生物活性炭使用过程中微生物群落变化规律及其对净化效能的影响

Variation Pattern of Microbial Communities and the Influence on Purification Efficiency in Operation Process of BAC

利用现场中试试验装置研究了水厂生物活性炭(BAC)应用过程中的微生物群落演变规律,并探讨了其净化效能的变化情况。结果表明,BAC颗粒上的生物量至5年时基本稳定,之后维持在一定范围内波动,但生物活性呈现下降的趋势。微生物群落结构分析表明,BAC颗粒上微生物种群主要为变形杆菌门(Proteobacteria)、酸杆菌门(Acidobacteria)和绿弯菌门(Chloroflexi)。硝化螺旋菌属(Nitrospira)、慢生根瘤菌属(Bradyrhizobium)和根瘤菌属(Rhizobium)等与净化效能直接相关的微生物在2~4年时相对丰度最高,之后随着使用时间的增长呈现下降的趋势。此外,随着时间的推移,BAC微生物群落机制由随机过程向确定过程转变,特别是8年、9年、10年BAC中,同质选择发展为主导作用(占59.09%~75.63%),导致BAC微生物群落多样性下降以及生物降解功能弱化。微生物群落的变化直接影响了其对氨氮、有机物的净化效能。

Pilot tests was used to study the variation law of biofilm characteristics, microbial community of biological activated carbon(BAC) and its treatment performance. The results showed that the biomass on BAC was basically stable up to 5 years, and then maintained a range of fluctuations, but the biological activity showed a decreasing trend. Microbial communities structure analysis revealed that the microbial populations on BAC were mainly Proteobacteria, Acidobacteria, Chloroflexi. The relative abundance of microorganisms associated with pollutants degradation, such as Nitrospira, Bradyrhizobium, and Rhizobium, was highest at 2 to 4 years and then decreased significantly with increasing usage time. In addition, over time, the BAC microbial community mechanism shifted from stochastic to deterministic processes, especially in the 8, 9, 10 year BAC, where homogeneous selection developed a dominant role(59.09%~75.63%), leading to a decrease in BAC microbial communities diversity as well as weakened biodegradation function. Changes in the microbial community directly affected its effectiveness in the purification of ammonia and organic matter.