实时控制实现短程硝化过程中种群结构的演变

Assessment of partial nitrification achieved by real-time aeration duration control through microbial population shift using FISH and SEM

摘要:

为了考察实时控制下实现短程硝化过程中硝化污泥种群结构的演变,采用荧光原位杂交技术(FISH)和扫描电镜(SEM)对处理生活污水的序批式反应器内污泥进行了跟踪观测.结果表明:通过检测pH曲线上的"氨谷"特征点快速启动了短程硝化,短程硝化维持期间亚硝化积累率平均在93%左右.接种污泥形态多样,含长杆、短杆及球状菌,而随着运行的延续,污泥形态呈现了向短杆状、球状转变的态势.实时控制下反应器内亚硝酸氧化菌(NOB)逐渐被淘洗,而氨氧化菌(AOB)得到了富集.从短程硝化启动初期到短程硝化稳定运行102d,AOB的相对数量从3.5%逐渐上升到8.5%,而对应的NOB相对数量从3.1%下降至0.5%以下.利用好氧曝气时间实时控制实现短程硝化是一种面向种群优化的控制方法,有利于短程硝化系统长期稳定的运行.

Abstract:

The shift of nitrifier population within a partial nitrification reactor was investigated using fluorescence in-situ hybridization(FISH) techniques and the floc morphology was observed using scan electron microscope(SEM).Partial nitrification to nitrite was achieved quickly by using real-time aeration duration control when domestic wastewater was treated in a lab-scale sequencing batch reactor(SBR).The average nitrite accumulation ratio was above 93%.The morphology photographs observed using SEM indicated that the sludge showed a shift towards spherical and small rod-shaped clusters from the diverse morphology.FISH analysis showed that ammonia-oxidizing bacteria(AOB) gradually out-competed nitrite-oxidizing bacteria(NOB).AOB population percentage increased from 3.5%(during the start-up period) to 8.5%(after achieving nitritation for 102 days),while NOB population percentage decreased from 3.1% to less than 0.5%.Accordingly,the long-term operation with the use of real-time aeration duration control was not only favorable for AOB community optimisation,but also for the achievement of partial nitrification in practice.