饮用水处理过程中微生物对亚硝胺物质的降解机制研究

Nitrosamines, as a group of emerging disinfection by-products(DBPs) in drinking water，have recently raised great concerns because of their high carcinogenic potency. However, it is difficult to control the nitrosamines formated in disinfection process in drinking water treatment. Though nitrosamines could produce eralier in different pre-oxidation processes, there are few efficent and economical technologies for removal of them.. In order to remove the nitrosamines formated in pre-oxidation processes in following processes and reduce the risks of chemical treatments in drinking water treatment, in this study, we would screen effective biodegradation strains by incubation, separation and purification of micro-organisms based on biological activated carbon in nine nitrosamine solutions, and clarify the biodegradation mechanism through a systematic review. With study on four tpyes of activated carbon and grain orientation modification technique, we optimazed the carrier material adapted to degradation strains, and have developed an effective and stable biological system to support water supply industry.

由于具有强致癌风险，饮用水处理过程中产生的亚硝胺物质（nitrosamines）已引起越来越多的关注。然而实际水处理对消毒单元产生的亚硝胺类消毒副产物难以控制，目前普遍采用的预氧化技术能使亚硝胺提前生成，但后续处理单元对其消减控制技术并不成熟。为使水处理过程中提前生成的亚硝胺得以去除，避免化学处理可能产生的风险，本项目从生物处理角度，选取九种亚硝胺物质为对象，以生物活性炭为载体，通过亚硝胺溶液驯化培养，分离纯化优势降解菌，在对降解效果系统评价的基础上阐明微生物降解途径和机制；通过对不同类型活性炭筛选及定向改性研究，优化适用于高效降解菌生长固定的载体材料，结合分子生物学技术，建立相应的在线生物调控方法，形成高效稳定的微生物处理系统，为饮用水安全生产提供技术支撑。

本项目以亚硝胺类物质为研究目标，采用先进的实时定量PCR和高通量测序等生物技术，对亚硝胺驯化下水处理过滤单元生物活性炭中微生物群落结构的影响机理进行研究，进而在降解效果评价的基础上阐明生物降解途径和机制。同时对生物负载载体对亚硝胺的去除性能进行了研究。结果表明，经亚硝胺驯化后生物活性炭中群落属的水平组成受到显著影响并产生新的属，同时筛选出具有亚硝胺降解功能的两株菌株：连香树红球菌A41 AS-1和苏云金芽孢杆菌LT1C。其分别对多种亚硝胺物质具有降解效果，进一步分析表明目标物降解率与其物质的分子结构及物化常数（LogKow and Hery′s Consistent）存在显著相关性。载体材料改性研究表明，颗粒状活性炭经负载纳米零价铁后能显著提高亚硝胺的去除效果，对7种亚硝胺的去除率达到70%以上。本研究的成果将进一步阐明痕量亚硝胺下生物处理单元生物降解机制，并为水处理过滤单元的优化改进提供技术支撑。相关研究成果发表在Science of the Total Environment, Water Science & Technology: Water Supply等环境类期刊上。目前仍有两篇SCI文章正在撰写。