气升式生物反应器用于废水脱氮的组合工艺研究

Study on gas-lift bioreactor in combined process for nitrogen removal from wastewater

在内循环气升式反应器中,研究开发了一套半硝化（PN）和厌氧氨氧化（ANAMMOX）单级一体化同步处理高浓度含氮废水工艺。反应器的内筒为限氧区,借助于富集的好氧氨氧化菌（AOB）活性污泥实现废水的半硝化反应,内筒底部进行间歇式曝气,提供半硝化反应所需氧气和水力环流所需动力;反应器的外环筒为厌氧区,借助于富集的厌氧氨氧化菌（ANAMMOX）活性污泥实现厌氧氨氧化反应。反应温度为（35±2）℃,p H维持在7.5~8.0。反应器成功启动并稳定运行120 d,考察反应器内、外筒溶解氧浓度（DO）的变化和系统的脱氮性能。结果表明,反应器内、外筒有效地分隔了限氧区和厌氧区,内筒平均DO值为2.5 mg/L,外筒平均DO值为1.5 mg/L,可满足半硝化和厌氧氨氧化的反应条件。合成废水的氨氮浓度最高达200 mg/L,氮负荷为280 g/（d·m3）,反应器运行120 d后,总氮去除率达到75%,表明反应器内AOB菌和ANAMMOX菌能够协同作用,从而实现了组合脱氮的工艺。

A single-stage process combined with Partial Nitration（ PN） and ANAMMOX in an inner loop gas-lift reactor is researched and developed. The inner tube is oxygen-limited,in which activated sludge enriched with ammonia oxidation bacteria（ AOB） is used to perform PN reaction. The batch aeration from the bottom of the inner tube can supply the oxgyen for PN reaction and power for hydraulic loop. The outer tube is an anaerobic zone,in which activated sludge enriched with ANAMMOX is used to conduct anaerobic ammonium oxidation reaction. At 35 ± 2℃ and p H 7. 5-8. 0,the reactor can start successfully and operate stably for 120 days. The effects of dissolved oxygen（ DO） in inner and outer tube and the nitrogen removal are investigated. The result shows that double-tube structure separates the oxygenlimited area and anaerobic area effectively. The average of DO in inner and outer tubes are 2. 5 mg / L and 1. 5 mg / L,respectively,which can meet the requirement for PN and ANAMMOX reactions. Ammonia concentration of synthetic wastewater is up to 200 mg / L and total nitrogen load is 280 g /（ d·m3）. After 120 days operation,the total nitrogen removal is up to 75%. It suggests that AOB and ANAMMOX cooperatively work well in the gas-lift reactor and the single-stage combined process is successfully performed.