再生水中不同材质水泥内衬的生物膜细菌群落结构及腐蚀特征

Structure and Corrosivity of Bacterial Community for Biofilms on Cement Mortars of Different Composition in Flowing Reclaimed Water

利用Miseq高通量测序技术分析模拟再生水管网SA1和SA2中具有不同水泥/矿渣粉比例的水泥砂浆试片A1 (5:5)和A2 (6:4)表面微生物群落结构,定期监测管网出水的关键指标,利用失重和X射线衍射(XRD)测试表征水泥内衬。结果表明,A1和A2表面生物膜均含有较高丰度的变形菌门、拟杆菌门和酸杆菌门等,但其优势菌门含量变化趋势不同。A2表面生物膜中优势腐蚀菌属Bacillus、Pseudomonas和Lactococcus含量较A1的高,且A2失重量和失重率较A1也高。SA2出水pH值、TOC、Ca2+和总硅含量较SA1出水高,XRD结果也表明A2腐蚀程度较A1高。具有较高掺量矿渣粉的A1试片抗化学和微生物腐蚀的能力较强,这可能与其成分和结构性质有关。

Two cement mortars of different cement/slag ratios, namely A1(5∶5) and A2(6∶4) were tested in flowing reclaimed water by means of simulated reclaim water distribution systems(RWDS) SA1 and SA2 respectively. While the key index of the effluents of SA1 and SA2, such as metal ions and microbial biomass, as well as the mass change of the tested cement mortars were monitored regularly. The microbial communities of biofilms formed on cement mortars A1(5:5) and A2(6:4) were characterized by mean of Miseq sequencing technology. The results showed that Proteobacteria, Bacteroidetes and Acidobacteria were the top three abundant phyla in biofilms on the surface of cement mortar specimens A1 and A2. However, due to different cement/slag ratios of the relevant mortars, the abundance variations of predominant phyla of A1 and A2 biofilm was different, and the A2 biofilm had higher abundance of corrosion related dominant genera: Bacillus, Pseudomonas and Lactococcus. The mass loss and mass loss rate of cement mortar A2 were higher than those of cement mortar A1. Also the pH, TOC, Ca2+ and total silicon contents of SA2 effluent were higher than those of SA1 effluent. Cement mortar A1 with higher mixing amount of slag powder had higher the anti-erosion ability for chemical and microbial corrosion owning to its peculiar composition and structural compactness.