限氧曝气实现亚硝酸型同步硝化反硝化的研究

Simultaneous Nitrification Denitrification via Nitrite Under Limited Aeration

在(19±1)℃条件下,采用SBR工艺处理低碳氮比实际生活污水,没有外加有机碳源,通过限氧曝气实现了亚硝酸型同步硝化反硝化生物脱氮(simultaneous nitrification denitrification via nitrite,亚硝酸型SND).试验结果表明,较长污泥龄下(50～66 d),通过控制曝气量使系统溶解氧处于较低水平,好氧末端ρDO<2.0 mg/L,平均ρDO≈0.65 mg/L,不仅可在常温条件下实现短程硝化,ρ(NO2--N)/ρ(NOx--N)稳定在95%以上,而且可同时在该好氧硝化系统中获得高效的反硝化效果,稳定运行后,经亚硝酸型SND途径的总氮去除率(ESND)平均为52%,最高可以达到63.1%.试验分析表明,低ρDO水平是实现亚硝酸型SND的关键因素,通过低ρDO影响硝化菌群的构成、反硝化菌的缺氧微环境以及有机物和ρ(NH4+-N)的降解特性,促进了亚硝酸型SND的形成.

At normal temperature of （ 19 ±1 ） ℃ , without the addition of external carbon sources, simultaneous nitrification denitrification via nitrite （SND via nitrite ） was studied in a lab-scale SBR treating domestic wastewater with low ratio of carbon to nitrogen. The results showed that under the long sludge retention time （SRT） of 50 - 66 d and limited aeration with the maximum ρDo below 2.0 mg/L and the average ρDo of 0. 65 mg/ L, partial nitrification to nitrite was successfully achieved with p （NO2 -N）/p（ NOx -N） over 95%. Moreover, denitrification occurred during the above aerobic nitrification phase. The average ρTN removal efficiency by SND via nitrite maintained 52% , and the maximum was up to 63.1%. The low PDO concentration under limited aeration is the key factor to achieving SND via nitrite. Under a long time operation with low ρDO concentrations, altering of nitrifying communities, micro-environment for denitrifiers growth and biodegradation characteristics of PCOD and p（ NH4＋-N） promoted the occurrence of SND via nitrite