃,adopted 12-hour cycle influent and all drainage mode. Through mathematical derivation and modeling analysis, free ammonia(FA),CO₂ and HNO2 was used as the direct control factors,whereas the influent cycle time was the indirect one,and shortcut nitrification was achieved effectively in SBBR. When the volume load of ammonia(NH4+-N) was 0.52kg/(m3·d) and NaHCO3 was 1.5mg/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. Meanwhile, equitable cycle time will play a very important role in maintaining the stability of whole system.