供氧充足环境下SBBR实现短程硝化的控制研究

Control of Shortcut Nitrification in SBBR with Adequate Oxygen Supply

在供氧充足条件下对序批式生物膜反应器SBBR实现短程硝化的途径和机理进行研究.以垃圾渗滤液为处理对象,控制反应器主要环境参数为:溶解氧(DO)5 mg/L,pH 7.0,温度(t)25℃,采用全排水方式,进水周期为12 h.通过数学推导和模型分析,确定以游离氨FA、CO2和HNO2浓度为直接控制因素,进水周期为间接控制因素,在SBBR反应器中实现了有效的短程硝化.结果表明,在氨氮NH4+-N容积负荷0.52 kg/(m3.d),NaHCO3浓度1.5 mg/L的进水条件下,NH4+-N转化率达到89%,NO2--N积累率达到83%,短程硝化作用显著.由此得出FA浓度是供氧充足情况下实现亚硝态氮NO2--N积累的关键因素,CO2作为氨氧化细菌AOB的碳源,则具有进一步提升反应器性能的作用.

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℃, 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 infiuent 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/（ m·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.