膜组合工艺对地下水中铀的去除及其微生物群落特征

含铀地下水因具有放射性和化学毒性对人类健康构成严重威胁，常规工艺有时无法有效去除地下水铀故需增加处理工艺以满足饮用水水质要求.以我国某地膜组合工艺处理工程为研究对象，监测了6个月运行过程中铀去除效果及常规水质参数，并对各工艺阶段出水及生物膜进行样品采集.结合水质分析与高通量测序探讨了不同工艺段出水水质参数变化，微生物群落的组成与差异.结果显示，原水中铀浓度为300~500 ppb，膜组合工艺中混凝沉淀对铀的去除率为86%，超滤对铀的去除率为15%，最终反渗透铀去除率高于99%.各工艺段出水微生物群落结构存在较大差异，冗余分析表明，硝酸盐、电导率、温度和pH值是影响微生物群落组成的主要环境因素.进一步Pearson相关性分析结果显示铀浓度与铀耐受菌假单胞菌（Pseudomonas）和紫杆菌属（Janthinobacterium），以及铀还原功能菌希瓦氏菌（Shewanella）的相对丰度呈显著正相关（p<0.01）.

Removal of uranium in groundwater by membrane combination process and the characterization of microbial community in treatment processes

Uranium-containing groundwater poses a serious threat to human health due to its radioactivity and chemical toxicity. Conventional processes sometimes cannot effectively remove uranium from groundwater and thus additional treatment processes are used to meet drinking water quality standard. Taking a pilot demonstration in China as study object, we monitored the uranium removal efficiency and other water quality indices during 6 months of operation. Samples including effluent water at various processes and biofilms were collected. Combining water quality analysis and high-throughput sequencing, we explored the variation of water quality indices and the corresponding changes of microbial community composition. The results showed that when uranium concentrations in source water ranged from 300 ppb to 500 ppb, the removals of uranium by coagulation precipitation, ultrafiltration, and reverse osmosis were approximately 86%, 15%, and almost 100%, respectively. Redundancy analysis results showed that the nitrate, conductivity, temperature and pH are the main environmental factors that affect the composition of the microbial community. Pearson correlation analysis revealed a significantly positive correlation between uranium concentration and the relative abundance of uranium-tolerant bacteria including Pseudomonas and Janthinobacterium, and the uranium-reducing bacteria Shewanella (p<0.01).