砂柱微生物堵塞过程及机理分析

Analysis of process and mechanism of bioclogging in aqueous media

采集青岛市大沽河下游潜水含水层的砂样为代表性含水介质,测定样品的组成和性质。设计渗流试验,考察介质不同渗流段渗透性的动态变化。利用PCR和DGGE技术鉴定了造成含水介质堵塞的微生物优势菌群,分析了不同渗流段微生物对营养物和氧的利用情况,探讨了含水介质微生物堵塞过程及机理。研究结果表明,生物堵塞程度随着渗流距离的增加而减缓,含水介质的渗透性呈现明显的非均质性。微生物经过短暂的适应期,快速进入生长、繁殖阶段,含水介质微生物堵塞迅速形成;造成含水介质微生物堵塞的优势菌群为甲基杆菌属(Methylobacterium)、紫色杆菌属(Janthinobacterium)、耶尔森菌属(Yersinia)、葡萄球菌属(Staphylococcus)、食酸菌属(Acidovorax)。其中,甲基杆菌属、紫色杆菌属、葡萄球菌属和食酸菌属均为产黏细菌(Myxobacterium);含水介质中存在微生物的繁衍、代谢等生命活动。进水营养液为好氧微生物的生长、繁殖提供了充足的氧气,好氧细菌生长旺盛,并大量分泌胞外聚合物,导致进水段微生物堵塞程度最严重。

Sand samples collecting from the Dagu River in Qingdao city were used as representative aquifer medium, and measured the composition and properties. Percolating experiments were conducted to investigate the dynamic changes of different flow systems. The molecular biological technology PCR-DGGE was used to identify the advantage microorganisms inducing bioclogging. In addition,the use of nutrients and oxygen by microbial were analysis in order to discuss the bioclogging process and its mechanism. The results indicate that the degree of bioclogging in aquifer media decreases as the percolating distances increase and the permeability of aquifer medium presents obvious heterogeneity. After a short adjusting period, microbial quickly enters a growth stage. Meanwhile, microbial clogging in aquifer media develops fast. The main microorganism which causing bioclogging are Methylobacterium、Janthinobacterium、Yersinia、Staphylococcus as well as Acidovorax. In particular, Methylobacterium、Janthinobacterium、Staphylococcus and Acidovorax are Myxobacterium. It is proved that there are microbial reproduction, metabolism as well as other activities in aquifer media. High nutrient loading provides ample oxygen for microbial growth and promotes production of large amounts of extracellular polymeric substances which caused the most bioclogging in media.