甲氧苄啶对好氧活性污泥硝化作用的长期影响

Long-term Effect of Trimethoprim on Nitrification of Aerobic Activated Sludge

通过考察活性污泥硝化作用、微观结构以及微生物群落结构的变化,研究甲氧苄啶(TMP)对好氧活性污泥的长期影响。结果表明,长期运行过程中不同浓度的TMP均对氨氮的去除有抑制作用,但该抑制作用是可逆的,在25 d后可恢复到高效去除氨氮水平。连续运行30 d后的典型周期试验发现,在不同TMP浓度下,硝化性能在周期内依旧受到一定程度的抑制,但在周期结束时氨氮均能得到稳定去除;此外,在10 mg/L的高浓度TMP条件下,亚硝态氮会出现积累。扫描电镜观察发现,随着TMP浓度的升高,污泥絮体破裂程度加剧,污泥颗粒变小。微生物群落结构分析表明,优势菌群中放线菌门相比拟杆菌门对TMP有更强的耐受性,另外,硝化螺旋菌门对TMP有较强的耐受性,随着TMP浓度的升高,硝化螺旋菌门的相对丰度从0.84%升高至1.60%;属水平上,TMP对Flavobacterium菌属的抑制最明显。

The long-term effect of trimethoprim(TMP)on aerobic activated sludge was explored by investigating the changes of nitrification,microstructure and microbial community composition of the activated sludge.Different concentrations of TMP inhibited the removal of ammonia nitrogen during long-term operation.However,removal ability of ammonia nitrogen could be gradually recovered and returned to stable after 25 days.Typical cycle experiments were conducted after 30 days of continuous operation.The results indicated that the nitrification performance was still inhibited to some extent under different TMP concentrations during a cycle.However,ammonia nitrogen could be stably removed at the end of one cycle.In addition,nitrite nitrogen was accumulated under high concentration of TMP(10 mg/L).Scanning electron microscopy showed that the breaking degree of sludge floc was more serious and the particles were smaller with the increase of TMP concentration.The analysis of microbial community composition showed that Actinobacteria had better tolerance to TMP than Bacteroidetes.In addition,the relative abundance of Nitrospirae increased from 0.84%to 1.60%with the increase of TMP concentration,indicating that Nitrospirae was more resistant to TMP.At the genus level,TMP had the most obvious inhibition on Flavobacterium.