限氧曝气实现亚硝酸型同步硝化反硝化的研究

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ρ_DO<2.0 mg/L,平均ρ_DO≈0.65 mg/L,不仅可在常温条件下实现短程硝化,ρ(NO₂^--N)/ρ(NO_x^--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(E_SND)平均为52%,最高可以达到63.1%.试验分析表明,低ρ_DO水平是实现亚硝酸型SND的关键因素,通过低ρ_DO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.

Simultaneous Nitrification Denitrification via Nitrite Under Limited Aeration

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 ρ(NO 2--N) /ρ(NO x--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 ρDO concentration under limited aeration is the key factor to achieving SND via nitrite.Under a long time operation with low ρDO concentrations,the altering of nitrifying communities,micro-environment for denitrifiers growth and biodegradation characteristics of ρCOD and ρ(NH 4+-N) promoted the occurrence of SND via nitrite.